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Li X, Chang P, Liu X, Zhao Z, Duan Y, Zhang W. Validation of a method for estimating pulmonary dead space in ventilated beagles to correct exhaled propofol concentration in mixed air. BMC Vet Res 2025; 21:9. [PMID: 39773486 PMCID: PMC11706130 DOI: 10.1186/s12917-024-04458-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Accepted: 12/22/2024] [Indexed: 01/11/2025] Open
Abstract
BACKGROUND Mixed exhaled air has been widely used to determine exhaled propofol concentrations with online analyzers, but changes in dead space proportions may lead to inaccurate assessments of critical drug concentration data. This study proposes a method to correct propofol concentration in mixed air by estimating pulmonary dead space through reconstructing volumetric capnography (Vcap) from time-CO2 and time-volume curves, validated with vacuum ultraviolet time-of-flight mass spectrometry (VUV-TOF MS). METHODS Existing monitoring parameters, including time-volume and time-CO2 curves, were used to determine Vcap. The ratio of physiological dead space to tidal volume (VD/VT) was calculated using Bohr's formula. Additionally, an animal experiment on beagles was conducted with continuous propofol administration until a pseudo-steady state in exhaled propofol concentration was achieved. The propofol concentration in mixed air (CONCmix), and in alveolar air combined with N2 (CONCAN) were measured using VUV-TOF MS to calculate VD/VT. The agreements between VD/VT values from the two methods, along with the predicted CONCAN values based on Vcap and the actual measured CONCAN values were evaluated using the intraclass correlation coefficient (ICC) and Pearson correlation analysis. RESULTS After 30 min of continuous propofol administration, a stable respiratory cycle was selected for analysis in each beagle. The calculated VD/VT-Bohr values were 0.535 for beagle A, 0.544 for beagle B, and 0.552 for beagle C. Additionally, based on CONCmix and CONCAN, the calculated VD/VT-VUV-TOF MS values were 0.494, 0.504, and 0.513, respectively. Strong agreement between the two methods was demonstrated by an ICC of 0.994 (P = 0.003) and Pearson's r of 0.995 (P = 0.045). Additionally, the predicted CONCAN values from mixed exhaled air (5.11 parts per billion by volume (ppbv) for beagle A, 5.93 ppbv for beagle B, and 2.56 ppbv for beagle C) showed strong agreement with the actual CONCAN values, with an ICC of 0.996 (P = 0.002) and Pearson's r of 0.994 (P = 0.046). CONCLUSION The physiological dead space to tidal volume ratio from mixed air in beagles can be accurately measured using the existing time-volume and time-CO2 curves from the anesthesia machine, enabling corrections of exhaled propofol concentrations in mixed air samples.
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Affiliation(s)
- Xiaoxiao Li
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital,, Sichuan University, Chengdu, China
| | - Pan Chang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital,, Sichuan University, Chengdu, China
| | - Xing Liu
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital,, Sichuan University, Chengdu, China
| | - Zhongjun Zhao
- School of Mechanical Engineering, Sichuan University, Chengdu, China
| | - Yixiang Duan
- School of Mechanical Engineering, Sichuan University, Chengdu, China
| | - Wensheng Zhang
- Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Centre of Translational Medicine of Anesthesiology, West China Hospital,, Sichuan University, Chengdu, China.
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Girotto CH, Ospina-Argüelles DA, Teixeira-Neto FJ, Assis-Vieira PV, Martins ARC, Kerr C. Dead space volumes in cats and dogs with small body mass ventilated with a fixed tidal volume. Vet Anaesth Analg 2024; 51:585-593. [PMID: 39138051 DOI: 10.1016/j.vaa.2024.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 06/16/2024] [Accepted: 06/18/2024] [Indexed: 08/15/2024]
Abstract
OBJECTIVE To compare the portion of tidal volume (VT) ventilating dead space volumes in nonbrachycephalic cats and dogs with small body mass receiving volume-controlled ventilation (VCV) with a fixed VT. STUDY DESIGN Prospective, experimental study. ANIMALS A group of eight healthy adult cats and dogs [ideal body weight (IBW): 3.0 ± 0.5 and 3.8 ± 1.1 kg, respectively]. METHODS Anesthetized cats and dogs received VCV with a 12 mL kg-1 VT (inspiratory pause ≥ 0.5 seconds). Respiratory rate (fR) was adjusted to maintain normocapnia. Airway dead space (VDaw) and alveolar tidal volume (VTalv) were measured by volumetric capnography. Physiological dead space (VDphys) and VDphys/VT ratio were calculated using the Bohr-Enghoff method. Data recorded before surgery were compared by an unpaired t-test or Mann-Whitney U test (p < 0.05 considered significant). RESULTS The IBW (p = 0.07), PaCO2 (p = 0.40) and expired VT [VT(exp)] (p = 0.77) did not differ significantly between species. The VDaw (mL kg-1) was lower in cats (3.7 ± 0.4) than in dogs (7.7 ± 0.9) (p < 0.0001). The VTalv (mL kg-1) was larger in cats (8.3 ± 0.7) than in dogs (4.3 ± 0.7) (p < 0.0001). Cats presented a smaller VDphys/VT ratio (0.33 ± 0.03) and VDphys (4.0 ± 0.3 mL kg-1) than dogs (VDphys/VT: 0.60 ± 0.09; VDphys: 7.2 ± 1.4 mL kg-1) (p < 0.0001). The fR and minute ventilation (VT(exp) × fR) were lower in cats than in dogs (p = 0.048 and p = 0.038, respectively). CONCLUSIONS AND CLINICAL RELEVANCE A fixed VT results in more effective ventilation in cats than in dogs with small body mass because of species-specific differences in and VDaw and VDphys. Because of the smaller VDaw and VDphys in cats than in dogs, a lower fR is required to maintain normocapnia in cats.
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Affiliation(s)
- Carolina H Girotto
- Department of Veterinary Surgery and Animal Reproduction, Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Diego A Ospina-Argüelles
- Department of Anesthesiology, Faculdade de Medicina, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | - Francisco J Teixeira-Neto
- Department of Veterinary Surgery and Animal Reproduction, Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil; Department of Anesthesiology, Faculdade de Medicina, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil.
| | - Paulo V Assis-Vieira
- Department of Veterinary Surgery and Animal Reproduction, Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista (UNESP), Botucatu, SP, Brazil
| | | | - Carolyn Kerr
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
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Jiménez-Posada LD, Palacio-Sánchez AF, Montagut-Ferizzola YJ, Ardila-Villegas M, Maya JC. Validation of Math Model Using Porous Media for Determining Alveolar CO 2 in Ventilated Patients. Crit Care Med 2024; 52:e503-e511. [PMID: 38856519 PMCID: PMC11392135 DOI: 10.1097/ccm.0000000000006350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
OBJECTIVES To validate a mathematical model using porous media theory for alveolar CO2 determination in ventilated patients. DESIGN Mathematical modeling study with prospective clinical validation to simulate CO2 exchange from bloodstream to airway entrance. SETTING ICU. PATIENTS Thirteen critically ill patients without chronic or acute lung disease. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Model outcomes compared with patient data showed correlations for end-tidal CO2 (EtCO 2 ), area under the CO2 curve, and Pa CO2 of 0.918, 0.954, and 0.995. Determination coefficients ( R2 ) were 0.843, 0.910, and 0.990, indicating precision and predictive power. CONCLUSIONS The mathematical model shows potential in pulmonary critical care. Although promising, practical application demands further validation, clinician training, and patient-specific adjustments. The path to clinical use will be iterative, involving validation and education.
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Affiliation(s)
- L D Jiménez-Posada
- Universidad EIA, Escuela de Ingeniería y Ciencias Básicas, Grupo de Investigación en Ingenieria Biomédica (GIBEC) Envigado, Antioquia, Colombia
| | - A F Palacio-Sánchez
- Universidad EIA, Escuela de Ingeniería y Ciencias Básicas, Grupo de Investigación en Ingenieria Biomédica (GIBEC) Envigado, Antioquia, Colombia
- Hospital Alma Mater de Antioquia, Servicio de Cuidados Intensivos, Medellín, Antioquia, Colombia
| | - Y J Montagut-Ferizzola
- Universidad EIA, Escuela de Ingeniería y Ciencias Básicas, Grupo de Investigación en Ingenieria Biomédica (GIBEC) Envigado, Antioquia, Colombia
| | - M Ardila-Villegas
- Universidad EIA, Escuela de Ingeniería y Ciencias Básicas, Grupo de Investigación en Ingenieria Biomédica (GIBEC) Envigado, Antioquia, Colombia
| | - Juan C Maya
- Departamento de Procesos y Energía-TAYEA, Facultad de Minas, Universidad Nacional de Colombia-Sede Medellín, Medellín, Colombia
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Raisis A, Mosing M, Sacks M, Hosgood G, Schramel J, Blumer S, Böhm SH. Breath-by-breath assessment of acute pulmonary edema using electrical impedance tomography, spirometry and volumetric capnography in a sheep ( Ovis Aries) model. Front Vet Sci 2024; 11:1402748. [PMID: 39051008 PMCID: PMC11267825 DOI: 10.3389/fvets.2024.1402748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 05/24/2024] [Indexed: 07/27/2024] Open
Abstract
Background The bedside diagnosis of acute pulmonary edema is challenging. This study evaluated the breath-by-breath information from electrical impedance tomography (EIT), respiratory mechanics and volumetric capnography (VCap) to assess acute pulmonary edema induced by xylazine administration in anesthetized sheep. Objective To determine the ability and efficiency of each monitoring modality in detecting changes in lung function associated with onset of pulmonary edema. Methods Twenty healthy ewes were anesthetized, positioned in sternal (prone) recumbency and instrumented. Synchronized recordings of EIT, spirometry and VCap were performed for 60 s prior to start of injection, during xylazine injection over 60 s (0-60 s) and continuously for 1 min (60-120 s) after the end of injection. After visual assessment of the recorded mean variables, statistical analysis was performed using a mixed effect model for repeated measures with Bonferroni's correction for multiple comparisons, to determine at which breath after start of injection the variable was significantly different from baseline. A significant change over time was defined as an adjusted p < 0.05. All statistics were performed using GraphPad Prism 0.1.0. Results Electrical impedance tomography showed significant changes from baseline in all but two variables. These changes were observed simultaneously during xylazine injection at 48 s and were consistent with development of edema in dependent lung (decreased end-expiratory lung impedance, ventilation in centro-ventral and ventral lung region) and shift of ventilation into non-dependent lung (decreased non-dependent silent spaces and increased center of ventilation ventral to dorsal and increased ventilation in centro-dorsal and dorsal lung region). All changes in lung mechanics also occurred during injection, including decreased dynamic respiratory system compliance and increased peak expiratory flow, peak inspiratory pressure and airway resistance at 48, 54 and 60 s, respectively. Changes in VCap variables were delayed with all occurring after completion of the injection. Conclusion In this model of pulmonary edema, EIT detected significant and rapid change in all assessed variables of lung function with changes in regional ventilation indicative of pulmonary edema. Volumetric capnography complemented the EIT findings, while respiratory mechanics were not specific to lung edema. Thus, EIT offers the most comprehensive method for pulmonary edema evaluation, including the assessment of ventilation distribution, thereby enhancing diagnostic capabilities.
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Affiliation(s)
- Anthea Raisis
- School of Veterinary Medicine, Murdoch University, Murdoch, WA, Australia
| | - Martina Mosing
- School of Veterinary Medicine, Murdoch University, Murdoch, WA, Australia
- Anaesthesiology and Perioperative Intensive Care, Department for Companion Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Muriel Sacks
- Department of Veterinary Anaesthesia and Analgesia, School of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Giselle Hosgood
- School of Veterinary Medicine, Murdoch University, Murdoch, WA, Australia
| | - Johannes Schramel
- Anaesthesiology and Perioperative Intensive Care, Department for Companion Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Sarah Blumer
- School of Veterinary Medicine, Murdoch University, Murdoch, WA, Australia
| | - Stephan H. Böhm
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, Rostock University Medical Centre, Rostock, Germany
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Konsberg Y, Åneman A, Olsen F, Hessulf F, Nellgård B, Hård Af Segerstad M, Dalla K. Progressive changes in pulmonary gas exchange during invasive respiratory support for COVID-19 associated acute respiratory failure: A retrospective study of the association with 90-day mortality. Acta Anaesthesiol Scand 2024; 68:803-811. [PMID: 38563250 DOI: 10.1111/aas.14415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 03/09/2024] [Accepted: 03/13/2024] [Indexed: 04/04/2024]
Abstract
BACKGROUND Ratio of arterial pressure of oxygen and fraction of inspired oxygen (P/F ratio) together with the fractional dead space (Vd/Vt) provides a global assessment of pulmonary gas exchange. The aim of this study was to assess the potential value of these variables to prognosticate 90-day survival in patients with COVID-19 associated ARDS admitted to the Intensive Care Unit (ICU) for invasive ventilatory support. METHODS In this single-center observational, retrospective study, P/F ratios and Vd/Vt were assessed up to 4 weeks after ICU-admission. Measurements from the first 2 weeks were used to evaluate the predictive value of P/F ratio and Vd/Vt for 90-day mortality and reported by the adjusted hazard ratio (HR) and 95% confidence intervals [95%CI] by Cox proportional hazard regression. RESULTS Almost 20,000 blood gases in 130 patients were analyzed. The overall 90-day mortality was 30% and using the data from the first ICU week, the HR was 0.85 [0.77-0.94] for every 10 mmHg increase in P/F ratio and 1.61 [1.20-2.16] for every 0.1 increase in Vd/Vt. In the second week, the HR for 90-day mortality was 0.82 [0.75-0.89] for every 10 mmHg increase in P/F ratio and 1.97 [1.42-2.73] for every 0.1 increase in Vd/Vt. CONCLUSION The progressive changes in P/F ratio and Vd/Vt in the first 2 weeks of invasive ventilatory support for COVID-19 ARDS were significant predictors for 90-day mortality.
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Affiliation(s)
- Ylva Konsberg
- Department of Anesthesiology and Intensive Care, Institute of Clinical Sciences, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Anders Åneman
- Department of Anesthesiology and Intensive Care, Institute of Clinical Sciences, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Intensive Care Unit, Liverpool Hospital, Southwestern Sydney Local Health District, Australia
- South Western Clinical School, University of New South Wales, Australia
- Ingham Institute for Applied Medical Science, Sydney, Australia
| | - Fredrik Olsen
- Department of Anesthesiology and Intensive Care, Institute of Clinical Sciences, the Sahlgrenska Academy at the University of Gothenburg, Sahlgrenska, Sweden
| | - Fredrik Hessulf
- Department of Anesthesiology and Intensive Care, Institute of Clinical Sciences, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Bengt Nellgård
- Department of Anesthesiology and Intensive Care, Institute of Clinical Sciences, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Mathias Hård Af Segerstad
- Department of Anesthesiology and Intensive Care, Institute of Clinical Sciences, the Sahlgrenska Academy at the University of Gothenburg, Sahlgrenska, Sweden
| | - Keti Dalla
- Department of Anesthesiology and Intensive Care, Institute of Clinical Sciences, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
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Sipmann FS, Giralt JAS, Tusman G. Monitoring CO2 kinetics as a marker of cardiopulmonary efficiency. Curr Opin Crit Care 2024; 30:251-259. [PMID: 38690954 DOI: 10.1097/mcc.0000000000001156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
PURPOSE OF REVIEW To describe current and near future developments and applications of CO2 kinetics in clinical respiratory and cardiovascular monitoring. RECENT FINDINGS In the last years, we have witnessed a renewed interest in CO2 kinetics in relation with a better understanding of volumetric capnography and its derived parameters. This together with technological advances and improved measurement systems have expanded the monitoring potential of CO2 kinetics including breath by breath continuous end-expiratory lung volume and continuous noninvasive cardiac output. Dead space has slowly been gaining relevance in clinical monitoring and prognostic evaluation. Easy to measure dead space surrogates such as the ventilatory ratio have demonstrated a strong prognostic value in patients with acute respiratory failure. SUMMARY The kinetics of carbon dioxide describe many relevant physiological processes. The clinical introduction of new ways of assessing respiratory and circulatory efficiency based on advanced analysis of CO2 kinetics are paving the road to a long-desired goal in clinical monitoring of critically ill patients: the integration of respiratory and circulatory monitoring during mechanical ventilation.
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Affiliation(s)
- Fernando Suarez Sipmann
- Department of Intensive Care Medicine, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid
- Ciber de enfermedades respiratorias, Instituto Carlos III, Madrid, Spain
| | - Juan Antonio Sanchez Giralt
- Department of Intensive Care Medicine, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid
| | - Gerardo Tusman
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
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Wen Y, Xie Y, Wang C, Hua L, Zhang L, Chen P, Li H. Determination of the two-compartment model parameters of exhaled HCN by fast negative photoionization mass spectrometry. Talanta 2024; 271:125710. [PMID: 38295448 DOI: 10.1016/j.talanta.2024.125710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 01/18/2024] [Accepted: 01/22/2024] [Indexed: 02/02/2024]
Abstract
Breath exhaled hydrogen cyanide (HCN) has been identified to be associated with several respiratory diseases. Accurately distinguishing the concentration and release rate of different HCN sources is of great value in clinical research. However, there are still significant challenges due to the high adsorption and low concentration characteristics of exhaled HCN. In this study, a two-compartment kinetic model method based on negative photoionization mass spectrometry was developed to simultaneously determine the kinetic parameters including concentrations and release rates in the airways and alveoli. The influences of the sampling line diameter, length, and temperature on the response time of the sampling system were studied and optimized, achieving a response time of 0.2 s. The negative influence of oral cavity-released HCN was reduced by employing a strategy based on anatomical lung volume calculation. The calibration for HCN in the dynamic range of 0.5-100 ppbv and limit of detection (LOD) at 0.3 ppbv were achieved. Subsequently, the experiments of smoking, short-term passive smoking, and intake of bitter almonds were performed to examine the influences of endogenous and exogenous factors on the dynamic parameters of the model method. The results indicate that compared with steady-state concentration measurements, the kinetic parameters obtained using this model method can accurately and significantly reflect the changes in different HCN sources, highlighting its potential for HCN-related disease research.
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Affiliation(s)
- Yuxuan Wen
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing, 100049, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China
| | - Yuanyuan Xie
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China
| | - Chen Wang
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing, 100049, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China
| | - Lei Hua
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China
| | - Lichuan Zhang
- Affiliated Zhongshan Hospital of Dalian University, Dalian, People's Republic of China
| | - Ping Chen
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China.
| | - Haiyang Li
- CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, 116023, People's Republic of China; Liaoning Key Laboratory for Mass Spectrometry Technology and Instrumentation, Dalian 116023, People's Republic of China; Dalian Key Laboratory for Online Analytical Instrumentation, 457 Zhongshan Road, Dalian, 116023, People's Republic of China.
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Buss P, Miller M, Fuller A, Haw A, Thulson E, Olea-Popelka F, Meyer L. Effects of Butorphanol on Respiration in White Rhinoceros (Ceratotherium simum) Immobilized with Etorphine-Azaperone. J Wildl Dis 2024; 60:388-400. [PMID: 38268196 DOI: 10.7589/jwd-d-23-00034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 10/10/2023] [Indexed: 01/26/2024]
Abstract
This article reports on respiratory function in white rhinoceros (Ceratotherium simum) immobilized with etorphine-azaperone and the changes induced by butorphanol administration as part of a multifaceted crossover study that also investigated the effects of etorphine or etorphine-butorphanol treatments. Six male white rhinoceros underwent two immobilizations by using 1) etorphine-azaperone and 2) etorphine-azaperone-butorphanol. Starting 10 min after recumbency, arterial blood gases, limb muscle tremors, expired minute ventilation, and respiratory rate were evaluated at 5-min intervals for 25 min. Alveolar to arterial oxygen gradient, expected respiratory minute volume, oxygen consumption, and carbon dioxide production were calculated. Etorphine-azaperone administration resulted in hypoxemia and hypercapnia, with increases in alveolar to arterial oxygen gradient, oxygen consumption, and carbon dioxide production, and a decrease in expired minute ventilation. Muscle tremors were also observed. Intravenous butorphanol administration in etorphine-azaperone-immobilized white rhinoceros resulted in less hypoxemia and hypercapnia; a decrease in oxygen consumption, carbon dioxide production, and expired minute ventilation; and no change in the alveolar to arterial oxygen gradient and rate of breathing. We show that the immobilization of white rhinoceros with etorphine-azaperone results in hypoxemia and hypercapnia and that the subsequent intravenous administration of butorphanol improves both arterial blood oxygen and carbon dioxide partial pressures.
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Affiliation(s)
- Peter Buss
- Veterinary Wildlife Services, South African National Parks, Kruger National Park, Private Bag X402, Skukuza 1350, South Africa
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 29 Princess of Wales Terrace, Private Bag 3, 2050, Parktown, South Africa
- Department of Paraclinical Sciences and Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Soutpan Road, Wildlife Hub Building, Private Bag X04, Onderstepoort 0110, South Africa
| | - Michele Miller
- Department of Science and Innovation, National Research Foundation Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, PO Box 241, Cape Town 8000, South Africa
| | - Andrea Fuller
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 29 Princess of Wales Terrace, Private Bag 3, 2050, Parktown, South Africa
- Department of Paraclinical Sciences and Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Soutpan Road, Wildlife Hub Building, Private Bag X04, Onderstepoort 0110, South Africa
| | - Anna Haw
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 29 Princess of Wales Terrace, Private Bag 3, 2050, Parktown, South Africa
| | - Emily Thulson
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Science, Colorado State University, 300 W. Drake Road, Fort Collins, Colorado 80523, USA
| | - Francisco Olea-Popelka
- Department of Pathology and Laboratory Medicine, Schulich School of Medicine & Dentistry, Dental Sciences Building Room 4044, Western University, 1151 Richmond Street, London, Ontario N6A5C1, Canada
| | - Leith Meyer
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, 29 Princess of Wales Terrace, Private Bag 3, 2050, Parktown, South Africa
- Department of Paraclinical Sciences and Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Soutpan Road, Wildlife Hub Building, Private Bag X04, Onderstepoort 0110, South Africa
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Campos MD, Palazzi LH, Böhm SH, Tusman G. Effects of apparatus dead space on volumetric capnograms in neonates with healthy lungs: a simulation study. Paediatr Anaesth 2023; 33:973-982. [PMID: 37403466 DOI: 10.1111/pan.14724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 06/19/2023] [Accepted: 06/22/2023] [Indexed: 07/06/2023]
Abstract
BACKGROUND Volumetric capnography in healthy ventilated neonates showed deformed waveforms, which are supposedly due to technological limitations of flow and carbon dioxide sensors. AIMS This bench study analyzed the role of apparatus dead space on the shape of capnograms in simulated neonates with healthy lungs. METHODS We simulated mechanical breaths in neonates of 2, 2.5, and 3 kg of body weight using a neonatal volumetric capnography simulator. The simulator was fed by a fixed amount of carbon dioxide of 6 mL/kg/min. Such simulator was ventilated in a volume control mode using fixed ventilatory settings with a tidal volume of 8 mL/kg and respiratory rates of 40, 35, and 30 breaths per minute for the 2, 2.5 and 3 kg neonates, respectively. We tested the above baseline ventilation with and without an additional apparatus dead space of 4 mL. RESULTS Simulations showed that adding the apparatus dead space to baseline ventilation increased the amount of re-inhaled carbon dioxide in all neonates: 0.16 ± 0.01 to 0.32 ± 0.03 mL (2 kg), 0.14 ± 0.02 to 0.39 ± 0.05 mL (2.5 kg), and 0.13 ± 0.01 to 0.36 ± 0.05 mL (3 kg); (p < .001). Apparatus dead space was computed as part of the airway dead space, and therefore, the ratio of airway dead space to tidal volume increased from 0.51 ± 0.04 to 0.68 ± 0.06, from 0.43 ± 0.04 to 0.62 ± 0.01 and from 0.38 ± 0.01 to 0.60 ± 0.02 in the 2, 2.5 and 3 kg simulated neonates, respectively (p < .001). Compared to baseline ventilation, adding apparatus dead space decreased the ratio of the volume of phase III to VT size from 31% to 11% (2 kg), from 40% to 16% (2.5 kg) and from 50% to 18% (3 kg); (p < .001). CONCLUSIONS The addition of a small apparatus dead space artificially deformed the volumetric capnograms in simulated neonates with healthy lungs.
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Affiliation(s)
- Marcelo D Campos
- Department of Anesthesiology, Sanatorio Finochietto, Buenos Aires, Argentina
| | - Lucio H Palazzi
- Department of Anesthesiology, Children Hospital Dr. Orlando Alassia, Santa Fe, Argentina
| | - Stephan H Böhm
- Clinic of Anesthesiology, Intensive Care Medicine and Pain Therapy, Rostock University Medical Center, Rostock, Germany
| | - Gerardo Tusman
- Department of Anesthesia, Hospital Privado de Comunidad, Mar del Plata, Argentina
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10
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Larrabee S, Nugen S, Bruhn A, Porter I, Stowe S, Adler A, Martin-Flores M, Araos J. Three-dimensional electrical impedance tomography to study regional ventilation/perfusion ratios in anesthetized pigs. Am J Physiol Lung Cell Mol Physiol 2023; 325:L638-L646. [PMID: 37724348 DOI: 10.1152/ajplung.00180.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 09/08/2023] [Accepted: 09/13/2023] [Indexed: 09/20/2023] Open
Abstract
This study aimed to develop a three-dimensional (3-D) method for assessing ventilation/perfusion (V/Q̇) ratios in a pig model of hemodynamic perturbations using electrical impedance tomography (EIT). To evaluate the physiological coherence of changes in EIT-derived V/Q̇ ratios, global EIT-derived V/Q̇ mismatches were compared with global gold standards. The study found regional heterogeneity in the distribution of V/Q̇ ratios in both the ventrodorsal and craniocaudal directions. Although global EIT-derived indices of V/Q̇ mismatch consistently underestimated both low and high V/Q̇ mismatch compared with global gold standards, the direction of the change was similar. We made the software available at no cost for other researchers to use. Future studies should compare regional V/Q̇ ratios determined by our method against other regional, high-resolution methods.NEW & NOTEWORTHY In this study, we introduce a novel 3-D method for assessing ventilation-perfusion (V/Q̇) ratios using electrical impedance tomography (EIT). Heterogeneity in V/Q̇ distribution showcases the significant potential for enhanced understanding of pulmonary conditions. This work signifies a substantial step forward in the application of EIT for monitoring and managing lung diseases.
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Affiliation(s)
- Shannon Larrabee
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States
| | - Sarah Nugen
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States
| | - Alejandro Bruhn
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Ian Porter
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States
| | - Symon Stowe
- Department of Systems and Computer Engineering, Carleton University, Ottawa, Ontario, Canada
| | - Andy Adler
- Department of Systems and Computer Engineering, Carleton University, Ottawa, Ontario, Canada
| | - Manuel Martin-Flores
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States
| | - Joaquin Araos
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States
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11
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Peyton PJ. A modal definition of ideal alveolar oxygen. Physiol Rep 2023; 11:e15787. [PMID: 37612050 PMCID: PMC10447219 DOI: 10.14814/phy2.15787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 07/21/2023] [Accepted: 07/21/2023] [Indexed: 08/25/2023] Open
Abstract
In the three-compartment model of lung ventilation-perfusion heterogeneity (VA/Q scatter), both Bohr dead space and shunt equations require values for central "ideal" compartment O2 and CO2 partial pressures. However, the ideal alveolar gas equation most accurately calculates mixed (ideal and alveolar dead space) PAO2 . A novel "modal" definition has been validated for ideal alveolar CO2 partial pressure, at the VA/Q ratio in a lung distribution where CO2 elimination is maximal. A multicompartment computer model of physiological, lognormal distributions of VA and Q was used to identify modal "ideal" PAO2 , and find a modification of the alveolar gas equation to estimate it across a wide range of severity of VA/Q heterogeneity and FIO2 . This was then validated in vivo using data from a study of 36 anesthetized, ventilated patients with FIO2 0.35-80. Substitution in the alveolar gas equation of respiratory exchange ratio R withmodalR = R - 1 - PEtC O 2 / P aCO 2 $$ \kern0.5em \mathrm{modalR}=\mathrm{R}\hbox{--} \left(1\hbox{--} \mathrm{PEtC}{\mathrm{O}}_2/\mathrm{P}{\mathrm{aCO}}_2\right) $$ achieved excellent agreement (r2 = 0.999) between the calculated ideal PAO2 and the alveolar-capillary Pc'O2 at the modal VO2 point ("modal" Pc'O2 ), across a range of log standard deviation of VA 0.25-1.75, true shunt 0%-20%, overall VA/Q 0.4-1.6, and FIO2 0.18-1.0, where the modeled PaO2 was over 50 mm Hg. Modal ideal PAO2 can be reliably estimated using routine blood gas measurements.
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Affiliation(s)
- Philip J. Peyton
- Department of Critical Care, Anaesthesia, Perioperative and Pain Medicine Program, Melbourne Medical SchoolUniversity of MelbourneMelbourneVictoriaAustralia
- Department of AnaesthesiaAustin HealthMelbourneVictoriaAustralia
- Institute for Breathing and SleepMelbourneVictoriaAustralia
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12
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Vallarino M, Quintela L, Jorge G, Lorenzo G, Nan C, Isper M, Bouchacourt JP, Grignola JC. SAMAY S24: a novel wireless 'online' device for real-time monitoring and analysis of volumetric capnography. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38083576 DOI: 10.1109/embc40787.2023.10340680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Volumetric capnography (VCap) provides information about CO2 exhaled per breath (VCO2br) and physiologic dead space (VDphys). A novel wireless device with a high response time CO2 mainstream sensor coupled with a digital flowmeter was designed to monitor all VCap parameters online in rabbits (SAMAY S24).Ten New Zealand rabbits were anesthetized and mechanically ventilated. VCO2br corresponds to the area under the VCap curve. We used the modified Langley method to assess the airway VD (VDaw) and the alveolar CO2 pressure. VDphys was estimated using Bohr's formula, and the alveolar VD was calculated by subtracting VDaw from VDphys. We compared (Bland-Altman) the critical VCap parameters obtained by SAMAY S24 (Langley) with the Functional Approximation based on the Levenberg-Marquardt Algorithm (FA-LMA) approach during closed and opened chest conditions.SAMAY S24 could assess dead space volumes and VCap shape in real time with similar accuracy and precision compared to the 'offline' FA-LMA approach. The opened chest condition impaired CO2 kinetics, decreasing the phase II slope, which was correlated with the volume of CO2 exhaled per minute.
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13
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Dianti J, McNamee JJ, Slutsky AS, Fan E, Ferguson ND, McAuley DF, Goligher EC. Determinants of Effect of Extracorporeal CO 2 Removal in Hypoxemic Respiratory Failure. NEJM EVIDENCE 2023; 2:EVIDoa2200295. [PMID: 38320056 DOI: 10.1056/evidoa2200295] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
BACKGROUND: Dead space and respiratory system elastance (Ers) may influence the clinical benefit of a ventilation strategy combining very low tidal volume (VT) with extracorporeal carbon dioxide removal (ECCO2R) in patients with acute hypoxemic respiratory failure. We sought to evaluate whether the effect of ECCO2R on mortality varies according to ventilatory ratio (VR; a composite variable reflective of dead space and shunt) and Ers. METHODS: Secondary analysis of a trial of a strategy combining very low VT and low-flow ECCO2R planned before the availability of trial results. Bayesian logistic regression was used to estimate the posterior probability of effect moderation by VR, Ers, and severity of hypoxemia (ratio of arterial partial pressure of oxygen to fraction of inspired oxygen [PaO2:FiO2]) on 90-day mortality. Credibility of effect moderation was appraised according to the Instrument for Assessing the Credibility of Effect Modification Analyses criteria. RESULTS: A total of 405 patients were available for analysis. The effect of the intervention on mortality varied substantially with VR (posterior probability of interaction, 94%; high credibility). Benefit was more probable than harm in patients with VR 3 or higher. In patients with VR less than 3, the probability of increased mortality with intervention was high (>90%). The effect of the intervention also varied with PaO2:FiO2 (posterior probability of interaction, >99%; low credibility). Benefit was more probable than harm in patients with PaO2:FiO2 110 mm Hg or higher. The effect of the intervention did not vary substantially with Ers (posterior probability of interaction, 68%; low credibility). CONCLUSIONS: VR has a highly credible influence on the effect of a strategy combining very low VT and low-flow ECCO2R on mortality. This intervention may reduce mortality in patients with high VR. (Funded by an Early Career Investigator Award from the Canadian Institutes of Health Research to Dr. Goligher.)
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Affiliation(s)
- Jose Dianti
- Department of Medicine, Division of Respirology, University Health Network, University of Toronto, Toronto, ON
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON
| | - James J McNamee
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Belfast, United Kingdom
- Regional Intensive Care Unit, Royal Victoria Hospital, Belfast, United Kingdom
| | - Arthur S Slutsky
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON
- Keenan Research Centre for Biomedical Science, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON
| | - Eddy Fan
- Department of Medicine, Division of Respirology, University Health Network, University of Toronto, Toronto, ON
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON
- Toronto General Hospital Research Institute, Toronto, ON
- Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, ON
| | - Niall D Ferguson
- Department of Medicine, Division of Respirology, University Health Network, University of Toronto, Toronto, ON
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON
- Toronto General Hospital Research Institute, Toronto, ON
- Institute of Health Policy, Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, ON
- Department of Physiology, University of Toronto, Toronto, ON
| | - Daniel F McAuley
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Belfast, United Kingdom
- Regional Intensive Care Unit, Royal Victoria Hospital, Belfast, United Kingdom
| | - Ewan C Goligher
- Department of Medicine, Division of Respirology, University Health Network, University of Toronto, Toronto, ON
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON
- Toronto General Hospital Research Institute, Toronto, ON
- Department of Physiology, University of Toronto, Toronto, ON
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14
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Capnography in newborns under mechanical ventilation and its relationship with the measurement of CO 2 in blood samples. An Pediatr (Barc) 2022; 97:255-261. [PMID: 36109326 DOI: 10.1016/j.anpede.2022.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/15/2022] [Indexed: 11/24/2022] Open
Abstract
INTRODUCTION Monitoring the partial pressure of CO2 (PCO2) in newborns who require ventilation would allow avoiding hypocapnia and hypercapnia. The measurement of end-tidal carbon dioxide (ETCO2) is an alternative rarely implemented in this population. OBJECTIVE To evaluate the relationship between ETCO2 and PCO2 in newborns. METHODS Cross-sectional study comparing two PCO2 measurement methods, the conventional one by analysis of blood samples and the one estimated by ETCO2. The study included hospitalized newborns that required conventional mechanical ventilation. The ETCO2 was measured with a Tecme GraphNet® neo, a neonatal ventilator with an integrated capnograph, and we obtained the ETCO2-PCO2 gradient. We conducted correlation and Bland-Altman plot analyses to estimate the agreement. RESULTS A total of 277 samples (ETCO2 / PCO2) from 83 newborns were analyzed. The mean values of ETCO2 and PCO2 were 41.36mmHg and 42.04mmHg. There was a positive and significant correlation between ETCO2 and PCO2 in the overall analysis (r=0.5402; P<.001) and in the analysis of each unit (P<.001). The mean difference was 0.68 mmHg (95% CI, -0.68 to 1.95) and was not significant. We observed a positive systematic error (PCO2 > ETCO2) in 2 of the units, and a negative difference in the third (PCO2 < ETCO2). DISCUSSION The correlation between ETCO and PCO2 was significant, although the obtained values were not equivalent, with differences ranging from 0.1mmHg and 20mmHg. Likewise, we found systematic errors that differed in sign (positive or negative) between institutions.
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15
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Dos Santos Rocha A, Diaper J, Balogh AL, Marti C, Grosgurin O, Habre W, Peták F, Südy R. Effect of body position on the redistribution of regional lung aeration during invasive and non-invasive ventilation of COVID-19 patients. Sci Rep 2022; 12:11085. [PMID: 35773299 PMCID: PMC9245873 DOI: 10.1038/s41598-022-15122-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 06/20/2022] [Indexed: 11/09/2022] Open
Abstract
Severe COVID-19-related acute respiratory distress syndrome (C-ARDS) requires mechanical ventilation. While this intervention is often performed in the prone position to improve oxygenation, the underlying mechanisms responsible for the improvement in respiratory function during invasive ventilation and awake prone positioning in C-ARDS have not yet been elucidated. In this prospective observational trial, we evaluated the respiratory function of C-ARDS patients while in the supine and prone positions during invasive (n = 13) or non-invasive ventilation (n = 15). The primary endpoint was the positional change in lung regional aeration, assessed with electrical impedance tomography. Secondary endpoints included parameters of ventilation and oxygenation, volumetric capnography, respiratory system mechanics and intrapulmonary shunt fraction. In comparison to the supine position, the prone position significantly increased ventilation distribution in dorsal lung zones for patients under invasive ventilation (53.3 ± 18.3% vs. 43.8 ± 12.3%, percentage of dorsal lung aeration ± standard deviation in prone and supine positions, respectively; p = 0.014); whereas, regional aeration in both positions did not change during non-invasive ventilation (36.4 ± 11.4% vs. 33.7 ± 10.1%; p = 0.43). Prone positioning significantly improved the oxygenation both during invasive and non-invasive ventilation. For invasively ventilated patients reduced intrapulmonary shunt fraction, ventilation dead space and respiratory resistance were observed in the prone position. Oxygenation is improved during non-invasive and invasive ventilation with prone positioning in patients with C-ARDS. Different mechanisms may underly this benefit during these two ventilation modalities, driven by improved distribution of lung regional aeration, intrapulmonary shunt fraction and ventilation-perfusion matching. However, the differences in the severity of C-ARDS may have biased the sensitivity of electrical impedance tomography when comparing positional changes between the protocol groups.Trial registration: ClinicalTrials.gov (NCT04359407) and Registered 24 April 2020, https://clinicaltrials.gov/ct2/show/NCT04359407 .
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Affiliation(s)
- André Dos Santos Rocha
- Unit for Anaesthesiological Investigations, Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva and University of Geneva, Rue Willy Donzé 6, 1205, Geneva, Switzerland.
| | - John Diaper
- Unit for Anaesthesiological Investigations, Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva and University of Geneva, Rue Willy Donzé 6, 1205, Geneva, Switzerland
| | - Adam L Balogh
- Unit for Anaesthesiological Investigations, Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva and University of Geneva, Rue Willy Donzé 6, 1205, Geneva, Switzerland
| | - Christophe Marti
- Department of Internal Medicine, University Hospitals of Geneva, Geneva, Switzerland
| | - Olivier Grosgurin
- Department of Internal Medicine, University Hospitals of Geneva, Geneva, Switzerland
| | - Walid Habre
- Unit for Anaesthesiological Investigations, Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva and University of Geneva, Rue Willy Donzé 6, 1205, Geneva, Switzerland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Roberta Südy
- Unit for Anaesthesiological Investigations, Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva and University of Geneva, Rue Willy Donzé 6, 1205, Geneva, Switzerland
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16
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Sosa I, Cardetti M, Favareto V, Maure C, Ceballos E, Abona H, Martínez F, Gigli M, Rodríguez S, Sola A. Capnografía en recién nacidos en ventilación mecánica y su relación con la medición de CO2 en muestras sanguíneas. An Pediatr (Barc) 2022. [DOI: 10.1016/j.anpedi.2022.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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17
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Clark-Price SC, Lascola KM, Auckburally A, Boone LH, Caldwell FJ, Weatherall KM, Hanson RR. The effect of inhaled albuterol on PaO2 in anesthetized horses receiving a FiO2 of 0.5 or > 0.95. J Equine Vet Sci 2022; 113:103944. [DOI: 10.1016/j.jevs.2022.103944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 04/04/2022] [Accepted: 04/04/2022] [Indexed: 11/27/2022]
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18
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Araos J, Cruces P, Martin-Flores M, Donati P, Gleed RD, Boullhesen-Williams T, Perez A, Staffieri F, Retamal J, Vidal Melo MF, Hurtado DE. Distribution and Magnitude of Regional Volumetric Lung Strain and Its Modification by PEEP in Healthy Anesthetized and Mechanically Ventilated Dogs. Front Vet Sci 2022; 9:839406. [PMID: 35359684 PMCID: PMC8964072 DOI: 10.3389/fvets.2022.839406] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 01/27/2022] [Indexed: 11/24/2022] Open
Abstract
The present study describes the magnitude and spatial distribution of lung strain in healthy anesthetized, mechanically ventilated dogs with and without positive end-expiratory pressure (PEEP). Total lung strain (LSTOTAL) has a dynamic (LSDYNAMIC) and a static (LSSTATIC) component. Due to lung heterogeneity, global lung strain may not accurately represent regional total tissue lung strain (TSTOTAL), which may also be described by a regional dynamic (TSDYNAMIC) and static (TSSTATIC) component. Six healthy anesthetized beagles (12.4 ± 1.4 kg body weight) were placed in dorsal recumbency and ventilated with a tidal volume of 15 ml/kg, respiratory rate of 15 bpm, and zero end-expiratory pressure (ZEEP). Respiratory system mechanics and full thoracic end-expiratory and end-inspiratory CT scan images were obtained at ZEEP. Thereafter, a PEEP of 5 cmH2O was set and respiratory system mechanics measurements and end-expiratory and end-inspiratory images were repeated. Computed lung volumes from CT scans were used to evaluate the global LSTOTAL, LSDYNAMIC, and LSSTATIC during PEEP. During ZEEP, LSSTATIC was assumed zero; therefore, LSTOTAL was the same as LSDYNAMIC. Image segmentation was applied to CT images to obtain maps of regional TSTOTAL, TSDYNAMIC, and TSSTATIC during PEEP, and TSDYNAMIC during ZEEP. Compliance increased (p = 0.013) and driving pressure decreased (p = 0.043) during PEEP. PEEP increased the end-expiratory lung volume (p < 0.001) and significantly reduced global LSDYNAMIC (33.4 ± 6.4% during ZEEP, 24.0 ± 4.6% during PEEP, p = 0.032). LSSTATIC by PEEP was larger than the reduction in LSDYNAMIC; therefore, LSTOTAL at PEEP was larger than LSDYNAMIC at ZEEP (p = 0.005). There was marked topographic heterogeneity of regional strains. PEEP induced a significant reduction in TSDYNAMIC in all lung regions (p < 0.05). Similar to global findings, PEEP-induced TSSTATIC was larger than the reduction in TSDYNAMIC; therefore, PEEP-induced TSTOTAL was larger than TSDYNAMIC at ZEEP. In conclusion, PEEP reduced both global and regional estimates of dynamic strain, but induced a large static strain. Given that lung injury has been mostly associated with tidal deformation, limiting dynamic strain may be an important clinical target in healthy and diseased lungs, but this requires further study.
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Affiliation(s)
- Joaquin Araos
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
- *Correspondence: Joaquin Araos
| | - Pablo Cruces
- Escuela de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
- Pediatric Intensive Care Unit, Hospital El Carmen de Maipu, Santiago, Chile
| | - Manuel Martin-Flores
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Pablo Donati
- Department of Anesthesiology and Pain Management, Faculty of Veterinary Sciences, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Robin D. Gleed
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Tomas Boullhesen-Williams
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
| | - Agustin Perez
- Department of Structural and Geotechnical Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Francesco Staffieri
- Department of Emergency and Organ Transplantation, Section of Veterinary Clinics and Animal Production, University of Bari, Bari, Italy
| | - Jaime Retamal
- Department of Intensive Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Marcos F. Vidal Melo
- Division of Cardiothoracic Anesthesiology, Department of Anesthesiology, Columbia University Irving Medical Center, New York, NY, United States
| | - Daniel E. Hurtado
- Department of Structural and Geotechnical Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- Daniel E. Hurtado
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Suárez-Sipmann F, Villar J, Ferrando C, Sánchez-Giralt JA, Tusman G. Monitoring Expired CO 2 Kinetics to Individualize Lung-Protective Ventilation in Patients With the Acute Respiratory Distress Syndrome. Front Physiol 2022; 12:785014. [PMID: 34992549 PMCID: PMC8724128 DOI: 10.3389/fphys.2021.785014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 10/18/2021] [Indexed: 11/13/2022] Open
Abstract
Mechanical ventilation (MV) is a lifesaving supportive intervention in the management of acute respiratory distress syndrome (ARDS), buying time while the primary precipitating cause is being corrected. However, MV can contribute to a worsening of the primary lung injury, known as ventilation-induced lung injury (VILI), which could have an important impact on outcome. The ARDS lung is characterized by diffuse and heterogeneous lung damage and is particularly prone to suffer the consequences of an excessive mechanical stress imposed by higher airway pressures and volumes during MV. Of major concern is cyclic overdistension, affecting those lung segments receiving a proportionally higher tidal volume in an overall reduced lung volume. Theoretically, healthier lung regions are submitted to a larger stress and cyclic deformation and thus at high risk for developing VILI. Clinicians have difficulties in detecting VILI, particularly cyclic overdistension at the bedside, since routine monitoring of gas exchange and lung mechanics are relatively insensitive to this mechanism of VILI. Expired CO2 kinetics integrates relevant pathophysiological information of high interest for monitoring. CO2 is produced by cell metabolism in large daily quantities. After diffusing to tissue capillaries, CO2 is transported first by the venous and then by pulmonary circulation to the lung. Thereafter diffusing from capillaries to lung alveoli, it is finally convectively transported by lung ventilation for its elimination to the atmosphere. Modern readily clinically available sensor technology integrates information related to pulmonary ventilation, perfusion, and gas exchange from the single analysis of expired CO2 kinetics measured at the airway opening. Current volumetric capnography (VCap), the representation of the volume of expired CO2 in one single breath, informs about pulmonary perfusion, end-expiratory lung volume, dead space, and pulmonary ventilation inhomogeneities, all intimately related to cyclic overdistension during MV. Additionally, the recently described capnodynamic method provides the possibility to continuously measure the end-expiratory lung volume and effective pulmonary blood flow. All this information is accessed non-invasively and breath-by-breath helping clinicians to personalize ventilatory settings at the bedside and minimize overdistension and cyclic deformation of lung tissue.
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Affiliation(s)
- Fernando Suárez-Sipmann
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.,Intensive Care Unit, Hospital Universitario La Princesa, Madrid, Spain.,Department of Surgical Sciences, Anesthesiology & Critical Care, Hedenstierna Laboratory, Uppsala University Hospital, Uppsala, Sweden
| | - Jesús Villar
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.,Multidisciplinary Organ Dysfunction Evaluation Research Network (MODERN), Research Unit, Hospital Universitario Dr. Negrín, Las Palmas de Gran Canaria, Spain.,Keenan Research Center at the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
| | - Carlos Ferrando
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.,Department of Anesthesiology and Critical Care, Hospital Clinic, Barcelona, Spain.,Hospital Clinic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | | | - Gerardo Tusman
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
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Peyton PJ. Ideal alveolar gas defined by modal gas exchange in ventilation-perfusion distributions. J Appl Physiol (1985) 2021; 131:1831-1838. [PMID: 34672764 DOI: 10.1152/japplphysiol.00597.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Under the three-compartment model of ventilation-perfusion (VA/Q) scatter, Bohr-Enghoff calculation of alveolar deadspace fraction (VDA/VA) uses arterial CO2 partial pressure measurement as an approximation of "ideal" alveolar CO2(ideal PACO2). However, this simplistic model suffers from several inconsistencies. Modelling of realistic physiological distributions of VA and Q instead suggests an alternative concept of "ideal" alveolar gas at the VA/Q ratio where uptake or elimination rate of a gas is maximal. The alveolar-capillary partial pressure at this "modal" point equals the mean of expired alveolar and arterial partial pressures, regardless of VA/Q scatter severity or overall VA/Q. For example, modal ideal PACO2 can be estimated from Estimated modal ideal PACO2 = (PACO2+PaCO2)/2 Using a multicompartment computer model of log normal distributions of VA and Q, agreement of this estimate with the modal ideal PACO2 located at the VA/Q ratio of maximal compartmental VCO2 was assessed across a wide range of severity of VA/Q scatter and overall VA/Q ratio. Agreement of VDA/VA for CO2 from the Bohr equation using modal idealPCO2 with that using the estimated value was also assessed. Estimated modal ideal PACO2 agreed closely with modal ideal PACO2, intraclass correlation (ICC) > 99.9%. There was no significant difference between VDA/VACO2 using either value for ideal PACO2. Modal ideal PACO2 reflects a physiologically realistic concept of ideal alveolar gas where there is maximal gas exchange effectiveness in a physiological distribution of VA/Q, which is generalizable to any inert gas, and is practical to estimate from arterial and end-expired CO2 partial pressures.
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Affiliation(s)
- Philip J Peyton
- Professorial Fellow, Anaesthesia, Perioperative and Pain Medicine Program, Department of Critical Care, University of Melbourne, Australia
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21
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Hirabayashi G, Yokose Y, Nagata K, Oshika H, Saito M, Akihisa Y, Maruyama K, Andoh T. Changes in dead space components during pressure-controlled inverse ratio ventilation: A secondary analysis of a randomized trial. PLoS One 2021; 16:e0258504. [PMID: 34644352 PMCID: PMC8513857 DOI: 10.1371/journal.pone.0258504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 09/15/2021] [Indexed: 11/22/2022] Open
Abstract
Background We previously reported that there were no differences between the lung-protective actions of pressure-controlled inverse ratio ventilation and volume control ventilation based on the changes in serum cytokine levels. Dead space represents a ventilation-perfusion mismatch, and can enable us to understand the heterogeneity and elapsed time changes in ventilation-perfusion mismatch. Methods This study was a secondary analysis of a randomized controlled trial of patients who underwent robot-assisted laparoscopic radical prostatectomy. The inspiratory to expiratory ratio was adjusted individually by observing the expiratory flow-time wave in the pressure-controlled inverse ratio ventilation group (n = 14) and was set to 1:2 in the volume-control ventilation group (n = 13). Using volumetric capnography, the physiological dead space was divided into three dead space components: airway, alveolar, and shunt dead space. The influence of pressure-controlled inverse ratio ventilation and time factor on the changes in each dead space component rate was analyzed using the Mann-Whitney U test and Wilcoxon’s signed rank test. Results The physiological dead space and shunt dead space rate were decreased in the pressure-controlled inverse ratio ventilation group compared with those in the volume control ventilation group (p < 0.001 and p = 0.003, respectively), and both dead space rates increased with time in both groups. The airway dead space rate increased with time, but the difference between the groups was not significant. There were no significant changes in the alveolar dead space rate. Conclusions Pressure-controlled inverse ratio ventilation reduced the physiological dead space rate, suggesting an improvement in the total ventilation/perfusion mismatch due to improved inflation of the alveoli affected by heterogeneous expansion disorder without hyperinflation of the normal alveoli. However, the shunt dead space rate increased with time, suggesting that atelectasis developed with time in both groups.
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Affiliation(s)
- Go Hirabayashi
- Department of Anaesthesiology, Mizonokuchi Hospital Teikyo University School of Medicine, Kanagawa, Japan
- * E-mail:
| | - Yuuki Yokose
- Department of Anaesthesiology, Mizonokuchi Hospital Teikyo University School of Medicine, Kanagawa, Japan
| | - Kohei Nagata
- Department of Anaesthesiology, Mizonokuchi Hospital Teikyo University School of Medicine, Kanagawa, Japan
| | - Hiroyuki Oshika
- Department of Anaesthesiology, Mizonokuchi Hospital Teikyo University School of Medicine, Kanagawa, Japan
| | - Minami Saito
- Department of Anaesthesiology, Mizonokuchi Hospital Teikyo University School of Medicine, Kanagawa, Japan
| | - Yuki Akihisa
- Department of Anaesthesiology, Mizonokuchi Hospital Teikyo University School of Medicine, Kanagawa, Japan
| | - Koichi Maruyama
- Department of Anaesthesiology, Mizonokuchi Hospital Teikyo University School of Medicine, Kanagawa, Japan
| | - Tomio Andoh
- Department of Anaesthesiology, Mizonokuchi Hospital Teikyo University School of Medicine, Kanagawa, Japan
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Peták F, Balogh ÁL, Hankovszky P, Fodor GH, Tolnai J, Südy R, Kovács BN, Molnár A, Babik B. Dopamine Reverses Lung Function Deterioration After Cardiopulmonary Bypass Without Affecting Gas Exchange. J Cardiothorac Vasc Anesth 2021; 36:1047-1055. [PMID: 34404593 DOI: 10.1053/j.jvca.2021.07.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/08/2021] [Accepted: 07/19/2021] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To investigate the effects of dopamine on the adverse pulmonary changes after cardiopulmonary bypass. DESIGN A prospective, nonrandomized clinical investigation. SETTING A university hospital. PARTICIPANTS One hundred fifty-seven patients who underwent elective cardiac surgery that required cardiopulmonary bypass. INTERVENTIONS Fifty-two patients were administered intravenous infusion of dopamine (3 µg/kg/min) for five minutes after weaning from cardiopulmonary bypass; no intervention was applied in the other 105 patients. MEASUREMENTS AND MAIN RESULTS Measurements were performed under general anesthesia and mechanical ventilation before cardiopulmonary bypass, after cardiopulmonary bypass, and after the intervention. In each protocol stage, forced oscillatory lung impedance was measured to assess airway and tissue mechanical changes. Mainstream capnography was performed to assess ventilation- and/or perfusion-matching by calculating the normalized phase-3 slopes of the time and volumetric capnograms and the physiologic deadspace. Arterial and central venous blood samples were analyzed to characterize lung oxygenation and intrapulmonary shunt. After cardiopulmonary bypass, dopamineinduced marked improvements in airway resistance and tissue damping, with relatively small decreases in lung tissue elastance. These changes were associated with decreases in the normalized phase-3 slopes of the time and volumetric capnograms. The inotrope had no effect on physiologic deadspace, intrapulmonary shunt, or lung oxygenation. CONCLUSION Dopamine reversed the complex detrimental lung mechanical changes induced by cardiopulmonary bypass and alleviated ventilation heterogeneities without affecting the physiologic deadspace or intrapulmonary shunt. Therefore, dopamine has a potential benefit on the gas exchange abnormalities after weaning from cardiopulmonary bypass.
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Affiliation(s)
- Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary.
| | - Ádám L Balogh
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Péter Hankovszky
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - József Tolnai
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Roberta Südy
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary; Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Barbara N Kovács
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary; Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Andrea Molnár
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary; Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Barna Babik
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
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Edlinger-Stanger M, Bernardi MH, Kovacs K, Mascha M, Neugebauer T, Böhme S, Ayoubi N, Christofi N, Garry J, Fleming N, Hiesmayr M. The effect of acute ventilation-perfusion mismatch on respiratory heat exchange in a porcine model. PLoS One 2021; 16:e0254399. [PMID: 34252138 PMCID: PMC8274834 DOI: 10.1371/journal.pone.0254399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 06/28/2021] [Indexed: 11/18/2022] Open
Abstract
Background Respiratory heat exchange is an important physiological process occurring in the upper and lower respiratory tract and is usually completed when inspired gases reach the alveoli. Animal and human studies demonstrated that heat exchange can be modulated by altering pulmonary ventilation and perfusion. The purpose of this study was to examine the effect of acute ventilation-perfusion (V/Q) mismatch on respiratory heat exchange. In clinical practice, monitoring respiratory heat exchange might offer the possibility of real-time tracking of acute V/Q-mismatch. Methods In 11 anesthetized, mechanically ventilated pigs, V/Q-mismatch was established by means of four interventions: single lung ventilation, high cardiac output, occlusion of the left pulmonary artery and repeated whole-lung lavage. V/Q-distributions were determined by the multiple inert gas elimination technique (MIGET). Respiratory heat exchange was measured as respiratory enthalpy using the novel, pre-commercial VQm™ monitor (development stage, Rostrum Medical Innovations, Vancouver, CA). According to MIGET, shunt perfusion of low V/Q compartments increased during single lung ventilation, high cardiac output and whole-lung lavage, whereas dead space and ventilation of high V/Q compartments increased during occlusion of the left pulmonary artery and whole-lung lavage. Results Bohr dead space increased after pulmonary artery occlusion and whole-lung lavage, venous admixture increased during single lung ventilation and whole-lung lavage, PaO2/FiO2 was decreased during all interventions. MIGET confirmed acute V/Q-mismatch. Respiratory enthalpy did not change significantly despite significant acute V/Q-mismatch. Conclusion Clinically relevant V/Q-mismatch does not impair respiratory heat exchange in the absence of additional thermal stressors and may not have clinical utility in the detection of acute changes.
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Affiliation(s)
- Maximilian Edlinger-Stanger
- Department of Cardiothoracic Anaesthesia, Intensive Care Medicine, Medical University of Vienna, Vienna, Austria
- * E-mail:
| | - Martin-Hermann Bernardi
- Department of Cardiothoracic Anaesthesia, Intensive Care Medicine, Medical University of Vienna, Vienna, Austria
| | - Katharina Kovacs
- Department of Cardiothoracic Anaesthesia, Intensive Care Medicine, Medical University of Vienna, Vienna, Austria
| | - Michael Mascha
- Department of Cardiothoracic Anaesthesia, Intensive Care Medicine, Medical University of Vienna, Vienna, Austria
| | - Thomas Neugebauer
- Department of Cardiothoracic Anaesthesia, Intensive Care Medicine, Medical University of Vienna, Vienna, Austria
| | - Stefan Böhme
- Department of Anaesthesia, Intensive Care Medicine and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | | | | | - James Garry
- Rostrum Medical Innovations Inc., Vancouver, Canada
| | - Neal Fleming
- University of California Davis, Davis, California, United States of America
| | - Michael Hiesmayr
- Department of Cardiothoracic Anaesthesia, Intensive Care Medicine, Medical University of Vienna, Vienna, Austria
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Use of Electrical Impedance Tomography (EIT) to Estimate Tidal Volume in Anaesthetized Horses Undergoing Elective Surgery. Animals (Basel) 2021; 11:ani11051350. [PMID: 34068514 PMCID: PMC8151473 DOI: 10.3390/ani11051350] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/05/2021] [Indexed: 11/30/2022] Open
Abstract
Simple Summary The aim of this study was to explore the usefulness of electrical impedance tomography (EIT), a novel monitoring tool measuring impedance change, to estimate tidal volume (volume of gas in litres moved in and out the airways and lungs with each breath) in anaesthetised horses. The results of this study, performed in clinical cases, demonstrated that there was a positive linear relationship between tidal volume measurements obtained with spirometry and impedance changes measured by EIT within each subject and this individual relationship could be used to estimate tidal volume that showed acceptable agreement with a measured tidal volume in each horse. Thus, EIT can be used to observe changes in tidal volume by the means of impedance changes. However, absolute measurement of tidal volume is only possible after establishment of the individual relationship. Abstract This study explores the application of electric impedance tomography (EIT) to estimate tidal volume (VT) by measuring impedance change per breath (∆Zbreath). Seventeen healthy horses were anaesthetised and mechanically ventilated for elective procedures requiring dorsal recumbency. Spirometric VT (VTSPIRO) and ∆Zbreath were recorded periodically; up to six times throughout anaesthesia. Part 1 assessed these variables at incremental delivered VT of 10, 12 and 15 mL/kg. Part 2 estimated VT (VTEIT) in litres from ∆Zbreath at three additional measurement points using a line of best fit obtained from Part 1. During part 2, VT was adjusted to maintain end-tidal carbon dioxide between 45–55 mmHg. Linear regression determined the correlation between VTSPIRO and ∆Zbreath (part 1). Estimated VTEIT was assessed for agreement with measured VTSPIRO using Bland Altman analysis (part 2). Marked variability in slope and intercepts was observed across horses. Strong positive correlation between ∆Zbreath and VTSPIRO was found in each horse (R2 0.9–0.99). The agreement between VTEIT and VTSPIRO was good with bias (LOA) of 0.26 (−0.36–0.88) L. These results suggest that, in anaesthetised horses, EIT can be used to monitor and estimate VT after establishing the individual relationship between these variables.
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Moreno‐Martinez F, Mosing M, Senior M. Controlled mechanical ventilation in equine anaesthesia: Physiological background and basic considerations (Part 1). EQUINE VET EDUC 2021. [DOI: 10.1111/eve.13476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- F. Moreno‐Martinez
- School of Veterinary and Life Sciences Murdoch University Perth Western Australia Australia
| | - M. Mosing
- School of Veterinary and Life Sciences Murdoch University Perth Western Australia Australia
| | - M. Senior
- Department of Equine Clinical Science Institute of Veterinary Science University of Liverpool Neston, Cheshire UK
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Turchetto E, Tusman G, Makinistian R. Mechanical ventilation in lung injury caused by SARS-CoV-2: What can contribute volumetric capnography? REVISTA ESPAÑOLA DE ANESTESIOLOGÍA Y REANIMACIÓN (ENGLISH EDITION) 2021. [PMCID: PMC7883698 DOI: 10.1016/j.redare.2020.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Turchetto E, Tusman G, Makinistian R. Ventilación mecánica en daño pulmonar por SARS-CoV-2: ¿qué puede aportar la capnografía volumétrica? REVISTA ESPAÑOLA DE ANESTESIOLOGÍA Y REANIMACIÓN 2021; 68:116-118. [PMID: 33468341 PMCID: PMC7245316 DOI: 10.1016/j.redar.2020.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 05/11/2020] [Accepted: 05/17/2020] [Indexed: 11/29/2022]
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Pauluhn J. Phosgene inhalation toxicity: Update on mechanisms and mechanism-based treatment strategies. Toxicology 2021; 450:152682. [PMID: 33484734 DOI: 10.1016/j.tox.2021.152682] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 11/28/2022]
Abstract
Phosgene (carbonyl dichloride) gas is an indispensable high-production-volume chemical intermediate used worldwide in numerous industrial processes. Published evidence of human exposures due to accidents and warfare (World War I) has been reported; however, these reports often lack specificity because of the uncharacterized exposure intensities of phosgene and/or related irritants. These may include liquid or solid congeners of phosgene, including di- and triphosgene and/or the respiratory tract irritant chlorine which are often collectively reported under the umbrella of phosgene exposure without any appreciation of their differences in causing acute lung injury (ALI). Among these irritants, phosgene gas is somewhat unique because of its poor water solubility. This prevents any appreciable retention of the gas in the upper airways and related trigeminal sensations of irritation. By contrast, in the pulmonary compartment, amphiphilic surfactant might scavenge this lipophilic gas. The interaction of phosgene and the surfactant may affect basic physiological functions controlled by Starling's and Laplace's laws, which can be followed by cardiogenic pulmonary edema. The phenotypic manifestations are dependent on the concentration × exposure duration (C × t); the higher the C × t is, the less time that is required for edema to appear. It is hypothesized that this type of edema is caused by cardiovascular and colloid osmotic imbalances to initial neurogenic events but not because of the injury itself. Thus, hemodynamic etiologies appear to cause imbalances in extravasated fluids and solute accumulation in the pulmonary interstitium, which is not drained away by the lymphatic channels of the lung. The most salient associated findings are hemoconcentration and hypoproteinemia. The involved intertwined pathophysiological processes coordinating pulmonary ventilation and cardiopulmonary perfusion under such conditions are complex. Pulmonary arterial catheter measurements on phosgene-exposed dogs provided evidence of 'cor pulmonale', a form of acute right heart failure produced by a sudden increase in resistance to blood flow in the pulmonary circulation about 20 h postexposure. The objective of this review is to critically analyze evidence from experimental inhalation studies in rats and dogs, and evidence from accidental human exposures to better understand the primary and secondary events causing cardiopulmonary dysfunction and an ensuing life-threatening lung edema. Mechanism-based diagnostic and therapeutic approaches are also considered for this form of cardiogenic edema.
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Affiliation(s)
- Juergen Pauluhn
- Covestro Deutschland AG, Global Phosgene Steering Group, 51365, Leverkusen, Germany; Hanover Medical School, Hanover, Germany; Bayer HealthCare, Wuppertal, Germany(1).
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Zuiki M, Naito Y, Kitamura K, Tsurukawa S, Matsumura U, Kanayama T, Komatsu H. Reduction in minute alveolar ventilation causes hypercapnia in ventilated neonates with respiratory distress. Eur J Pediatr 2021; 180:241-246. [PMID: 32748016 PMCID: PMC7397965 DOI: 10.1007/s00431-020-03761-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/19/2020] [Accepted: 07/28/2020] [Indexed: 11/28/2022]
Abstract
Hypercapnia occurs in ventilated infants even if tidal volume (VT) and minute ventilation (VE) are maintained. We hypothesised that increased physiological dead space (Vd,phys) caused decreased minute alveolar ventilation (VA; alveolar ventilation (VA) × respiratory rate) in well-ventilated infants with hypercapnia. We investigated the relationship between dead space and partial pressure of carbon dioxide (PaCO2) and assessed VA. Intubated infants (n = 33; mean birth weight, 2257 ± 641 g; mean gestational age, 35.0 ± 3.3 weeks) were enrolled. We performed volumetric capnography (Vcap), and calculated Vd,phys and VA when arterial blood sampling was necessary. PaCO2 was positively correlated with alveolar dead space (Vd,alv) (r = 0.54, p < 0.001) and Vd,phys (r = 0.48, p < 0.001), but not Fowler dead space (r = 0.14, p = 0.12). Normocapnia (82 measurements; 35 mmHg ≤ PaCO2 < 45 mmHg) and hypercapnia groups (57 measurements; 45 mmHg ≤ PaCO2) were classified. The hypercapnia group had higher Vd,phys (median 0.57 (IQR, 0.44-0.67)) than the normocapnia group (median Vd,phys/VT = 0.46 (IQR, 0.37-0.58)], with no difference in VT. The hypercapnia group had lower VA (123 (IQR, 87-166) ml/kg/min) than the normocapnia group (151 (IQR, 115-180) ml/kg/min), with no difference in VE.Conclusion: Reduction of VA in well-ventilated neonates induces hypercapnia, caused by an increase in Vd,phys. What is Known: • Volumetric capnography based on ventilator graphics and capnograms is a useful tool in determining physiological dead space of ventilated infants and investigating the cause of hypercapnia. What is New: • This study adds evidence that reduction in minute alveolar ventilation causes hypercapnia in ventilated neonates.
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Affiliation(s)
- Masashi Zuiki
- Department of Pediatrics, National Hospital Organization Maizuru Medical Center, 2410 Yukinaga, Maizuru, Kyoto, 625-8502, Japan.
| | - Yuki Naito
- Department of Pediatrics, National Hospital Organization Maizuru Medical Center, 2410 Yukinaga, Maizuru, Kyoto, 625-8502 Japan
| | - Kazumasa Kitamura
- Department of Pediatrics, National Hospital Organization Maizuru Medical Center, 2410 Yukinaga, Maizuru, Kyoto, 625-8502 Japan
| | - Shinichiro Tsurukawa
- Department of Pediatrics, National Hospital Organization Maizuru Medical Center, 2410 Yukinaga, Maizuru, Kyoto, 625-8502 Japan
| | - Utsuki Matsumura
- Department of Pediatrics, National Hospital Organization Maizuru Medical Center, 2410 Yukinaga, Maizuru, Kyoto, 625-8502 Japan
| | - Takuyo Kanayama
- Department of Pediatrics, National Hospital Organization Maizuru Medical Center, 2410 Yukinaga, Maizuru, Kyoto, 625-8502 Japan
| | - Hiroshi Komatsu
- Department of Pediatrics, National Hospital Organization Maizuru Medical Center, 2410 Yukinaga, Maizuru, Kyoto, 625-8502 Japan
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Wittenstein J, Scharffenberg M, Ran X, Keller D, Michler P, Tauer S, Theilen R, Kiss T, Bluth T, Koch T, Gama de Abreu M, Huhle R. Comparative effects of flow vs. volume-controlled one-lung ventilation on gas exchange and respiratory system mechanics in pigs. Intensive Care Med Exp 2020; 8:24. [PMID: 33336305 PMCID: PMC7746431 DOI: 10.1186/s40635-020-00308-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 05/21/2020] [Indexed: 01/23/2023] Open
Abstract
Background Flow-controlled ventilation (FCV) allows expiratory flow control, reducing the collapse of the airways during expiration. The performance of FCV during one-lung ventilation (OLV) under intravascular normo- and hypovolaemia is currently unknown. In this explorative study, we hypothesised that OLV with FCV improves PaO2 and reduces mechanical power compared to volume-controlled ventilation (VCV). Sixteen juvenile pigs were randomly assigned to one of two groups: (1) intravascular normovolaemia (n = 8) and (2) intravascular hypovolaemia (n = 8). To mimic inflammation due to major thoracic surgery, a thoracotomy was performed, and 0.5 μg/kg/h lipopolysaccharides from Escherichia coli continuously administered intravenously. Animals were randomly assigned to OLV with one of two sequences (60 min per mode): (1) VCV–FCV or (2) FCV–VCV. Variables of gas exchange, haemodynamics and respiratory signals were collected 20, 40 and 60 min after initiation of OLV with each mechanical ventilation mode. The distribution of ventilation was determined using electrical impedance tomography (EIT). Results Oxygenation did not differ significantly between modes (P = 0.881). In the normovolaemia group, the corrected expired minute volume (P = 0.022) and positive end-expiratory pressure (PEEP) were lower during FCV than VCV. The minute volume (P ≤ 0.001), respiratory rate (P ≤ 0.001), total PEEP (P ≤ 0.001), resistance of the respiratory system (P ≤ 0.001), mechanical power (P ≤ 0.001) and resistive mechanical power (P ≤ 0.001) were lower during FCV than VCV irrespective of the volaemia status. The distribution of ventilation did not differ between both ventilation modes (P = 0.103). Conclusions In a model of OLV in normo- and hypovolemic pigs, mechanical power was lower during FCV compared to VCV, without significant differences in oxygenation. Furthermore, the efficacy of ventilation was higher during FCV compared to VCV during normovolaemia.
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Affiliation(s)
- Jakob Wittenstein
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Martin Scharffenberg
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Xi Ran
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Diana Keller
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Pia Michler
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Sebastian Tauer
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Raphael Theilen
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Thomas Kiss
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Thomas Bluth
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Thea Koch
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Marcelo Gama de Abreu
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
| | - Robert Huhle
- Pulmonary Engineering Group, Dept. of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus at Technische Universität Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
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Südy R, Peták F, Kiss L, Balogh ÁL, Fodor GH, Korsós A, Schranc Á, Babik B. Obesity and diabetes: similar respiratory mechanical but different gas exchange defects. Am J Physiol Lung Cell Mol Physiol 2020; 320:L368-L376. [PMID: 33264577 DOI: 10.1152/ajplung.00439.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Diabetes mellitus increases smooth muscle tone and causes tissue remodeling, affecting elastin and collagen. Although the lung is dominated by these elements, diabetes is expected to modify the airway function and respiratory tissue mechanics. Therefore, we characterized the respiratory function in patients with diabetes with and without associated obesity. Mechanically ventilated patients with normal body shapes were divided into the control nondiabetic (n = 73) and diabetic (n = 31) groups. The other two groups included obese patients without diabetes (n = 43) or with diabetes (n = 30). The mechanical properties of the respiratory system were determined by forced oscillation technique. Airway resistance (Raw), tissue damping (G), and tissue elastance (H) were assessed by forced oscillation. Capnography was applied to determine phase 3 slopes and dead space indices. The intrapulmonary shunt fraction (Qs/Qt) and the lung oxygenation index (PaO2/FIO2) were estimated from arterial and central venous blood samples. Compared with the corresponding control groups, diabetes alone increased the Raw (7.6 ± 6 cmH2O.s/l vs. 3.1 ± 1.9 cmH2O.s/l), G (11.7 ± 5.5 cmH2O/l vs. 6.5 ± 2.8 cmH2O/l), and H (31.5 ± 11.8 cmH2O/l vs. 24.2 ± 7.2 cmH2O/l (P < 0.001 for all). Diabetes increased the capnographic phase 3 slope, whereas PaO2/FIO2 or Qs/Qt was not affected. Obesity alone caused similar detrimental changes in respiratory mechanics and alveolar heterogeneity, but these alterations also compromised gas exchange. We conclude that diabetes-induced intrinsic mechanical abnormalities are counterbalanced by hypoxic pulmonary vasoconstriction, which maintained intrapulmonary shunt fraction and oxygenation ability of the lungs.
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Affiliation(s)
- Roberta Südy
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary.,Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Liliána Kiss
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary.,Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Ádám L Balogh
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary.,Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Anita Korsós
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Álmos Schranc
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Barna Babik
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
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32
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Leonard TGA. Respiratory equations – behind the numbers. SOUTHERN AFRICAN JOURNAL OF ANAESTHESIA AND ANALGESIA 2020. [DOI: 10.36303/sajaa.2020.26.6.s3.2546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Candidates for the FCA 1 exam will come across dozens of equations that eventually all merge into something complicated and daunting. The purpose of this review is to highlight some of the respiratory equations that are important and that candidates find confusing and explain the mathematical and physiological principles behind them.
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33
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Goenaga-Diaz EJ, Smith LD, Pecorella SH, Smith TE, Russell GB, Johnson KN, Downard MG, Ririe DG, Hammon DE, Hodges AS, Templeton TW. A comparison of the breathing apparatus deadspace associated with a supraglottic airway and endotracheal tube using volumetric capnography in young children. Korean J Anesthesiol 2020; 74:218-225. [PMID: 33198431 PMCID: PMC8175872 DOI: 10.4097/kja.20518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/03/2020] [Indexed: 11/30/2022] Open
Abstract
Background Supraglottic airway (SGA) devices including the air-Q® are being used with increasing frequency for anesthesia in infants and younger pediatric patients. To date, there is minimal research documenting the potentially significant airway deadspace these devices may contribute to the ventilation circuit when compared to an endotracheal tube (ETT). The aim of this study was to evaluate the airway apparatus deadspace associated with an air-Q® versus an ETT in young children. Methods In a prospective cohort study, 59 patients between 3 months and 6 years of age, weighing between 5 and 20 kg, scheduled for outpatient urologic or general surgery procedures were recruited. An air-Q® or ETT was inserted at the discretion of the attending anesthesiologist, and tidal volume, positive end expiratory pressure, respiratory rate, and end-tidal CO2 were controlled according to protocol. Airway deadspace was recorded using volumetric capnography every 2 min for 10 min. Results Groups were similar in demographics. There was a significant difference in weight-adjusted deadspace volume between the air-Q® and ETT groups, 4.1 ± 0.8 ml/kg versus 3.0 ± 0.7 ml/kg, respectively (P < 0.001). Weight-adjusted deadspace volume (ml/kg) increased significantly with decreasing weight for both the air-Q® and ETT groups. Conclusions In healthy children undergoing positive pressure ventilation for elective surgery, the air-Q® SGA introduces significantly greater airway deadspace than an ETT. Additionally, airway deadspace, and minute ventilation required to maintain normocarbia, appear to increase with decreasing patient weight irrespective of whether a SGA or ETT is used.
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Affiliation(s)
| | - Lauren Daniela Smith
- Department of Anesthesiology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | | | - Timothy Earl Smith
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Gregory B Russell
- Department of Biostatistics and Data Sciences, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | | | - Martina Gomez Downard
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Douglas Gordon Ririe
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Dudley Elliott Hammon
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Ashley Sloan Hodges
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC, USA
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34
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Mosing M, Waldmann AD, Sacks M, Buss P, Boesch JM, Zeiler GE, Hosgood G, Gleed RD, Miller M, Meyer LCR, Böhm SH. What hinders pulmonary gas exchange and changes distribution of ventilation in immobilized white rhinoceroses ( Ceratotherium simum) in lateral recumbency? J Appl Physiol (1985) 2020; 129:1140-1149. [PMID: 33054661 DOI: 10.1152/japplphysiol.00359.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
This study used electrical impedance tomography (EIT) measurements of regional ventilation and perfusion to elucidate the reasons for severe gas exchange impairment reported in rhinoceroses during opioid-induced immobilization. EIT values were compared with standard monitoring parameters to establish a new monitoring tool for conservational immobilization and future treatment options. Six male white rhinoceroses were immobilized using etorphine, and EIT ventilation variables, venous admixture, and dead space were measured 30, 40, and 50 min after becoming recumbent in lateral position. Pulmonary perfusion mapping using impedance-enhanced EIT was performed at the end of the study period. The measured impedance (∆Z) by EIT was compared between pulmonary regions using mixed linear models. Measurements of regional ventilation and perfusion revealed a pronounced disproportional shift of ventilation and perfusion toward the nondependent lung. Overall, the dependent lung was minimally ventilated and perfused, but remained aerated with minimal detectable lung collapse. Perfusion was found primarily around the hilum of the nondependent lung and was minimal in the periphery of the nondependent and the entire dependent lung. These shifts can explain the high amount of venous admixture and physiological dead space found in this study. Breath holding redistributed ventilation toward dependent and ventral lung areas. The findings of this study reveal important pathophysiological insights into the changes in lung ventilation and perfusion during immobilization of white rhinoceroses. These novel insights might induce a search for better therapeutic options and is establishing EIT as a promising monitoring tool for large animals in the field.NEW & NOTEWORTHY Electrical impedance tomography measurements of regional ventilation and perfusion applied to etorphine-immobilized white rhinoceroses in lateral recumbency revealed a pronounced disproportional shift of the measured ventilation and perfusion toward the nondependent lung. The dependent lung was minimally ventilated and perfused, but still aerated. Perfusion was found primarily around the hilum of the nondependent lung. These shifts can explain the gas exchange impairments found in this study. Breath holding can redistribute ventilation.
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Affiliation(s)
- Martina Mosing
- School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Australia
| | - Andreas D Waldmann
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
| | - Muriel Sacks
- School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Australia
| | - Peter Buss
- Veterinary Wildlife Services, South African National Parks, Kruger National Park, Skukuza, South Africa
| | - Jordyn M Boesch
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Gareth E Zeiler
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.,Centre for Veterinary Wildlife Studies and Department of Paraclinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Giselle Hosgood
- School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Australia
| | - Robin D Gleed
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Michele Miller
- Department of Science and Technology-National Research Foundation Centre of Excellence for Biomedical TB Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Leith C R Meyer
- Centre for Veterinary Wildlife Studies and Department of Paraclinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Stephan H Böhm
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
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35
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Volumetrische Kapnographie zur Analyse und Optimierung von Ventilation und Gasaustausch. Anaesthesist 2020; 69:361-370. [DOI: 10.1007/s00101-020-00747-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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36
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Ospina-Tascón GA, Bautista DF, Madriñán HJ, Valencia JD, Bermúdez WF, Quiñones E, Calderón-Tapia LE, Hernandez G, Bruhn A, De Backer D. Microcirculatory dysfunction and dead-space ventilation in early ARDS: a hypothesis-generating observational study. Ann Intensive Care 2020; 10:35. [PMID: 32211957 PMCID: PMC7093634 DOI: 10.1186/s13613-020-00651-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 03/16/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Ventilation/perfusion inequalities impair gas exchange in acute respiratory distress syndrome (ARDS). Although increased dead-space ventilation (VD/VT) has been described in ARDS, its mechanism is not clearly understood. We sought to evaluate the relationships between dynamic variations in VD/VT and extra-pulmonary microcirculatory blood flow detected at sublingual mucosa hypothesizing that an altered microcirculation, which is a generalized phenomenon during severe inflammatory conditions, could influence ventilation/perfusion mismatching manifested by increases in VD/VT fraction during early stages of ARDS. METHODS Forty-two consecutive patients with early moderate and severe ARDS were included. PEEP was set targeting the best respiratory-system compliance after a PEEP-decremental recruitment maneuver. After 60 min of stabilization, hemodynamics and respiratory mechanics were recorded and blood gases collected. VD/VT was calculated from the CO2 production ([Formula: see text]) and CO2 exhaled fraction ([Formula: see text]) measurements by volumetric capnography. Sublingual microcirculatory images were simultaneously acquired using a sidestream dark-field device for an ulterior blinded semi-quantitative analysis. All measurements were repeated 24 h after. RESULTS Percentage of small vessels perfused (PPV) and microcirculatory flow index (MFI) were inverse and significantly related to VD/VT at baseline (Spearman's rho = - 0.76 and - 0.63, p < 0.001; R2 = 0.63, and 0.48, p < 0.001, respectively) and 24 h after (Spearman's rho = - 0.71, and - 0.65; p < 0.001; R2 = 0.66 and 0.60, p < 0.001, respectively). Other respiratory, macro-hemodynamic and oxygenation parameters did not correlate with VD/VT. Variations in PPV between baseline and 24 h were inverse and significantly related to simultaneous changes in VD/VT (Spearman's rho = - 0.66, p < 0.001; R2 = 0.67, p < 0.001). CONCLUSION Increased heterogeneity of microcirculatory blood flow evaluated at sublingual mucosa seems to be related to increases in VD/VT, while respiratory mechanics and oxygenation parameters do not. Whether there is a cause-effect relationship between microcirculatory dysfunction and dead-space ventilation in ARDS should be addressed in future research.
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Affiliation(s)
- Gustavo A Ospina-Tascón
- Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia. .,Translational Medicine Laboratory for Critical Care and Advanced Trauma Surgery, Fundación Valle del Lili - Universidad Icesi, Cali, Colombia.
| | - Diego F Bautista
- Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia
| | - Humberto J Madriñán
- Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia
| | - Juan D Valencia
- Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia
| | - William F Bermúdez
- Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia
| | - Edgardo Quiñones
- Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia
| | - Luis Eduardo Calderón-Tapia
- Department of Intensive Care, Fundación Valle del Lili - Universidad ICESI, Av. Simón Bolívar Cra. 98, Cali, Valle del Cauca, Colombia
| | - Glenn Hernandez
- Departamento de Medicina Intensiva, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alejandro Bruhn
- Departamento de Medicina Intensiva, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Daniel De Backer
- Department of Intensive Care, CHIREC Hospitals, Université Libre de Bruxelles, Brussels, Belgium
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37
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Sigmundsson TS, Öhman T, Hallbäck M, Redondo E, Sipmann FS, Wallin M, Oldner A, Hällsjö-Sander C, Björne H. Performance of a capnodynamic method estimating cardiac output during respiratory failure - before and after lung recruitment. J Clin Monit Comput 2019; 34:1199-1207. [PMID: 31745763 PMCID: PMC7548027 DOI: 10.1007/s10877-019-00421-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/12/2019] [Indexed: 01/06/2023]
Abstract
Respiratory failure may cause hemodynamic instability with strain on the right ventricle. The capnodynamic method continuously calculates cardiac output (CO) based on effective pulmonary blood flow (COEPBF) and could provide CO monitoring complementary to mechanical ventilation during surgery and intensive care. The aim of the current study was to evaluate the ability of a revised capnodynamic method, based on short expiratory holds (COEPBFexp), to estimate CO during acute respiratory failure (LI) with high shunt fractions before and after compliance-based lung recruitment. Ten pigs were submitted to lung lavage and subsequent ventilator-induced lung injury. COEPBFexp, without any shunt correction, was compared to a reference method for CO, an ultrasonic flow probe placed around the pulmonary artery trunk (COTS) at (1) baseline in healthy lungs with PEEP 5 cmH2O (HLP5), (2) LI with PEEP 5 cmH2O (LIP5) and (3) LI after lung recruitment and PEEP adjustment (LIPadj). CO changes were enforced during LIP5 and LIPadj to estimate trending. LI resulted in changes in shunt fraction from 0.1 (0.03) to 0.36 (0.1) and restored to 0.09 (0.04) after recruitment manoeuvre. Bias (levels of agreement) and percentage error between COEPBFexp and COTS changed from 0.5 (− 0.5 to 1.5) L/min and 30% at HLP5 to − 0.6 (− 2.3 to 1.1) L/min and 39% during LIP5 and finally 1.1 (− 0.3 to 2.5) L/min and 38% at LIPadj. Concordance during CO changes improved from 87 to 100% after lung recruitment and PEEP adjustment. COEPBFexp could possibly be used for continuous CO monitoring and trending in hemodynamically unstable patients with increased shunt and after recruitment manoeuvre.
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Affiliation(s)
- Thorir Svavar Sigmundsson
- Function Perioperative Medicine and Intensive Care, Karolinska University Hospital, 171 76, Solna, Stockholm, Sweden. .,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
| | - Tomas Öhman
- Function Perioperative Medicine and Intensive Care, Karolinska University Hospital, 171 76, Solna, Stockholm, Sweden.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | | | - Eider Redondo
- Department of Intensive Care Medicine, Complejo Hospitalario de Navarra, Pamplona, Spain
| | - Fernando Suarez Sipmann
- Department of Surgical Sciences, Section of Anaesthesiology and Critical Care, Hedenstierna's Laboratory, Uppsala University, Uppsala, Sweden.,CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Mats Wallin
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Maquet Critical Care AB, Solna, Sweden
| | - Anders Oldner
- Function Perioperative Medicine and Intensive Care, Karolinska University Hospital, 171 76, Solna, Stockholm, Sweden.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Caroline Hällsjö-Sander
- Function Perioperative Medicine and Intensive Care, Karolinska University Hospital, 171 76, Solna, Stockholm, Sweden.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Håkan Björne
- Function Perioperative Medicine and Intensive Care, Karolinska University Hospital, 171 76, Solna, Stockholm, Sweden.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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38
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Cracco O, Degrugilliers L, Rames C, Bécourt A, Bayat S. Change in capnogram waveform is associated with bronchodilator response and asthma control in children. Pediatr Pulmonol 2019; 54:698-705. [PMID: 30809972 DOI: 10.1002/ppul.24282] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/02/2019] [Accepted: 01/20/2019] [Indexed: 11/06/2022]
Abstract
BACKGROUND Airway hyper-reactivity, inflammation and remodeling contribute to inhomogeneity of ventilation-perfusion ratio VA·/Q· in asthma. Short-term variations in V.A/Q· can cause changes in expired capnographic indices. OBJECTIVES To measure acute changes in the phase 3 slope of the volumetric capnogram after β2-agonist inhalation (ΔSIII), for comparison with airway response based on FEV1 (ΔFEV1), and asthma control. SUBJECTS AND METHODS After ethical approval and informed consent, 72 children aged 6-18 y, followed up for asthma underwent spirometry and capnography before and after β-agonist inhalation through a spacer, using a side-stream rapid infrared analyzer. Asthma control was assessed using the GINA questionnaire. RESULTS Children with positive reversibility tests (defined as ΔFEV1>12%) had a significantly higher ΔSIII (m ± SE: 87.4 ± 41.4) versus those with negative tests (31.3 ± 14.0%, P = 0.001). Uncontrolled asthma was associated with a significantly larger ΔSIII (103.4 ± 64.0%, n = 7) compared to partly controlled (52.0 ± 26.1, n = 24; P = 0.009) and controlled asthma (30.8 ± 16.3, n = 41; P = 0.003). Neither Bohr dead space nor ΔFEV1 were different between asthma control groups. CONCLUSIONS ΔSIII was significantly larger in children with positive response to β2-agonist, and in uncontrolled asthmatics. To our knowledge these are the first data on exhaled CO2 phase III volumetric slope change and asthma control. The observed ΔSIII could be due to an increased ventilation of inhomogeneous peripheral lung units, and merits further evaluation as a potential phenotypic biomarker in asthma.
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Affiliation(s)
- Ophélie Cracco
- Department of Pediatric Pulmonology, Amiens University Hospital, Amiens, France
| | - Loïc Degrugilliers
- Department of Pediatric Intensive Care, Amiens University Hospital, Amiens, France
| | - Cynthia Rames
- Department of Pediatric Pulmonology, Amiens University Hospital, Amiens, France
| | - Arnaud Bécourt
- Department of Pediatric Pulmonology, Amiens University Hospital, Amiens, France
| | - Sam Bayat
- University of Grenoble Alps & Inserm UA7 STROBE Laboratory, Grenoble, France.,Department of Pulmonology and Physiology, Grenoble University Hospital, Grenoble, France
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39
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Clinical use of volumetric capnography in mechanically ventilated patients. J Clin Monit Comput 2019; 34:7-16. [PMID: 31152285 DOI: 10.1007/s10877-019-00325-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/21/2019] [Indexed: 10/26/2022]
Abstract
Capnography is a first line monitoring system in mechanically ventilated patients. Volumetric capnography supports noninvasive and breath-by-breath information at the bedside using mainstream CO2 and flow sensors placed at the airways opening. This volume-based capnography provides information of important body functions related to the kinetics of carbon dioxide. Volumetric capnography goes one step forward standard respiratory mechanics and provides a new dimension for monitoring of mechanical ventilation. The article discusses the role of volumetric capnography for the clinical monitoring of mechanical ventilation.
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40
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Gogniat E, Ducrey M, Dianti J, Madorno M, Roux N, Midley A, Raffo J, Giannasi S, San Roman E, Suarez-Sipmann F, Tusman G. Dead space analysis at different levels of positive end-expiratory pressure in acute respiratory distress syndrome patients. J Crit Care 2019; 45:231-238. [PMID: 29754942 DOI: 10.1016/j.jcrc.2018.01.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 01/03/2018] [Accepted: 01/07/2018] [Indexed: 01/25/2023]
Abstract
PURPOSE To analyze the effects of positive end-expiratory pressure (PEEP) on Bohr's dead space (VDBohr/VT) in patients with acute respiratory distress syndrome (ARDS). MATERIAL AND METHODS Fourteen ARDS patients under lung protective ventilation settings were submitted to 4 different levels of PEEP (0, 6, 10, 16 cmH2O). Respiratory mechanics, hemodynamics and volumetric capnography were recorded at each protocol step. RESULTS Two groups of patients responded differently to PEEP when comparing baseline with 16-PEEP: those in which driving pressure increased > 15% (∆P˃15%, n = 7, p = .016) and those in which the change was ≤15% (∆P≤15%, n = 7, p = .700). VDBohr/VT was higher in ∆P≤15% than in ∆P≤15% patients at baseline ventilation [0.58 (0.49-0.60) vs 0.46 (0.43-0.46) p = .018], at 0-PEEP [0.50 (0.47-0.54) vs 0.41 (0.40-0.43) p = .012], at 6-PEEP [0.55 (0.49-0.57) vs 0.44 (0.42-0.45) p = .008], at 10-PEEP [0.59 (0.51-0.59) vs 0.45 (0.44-0.46) p = .006] and at 16-PEEP [0.61 (0.56-0.65) vs 0.47 (0.45-0.48) p = .001]. We found a good correlation between ∆P and VDBohr/VT only in the ∆P˃15% group (r = 0.74, p < .001). CONCLUSIONS Increases in PEEP result in higher VDBohr/VT only when associated with an increase in driving pressure.
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Affiliation(s)
- Emiliano Gogniat
- Department of Intensive Care Medicine, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Marcela Ducrey
- Department of Intensive Care Medicine, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - José Dianti
- Department of Intensive Care Medicine, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Matías Madorno
- Instituto Tecnológico Buenos Aires (ITBA), Buenos Aires, Argentina
| | - Nicolás Roux
- Department of Intensive Care Medicine, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Alejandro Midley
- Department of Intensive Care Medicine, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Julio Raffo
- Department of Intensive Care Medicine, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Sergio Giannasi
- Department of Intensive Care Medicine, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Eduardo San Roman
- Department of Intensive Care Medicine, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Fernando Suarez-Sipmann
- Department of surgical Sciences, Section of Anesthesia and Critical Care, Uppsala University Hospital, Hedenstierna Laboratory, Uppsala, Sweden; CIBERES, Madrid, Spain; Servicio de Medicina Intensiva, Hospital Universitario y Politécnico La Fe, Valencia, Spain
| | - Gerardo Tusman
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina.
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Suarez-Sipmann F, Blanch L. Physiological Markers for Acute Respiratory Distress Syndrome: Let’s Get More Efficient! Am J Respir Crit Care Med 2019; 199:260-261. [DOI: 10.1164/rccm.201809-1653ed] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Fernando Suarez-Sipmann
- Hospital Universitario de la PrincesaUniversidad Autónoma de MadridMadrid, Spain
- Department of Surgical SciencesUppsala UniversityUppsala, Sweden
- CIBER Enfermedades RespiratoriasInstituto de Salud Carlos IIIMadrid, Spainand
| | - Lluís Blanch
- CIBER Enfermedades RespiratoriasInstituto de Salud Carlos IIIMadrid, Spainand
- Institut d’Investigació i Innovació Parc Taulí I3PTUniversitat Autònoma de BarcelonaSabadell, Spain
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42
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Gerber D, Vasireddy R, Varadarajan B, Hartwich V, Schär MY, Eberle B, Vogt A. Near-real-time pulmonary shunt and dead space measurement with micropore membrane inlet mass spectrometry in pigs with induced pulmonary embolism or acute lung failure. J Clin Monit Comput 2019; 33:1033-1041. [PMID: 30603824 DOI: 10.1007/s10877-018-00245-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/22/2018] [Indexed: 10/27/2022]
Abstract
The multiple inert gas elimination technique (MIGET) using gas chromatography (GC) is an established but time-consuming method of determining ventilation/perfusion (VA/Q) distributions. MIGET-when performed using Micropore Membrane Inlet Mass Spectrometry (MMIMS)-has been proven to correlate well with GC-MIGET and reduces analysis time substantially. We aimed at comparing shunt fractions and dead space derived from MMIMS-MIGET with Riley shunt and Bohr dead space, respectively. Thirty anesthetized pigs were randomly assigned to lavage or pulmonary embolism groups. Inert gas infusion (saline mixture of SF6, krypton, desflurane, enflurane, diethyl ether, acetone) was maintained, and after induction of lung damage, blood and breath samples were taken at 15-min intervals over 4 h. The samples were injected into the MMIMS, and resultant retention and excretion data were translated to VA/Q distributions. We compared MMIMS-derived shunt (MM-S) to Riley shunt, and MMIMS-derived dead space (MM-VD) to Bohr dead space in 349 data pairs. MM-S was on average lower than Riley shunt (- 0.05 ± 0.10), with lower and upper limits of agreement of - 0.15 and 0.04, respectively. MM-VD was on average lower than Bohr dead space (- 0.09 ± 0.14), with lower and upper limits of agreement of - 0.24 and 0.05. MM-S and MM-VD correlated and agreed well with Riley shunt and with Bohr dead space. MM-S increased significantly after lung injury only in the lavage group, whereas MM-VD increased significantly in both groups. This is the first work evaluating and demonstrating the feasibility of near real-time VA/Q distribution measurements with the MIGET and the MMIMS methods.
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Affiliation(s)
- D Gerber
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland
| | - R Vasireddy
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland
| | - B Varadarajan
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland
| | - V Hartwich
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland
| | - M Y Schär
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland
| | - B Eberle
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland
| | - A Vogt
- Department of Anaesthesiology and Pain Medicine, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland.
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van der Staay M, Chatburn RL. Advanced modes of mechanical ventilation and optimal targeting schemes. Intensive Care Med Exp 2018; 6:30. [PMID: 30136011 PMCID: PMC6104409 DOI: 10.1186/s40635-018-0195-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 07/30/2018] [Indexed: 11/26/2022] Open
Abstract
Recent research results provide new incentives to recognize and prevent ventilator-induced lung injury (VILI) and create targeting schemes for new modes of mechanical ventilation. For example, minimization of breathing power, inspiratory power, and inspiratory pressure are the underlying goals of optimum targeting schemes used in the modes called adaptive support ventilation (ASV), adaptive ventilation mode 2 (AVM2), and MID-frequency ventilation (MFV). We describe the mathematical models underlying these targeting schemes and present theoretical analyses for minimizing tidal volume, tidal pressure (also known as driving pressure), or tidal power as functions of ventilatory frequency. To go beyond theoretical equations, these targeting schemes were compared in terms of expected tidal volumes using different patient models. Results indicate that at the same ventilation efficiency (same PaCO2 level), we expect tidal volume dosage in the range of 7.4 mL/kg (for ASV), 6.2 mL/kg (for AVM2), and 6.7 mL/kg (for MFV) for adult ARDS simulation. For a neonatal RDS model, we expect 5.5 mL/kg (for ASV), 4.6 mL/kg (for AVM2), and 4.5 (for MFV).
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Balogh AL, Petak F, Fodor GH, Tolnai J, Csorba Z, Babik B. Capnogram slope and ventilation dead space parameters: comparison of mainstream and sidestream techniques. Br J Anaesth 2018; 117:109-17. [PMID: 27317710 DOI: 10.1093/bja/aew127] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2016] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Capnography may provide useful non-invasive bedside information concerning heterogeneity in lung ventilation, ventilation-perfusion mismatching and metabolic status. Although the capnogram may be recorded by mainstream and sidestream techniques, the capnogram indices furnished by these approaches have not previously been compared systematically. METHODS Simultaneous mainstream and sidestream time and volumetric capnography was performed in anaesthetized, mechanically ventilated patients undergoing elective heart surgery. Time capnography was used to assess the phase II (SII,T) and III slopes (SIII,T). The volumetric method was applied to estimate phase II (SII,V) and III slopes (SIII,V), together with the dead space values according to the Fowler (VDF), Bohr (VDB), and Enghoff (VDE) methods and the volume of CO2 eliminated per breath ([Formula: see text]). The partial pressure of end-tidal CO2 ([Formula: see text]) was registered. RESULTS Excellent correlation and good agreement were observed in SIII,T measured by the mainstream and sidestream techniques [ratio=1.05 (sem 0.16), R(2)=0.92, P<0.0001]. Although the sidestream technique significantly underestimated [Formula: see text] and overestimated SIII,V [1.32 (0.28), R(2)=0.93, P<0.0001], VDF, VDB, and VDE, the agreement between the mainstream and sidestream techniques in the difference between VDE and VDB, reflecting the intrapulmonary shunt, was excellent [0.97 (0.004), R(2)=0.92, P<0.0001]. The [Formula: see text] exhibited good correlation and mild differences between the mainstream and sidestream approaches [0.025 (0.005) kPa]. CONCLUSIONS Sidestream capnography provides adequate quantitative bedside information about uneven alveolar emptying and ventilation-perfusion mismatching, because it allows reliable assessments of the phase III slope, [Formula: see text] and intrapulmonary shunt. Reliable measurement of volumetric parameters (phase II slope, dead spaces, and eliminated CO2 volumes) requires the application of a mainstream device.
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Affiliation(s)
- A L Balogh
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, 6 Semmelweis u. H-6725, Szeged, Hungary Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, H-6720, Szeged, Hungary
| | - F Petak
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, H-6720, Szeged, Hungary
| | - G H Fodor
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, H-6720, Szeged, Hungary
| | - J Tolnai
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, H-6720, Szeged, Hungary
| | - Z Csorba
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, 6 Semmelweis u. H-6725, Szeged, Hungary
| | - B Babik
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, 6 Semmelweis u. H-6725, Szeged, Hungary
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Mosing M, Böhm SH, Rasis A, Hoosgood G, Auer U, Tusman G, Bettschart-Wolfensberger R, Schramel JP. Physiologic Factors Influencing the Arterial-To-End-Tidal CO 2 Difference and the Alveolar Dead Space Fraction in Spontaneously Breathing Anesthetised Horses. Front Vet Sci 2018; 5:58. [PMID: 29644221 PMCID: PMC5882784 DOI: 10.3389/fvets.2018.00058] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/12/2018] [Indexed: 01/21/2023] Open
Abstract
The arterial to end-tidal CO2 difference (P(a-ET)CO2) and alveolar dead space fraction (VDalvfrac = P(a-ET)CO2/PaCO2), are used to estimate Enghoff's "pulmonary dead space" (V/QEng), a factor which is also influenced by venous admixture and other pulmonary perfusion abnormalities and thus is not just a measure of dead space as the name suggests. The aim of this experimental study was to evaluate which factors influence these CO2 indices in anesthetized spontaneously breathing horses. Six healthy adult horses were anesthetized in dorsal recumbency breathing spontaneously for 3 h. Data to calculate the CO2 indices (response variables) and dead space variables were measured every 30 min. Bohr's physiological and alveolar dead space variables, cardiac output (CO), mean pulmonary pressure (MPP), venous admixture [Formula: see text], airway dead space, tidal volume, oxygen consumption, and slope III of the volumetric capnogram were evaluated (explanatory variables). Univariate Pearson correlation was first explored for both CO2 indices before V/QEng and the explanatory variables with rho were reported. Multiple linear regression analysis was performed on P(a-ET)CO2 and VDalvfrac assessing which explanatory variables best explained the variance in each response. The simplest, best-fit model was selected based on the maximum adjusted R2 and smallest Mallow's p (Cp). The R2 of the selected model, representing how much of the variance in the response could be explained by the selected variables, was reported. The highest correlation was found with the alveolar part of V/QEng to alveolar tidal volume ratio for both, P(a-ET)CO2 (r = 0.899) and VDalvfrac (r = 0.938). Venous admixture and CO best explained P(a-ET)CO2 (R2 = 0.752; Cp = 4.372) and VDalvfrac (R2 = 0.711; Cp = 9.915). Adding MPP (P(a-ET)CO2) and airway dead space (VDalvfrac) to the models improved them only marginally. No "real" dead space variables from Bohr's equation contributed to the explanation of the variance of the two CO2 indices. P(a-ET)CO2 and VDalvfrac were closely associated with the alveolar part of V/QEng and as such, were also influenced by variables representing a dysfunctional pulmonary perfusion. Neither P(a-ET)CO2 nor VDalvfrac should be considered pulmonary dead space, but used as global indices of V/Q mismatching under the described conditions.
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Affiliation(s)
- Martina Mosing
- College of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Stephan H Böhm
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
| | - Anthea Rasis
- College of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Giselle Hoosgood
- College of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Ulrike Auer
- Anaesthesiology and Perioperative Intensive Care Medicine, Veterinary University Vienna, Vienna, Austria
| | - Gerardo Tusman
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
| | | | - Johannes P Schramel
- Anaesthesiology and Perioperative Intensive Care Medicine, Veterinary University Vienna, Vienna, Austria
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Kacmarek RM, Villar J, Berra L. Exhaled CO 2, a guide to ARDS management during lung-protective ventilation? J Crit Care 2018; 45:229-230. [PMID: 29550109 PMCID: PMC9170239 DOI: 10.1016/j.jcrc.2018.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 03/05/2018] [Indexed: 11/26/2022]
Affiliation(s)
- Robert M Kacmarek
- Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
| | - Jesús Villar
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain; Multidisciplinary Organ Dysfunction Evaluation Research Network, Research Unit, Hospital Universitario Dr. Negrín, Las Palmas de Gran Canaria, Spain.
| | - Lorenzo Berra
- Massachusetts General Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
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Modrin A, Gilbert ML. De l’entrée à la sortie du service de réanimation adulte : une mise au point sur l’utilisation courante du monitoring du CO 2 expiré. MEDECINE INTENSIVE REANIMATION 2018. [DOI: 10.3166/rea-2018-0018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
L’objectif de cette mise au point est d’effectuer une revue des indications de l’utilisation du monitorage du CO2 expiré en réanimation adulte. De par sa physiologie, sa mesure est un reflet de l’état hémodynamique, respiratoire et métabolique du patient. La spectrométrie infrarouge est la méthode de mesure la plus courante. La capnographie commune (CO2 expiré en fonction du temps) est divisée en plusieurs phases dont l’analyse visuelle peut faire évoquer de nombreuses anomalies ventilatoires. La capnographie volumétrique fournit une mesure de l’espace mort. La capnométrie est recommandée en réanimation pour contrôler l’intubation trachéale ou bien au cours d’un arrêt cardiorespiratoire comme facteur pronostique. Tout patient traité par ventilation mécanique invasive, surtout lors d’un transport, doit être équipé d’un capnomètre afin d’anticiper toute complication respiratoire (extubation, bronchospasme, hypoventilation). La pression de fin d’expiration en CO2 (PetCO2) est une évaluation de la pression artérielle en CO2 (PaCO2) utile pour limiter le nombre de prélèvements biologiques, par exemple en neuroréanimation, mais de nombreux facteurs font varier le gradient entre ces deux valeurs. Les études n’apportent pas de preuve pour l’utilisation de la capnographie volumétrique dans le diagnostic d’embolie pulmonaire en réanimation. Chez les patients souffrant de syndrome de détresse respiratoire aiguë, la littérature médicale n’apporte pas de preuve suffisante pour un intérêt en pratique clinique courante de la capnométrie volumétrique qui semble limitée dans ce cas à la recherche.
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48
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Tusman G, Suarez-Sipmann F. In Response. Anesth Analg 2018; 123:1332-1333. [PMID: 27644055 DOI: 10.1213/ane.0000000000001491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Gerardo Tusman
- Department of Anesthesia, Hospital Privado de Comunidad, Mar del Plata, Buenos Aires, Argentina, Department of Surgical Sciences section of Anesthesiology and Critical Care, Hedenstierna Laboratory, University Hospital, Uppsala, Sweden, CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
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Li W, Pauluhn J. Phosgene-induced acute lung injury (ALI): differences from chlorine-induced ALI and attempts to translate toxicology to clinical medicine. Clin Transl Med 2017; 6:19. [PMID: 28577109 PMCID: PMC5457389 DOI: 10.1186/s40169-017-0149-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 05/15/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Phosgene (carbonyl dichloride) gas is an indispensable chemical inter-mediate used in numerous industrial processes. There is no clear consensus as to its time- and inhaled-dose-dependent etiopathologies and associated preventive or therapeutic treatment strategies. METHODS Cardiopulmonary function was examined in rats exposed by inhalation to the alveolar irritant phosgene or to the airway irritant chlorine during and following exposure. Terminal measurements focused on hematology, protein extravasation in bronchoalveolar lavage (BAL), and increased lung weight. Noninvasive diagnostic and prognostic endpoints in exhaled breath (carbon dioxide and nitric oxide) were used to detect the clinically occult stage of pulmonary edema. RESULTS The first event observed in rats following high but sublethal acute exposure to phosgene was the stimulation of alveolar nociceptive vagal receptors. This afferent stimulation resulted in dramatic changes in cardiopulmonary functions, ventilation: perfusion imbalances, and progressive pulmonary edema and phospholipoproteinosis. Hematology revealed hemoconcentration to be an early marker of pulmonary edema and fibrin as a discriminating endpoint that was positive for the airway irritant chlorine and negative for the alveolar irritant phosgene. CONCLUSIONS The application of each gas produced typical ALI/ARDS (acute lung injury/acute respiratory distress syndrome) characteristics. Phosgene-induced ALI showed evidence of persistent apnea periods, bradycardia, and shifts of vascular fluid from the peripheral to the pulmonary circulation. Carbon dioxide in expired gas was suggestive of increased ventilation dead space and appeared to be a harbinger of progressively developing lung edema. Treatment with the iNOS inhibitor aminoguanidine aerosol by inhalation reduced the severity of phosgene-induced ALI when applied at low dose-rates. Symptomatic treatment regimens were considered inferior to causal modes of treatment.
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Affiliation(s)
- Wenli Li
- 4th Department of Toxicology, Fourth Military Medical University, No. 169 Changle West Road, Xi’an, 710032 Shaanxi Province China
| | - Juergen Pauluhn
- 4th Department of Toxicology, Fourth Military Medical University, No. 169 Changle West Road, Xi’an, 710032 Shaanxi Province China
- Covestro Deutschland AG, Global Phosgene Steering Group, K9, 565, 51365 Leverkusen, Germany
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Goligher EC, Amato MBP, Slutsky AS. Applying Precision Medicine to Trial Design Using Physiology. Extracorporeal CO 2 Removal for Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med 2017. [PMID: 28636403 DOI: 10.1164/rccm.201701-0248cp] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In clinical trials of therapies for acute respiratory distress syndrome (ARDS), the average treatment effect in the study population may be attenuated because individual patient responses vary widely. This inflates sample size requirements and increases the cost and difficulty of conducting successful clinical trials. One solution is to enrich the study population with patients most likely to benefit, based on predicted patient response to treatment (predictive enrichment). In this perspective, we apply the precision medicine paradigm to the emerging use of extracorporeal CO2 removal (ECCO2R) for ultraprotective ventilation in ARDS. ECCO2R enables reductions in tidal volume and driving pressure, key determinants of ventilator-induced lung injury. Using basic physiological concepts, we demonstrate that dead space and static compliance determine the effect of ECCO2R on driving pressure and mechanical power. This framework might enable prediction of individual treatment responses to ECCO2R. Enriching clinical trials by selectively enrolling patients with a significant predicted treatment response can increase treatment effect size and statistical power more efficiently than conventional enrichment strategies that restrict enrollment according to the baseline risk of death. To support this claim, we simulated the predicted effect of ECCO2R on driving pressure and mortality in a preexisting cohort of patients with ARDS. Our computations suggest that restricting enrollment to patients in whom ECCO2R allows driving pressure to be decreased by 5 cm H2O or more can reduce sample size requirement by more than 50% without increasing the total number of patients to be screened. We discuss potential implications for trial design based on this framework.
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Affiliation(s)
- Ewan C Goligher
- 1 Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada.,2 Division of Respirology, Department of Medicine, University Health Network and Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Marcelo B P Amato
- 3 Laboratório de Pneumologia LIM-09, Disciplina de Pneumologia, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil; and
| | - Arthur S Slutsky
- 1 Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada.,4 Keenan Centre for Biomedical Research, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada
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