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García-Sanz V, Canfrán S, Gómez de Segura IA, Aguado D. Effect of end-inspiratory pause duration on respiratory system compliance calculation in mechanically ventilated dogs with healthy lungs. Vet Anaesth Analg 2024; 51:333-342. [PMID: 38772855 DOI: 10.1016/j.vaa.2024.03.009] [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: 02/21/2022] [Revised: 03/01/2024] [Accepted: 03/20/2024] [Indexed: 05/23/2024]
Abstract
OBJECTIVE To compare respiratory system compliance (CRS), expressed per kilogram of bodyweight (CRSBW), calculated without end-inspiratory pause (EIP) and after three EIP times (0.2, 0.5 and 1 seconds) with that after 3 second EIP (considered the reference EIP for static CRS) and to determine the EIP times that provided CRSBW values in acceptable agreement with static CRSBW during controlled mechanical ventilation (CMV) in anaesthetized dogs. STUDY DESIGN Prospective, randomized, nonblinded, crossover clinical study. ANIMALS A group of 24 client-owned dogs with healthy lungs undergoing surgery in lateral recumbency. METHODS During CMV in dogs undergoing general anaesthesia, five EIPs [0 (no EIP), 0.2, 0.5, 1 and 3 seconds] were consecutively applied in random order. Tidal volume (Vt) was set at 10 mL kg-1 and positive end-expiratory pressure (PEEP) was not applied. Respiratory rate and inspiratory time were established according to each EIP time, setting EIP between 0 and 50% of the inspiratory time. The CRSBW was calculated as [expired Vt/(plateau pressure - PEEP)]/bodyweight and recorded every 15 seconds for 2 minutes after a 5 minute equilibration period with each EIP. One-way anova for repeated measures and the Bland-Altman analysis were used to compare CRSBW and evaluate agreement between EIP times, respectively. RESULTS The CRSBW was significantly greater as the EIP time increased up to 1 second (p < 0.05). In the Bland-Altman analysis, none of the tested EIPs (0, 0.2, 0.5 and 1 seconds) provided 95% confidence intervals for limits of agreement within the maximum allowed difference considered for acceptable agreement with 3 second EIP. CONCLUSIONS and clinical relevance An EIP ≤ to 1 second does not provide a CRSBW value in acceptable agreement with static CRSBW in healthy dogs. Besides, the application of an EIP ≤ to 0.5 seconds underestimates the static CRSBW to an increasing extent as the EIP time decreases.
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Affiliation(s)
- Virginia García-Sanz
- Department of Animal Medicine and Surgery, Veterinary Teaching Hospital, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain
| | - Susana Canfrán
- Department of Animal Medicine and Surgery, Veterinary Teaching Hospital, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain.
| | - Ignacio A Gómez de Segura
- Department of Animal Medicine and Surgery, Veterinary Teaching Hospital, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain
| | - Delia Aguado
- Department of Animal Medicine and Surgery, Veterinary Teaching Hospital, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain
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Ben-Aderet D, Soares JH, Bueno ML. Effect of increased resistance on dynamic compliance assessed by two clinical monitors during volume-controlled ventilation: A test-lung study. Vet Anaesth Analg 2024; 51:322-332. [PMID: 38677969 DOI: 10.1016/j.vaa.2024.03.003] [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: 08/29/2023] [Revised: 02/12/2024] [Accepted: 03/04/2024] [Indexed: 04/29/2024]
Abstract
OBJECTIVE To evaluate the effect of increased respiratory system resistance (RRS) on dynamic compliance (Cdyn) assessed by the NM3 monitor (Cdyn(NM3)) and the E-CAiOV module (Cdyn(ECAiOV)). STUDY DESIGN Prospective laboratory study. METHODS A training test lung (TTL) simulated the mechanical ventilation of a mammal with 50 and 300 mL tidal volumes in three conditions of RRS [normal (RBL), moderately increased (R1) and severely increased (R2)] and a wide range of clinically relevant Cdyn. Simulations at increased RRS were paired with simulations at RBL with the same static compliance for comparisons. Pearson's correlation coefficient and concordance correlation coefficient between the measurements at RBL with the ones with increased RRS were calculated. Bland-Altman plots were also used to evaluate the agreement of Cdyn(ECAiOV) and Cdyn(NM3) at RBL (control values) with their paired values at R1 and R2. Relative bias and limits of agreement (LOAs) were calculated and LOAs larger than 30% were considered unacceptable. Trending ability of Cdyn(NM3) and Cdyn(ECAiOV) were evaluated by polar plots. Values of p < 0.05 were considered significant. RESULTS The effect of increased RRS was more pronounced for Cdyn(ECAiOV) than for Cdyn(NM3). Unacceptable agreement was only observed in Cdyn(NM3) at R2 in the 300 mL simulation (bias = -18.3% and lower LOA = -45%). For Cdyn(ECAiOV), agreement was unacceptable for all tested RRS in both simulations, being the worst at R2 in the 300 mL simulation (bias = -54.7% and lower LOA = -100.2%). Both levels of increased RRS caused poor trending ability for Cdyn(ECAiOV), whereas the same effect was only observed for Cdyn(NM3) at R2. CONCLUSIONS AND CLINICAL RELEVANCE In the presence of increased RRS, Cdyn estimated by the NM3 monitor presented better capability to distinguish between changes in RRS from changes in respiratory system compliance.
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Affiliation(s)
- Daniel Ben-Aderet
- William Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - João Hn Soares
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
| | - Melissa Lc Bueno
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
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Yue H, Yong T. Progress in the relationship between mechanical ventilation parameters and ventilator-related complications during perioperative anesthesia. Postgrad Med J 2024:qgae035. [PMID: 38507221 DOI: 10.1093/postmj/qgae035] [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: 10/12/2023] [Revised: 01/27/2024] [Accepted: 02/13/2024] [Indexed: 03/22/2024]
Abstract
BACKGROUND Mechanical ventilation, as an important respiratory support, plays an important role in general anesthesia and it is the cornerstone of intraoperative management of surgical patients. Different from spontaneous respiration, intraoperative mechanical ventilation can lead to postoperative lung injury, and its impact on surgical mortality cannot be ignored. Postoperative lung injury increases hospital stay and is related to preoperative conditions, anesthesia time, and intraoperative ventilation settings. METHOD Through reading literature and research reports, the relationship between perioperative input parameters and output parameters related to mechanical ventilation and ventilator-related complications was reviewed, providing reference for the subsequent setting of input parameters of mechanical ventilation and new ventilation strategies. RESULTS The parameters of inspiratory pressure rise time and inspiratory time can change the gas distribution, gas flow rate and airway pressure into the lungs, but there are few clinical studies on them. It can be used as a prospective intervention to study the effect of specific protective ventilation strategies on pulmonary complications after perioperative anesthesia. CONCLUSION There are many factors affecting lung function after perioperative mechanical ventilation. Due to the difference of human body, the ventilation parameters suitable for each patient are different, and the deviation of each ventilation parameter can lead to postoperative pulmonary complications. Inspiratory pressure rise time and inspiratory time will be used as the new ventilation strategy.
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Affiliation(s)
- Hu Yue
- Department of Anesthesia Operation, The First People's Hospital of Shuangliu District, Chengdu (West China Airport Hospital of Sichuan University), Chengdu 610200, China
| | - Tao Yong
- Department of Anesthesia Operation, The First People's Hospital of Shuangliu District, Chengdu (West China Airport Hospital of Sichuan University), Chengdu 610200, China
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Scharffenberg M, Mandelli M, Bluth T, Simonassi F, Wittenstein J, Teichmann R, Birr K, Kiss T, Ball L, Pelosi P, Schultz MJ, Gama de Abreu M, Huhle R. Respiratory mechanics and mechanical power during low vs. high positive end-expiratory pressure in obese surgical patients - A sub-study of the PROBESE randomized controlled trial. J Clin Anesth 2024; 92:111242. [PMID: 37833194 DOI: 10.1016/j.jclinane.2023.111242] [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: 06/08/2023] [Revised: 08/21/2023] [Accepted: 08/26/2023] [Indexed: 10/15/2023]
Abstract
STUDY OBJECTIVE We aimed to characterize intra-operative mechanical ventilation with low or high positive end-expiratory pressure (PEEP) and recruitment manoeuvres (RM) regarding intra-tidal recruitment/derecruitment and overdistension using non-linear respiratory mechanics, and mechanical power in obese surgical patients enrolled in the PROBESE trial. DESIGN Prospective, two-centre substudy of the international, multicentre, two-arm, randomized-controlled PROBESE trial. SETTING Operating rooms of two European University Hospitals. PATIENTS Forty-eight adult obese patients undergoing abdominal surgery. INTERVENTIONS Intra-operative protective ventilation with either PEEP of 12 cmH2O and repeated RM (HighPEEP+RM) or 4 cmH2O without RM (LowPEEP). MEASUREMENTS The index of intra-tidal recruitment/de-recruitment and overdistension (%E2) as well as airway pressure, tidal volume (VT), respiratory rate (RR), resistance, elastance, and mechanical power (MP) were calculated from respiratory signals recorded after anesthesia induction, 1 h thereafter, and end of surgery (EOS). MAIN RESULTS Twenty-four patients were analyzed in each group. PEEP was higher (mean ± SD, 11.7 ± 0.4 vs. 3.7 ± 0.6 cmH2O, P < 0.001) and driving pressure lower (12.8 ± 3.5 vs. 21.7 ± 6.8 cmH2O, P < 0.001) during HighPEEP+RM than LowPEEP, while VT and RR did not differ significantly (7.3 ± 0.6 vs. 7.4 ± 0.8 ml∙kg-1, P = 0.835; and 14.6 ± 2.5 vs. 15.7 ± 2.0 min-1, P = 0.150, respectively). %E2 was higher in HighPEEP+RM than in LowPEEP following induction (-3.1 ± 7.2 vs. -12.4 ± 10.2%; P < 0.001) and subsequent timepoints. Total resistance and elastance (13.3 ± 3.8 vs. 17.7 ± 6.8 cmH2O∙l∙s-2, P = 0.009; and 15.7 ± 5.5 vs. 28.5 ± 8.4 cmH2O∙l, P < 0.001, respectively) were lower during HighPEEP+RM than LowPEEP. Additionally, MP was lower in HighPEEP+RM than LowPEEP group (5.0 ± 2.2 vs. 10.4 ± 4.7 J∙min-1, P < 0.001). CONCLUSIONS In this sub-cohort of PROBESE, intra-operative ventilation with high PEEP and RM reduced intra-tidal recruitment/de-recruitment as well as driving pressure, elastance, resistance, and mechanical power, as compared with low PEEP. TRIAL REGISTRATION The PROBESE study was registered at www. CLINICALTRIALS gov, identifier: NCT02148692 (submission for registration on May 23, 2014).
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Affiliation(s)
- Martin Scharffenberg
- Department of Anaesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
| | - Maura Mandelli
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Largo Rosanna Benzi 8, 16131 Genoa, Italy
| | - Thomas Bluth
- Department of Anaesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
| | - Francesca Simonassi
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Largo Rosanna Benzi 8, 16131 Genoa, Italy
| | - Jakob Wittenstein
- Department of Anaesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
| | - Robert Teichmann
- Department of Anaesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
| | - Katharina Birr
- Department of Anaesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
| | - Thomas Kiss
- Department of Anaesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden, Germany; Department of Anaesthesiology, Intensive-, Pain- and Palliative Care Medicine, Radebeul Hospital, Academic Hospital of the Technische Universität Dresden, Heinrich-Zille-Strasse 13, 01445 Radebeul, Germany
| | - Lorenzo Ball
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Largo Rosanna Benzi 8, 16131 Genoa, Italy; Anesthesia and Critical Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, Largo Rosanna Benzi, 10, 16132 Genoa, Italy
| | - Paolo Pelosi
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Largo Rosanna Benzi 8, 16131 Genoa, Italy; Anesthesia and Critical Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, Largo Rosanna Benzi, 10, 16132 Genoa, Italy
| | - Marcus J Schultz
- Department of Intensive Care, Laboratory of Experimental Intensive Care & Anesthesiology (L E I C A), Amsterdam University Medical Centers, location AMC, Meibergdreef 9, 1105 AZ Amsterdam, Netherlands
| | - Marcelo Gama de Abreu
- Department of Anaesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden, Germany; Department of Intensive Care and Resuscitation, Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, 44195, OH, USA; Department of Outcomes Research, Anesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, 44195, OH, USA.
| | - Robert Huhle
- Department of Anaesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden, Germany
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da Silva K, Oliveira CC, Cabral LF, Malaguti C, José A. Pulmonary expansion manoeuvres compared to usual care on ventilatory mechanics, oxygenation, length of mechanical ventilation and hospital stay, extubation, atelectasis, and mortality of patients in mechanical ventilation: A randomized clinical trial. PLoS One 2023; 18:e0295775. [PMID: 38079432 PMCID: PMC10712844 DOI: 10.1371/journal.pone.0295775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 11/10/2023] [Indexed: 12/18/2023] Open
Abstract
Pulmonary expansion manoeuvres are therapeutic techniques used to prevent and reverse atelectasis; however, no randomized controlled trials have provided evidence supporting the use of this intervention among individuals on mechanical ventilation. OBJECTIVE To evaluate the effects of chest compression-decompression and chest block manoeuvres compared to usual care among patients on mechanical ventilation. METHODS The current study was a randomized clinical trial of adult subjects on mechanical ventilation for 12 to 48 hours. The control group received usual care (passive or active mobilization, manoeuvres for airway clearance and tracheal aspiration). The intervention group received usual care plus two lung expansion manoeuvres, i.e., chest decompression and chest block, while remaining on mechanical ventilation. Assessments were performed before and after usual care, immediately after the intervention and 30 minutes after the intervention. The primary outcome was static compliance. The secondary outcomes were the incidence of atelectasis, dynamic compliance, airway resistance, driving pressure, oxygenation, duration of mechanical ventilation, extubation success, length of hospital and ICU stay, and mortality. RESULTS Fifty-one participants (67±15 years old, 53% men, 26 in the control group and 25 in the intervention group) were evaluated. No differences in static compliance were observed between groups (intervention minus control) before and after expansion manoeuvres [3.64 ml/cmH2O (95% CI: -0.36-7.65, p = 0.074)]. Peripheral oxygen saturation differed between groups before and after expansion manoeuvres, with more favourable outcome observed in the control group [-1.04% (95% CI: -1.94 --0.14), p = 0.027]. No differences were found in other outcomes. CONCLUSION Chest compression-decompression and chest block manoeuvres did not improve ventilatory mechanics, the incidence of atelectasis, oxygenation, the duration of mechanical ventilation, the length of stay in the ICU and hospital, or mortality in individuals on mechanical ventilation. The findings of this study can be valuable for guiding evidence-based clinical practice and developing a therapeutic approach that provides real benefits for this population.
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Affiliation(s)
- Karina da Silva
- Postgraduate Program in Rehabilitation Sciences and Physical Functional Performance, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
| | - Cristino Carneiro Oliveira
- Postgraduate Program in Rehabilitation Sciences and Physical Functional Performance, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
| | - Leandro Ferracini Cabral
- Department of Cardiorespiratory and Musculoskeletal Physiotherapy, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
| | - Carla Malaguti
- Postgraduate Program in Rehabilitation Sciences and Physical Functional Performance, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
| | - Anderson José
- Postgraduate Program in Rehabilitation Sciences and Physical Functional Performance, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil
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Chudow MB, Condeni MS, Dhar S, Heavner MS, Nei AM, Bissell BD. Current Practice Review in the Management of Acute Respiratory Distress Syndrome. J Pharm Pract 2023; 36:1454-1471. [PMID: 35728076 DOI: 10.1177/08971900221108713] [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] [Indexed: 12/15/2022]
Abstract
Acute respiratory distress syndrome (ARDS) presents as an acute inflammatory lung injury characterized by refractory hypoxemia and non-cardiac pulmonary edema. An estimated 10% of patients in the intensive care unit and 25% of those who are mechanically ventilated are diagnosed with ARDS. Increased awareness is warranted as mortality rates remain high and delays in diagnosing ARDS are common. The COVID-19 pandemic highlights the importance of understanding ARDS management. Treatment of ARDS can be challenging due to the complexity of the disease state and conflicting existing evidence. Therefore, it is imperative that pharmacists understand both pharmacologic and non-pharmacologic treatment strategies to optimize patient care. This narrative review provides a critical evaluation of current literature describing management practices for ARDS. A review of treatment modalities and supportive care strategies will be presented.
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Affiliation(s)
- Melissa B Chudow
- Department of Pharmacotherapeutics and Clinical Research, University of South Florida Taneja College of Pharmacy, Tampa, FL, USA
| | - Melanie S Condeni
- MUSC College of Pharmacy, Medical University of South Carolina, Charleston, SC, USA
| | - Sanjay Dhar
- Pulmonary Critical Care Ultrasound and Research, Pulmonary and Critical Care Fellowship Program, Division of Pulmonary, Critical Care & Sleep Medicine, University of Kentucky, Lexington, KY, USA
| | - Mojdeh S Heavner
- Department of Pharmacy Practice and Science, University of Maryland School of Pharmacy, Baltimore, MD, USA
| | - Andrea M Nei
- Mayo Clinic College of Medicine & Science, Critical Care Pharmacist, Department of Pharmacy, Mayo Clinic Hospital, Rochester, MN, USA
| | - Brittany D Bissell
- Department of Pharmacy Practice and Science, College of Pharmacy, University of Kentucky, Lexington, KY, USA
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Chen Y, Yuan Y, Zhang H, Li F. Accuracy of the estimations of respiratory mechanics using an expiratory time constant in passive and active breathing conditions: a bench study. Eur J Med Res 2023; 28:195. [PMID: 37355638 DOI: 10.1186/s40001-023-01146-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 05/23/2023] [Indexed: 06/26/2023] Open
Abstract
BACKGROUND Respiratory mechanics monitoring provides useful information for guiding mechanical ventilation, but many measuring methods are inappropriate for awake patients. This study aimed to evaluate the accuracy of dynamic mechanics estimation using expiratory time constant (RCexp) calculation during noninvasive pressure support ventilation (PSV) with air leak in different lung models. METHODS A Respironics V60 ventilator was connected to an active breathing simulator for modeling five profiles: normal adult, restrictive, mildly and severely obstructive, and mixed obstructive/restrictive. Inspiratory pressure support was adjusted to maintain tidal volumes (VT), achieving 5.0, 7.0, and 10.0 ml/kg body weight. PEEP was set at 5 cmH2O, and the back-up rate was 10 bpm. Measurements were conducted at system leaks of 25-28 L/min. RCexp was estimated from the ratio at 75% exhaled VT and flow rate, which was then used to determine respiratory system compliance (Crs) and airway resistance (Raw). RESULTS In non-obstructive conditions (Raw ≤ 10 cmH2O/L/s), the Crs was overestimated in the PSV mode. Peak inspiratory and expiratory flow and VT increased with PS levels, as calculated Crs decreased. In passive breathing, the difference of Crs between different VT was no significant. Underestimations of inspiratory resistance and expiratory resistance were observed at VT of 5.0 ml/kg. The difference was minimal at VT of 7.0 ml/kg. During non-invasive PSV, the estimation of airway resistance with the RCexp method was accurately at VT of 7.0 ml/kg. CONCLUSIONS The difference between the calculated Crs and the preset value was influenced by the volume, status and inspiratory effort in spontaneously breathing.
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Affiliation(s)
- Yuqing Chen
- Department of Respiratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, 200030, China.
| | - Yueyang Yuan
- School of Mechanical and Electrical Engineering, Hu Nan City University, Yi Yang, 413099, China
| | - Hai Zhang
- Department of Respiratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Feng Li
- Department of Respiratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, 200030, China
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Angus SA, Henderson WR, Banoei MM, Molgat‐Seon Y, Peters CM, Parmar HR, Griesdale DEG, Sekhon M, Sheel AW, Winston BW, Dominelli PB. Therapeutic hypothermia attenuates physiologic, histologic, and metabolomic markers of injury in a porcine model of acute respiratory distress syndrome. Physiol Rep 2022; 10:e15286. [PMID: 35510328 PMCID: PMC9069168 DOI: 10.14814/phy2.15286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 03/29/2022] [Accepted: 04/02/2022] [Indexed: 06/14/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a lung injury characterized by noncardiogenic pulmonary edema and hypoxic respiratory failure. The purpose of this study was to investigate the effects of therapeutic hypothermia on short-term experimental ARDS. Twenty adult female Yorkshire pigs were divided into four groups (n = 5 each): normothermic control (C), normothermic injured (I), hypothermic control (HC), and hypothermic injured (HI). Acute respiratory distress syndrome was induced experimentally via intrapulmonary injection of oleic acid. Target core temperature was achieved in the HI group within 1 h of injury induction. Cardiorespiratory, histologic, cytokine, and metabolomic data were collected on all animals prior to and following injury/sham. All data were collected for approximately 12 h from the beginning of the study until euthanasia. Therapeutic hypothermia reduced injury in the HI compared to the I group (histological injury score = 0.51 ± 0.18 vs. 0.76 ± 0.06; p = 0.02) with no change in gas exchange. All groups expressed distinct phenotypes, with a reduction in pro-inflammatory metabolites, an increase in anti-inflammatory metabolites, and a reduction in inflammatory cytokines observed in the HI group compared to the I group. Changes to respiratory system mechanics in the injured groups were due to increases in lung elastance (E) and resistance (R) (ΔE from pre-injury = 46 ± 14 cmH2 O L-1 , p < 0.0001; ΔR from pre-injury: 3 ± 2 cmH2 O L-1 s- , p = 0.30) rather than changes to the chest wall (ΔE from pre-injury: 0.7 ± 1.6 cmH2 O L-1 , p = 0.99; ΔR from pre-injury: 0.6 ± 0.1 cmH2 O L-1 s- , p = 0.01). Both control groups had no change in respiratory mechanics. In conclusion, therapeutic hypothermia can reduce markers of injury and inflammation associated with experimentally induced short-term ARDS.
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Affiliation(s)
- Sarah A. Angus
- Department of KinesiologyUniversity of WaterlooWaterlooOntarioCanada
| | - William R. Henderson
- Division of Critical Care MedicineDepartment of MedicineFaculty of MedicineUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Mohammad M. Banoei
- Department of Critical Care MedicineUniversity of CalgaryCalgaryAlbertaCanada
| | - Yannick Molgat‐Seon
- Department Kinesiology and Applied HealthUniversity of WinnipegWinnipegManitobaCanada
| | - Carli M. Peters
- School of KinesiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Hanna R. Parmar
- School of KinesiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Donald E. G. Griesdale
- Division of Critical Care MedicineDepartment of MedicineFaculty of MedicineUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of AnesthesiologyPharmacology & TherapeuticsUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Mypinder Sekhon
- Division of Critical Care MedicineDepartment of MedicineFaculty of MedicineUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Andrew William Sheel
- School of KinesiologyUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Brent W. Winston
- Department of Critical Care MedicineUniversity of CalgaryCalgaryAlbertaCanada
- Departments of Medicine and Biochemistry & Molecular BiologyUniversity of CalgaryCalgaryAlbertaCanada
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Kramek-Romanowska K, Stecka AM, Zieliński K, Dorosz A, Okrzeja P, Michnikowski M, Odziomek M. Independent Lung Ventilation-Experimental Studies on a 3D Printed Respiratory Tract Model. MATERIALS 2021; 14:ma14185189. [PMID: 34576415 PMCID: PMC8472474 DOI: 10.3390/ma14185189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 12/04/2022]
Abstract
Independent lung ventilation (ILV) is a life-saving procedure in unilateral pulmonary pathologies. ILV is underused in clinical practice, mostly due to the technically demanding placement of a double lumen endotracheal tube (ETT). Moreover, the determination of ventilation parameters for each lung in vivo is limited. In recent years, the development of 3D printing techniques enabled the production of highly accurate physical models of anatomical structures used for in vitro research, considering the high risk of in vivo studies. The purpose of this study was to assess the influence of double-lumen ETT on the gas transport and mixing in the anatomically accurate 3D-printed model of the bronchial tree, with lung lobes of different compliances, using various ventilation modes. The bronchial tree was obtained from Respiratory Drug Delivery (RDD Online, Richmond, VA, USA), processed and printed by a dual extruder FFF 3D printer. The test system was also composed of left side double-lumen endotracheal tube, Siemens Test Lung 190 and anesthetic breathing bag (as lobes). Pressure and flow measurements were taken at the outlets of the secondary bronchus. The measured resistance increased six times in the presence of double-lumen ETT. Differences between the flow distribution to the less and more compliant lobe were more significant for the airways with double-lumen ETT. The ability to predict the actual flow distribution in model airways is necessary to conduct effective ILV in clinical conditions.
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Affiliation(s)
- Katarzyna Kramek-Romanowska
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Ks Trojdena 4, 02-109 Warsaw, Poland; (A.M.S.); (K.Z.); (P.O.); (M.M.)
- Faculty of Chemical and Process Engineering, Warsaw University of Technology, Waryńskiego 1, 00-645 Warsaw, Poland; (A.D.); (M.O.)
- Correspondence:
| | - Anna M. Stecka
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Ks Trojdena 4, 02-109 Warsaw, Poland; (A.M.S.); (K.Z.); (P.O.); (M.M.)
| | - Krzysztof Zieliński
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Ks Trojdena 4, 02-109 Warsaw, Poland; (A.M.S.); (K.Z.); (P.O.); (M.M.)
| | - Agata Dorosz
- Faculty of Chemical and Process Engineering, Warsaw University of Technology, Waryńskiego 1, 00-645 Warsaw, Poland; (A.D.); (M.O.)
| | - Piotr Okrzeja
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Ks Trojdena 4, 02-109 Warsaw, Poland; (A.M.S.); (K.Z.); (P.O.); (M.M.)
| | - Marcin Michnikowski
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Ks Trojdena 4, 02-109 Warsaw, Poland; (A.M.S.); (K.Z.); (P.O.); (M.M.)
| | - Marcin Odziomek
- Faculty of Chemical and Process Engineering, Warsaw University of Technology, Waryńskiego 1, 00-645 Warsaw, Poland; (A.D.); (M.O.)
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10
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Chen Y, Yuan Y, Zhang H, Li F, Wang X. Continuous estimation of airway resistance in non-invasive ventilation. Respir Physiol Neurobiol 2021; 294:103738. [PMID: 34242813 DOI: 10.1016/j.resp.2021.103738] [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: 03/30/2021] [Revised: 06/18/2021] [Accepted: 07/03/2021] [Indexed: 11/16/2022]
Abstract
BACKGROUND This study aimed to evaluate the accuracy of expiratory time constant (RCexp) to continuously calculate the airway resistance (Raw). MATERIAL AND METHODS A Respironics V60 ventilator was connected to a lung simulator for modeling different profiles of respiratory mechanics. RESULTS During assisted ventilation, the respiratory system compliance (Crs) calculation was always overestimated in most lung models. The Raw estimation using the expiratory resistance (Rexp) method was close to the calculated value with the occlusion method during volume-controlled ventilation (VCV). In expiratory flow limitation (EFL) lung models, similar results were obtained in the estimation of inspiratory resistance (Rinsp), but different variations were observed in the calculation of the Rexp. The results estimated with RCexp and with dynamic signal analysis had significant variation and accuracy (p < 0.001). CONCLUSION The RCexp method is a robust approach to provide real-time assessments of Rinsp and Rexp in spontaneously breathing patients during noninvasive ventilation. An underestimation of Rexp was observed in EFL lung models.
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Affiliation(s)
- Yuqing Chen
- Department of Respiratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, China.
| | - Yueyang Yuan
- School of Mechanical and Electrical Engineering, Hu Nan City University, Yi Yang 413099, Hunan, China
| | - Hai Zhang
- Department of Respiratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Feng Li
- Department of Respiratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Xiaohui Wang
- Department of Pharmaceutical Science, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai 200030, China
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11
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Chen Y, Yuan Y, Zhang H, Li F, Zhou X. Accuracy of the dynamic signal analysis approach in respiratory mechanics during noninvasive pressure support ventilation: a bench study. J Int Med Res 2021; 49:300060521992184. [PMID: 33626940 PMCID: PMC7925949 DOI: 10.1177/0300060521992184] [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] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE To evaluate the accuracy of respiratory mechanics using dynamic signal analysis during noninvasive pressure support ventilation (PSV). METHODS A Respironics V60 ventilator was connected to an active lung simulator to model normal, restrictive, obstructive, and mixed obstructive and restrictive profiles. The PSV was adjusted to maintain tidal volumes (VT) that achieved 5.0, 7.0, and 10.0 mL/kg body weight, and the positive end-expiration pressure (PEEP) was set to 5 cmH2O. Ventilator performance was evaluated by measuring the flow, airway pressure, and volume. The system compliance (Crs) and airway resistance (inspiratory and expiratory resistance, Rinsp and Rexp, respectively) were calculated. RESULTS Under active breathing conditions, the Crs was overestimated in the normal and restrictive models, and it decreased with an increasing pressure support (PS) level. The Rinsp calculated error was approximately 10% at 10.0 mL/kg of VT, and similar results were obtained for the calculated Rexp at 7.0 mL/kg of VT. CONCLUSION Using dynamic signal analysis, appropriate tidal volume was beneficial for Rrs, especially for estimating Rexp during assisted ventilation. The Crs measurement was also relatively accurate in obstructive conditions.
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Affiliation(s)
- Yuqing Chen
- Department of Pulmonary and Critical Care Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yueyang Yuan
- School of Mechanical and Electrical Engineering, Hu Nan City University, Yi Yang, China
| | - Hai Zhang
- Department of Pulmonary and Critical Care Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Feng Li
- Department of Pulmonary and Critical Care Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xin Zhou
- Department of Pulmonary and Critical Care Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
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12
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Effect of Tiotropium Soft Mist Inhalers on Dynamic Changes in Lung Mechanics of Patients with Chronic Obstructive Pulmonary Disease Receiving Mechanical Ventilation: A Prospective Pilot Study. Pharmaceutics 2020; 13:pharmaceutics13010051. [PMID: 33396552 PMCID: PMC7824634 DOI: 10.3390/pharmaceutics13010051] [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] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 12/24/2020] [Accepted: 12/26/2020] [Indexed: 02/07/2023] Open
Abstract
The effects of tiotropium bromide soft mist inhalers (SMIs) in patients with chronic obstructive pulmonary disease (COPD) receiving mechanical ventilation remain unexplored. This study investigated the dynamic effects of a tiotropium SMI on lung mechanics and gas exchange in these patients. We analyzed 11 mechanically ventilated and hemodynamically stable patients with COPD who experienced acute exacerbation and were ready to be weaned from the ventilator. Two puffs of tiotropium (2.5 μg/puff) were administered with a T-adaptor connected to the ventilator circuit. Lung mechanics—peak inspiratory pressure, plateau pressure, mean airway pressure, maximum respiratory resistance (Rrs), and gas exchange function—were analyzed. The two-puff tiotropium SMI treatment led to the greatest reduction in Rrs at 6 h, with the Rrs returning to baseline gradually, and significantly improved the PaO2/FiO2 ratio at 24 h. Compared with baseline values, tiotropium SMI had the strongest effect on Rrs between hours 3 and 6 but did not significantly affect hemodynamic parameters. Tiotropium SMI administration in mechanically ventilated patients with COPD achieved the greatest reduction in Rrs at 6 h and significantly improved the PaO2/FiO2 ratio at 24 h. Future studies should investigate whether the bronchodilation effect can be improved with increased dosage or frequency.
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13
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Asorey I, Pellegrini L, Canfrán S, Ortiz-Díez G, Aguado D. Factors affecting respiratory system compliance in anaesthetised mechanically ventilated healthy dogs: a retrospective study. J Small Anim Pract 2020; 61:617-623. [PMID: 32715489 DOI: 10.1111/jsap.13194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 05/25/2020] [Accepted: 06/15/2020] [Indexed: 12/25/2022]
Abstract
OBJECTIVES To determine the influence of several factors on respiratory system compliance in volume-controlled mechanically ventilated healthy anaesthetised dogs. MATERIALS AND METHODS Review of 100 dogs anaesthetised for elective surgeries between 2015 and 2016. Dogs were mechanically ventilated with a respiratory rate adjusted to maintain normocapnia and a fraction of inspired oxygen of 50%. Body weight, body condition score, age, thoracic shape, time in spontaneous ventilation before volume-controlled ventilation, time with a fraction of inspired oxygen of 100% until starting mechanical ventilation, type of surgery and patient position were recorded. Respiratory system compliance, expressed per kg of bodyweight, was recorded every 15 minutes following initiation of volume-controlled ventilation. RESULTS Baseline respiratory system compliance was 1.3 ± 0.3 mL/cmH2 O/kg and was reduced by high body condition score and barrel-shaped thorax but not by age, type of surgery or patient position, time in spontaneous ventilation nor time with a fraction of inspired oxygen of 100%. CLINICAL SIGNIFICANCE Respiratory system compliance is lower in overweight and barrel-chested dogs and should be taken into account during monitoring of lung function and ventilation management under general anaesthesia.
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Affiliation(s)
- I Asorey
- Dick White Referrals, Station Farm - London Road, Six Mile Bottom, Cambridgeshire, CB8 0UH, UK
| | - L Pellegrini
- Department of Animal Medicine and Surgery, School of Veterinary Medicine, Complutense University of Madrid, Avda. Puerta de Hierro s/n, Madrid, 28040, Spain
| | - S Canfrán
- Department of Animal Medicine and Surgery, School of Veterinary Medicine, Complutense University of Madrid, Avda. Puerta de Hierro s/n, Madrid, 28040, Spain
| | - G Ortiz-Díez
- Department of Animal Medicine and Surgery, School of Veterinary Medicine, Complutense University of Madrid, Avda. Puerta de Hierro s/n, Madrid, 28040, Spain
| | - D Aguado
- Department of Animal Medicine and Surgery, School of Veterinary Medicine, Complutense University of Madrid, Avda. Puerta de Hierro s/n, Madrid, 28040, Spain
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14
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Menezes Júnior JDN, Silva LM, Santos LJM, Correia HF, Lopes W, Silva VEPE, Anjos JLMD, Martinez BP. Reproducibility of respiratory mechanics measurements in patients on invasive mechanical ventilation. Rev Bras Ter Intensiva 2020; 32:398-404. [PMID: 33053029 PMCID: PMC7595717 DOI: 10.5935/0103-507x.20200068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 03/01/2020] [Indexed: 11/26/2022] Open
Abstract
Objective To evaluate the intra- and interexaminer reproducibility of measurements of the resistance and static and dynamic compliance of the respiratory system in patients on mechanical ventilation. Methods This was an analytical study conducted with individuals aged ≥ 18 years who were on invasive mechanical ventilation and had no clinical diagnosis of respiratory system disease and/or chest abnormality. Three measurements of respiratory mechanics were performed with a 1-minute interval between them. The first and third measurements were performed by examiner A, the second by examiner B. The values for the resistance and static and dynamic compliance of the respiratory system were compared using the intraclass correlation coefficient. Results A total of 198 measurements of respiratory mechanics were performed for 66 patients on mechanical ventilation. The patients had a mean age of 52.6 ± 18.6 years and a mean body mass index of 21.6 ± 2.1kg/m2; a surgical profile (61.5%) and female sex (53.8%) were predominant. Mean values were obtained for the three measurements of respiratory system resistance (A1: 15.7 ± 6.8cmH2O/L/s; B1: 15.7 ± 6.4cmH2O/L/s and A2: 15.9 ± 6.2cmH2O/L/s), respiratory system static compliance (A1: 42.1 ± 13.7mL/cmH2O; B1: 42.4 ± 14.6mL/cmH2O and A2: 42.2 ± 14.5mL/cmH2O) and respiratory system dynamic compliance (A1: 21.3 ± 7.3mL/cmH2O; B1: 21.4 ± 7.5mL/cmH2O and A2: 21.3 ± 6.2mL/cmH2O). The intraclass correlation coefficient was also calculated for respiratory system resistance (R = 0.882 and p = 0.001; R = 0.949 and p = 0.001 - interexaminer A1 versus B and B versus A2, respectively; R = 0.932 and p = 0.001 - intraexaminer); respiratory system static compliance (R = 0.951 and p = 0.001; R = 0.958 and p = 0.001 - interexaminer A1 versus B and B versus A2, respectively; R = 0.965 and p = 0.001 - intraexaminer) and respiratory system dynamic compliance (R = 0.957 and p = 0.001; R = 0.946 and p = 0.001 - interexaminer A1 versus B and B versus A2, respectively; R = 0.926 and p = 0.001 - intraexaminer). Conclusion The measurements of resistance and static and dynamic compliance of the respiratory system show good intra- and interexaminer reproducibility for ventilated patients.
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Affiliation(s)
| | | | - Leonardo José Morais Santos
- Programa de Pós-Graduação em Processos Interativos de Órgãos e Sistemas, Universidade Federal da Bahia - Salvador (BA), Brasil
| | - Helena França Correia
- Programa de Pós-Graduação em Processos Interativos de Órgãos e Sistemas, Universidade Federal da Bahia - Salvador (BA), Brasil
| | - Wende Lopes
- Universidade do Estado da Bahia - Salvador (BA), Brasil
| | | | | | - Bruno Prata Martinez
- Universidade do Estado da Bahia - Salvador (BA), Brasil.,Programa de Pós-Graduação em Medicina e Saúde, Universidade Federal da Bahia - Salvador (BA), Brasil
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16
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Schwartz L, Lafitte O, da Veiga Moreira J. Toward a Reasoned Classification of Diseases Using Physico-Chemical Based Phenotypes. Front Physiol 2018. [PMID: 29541031 PMCID: PMC5835834 DOI: 10.3389/fphys.2018.00094] [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] [Indexed: 11/13/2022] Open
Abstract
Background: Diseases and health conditions have been classified according to anatomical site, etiological, and clinical criteria. Physico-chemical mechanisms underlying the biology of diseases, such as the flow of energy through cells and tissues, have been often overlooked in classification systems. Objective: We propose a conceptual framework toward the development of an energy-oriented classification of diseases, based on the principles of physical chemistry. Methods: A review of literature on the physical chemistry of biological interactions in a number of diseases is traced from the point of view of the fluid and solid mechanics, electricity, and chemistry. Results: We found consistent evidence in literature of decreased and/or increased physical and chemical forces intertwined with biological processes of numerous diseases, which allowed the identification of mechanical, electric and chemical phenotypes of diseases. Discussion: Biological mechanisms of diseases need to be evaluated and integrated into more comprehensive theories that should account with principles of physics and chemistry. A hypothetical model is proposed relating the natural history of diseases to mechanical stress, electric field, and chemical equilibria (ATP) changes. The present perspective toward an innovative disease classification may improve drug-repurposing strategies in the future.
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Affiliation(s)
| | - Olivier Lafitte
- LAGA, UMR 7539, Paris 13 University, Sorbonne Paris Cité, Villetaneuse, France
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17
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Kock KDS, Maurici R. Respiratory mechanics, ventilator-associated pneumonia and outcomes in intensive care unit. World J Crit Care Med 2018; 7:24-30. [PMID: 29430405 PMCID: PMC5797973 DOI: 10.5492/wjccm.v7.i1.24] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 11/05/2017] [Accepted: 12/04/2017] [Indexed: 02/06/2023] Open
Abstract
AIM To evaluate the predictive capability of respiratory mechanics for the development of ventilator-associated pneumonia (VAP) and mortality in the intensive care unit (ICU) of a hospital in southern Brazil.
METHODS A cohort study was conducted between, involving a sample of 120 individuals. Static measurements of compliance and resistance of the respiratory system in pressure-controlled ventilation (PCV) and volume-controlled ventilation (VCV) modes in the 1st and 5th days of hospitalization were performed to monitor respiratory mechanics. The severity of the patients’ illness was quantified by the Acute Physiology and Chronic Health Evaluation II (APACHE II). The diagnosis of VAP was made based on clinical, radiological and laboratory parameters.
RESULTS The significant associations found for the development of VAP were APACHE II scores above the average (P = 0.016), duration of MV (P = 0.001) and ICU length of stay above the average (P = 0.003), male gender (P = 0.004), and worsening of respiratory resistance in PCV mode (P = 0.010). Age above the average (P < 0.001), low level of oxygenation on day 1 (P = 0.003) and day 5 (P = 0.004) and low lung compliance during VCV on day 1 (P = 0.032) were associated with death as the outcome.
CONCLUSION The worsening of airway resistance in PCV mode indicated the possibility of early diagnosis of VAP. Low lung compliance during VCV and low oxygenation index were death-related prognostic indicators.
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Affiliation(s)
- Kelser de Souza Kock
- Department of Physiotherapy, University of South of Santa Catarina, Tubarão, SC 88704-001, Brazil
| | - Rosemeri Maurici
- Graduate Program in Medical Sciences, Federal University of Santa Catarina, Florianópolis, SC 88700-000, Brazil
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18
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Mehta NJ, Latoures R, Stechert MM, Fidler RL, Hirsch J. Interventions to improve the mechanical ventilation fidelity of the Laerdal SimMan® 3G simulation mannequin. Can J Anaesth 2017; 65:600-602. [PMID: 29243162 DOI: 10.1007/s12630-017-1040-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 12/04/2017] [Accepted: 12/04/2017] [Indexed: 11/25/2022] Open
Affiliation(s)
- Neil J Mehta
- Simulation Center and Anesthesia Service, San Francisco VA Medical Center and University of California San Francisco, San Francisco, CA, USA.
| | - Renee Latoures
- Simulation Center and Anesthesia Service, San Francisco VA Medical Center and University of California San Francisco, San Francisco, CA, USA
| | - Martin M Stechert
- Simulation Center and Anesthesia Service, San Francisco VA Medical Center and University of California San Francisco, San Francisco, CA, USA
| | - Richard L Fidler
- Simulation Center and Anesthesia Service, San Francisco VA Medical Center and University of California San Francisco, San Francisco, CA, USA
| | - Jan Hirsch
- Simulation Center and Anesthesia Service, San Francisco VA Medical Center and University of California San Francisco, San Francisco, CA, USA
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19
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Rodrigues JC, Teixeira-Neto FJ, Cerejo SA, Celeita-Rodríguez N, Garofalo NA, Quitzan JG, Rocha TLA. Effects of pneumoperitoneum and of an alveolar recruitment maneuver followed by positive end-expiratory pressure on cardiopulmonary function in sheep anesthetized with isoflurane-fentanyl. Vet Anaesth Analg 2017; 44:841-853. [PMID: 28888803 DOI: 10.1016/j.vaa.2016.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/13/2016] [Accepted: 05/29/2016] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To investigate the effects of pneumoperitoneum alone or combined with an alveolar recruitment maneuver (ARM) followed by positive end-expiratory pressure (PEEP) on cardiopulmonary function in sheep. STUDY DESIGN Prospective, randomized, crossover study. ANIMALS A total of nine adult sheep (36-52 kg). METHODS Sheep were administered three treatments (≥10-day intervals) during isoflurane-fentanyl anesthesia and volume-controlled ventilation (tidal volume: 12 mL kg-1) with oxygen: CONTROL (no intervention); PNEUMO (120 minutes of CO2 pneumoperitoneum); PNEUMOARM/PEEP (PNEUMO protocol with an ARM instituted after 60 minutes of pneumoperitoneum). The ARM (5 cmH2O increases in PEEP of 1 minute duration until 20 cmH2O of PEEP) was followed by 10 cmH2O of PEEP until the end of anesthesia. Cardiopulmonary data were recorded until 30 minutes after abdominal deflation. RESULTS PaO2 was decreased from 435-462 mmHg (58.0-61.6 kPa) (range of mean values in CONTROL) to 377-397 mmHg (50.3-52.9 kPa) in PNEUMO (p < 0.05). Quasistatic compliance (Cqst, mL cmH2O-1 kg-1) was decreased from 0.85-0.92 in CONTROL to 0.52-0.58 in PNEUMO. PaO2 increased from 383-385 mmHg (51.1-51.3 kPa) in PNEUMO to 429-444 mmHg (57.2-59.2 kPa) in PNEUMOARM/PEEP (p < 0.05) and Cqst increased from 0.52-0.53 in PNEUMO to 0.70-0.74 in PNEUMOARM/PEEP. Abdominal deflation in PNEUMO did not restore PaO2 and Cqst to control values. Cardiac index (L minute-1 m2) decreased from 4.80-4.70 in CONTROL to 3.45-3.74 in PNEUMO and 3.63-3.76 in PNEUMOARM/PEEP. Compared with controls, ARM/PEEP with pneumoperitoneum decreased mean arterial pressure from 81 to 68 mmHg and increased mean pulmonary artery pressure from 10 to 16 mmHg. CONCLUSIONS AND CLINICAL RELEVANCE Abdominal deflation did not reverse the pulmonary function impairment associated with pneumoperitoneum. The ARM/PEEP improved respiratory compliance and reversed the oxygenation impairment induced by pneumoperitoneum with acceptable hemodynamic changes in healthy sheep.
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Affiliation(s)
| | - Francisco J Teixeira-Neto
- Faculdade de Medicina, Univ Estadual Paulista (UNESP), Botucatu, Brazil; Faculdade de Medicina Veterinária e Zootecnia, Univ Estadual Paulista (UNESP), Botucatu, Brazil.
| | - Sofia A Cerejo
- Faculdade de Medicina, Univ Estadual Paulista (UNESP), Botucatu, Brazil
| | | | - Natache A Garofalo
- Faculdade de Medicina Veterinária e Zootecnia, Univ Estadual Paulista (UNESP), Botucatu, Brazil
| | - Juliany G Quitzan
- Faculdade de Medicina Veterinária e Zootecnia, Univ Estadual Paulista (UNESP), Botucatu, Brazil
| | - Thalita L A Rocha
- Faculdade de Medicina, Univ Estadual Paulista (UNESP), Botucatu, Brazil
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Henderson WR, Molgat-Seon Y, Dominelli PB, Brasher PMA, Griesdale DEG, Foster GE, Yacyshyn A, Ayas NT, Sheel AW. Gas density alters expiratory time constants before and after experimental lung injury. Exp Physiol 2016; 100:1217-28. [PMID: 26289254 DOI: 10.1113/ep085205] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 08/17/2015] [Indexed: 01/10/2023]
Abstract
NEW FINDINGS What is the central question of this study? Does the induction of a model of lung injury affect the expiratory time constant (τE) in terms of either total duration or morphology? Does ventilation with gases of different densities alter the duration or morphology of τE either before or after injury? What is the main finding and its importance? The use of sulfur hexafluoride in ventilating gas mixtures lengthens total expiratory time constants before and after lung injury compared with both nitrogen and helium mixtures. Sulfur hexafluoride mixtures also decrease the difference and variability of τE between fast- and slow-emptying compartments before and after injury when compared with nitrogen and helium mixtures. Acute lung injury is characterized by regional heterogeneity of lung resistance and elastance that may lead to regional heterogeneity of expiratory time constants (τE). We hypothesized that increasing airflow resistance by using inhaled sulfur hexafluoride (SF6) would lengthen time constants and decrease their heterogeneity in an experimental model of lung injury when compared with nitrogen or helium mixtures. To overcome the limitations of a single-compartment model, we employed a multisegment model of expiratory gas flow. An experimental model of lung injury was created using intratracheal injection of sodium polyacrylate in anaesthetized and mechanically ventilated female Yorkshire-cross pigs (n = 7). The animals were ventilated with 50% O2 and the remaining 50% as nitrogen (N2), helium (He) or sulfur hexafluoride (SF6). Values for τE decreased with injury and were more variable after injury than before (P < 0.001). Values for τE increased throughout expiration both before and after injury, and the rate of increase in τE was lessened by SF6 (P < 0.001 when compared with N2 both before and after injury). Altering the inhaled gas density did not affect indices of oxygenation, dead space or shunt. The use of SF6 in ventilating gas mixtures lengthens total expiratory time constants before and after lung injury compared with both N2 and He mixtures. Importantly, SF6 mixtures also decrease the difference and variability of τE between fast- and slow-emptying compartments before and after injury when compared with N2 and He mixtures.
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Affiliation(s)
- William R Henderson
- Division of Critical Care Medicine, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yannick Molgat-Seon
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Paolo B Dominelli
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Penelope M A Brasher
- Centre for Clinical Epidemiology & Evaluation, Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada
| | - Donald E G Griesdale
- Division of Critical Care Medicine, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Glen E Foster
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Alexandra Yacyshyn
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Najib T Ayas
- Division of Critical Care Medicine, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - A William Sheel
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
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Kock KDS, Rosa BCD, Martignago N, Reis C, Maurici R. Comparison of respiratory mechanics measurements in the volume cycled ventilation (VCV) and pressure controlled ventilation (PCV). FISIOTERAPIA EM MOVIMENTO 2016. [DOI: 10.1590/0103-5150.029.002.ao02] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Abstract Introduction Monitoring respiratory mechanics may provide important information for the intensivist, assisting in the early detection of pulmonary function changes of patients hospitalized in ICU. Objective: To compare measurements of respiratory mechanics in VCV and PCV modes, and correlate them with age and oxygenation index. Materials and methods: Cross-sectional study conducted in the adult ICU of the Hospital Nossa Senhora da Conceição, in Tubarão - SC. A hundred and twenty individuals were selected between March and August 2013. The respiratory mechanics measurements were evaluated using compliance and resistance static measures of the respiratory system in PCV and VCV modes between the 1st and 5th day of hospitalization. Simultaneously, the oxygenation index PaO2/FiO2 was collected. Results: The obtained results were: compliance (VCV) = 40.9 ± 12.8 mL/cmH2O, compliance (PCV) = 35.0 ± 10.0 mL/cmH2O, resistance (VCV) = 13.2 ± 4.9 cmH2O/L/s, resistance (PCV) = 27.3 ± 16.2 cmH2O/L/s and PaO2/FiO2 = 236.0 ± 97.6 mmHg. There was statistical difference (p < 0.001) between the compliance and resistance measures in VCV and PCV modes. The correlations between the oxygenation index and compliance in VCV and PCV modes and resistance in VCV and PCV modes were, respectively, r = 0.381 (p < 0.001), r = 0.398 (p < 0.001), r = -0.188 (p = 0.040), r = -0.343 (p < 0.001). Conclusion: Despite the differences between the respiratory mechanics measurements the monitoring using VCV and PCV modes seems to show complementary aspects.
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Reiterer F, Sivieri E, Abbasi S. Evaluation of bedside pulmonary function in the neonate: From the past to the future. Pediatr Pulmonol 2015; 50:1039-50. [PMID: 26139200 DOI: 10.1002/ppul.23245] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 04/01/2015] [Accepted: 05/08/2015] [Indexed: 01/10/2023]
Abstract
Pulmonary function testing and monitoring plays an important role in the respiratory management of neonates. A noninvasive and complete bedside evaluation of the respiratory status is especially useful in critically ill neonates to assess disease severity and resolution and the response to pharmacological interventions as well as to guide mechanical respiratory support. Besides traditional tools to assess pulmonary gas exchage such as arterial or transcutaenous blood gas analysis, pulse oximetry, and capnography, additional valuable information about global lung function is provided through measurement of pulmonary mechanics and volumes. This has now been aided by commercially available computerized pulmonary function testing systems, respiratory monitors, and modern ventilators with integrated pulmonary function readouts. In an attempt to apply easy-to-use pulmonary function testing methods which do not interfere with the infant́s airflow, other tools have been developed such as respiratory inductance plethysmography, and more recently, electromagnetic and optoelectronic plethysmography, electrical impedance tomography, and electrical impedance segmentography. These alternative technologies allow not only global, but also regional and dynamic evaluations of lung ventilation. Although these methods have proven their usefulness for research applications, they are not yet broadly used in a routine clinical setting. This review will give a historical and clinical overview of different bedside methods to assess and monitor pulmonary function and evaluate the potential clinical usefulness of such methods with an outlook into future directions in neonatal respiratory diagnostics.
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Affiliation(s)
- F Reiterer
- Division of Neonatology, Department of Pediatrics and Adolescence Medicine, Medical University Graz, Graz, Austria
| | - E Sivieri
- Section on Newborn Pediatrics, Pennsylvania Hospital, Philadelphia, Pennsylvania.,Division of Neonatology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - S Abbasi
- Section on Newborn Pediatrics, Pennsylvania Hospital, Philadelphia, Pennsylvania.,Division of Neonatology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Abstract
Ventilator waveforms are graphic representations of changes in pressure, flow, and volume within a ventilator circuit. The changes in these parameters over time may be displayed individually (scalars) or plotted one against another (pressure-volume and flow-volume loops). There are 6 basic shapes of scalar waveforms, but only 3 are functionally distinct (square, ramp, and sine). The pressure scalar is a particularly valuable tool when constant flow (e.g., volume control) modes are employed and an inspiratory pause is added. In this setting, inspection of the pressure waveform can allow determination of static, quasistatic, and dynamic compliance, as well as relative changes in airway resistance. Inspection of the pressure waveform can also help to identify many important aspects of patient drug responses, dyssynchrony, and air trapping (auto positive end-expiratory pressure [auto-PEEP]). Depending on the ventilation mode employed, the shape of the flow waveform may be set by the ventilator operator or may be dependent on patient effort and lung mechanics. Decelerating flow patterns have several important advantages when this option is available. Inspection of flow waveforms is crucial in the recognition of dyssynchrony, setting optimal inspiratory times, evaluating responses to bronchodilators, and the recognition of auto-PEEP. The volume waveform often contains somewhat less useful information than the other 2 scalars, but plays a crucial role in the identification of leaks in the circuit. Pressure-volume loops are particularly useful in setting PEEP and peak inspiratory pressure ranges. Inspection of these loops also often helps in the evaluation of lung mechanics, in the identification of circuit leaks, and in the assessment of patient triggering effort. Flow-volume loops are extremely useful in the identification of leaks and excessive airway secretions as well as alterations in airway resistance. Lastly, serial waveform inspection is crucial to the identification and resolution of patient-ventilator dyssynchrony in many cases.
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Affiliation(s)
- Matthew S Mellema
- Small Animal Emergency and Critical Care Service, Department of Veterinary Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
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24
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Henderson WR, Barnbrook J, Dominelli PB, Griesdale DE, Arndt T, Molgat-Seon Y, Foster G, Ackland GL, Xu J, Ayas NT, Sheel AW. Administration of intrapulmonary sodium polyacrylate to induce lung injury for the development of a porcine model of early acute respiratory distress syndrome. Intensive Care Med Exp 2014; 2:5. [PMID: 26266906 PMCID: PMC4513039 DOI: 10.1186/2197-425x-2-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/10/2014] [Indexed: 12/15/2022] Open
Abstract
Background The loss of alveolar epithelial and endothelial integrity is a central component in acute respiratory distress syndrome (ARDS); however, experimental models investigating the mechanisms of epithelial injury are lacking. The purpose of the present study was to design and develop an experimental porcine model of ARDS by inducing lung injury with intrapulmonary administration of sodium polyacrylate (SPA). Methods The present study was performed at the Centre for Comparative Medicine, University of British Columbia, Vancouver, British Columbia. Human alveolar epithelial cells were cultured with several different concentrations of SPA; a bioluminescence technique was used to assess cell death associated with each concentration. In the anesthetized pig model (female Yorkshire X pigs (n = 14)), lung injury was caused in 11 animals (SPA group) by injecting sequential aliquots (5 mL) of 1% SPA gel in aqueous solution into the distal airway via a rubber catheter through an endotracheal tube. The SPA was dispersed throughout the lungs by manual bag ventilation. Three control animals (CON group) underwent all experimental procedures and measurements with the exception of SPA administration. Results The mean (± SD) ATP concentration after incubation of human alveolar epithelial cells with 0.1% SPA (0.92 ± 0.27 μM/well) was approximately 15% of the value found for the background control (6.30 ± 0.37 μM/well; p < 0.001). Elastance of the respiratory system (ERS) and the lung (EL) increased in SPA-treated animals after injury (p = 0.003 and p < 0.001, respectively). Chest wall elastance (ECW) did not change in SPA-treated animals. There were no differences in ERS,EL, or ECW in the CON group when pre- and post-injury values were compared. Analysis of bronchoalveolar lavage fluid showed a significant shift toward neutrophil predominance from before to after injury in SPA-treated animals (p < 0.001) but not in the CON group (p = 0.38). Necropsy revealed marked consolidation and congestion of the dorsal lung lobes in SPA-treated animals, with light-microscopy evidence of bronchiolar and alveolar spaces filled with neutrophilic infiltrate, proteinaceous debris, and fibrin deposition. These findings were absent in animals in the CON group. Electron microscopy of lung tissue from SPA-treated animals revealed injury to the alveolar epithelium and basement membranes, including intra-alveolar neutrophils and fibrin on the alveolar surface and intravascular fibrin (microthrombosis). Conclusions In this particular porcine model, the nonimmunogenic polymer SPA caused a rapid exudative lung injury. This model may be useful to study ARDS caused by epithelial injury and inflammation.
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Affiliation(s)
- William R Henderson
- Wolfson Institute for Biomedical Research, Department of Medicine, University College London, London, WC1E 6BT, UK,
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