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Effect of positive end-expiratory pressure during anaesthesia induction on non-hypoxic apnoea time in infants: A randomised controlled trial. Eur J Anaesthesiol 2021; 38:1012-1018. [PMID: 33259454 DOI: 10.1097/eja.0000000000001400] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Hypoxaemia occurs frequently in infants during anaesthetic induction. OBJECTIVE We evaluated the effect of positive end-expiratory pressure during anaesthesia induction on nonhypoxic apnoea time in infants. DESIGN Randomised controlled trial. SETTING Tertiary care children's hospital, single centre, from November 2018 to October 2019. PATIENTS We included patients under 1 year of age receiving general anaesthesia. INTERVENTION We assigned infants to a 7 cmH2O or 0 cmH2O positive end-expiratory pressure group. Anaesthesia was induced with 0.02 mg kg-1 atropine, 5 mg kg-1 thiopental sodium and 3 to 5% sevoflurane, and neuromuscular blockade with 0.6 mg kg-1 rocuronium. Thereafter, 100% oxygen was provided via face mask with volume-controlled ventilation of 6 ml kg-1 tidal volume, and either 7 cmH2O or no positive end-expiratory pressure. After 3 min of ventilation, the infants' trachea was intubated but disconnected from the breathing circuit, and ventilation resumed when pulse oximetry reached 95%. MAIN OUTCOME MEASURE The primary outcome was nonhypoxic apnoea time defined as the time from cessation of ventilation to a pulse oximeter reading of 95%, whereas the secondary outcome was the incidence of significant atelectasis (consolidation score ≥2) assessed by lung ultrasound. RESULTS Sixty patients were included in the final analysis. Apnoea time in the 7 cmH2O positive end-expiratory pressure group (105.2 s) increased compared with that in the control group (92.1 s) (P = 0.011, mean difference 13.0 s, 95% CI, 3.1 to 22.9 s). Significant atelectasis was observed in all patients without positive end-expiratory pressure and 66.7% of those with 7 cmH2O positive end-expiratory pressure (P = 0.019, 95% CI, 1.7 to 563.1, odds ratio 31.2). CONCLUSION Positive end-expiratory pressure during anaesthesia induction with face mask ventilation increased nonhypoxic apnoea time in infants. CLINICAL TRIAL REGISTRATION www.clinicaltrials.gov, NCT03540940.
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Cumin D, Baker PA, Anderson BJ. Incidence of post-induction hypoxemia in children and the effect of induction gas composition. Paediatr Anaesth 2021; 31:763-769. [PMID: 33615619 DOI: 10.1111/pan.14161] [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: 12/06/2020] [Revised: 02/11/2021] [Accepted: 02/13/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Pediatric preoxygenation and inhalation induction of anesthesia can include a mixture of gases. In children, the clinical impact on oxygenation while using other gases with oxygen during an inhalation induction is unknown. AIM We aimed to determine the impact of oxygen, nitrous oxide, and air concentrations added to the volatile agent by recording the incidence of hypoxemia following an inhalation gaseous induction in children. METHOD Records from an Automated Information Management System were used to find the incidence of hypoxemia following an inhalation induction of anesthesia. Episodes of hypoxemia (SaO2 < 90% sustained for at least 120 s) were recorded in the 10 min after the 3-min induction period. Nitrous oxide and oxygen concentrations were recorded and nitrogen concentration was deduced. We also considered patient sex, age, and ASA status as covariates. RESULTS A total of 27 258 cases were included in the analysis. The overall incidence of hypoxemia following an inhalation induction of anesthesia was 5.08% (95% CI 4.83 5.35). Hypoxemia was more common in younger patients and those with higher ASA scores. Controlling for those factors and sex, the incidence of hypoxemia increased 1.2-fold when inspired oxygen concentration was less than 60% and hypoxemia was 2.37 times greater than the overall incidence when the inspired oxygen concentration was less than 40%. There was no clear effect of different concentrations of nitrous oxide or nitrogen when those were factored into the model. CONCLUSION The risk of hypoxemia following an inhalation induction of anesthesia in children is minimized when the inspired concentration of oxygen is greater than 60%.
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Affiliation(s)
- David Cumin
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand
| | - Paul A Baker
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand
| | - Brian J Anderson
- Department of Anaesthesiology, University of Auckland, Auckland, New Zealand.,Department of Paediatric Anaesthesia, Starship Children's Hospital, Auckland, New Zealand
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Forsberg I, Ullman J, Hoffman A, Eriksson LI, Lodenius Å, Fagerlund MJ. Lung volume changes in Apnoeic Oxygenation using Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) compared to mechanical ventilation in adults undergoing laryngeal surgery. Acta Anaesthesiol Scand 2020; 64:1491-1498. [PMID: 32794176 PMCID: PMC7589281 DOI: 10.1111/aas.13686] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 06/22/2020] [Accepted: 08/04/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE) using high-flow 100% oxygen during apnoea has gained increased use during difficult airway management and laryngeal surgery due to a slower carbon dioxide rise compared to traditional apnoeic oxygenation. We have previously demonstrated high arterial oxygen partial pressures and an increasing arterial-alveolar carbon dioxide difference during THRIVE. Primary aim of this study was to characterise lung volume changes measured with electrical impedance tomography during THRIVE compared to mechanical ventilation. METHODS Thirty adult patients undergoing laryngeal surgery under general anaesthesia were randomised to THRIVE or mechanical ventilation. Subjects were monitored with electrical impedance tomography and repeated blood gas measurement perioperatively. The THRIVE group received 100% oxygen at 70 l min-1 during apnoea. The mechanical ventilation group was intubated and normoventilated with an FiO2 of 0.4. RESULTS Mean age were 48.2 (19.9) and 51.3 (12.3) years, and BMI 26.0 (4.5) and 26.0 (3.9) in the THRIVE and mechanical ventilation group respectively. Mean apnoea time in the THRIVE group was 17.9 (4.8) min. Mean apnoea to end-of-surgery time was 28.1 (12.8) min in the mechanical ventilation group. No difference in delta End Expiratory Lung Impedance was seen between groups over time. In the THRIVE group all but three subjects were well oxygenated during apnoea. THRIVE was discontinued for the three patients who desaturated. CONCLUSIONS No difference in lung volume change over time, measured by electrical impedance tomography, was detected when using THRIVE compared to mechanical ventilation during laryngeal surgery.
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Affiliation(s)
- Ida‐Maria Forsberg
- Perioperative Medicine and Intensive Care Karolinska University Hospital Stockholm Sweden
- Department of Physiology and Pharmacology Section for Anesthesiology and Intensive Care Medicine Karolinska Institutet Stockholm Sweden
| | - Johan Ullman
- Perioperative Medicine and Intensive Care Karolinska University Hospital Stockholm Sweden
- Department of Physiology and Pharmacology Section for Anesthesiology and Intensive Care Medicine Karolinska Institutet Stockholm Sweden
| | - Anton Hoffman
- Medical School Karolinska Institutet Stockholm Sweden
| | - Lars I. Eriksson
- Perioperative Medicine and Intensive Care Karolinska University Hospital Stockholm Sweden
- Department of Physiology and Pharmacology Section for Anesthesiology and Intensive Care Medicine Karolinska Institutet Stockholm Sweden
| | - Åse Lodenius
- Department of Physiology and Pharmacology Section for Anesthesiology and Intensive Care Medicine Karolinska Institutet Stockholm Sweden
| | - Malin J. Fagerlund
- Perioperative Medicine and Intensive Care Karolinska University Hospital Stockholm Sweden
- Department of Physiology and Pharmacology Section for Anesthesiology and Intensive Care Medicine Karolinska Institutet Stockholm Sweden
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Gonçalves-Ferri WA, Jauregui A, Martins-Celini FP, Sansano I, Fabro AT, Sacramento EMF, Aragon DC, Ochoa JM. Analysis of different levels of positive end-expiratory pressure during lung retrieval for transplantation: an experimental study. ACTA ACUST UNITED AC 2019; 52:e8585. [PMID: 31314854 PMCID: PMC6644527 DOI: 10.1590/1414-431x20198585] [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: 03/08/2019] [Accepted: 04/24/2019] [Indexed: 11/22/2022]
Abstract
Atelectasis and inadequate oxygenation in lung donors is a common problem during the retrieval of these organs. Nevertheless, the use of high positive end-expiratory pressure (PEEP) is not habitual during procedures of lung retrieval. Twenty-one Sprague-Dawley male consanguineous rats were used in the study. The animals were divided into 3 groups according to the level of PEEP used: low (2 cmH2O), moderate (5 cmH2O), and high (10 cmH2O). Animals were ventilated with a tidal volume of 6 mL/kg. Before lung removal, the lungs were inspected for the presence of atelectasis. When atelectasis was detected, alveolar recruitment maneuvers were performed. Blood gasometric analysis was performed immediately. Finally, the lungs were retrieved, weighed, and submitted to histological analysis. The animals submitted to higher PEEP showed higher levels of oxygenation with the same tidal volumes PO2=262.14 (PEEP 2), 382.4 (PEEP 5), and 477.0 (PEEP 10). The occurrence of atelectasis was rare in animals with a PEEP of 10 cmH2O, which therefore required less frequent recruitment maneuvers (need for recruitment: PEEP 2=100%, PEEP 5 =100%, and PEEP 10=14.3%). There was no change in hemodynamic stability, occurrence of pulmonary edema, or other histological injuries with the use of high PEEP. The use of high PEEP (10 cmH2O) was feasible and probably a beneficial strategy for the prevention of atelectasis and the optimization of oxygenation during lung retrieval. Clinical studies should be performed to confirm this hypothesis.
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Affiliation(s)
- W A Gonçalves-Ferri
- Departamento de Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - A Jauregui
- Department of Thoracic Surgery, Hospital Vall d'Hebron, Barcelona, Spain
| | - F P Martins-Celini
- Departamento de Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - I Sansano
- Department of Pathology, Hospital Vall d'Hebron, Barcelona, Spain
| | - A T Fabro
- Departamento de Patologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - E M F Sacramento
- Departamento de Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - D C Aragon
- Departamento de Pediatria, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - J M Ochoa
- Department of Thoracic Surgery, Hospital Vall d'Hebron, Barcelona, Spain
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El-Sayed KM, Tawfeek MM. Perioperative ventilatory strategies for improving arterial oxygenation and respiratory mechanics in morbidly obese patients undergoing laparoscopic bariatric surgery. EGYPTIAN JOURNAL OF ANAESTHESIA 2019. [DOI: 10.1016/j.egja.2011.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
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6
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Grandville BDL, Petak F, Albu G, Bayat S, Pichon I, Habre W. High inspired oxygen fraction impairs lung volume and ventilation heterogeneity in healthy children: a double-blind randomised controlled trial. Br J Anaesth 2019; 122:682-691. [DOI: 10.1016/j.bja.2019.01.036] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/23/2019] [Accepted: 01/23/2019] [Indexed: 10/27/2022] Open
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Abstract
Perioperative lung injury is a major source of postoperative morbidity, excess healthcare use, and avoidable mortality. Many potential inciting factors can lead to this condition, including intraoperative ventilator induced lung injury. Questions exist as to whether protective ventilation strategies used in the intensive care unit for patients with acute respiratory distress syndrome are equally beneficial for surgical patients, most of whom do not present with any pre-existing lung pathology. Studied both individually and in combination as a package of intraoperative lung protective ventilation, the use of low tidal volumes, moderate positive end expiratory pressure, and recruitment maneuvers have been shown to improve oxygenation and pulmonary physiology and to reduce postoperative pulmonary complications in at risk patient groups. Further work is needed to define the potential contributions of alternative ventilator strategies, limiting excessive intraoperative oxygen supplementation, use of non-invasive techniques in the postoperative period, and personalized mechanical ventilation. Although the weight of evidence strongly suggests a role for lung protective ventilation in moderate risk patient groups, definitive evidence of its benefit for the general surgical population does not exist. However, given the shift in understanding of what is needed for adequate oxygenation and ventilation under anesthesia, the largely historical arguments against the use of intraoperative lung protective ventilation may soon be outdated, on the basis of its expanding track record of safety and efficacy in multiple settings.
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Affiliation(s)
- Brian O'Gara
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Daniel Talmor
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
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Soleimanpour H, Safari S, Sanaie S, Nazari M, Alavian SM. Anesthetic Considerations in Patients Undergoing Bariatric Surgery: A Review Article. Anesth Pain Med 2017; 7:e57568. [PMID: 29430407 PMCID: PMC5797674 DOI: 10.5812/aapm.57568] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 10/03/2016] [Accepted: 06/12/2017] [Indexed: 01/14/2023] Open
Abstract
Context This article discusses the anesthetic considerations in patients undergoing bariatric surgery in the preoperative, intraoperative, and postoperative phases of surgery. Evidence Acquisition This review includes studies involving obese patients undergoing bariatric surgery. Searches have been conducted in PubMed, MEDLINE, EMBASE, Google Scholar, Scopus, and Cochrane Database of Systematic Review using the terms obese, obesity, bariatric, anesthesia, perioperative, preoperative, perioperative, postoperative, and their combinations. Results Obesity is a major worldwide health problem associated with many comorbidities. Bariatric surgery has been proposed as the best alternative treatment for extreme obese patients when all other therapeutic options have failed. Conclusions Anesthetists must completely assess the patients before the surgery to identify anesthesia- related potential risk factors and prepare for management during the surgery.
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Affiliation(s)
- Hassan Soleimanpour
- Road Traffic Injury Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Saeid Safari
- Pain Research Center, Iran University of Medical Sciences, Tehran, Iran
- Corresponding author: Saeid Safari, Pain Research Center, Rasoul Akram Medical Center, Iran University of Medical Sciences, Tehran, IR Iran. Tel: +98-9392117300, E-mail:
| | - Sarvin Sanaie
- Tuberculosis and Lung Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mehdi Nazari
- Anesthesiology Research Team, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Seyed Moayed Alavian
- Baqiyatallah Research Center for Gastroenterology and Liver Diseases, Baqiyatallah University of Medical Sciences, Tehran, Iran
- Tehran Hepatitis Center, Tehran, Iran
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10
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Fassoulaki A, Staikou C. Pretreatment with nitrous oxide enhances induction of anesthesia with sevoflurane: A randomized controlled trial. J Anaesthesiol Clin Pharmacol 2015; 31:511-6. [PMID: 26702210 PMCID: PMC4676242 DOI: 10.4103/0970-9185.169079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background and Aims: Inhalation anesthesia with sevoflurane may be enhanced by several drugs or techniques. The aim of the present study was to investigate the effect of nitrous oxide (N2O) pretreatment on the speed of anesthesia induction with sevoflurane. Material and Methods: Eighty patients scheduled for hysteroscopy under general anesthesia were randomly assigned to inhale for 10 min before induction 50% N2O in oxygen or air via a facemask. Anesthesia was induced with 7-8% sevoflurane in oxygen via a facemask. Bispectral index (BIS), end-tidal carbon dioxide (EtCO2) tidal volume, respiratory rate, oxygen saturation (SpO2), and heart rate were recorded every minute during the 10 min pretreatment periods and every 30 s during the first 300 s of induction with sevoflurane. During induction of anesthesia inspired and end-tidal sevoflurane concentrations were also recorded. Results: During the 10 min of inspired 50% N2O or air BIS, EtCO2, tidal volume, respiratory rate and heart rate values did not differ between the two groups except for the SpO2, which was higher in the N2O group (P < 0.001). During induction of anesthesia the N2O group exhibited lower BIS values (P = 0.001), being significant at 60-150 s (P < 0.001, P < 0.001, P = 0.002, P = 0.014) as well as at 270 s (P = 0.004). EtCO2 and tidal volume were consistently lower in the N2O group (P = 0.001, P = 0.041 respectively) and respiratory rate was higher (P = 0.007). Conclusion: Our results show that pretreatment of the patients with 50% N2O for 10 min enhances the speed of induction with sevoflurane as assessed by the BIS monitoring.
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Affiliation(s)
- Argyro Fassoulaki
- Department of Anesthesiology, Medical School, Aretaieio Hospital, University of Athens, Athens, Greece
| | - Chryssoula Staikou
- Department of Anesthesiology, Medical School, Aretaieio Hospital, University of Athens, Athens, Greece
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Hafner S, Beloncle F, Koch A, Radermacher P, Asfar P. Hyperoxia in intensive care, emergency, and peri-operative medicine: Dr. Jekyll or Mr. Hyde? A 2015 update. Ann Intensive Care 2015; 5:42. [PMID: 26585328 PMCID: PMC4653126 DOI: 10.1186/s13613-015-0084-6] [Citation(s) in RCA: 123] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 11/02/2015] [Indexed: 12/22/2022] Open
Abstract
This review summarizes the (patho)-physiological effects of ventilation with high FiO2 (0.8–1.0), with a special focus on the most recent clinical evidence on its use for the management of circulatory shock and during medical emergencies. Hyperoxia is a cornerstone of the acute management of circulatory shock, a concept which is based on compelling experimental evidence that compensating the imbalance between O2 supply and requirements (i.e., the oxygen dept) is crucial for survival, at least after trauma. On the other hand, “oxygen toxicity” due to the increased formation of reactive oxygen species limits its use, because it may cause serious deleterious side effects, especially in conditions of ischemia/reperfusion. While these effects are particularly pronounced during long-term administration, i.e., beyond 12–24 h, several retrospective studies suggest that even hyperoxemia of shorter duration is also associated with increased mortality and morbidity. In fact, albeit the clinical evidence from prospective studies is surprisingly scarce, a recent meta-analysis suggests that hyperoxia is associated with increased mortality at least in patients after cardiac arrest, stroke, and traumatic brain injury. Most of these data, however, originate from heterogenous, observational studies with inconsistent results, and therefore, there is a need for the results from the large scale, randomized, controlled clinical trials on the use of hyperoxia, which can be anticipated within the next 2–3 years. Consequently, until then, “conservative” O2 therapy, i.e., targeting an arterial hemoglobin O2 saturation of 88–95 % as suggested by the guidelines of the ARDS Network and the Surviving Sepsis Campaign, represents the treatment of choice to avoid exposure to both hypoxemia and excess hyperoxemia.
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Affiliation(s)
- Sebastian Hafner
- Institut für Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Universitätsklinikum Ulm, Helmholtzstrasse 8-1, 89081, Ulm, Germany. .,Klinik für Anästhesiologie, Universitätsklinikum Ulm, Albert-Einstein-Allee 23, 89081, Ulm, Germany.
| | - François Beloncle
- Département de Réanimation Médicale et de Médecine Hyperbare, Centre Hospitalier Universitaire, 4 rue Larrey, Cedex 9, 49933, Angers, France. .,Laboratoire de Biologie Neurovasculaire et Mitochondriale Intégrée, CNRS UMR 6214-INSERM U1083, Université Angers, PRES L'UNAM, Nantes, France.
| | - Andreas Koch
- Sektion Maritime Medizin, Institut für Experimentelle Medizin, Christian-Albrechts-Universität, 24118, Kiel, Germany. .,Schifffahrtmedizinisches Institut der Marine, 24119, Kronshagen, Germany.
| | - Peter Radermacher
- Institut für Anästhesiologische Pathophysiologie und Verfahrensentwicklung, Universitätsklinikum Ulm, Helmholtzstrasse 8-1, 89081, Ulm, Germany.
| | - Pierre Asfar
- Département de Réanimation Médicale et de Médecine Hyperbare, Centre Hospitalier Universitaire, 4 rue Larrey, Cedex 9, 49933, Angers, France. .,Laboratoire de Biologie Neurovasculaire et Mitochondriale Intégrée, CNRS UMR 6214-INSERM U1083, Université Angers, PRES L'UNAM, Nantes, France.
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Images in Anesthesiology: Severe Unilateral Atelectasis during Induction of Anesthesia. Anesthesiology 2014; 121:876. [DOI: 10.1097/aln.0b013e31829f02a0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
This article describes the gas exchange abnormalities occurring in the acute respiratory distress syndrome seen in adults and children and in the respiratory distress syndrome that occurs in neonates. Evidence is presented indicating that the major gas exchange abnormality accounting for the hypoxemia in both conditions is shunt, and that approximately 50% of patients also have lungs regions in which low ventilation-to-perfusion ratios contribute to the venous admixture. The various mechanisms by which hypercarbia may develop and by which positive end-expiratory pressure improves gas exchange are reviewed, as are the effects of vascular tone and airway narrowing. The mechanisms by which surfactant abnormalities occur in the two conditions are described, as are the histological findings that have been associated with shunt and low ventilation-to-perfusion.
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Affiliation(s)
- Richard K Albert
- Chief of Medicine, Denver Health, Professor of Medicine, University of Colorado, Adjunct Professor of Engineering and Computer Science, University of Denver, Denver, Colorado, USA.
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Ambrósio AM, Ida KK, Souto MTMR, Oshiro AH, Fantoni DT. Effects of positive end‐expiratory pressure titration on gas exchange, respiratory mechanics and hemodynamics in anesthetized horses. Vet Anaesth Analg 2013; 40:564-72. [DOI: 10.1111/vaa.12068] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 05/02/2013] [Indexed: 12/22/2022]
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D'HAESE J, DE KEUKELEIRE T, REMORY I, VAN ROMPAEY K, UMBRAIN V, POELAERT J. Assessment of intraoperative microaspiration: does a modified cuff shape improve sealing? Acta Anaesthesiol Scand 2013; 57:873-80. [PMID: 23556486 DOI: 10.1111/aas.12119] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND Intra-operative aspiration of oropharyngeal secretions is associated with post-operative pneumonia. The use of endotracheal tubes (ETTs) with a modified cuff shape could be one preventive action. In this clinical, prospective, randomised controlled trial, we hypothesised that altering the cuff shape to a tapered shape could reduce the aspiration incidence. The primary outcome was aspiration of dye solution into the trachea. METHODS Patients scheduled for lumbar surgery were intubated with either an ETT with a barrel-shaped polyvinylchloride cuff (control group, n = 30) or tapered-shaped polyvinylchloride cuff (intervention group, n = 30). Subsequently, instillation with methylthioninium chloride was performed. At 10, 30, 60, 90, and 120 min after intubation, bronchoscopy was performed assessing the degree of dye descent along the cuff and digitally stored. Single blind review of the videoclips provided data on incidence of dye aspiration and depth of penetration along the cuff. RESULTS The traditional cuff showed descent of dye into the trachea in 20% of the patients. Although a tapered-shaped polyvinylchloride cuff leaked up to the second third of the cuff, no dye leakage into the trachea was observed. The use of a tapered-shaped cuff had a protective role against aspiration (T30: OR 3.0, CI 1.57-5.75; P = 0.001). CONCLUSIONS Short-term use of tapered-shaped polyvinylchloride cuffs in surgical patients results in more effective sealing of the tracheal lumen in comparison with a traditional barrel-shaped polyvinylchloride cuffs. Further evaluation is needed to determine whether a reduction in post-operative pneumonia can be demonstrated when these cuffs are used.
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Affiliation(s)
- J. D'HAESE
- Department of Anaesthesiology and Perioperative Medicine; Pneumology and Neurosurgery; University Hospital; Brussels; Belgium
| | - T. DE KEUKELEIRE
- Department of Anaesthesiology and Perioperative Medicine; Pneumology and Neurosurgery; University Hospital; Brussels; Belgium
| | - I. REMORY
- Department of Anaesthesiology and Perioperative Medicine; Pneumology and Neurosurgery; University Hospital; Brussels; Belgium
| | - K. VAN ROMPAEY
- Department of Anaesthesiology and Perioperative Medicine; Pneumology and Neurosurgery; University Hospital; Brussels; Belgium
| | - V. UMBRAIN
- Department of Anaesthesiology and Perioperative Medicine; Pneumology and Neurosurgery; University Hospital; Brussels; Belgium
| | - J. POELAERT
- Department of Anaesthesiology and Perioperative Medicine; Pneumology and Neurosurgery; University Hospital; Brussels; Belgium
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Pilla R, Landon CS, Dean JB. A potential early physiological marker for CNS oxygen toxicity: hyperoxic hyperpnea precedes seizure in unanesthetized rats breathing hyperbaric oxygen. J Appl Physiol (1985) 2013; 114:1009-20. [PMID: 23429869 DOI: 10.1152/japplphysiol.01326.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Hyperbaric oxygen (HBO(2)) stimulates presumptive central CO2-chemoreceptor neurons, increases minute ventilation (V(min)), decreases heart rate (HR) and, if breathed sufficiently long, produces central nervous system oxygen toxicity (CNS-OT; i.e., seizures). The risk of seizures when breathing HBO(2) is variable between individuals and its onset is difficult to predict. We have tested the hypothesis that a predictable pattern of cardiorespiration precedes an impending seizure when breathing HBO2. To test this hypothesis, 27 adult male Sprague-Dawley rats were implanted with radiotelemetry transmitters to assess diaphragmatic/abdominal electromyogram, electrocardiogram, and electroencephalogram. Seven days after surgery, each rat was placed in a sealed, continuously ventilated animal chamber inside a hyperbaric chamber. Both chambers were pressurized in parallel using poikilocapnic 100% O(2) (animal chamber) and air (hyperbaric chamber) to 4, 5, or 6 atmospheres absolute (ATA). Breathing 1 ATA O(2) initially decreased V(min) and HR (Phase 1 of the compound hyperoxic ventilatory response). With continued exposure to normobaric hyperoxia, however, V(min) began increasing toward the end of exposure in one-third of the animals tested. Breathing HBO2 induced an early transient increase in V(min) (Phase 2) and HR during the chamber pressurization, followed by a second significant increase of V(min) ≤8 min prior to seizure (Phase 3). HR, which subsequently decreased during sustained hyperoxia, showed no additional changes prior to seizure. We conclude that hyperoxic hyperpnea (Phase 3 of the compound hyperoxic ventilatory response) is a predictor of an impending seizure while breathing poikilocapnic HBO(2) at rest in unanesthetized rats.
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Affiliation(s)
- Raffaele Pilla
- Department of Molecular Pharmacology & Physiology, Hyperbaric Biomedical Research Laboratory, University of South Florida, Morsani College of Medicine, Tampa, FL 33612, USA
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Ferrando C, Carbonell JA, Gutierrez A, Hernandez J, Belda J. Mechanical ventilation in the operating room: Adjusting VT, PEEP, and FiO2. TRENDS IN ANAESTHESIA AND CRITICAL CARE 2012. [DOI: 10.1016/j.tacc.2012.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Remístico PPJ, Araújo S, de Figueiredo LC, Aquim EE, Gomes LM, Sombrio ML, Ambiel SDF. Impact of alveolar recruitment maneuver in the postoperative period of videolaparoscopic bariatric surgery. Rev Bras Anestesiol 2011; 61:163-8, 169-76, 88-94. [PMID: 21474024 DOI: 10.1016/s0034-7094(11)70021-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 09/09/2010] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Pulmonary complications in bariatric surgery are common and, therefore, alveolar recruitment maneuvers (ARM) have been used to prevent or reduce them in the postoperative period (POP). The aim of this study was to evaluate the impact of ARM performed intraoperatively in patients undergoing bariatric surgery by videolaparoscopy in the incidence of postoperative pulmonary complications. METHODS Randomized clinical trial with 30 patients divided into control group (CG) and experimental group (EG), with analysis of spirometric, ventilatory, hemodynamic, and radiographic variables. ARM was performed in EG with positive end expiratory pressure of 30 cmH₂O and inspiratory plateau pressure of 45 cmH₂O for 2 minutes after pneumoperitoneum deflation. RESULTS We observed a significant decrease in spirometric values (p ≤ 0.001) and higher incidence of pulmonary complications on chest radiograph (p=0.02) in CG, as well as significant improvement in dyspnoea Borg scale (p ≤ 0.001) in EG. CONCLUSIONS We conclude that ARM is a safe and effective technique when used for prevention of pulmonary complications in patients undergoing bariatric surgery, resulting in more favorable radiological and spirometric findings in the experimental group compared to the control group in the PO.
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Affiliation(s)
- Paula Patelli Juliani Remístico
- Faculty of Medical Sciences, Universidade Estadual de Campinas Rua Tessália Vieira de Camargo, 126 Cidade Universitária "Zeferino Vaz" 13083-887, PO Box 6111-Campinas, SP, Brazil.
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Prevention and reversal of lung collapse during the intra-operative period. Best Pract Res Clin Anaesthesiol 2010; 24:183-97. [PMID: 20608556 DOI: 10.1016/j.bpa.2010.02.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
General anaesthesia induces ventilation/perfusion mismatch by lung collapse. Such lung collapse predisposes patients to preoperative complications since it can persist for several hours or days after surgery. Atelectasis can be partially prevented by using continuous positive airway pressure (CPAP) and/or by lowering FiO2 during anaesthesia induction. However, these manoeuvres are dangerous for patients presenting with challenging airway or ventilator conditions. Lung recruitment manoeuvres (RMs) are ventilatory strategies that aim to restore the aeration of normal lungs. They consist of a brief and controlled increment in airway pressure to open up collapsed areas of the lungs and sufficient positive end-expiratory pressure (PEEP) to keep them open afterward. The application of RMs during anaesthesia normalises lung function along the intraoperative period. There is physiological evidence that patients of all ages and any kind of surgery benefit from such an active intervention. The effect of RMs on patient outcome in the postoperative period is, however, not yet known.
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Zoremba M, Kalmus G, Dette F, Kuhn C, Wulf H. Effect of intra-operative pressure support vs pressure controlled ventilation on oxygenation and lung function in moderately obese adults*. Anaesthesia 2010; 65:124-9. [DOI: 10.1111/j.1365-2044.2009.06187.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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[Peri-operative atelectasis and alveolar recruitment manoeuvres]. Arch Bronconeumol 2009; 46:317-24. [PMID: 19959274 DOI: 10.1016/j.arbres.2009.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 10/08/2009] [Accepted: 10/10/2009] [Indexed: 10/20/2022]
Abstract
Respiratory complications are a significant cause of post-operative morbidity and mortality. Peri-operative atelectasis, in particular, affects 90% of surgical patients and its effects can be prolonged, due to changes in respiratory mechanics, pulmonary circulation and hypoxaemia. Alveolar collapse is caused by certain predisposing factors, mainly by compression and absorption mechanisms. To prevent or treat these atelectasis several therapeutic strategies have been proposed, such as alveolar recruitment manoeuvres, which has become popular in the last few years. Its application in patients with alveolar collapse, but without a previous significant acute lung lesion, has some special features, therefore its use is not free of uncertainties and complications. This review describes the frequency, pathophysiology, importance and treatment of peri-operative atelectasis. Special attention is paid to treatment with recruitment manoeuvres, with the purpose of providing a basis for the their rational and appropriate use.
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Ferreira FAPB, Marin MLG, Strabelli TMV, Carmona MJC. Ways the Anesthesiologist Can Contribute to the Prophylaxis of Infection in the Surgical Patient. Braz J Anesthesiol 2009; 59:756-66. [DOI: 10.1016/s0034-7094(09)70102-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2009] [Accepted: 08/11/2009] [Indexed: 01/08/2023] Open
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Prevention of pulmonary dysfunction after cardiac surgery by a vital capacity maneuver: is it so simple? Crit Care Med 2009; 37:762-3. [PMID: 19325377 DOI: 10.1097/ccm.0b013e318194dee3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Martínez G, Cruz P. [Atelectasis in general anesthesia and alveolar recruitment strategies]. ACTA ACUST UNITED AC 2009; 55:493-503. [PMID: 18982787 DOI: 10.1016/s0034-9356(08)70633-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Atelectasis occurs in most patients during general anesthesia and is the main cause of hypoxemia. The objective of this review is to examine the causes and diagnosis of atelectasis and the different strategies for reducing or preventing this complication and improving oxygenation. Pulmonary atelectasis is mainly caused by 3 factors: compression, gas absorption, and lack of surfactant. Compression and gas absorption are, however, the 2 most commonly implicated factors. Lung collapse is accentuated if pure oxygen is inhaled during induction or if the patient is morbidly obese. Laparoscopic, thoracic, and upper abdominal interventions also carry risk of lung collapse. Various techniques may be used to prevent atelectasis or to reopen collapsed lung tissue. These include using positive end-expiratory pressure or a high tidal volume-thus providing a higher airway pressure (vital capacity maneuver)-or both in combination. Alveolar recruitment strategies have been tried in bariatric surgery, single-lung ventilation, laparoscopy, and adult respiratory distress syndrome. Their application has reduced or prevented atelectasis, thereby reducing postoperative pulmonary complications.
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Affiliation(s)
- G Martínez
- Servicio de Anestesiología y Reanimación, Hospital General Universitario Gregorio Marañón, Madrid.
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Cinnella G, Grasso S, Natale C, Sollitto F, Cacciapaglia M, Angiolillo M, Pavone G, Mirabella L, Dambrosio M. Physiological effects of a lung-recruiting strategy applied during one-lung ventilation. Acta Anaesthesiol Scand 2008; 52:766-75. [PMID: 18582305 DOI: 10.1111/j.1399-6576.2008.01652.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND One-lung ventilation (OLV) affects respiratory mechanics and ventilation/perfusion matching, reducing functional residual capacity of the ventilated lung. While the application of a lung-recruiting manoeuvre (RM) on the ventilated lung has been shown to improve oxygenation, data regarding the impact of RM on respiratory mechanics are not available. METHODS Thirteen patients undergoing lung resection in lateral decubitus were studied. During OLV, a lung-recruiting strategy consisting in a RM lasting 1 min followed by the application of positive end-expiratory pressure 5 cmH(2)O was applied to the ventilated lung. Haemodynamics, gas exchange and respiratory mechanics parameters were recorded on two-lung ventilation (TLV(baseline)), OLV before and 20 min after the RM (OLV(pre-RM), OLV(post-RM), respectively) and TLV(end). Haemodynamics parameters were also recorded during the RM. RESULTS The PaO(2)/FiO(2) ratio was 358+/-126 on TLV(baseline); it decreased to 235+/-113 on OLV(pre-RM) (P<0.01) increased to 351+/-120 on OLV(post-RM) (P<0.01 vs. OLV(pre-RM)), and remain stable thereafter. During the RM, CI decreased from 3.04+/-0.7 l/m(2) OLV(pre-RM) to 2.4+/-0.6 l/m(2) (P<0.05), and returned to baseline on OLV(post-RM) (3.1+/-0.7 l/m(2), NS vs. OLV(pre-RM)). The RM resulted in alveolar recruitment and caused a significant decrease in static elastance of the dependent lung (16.6+/-8.9 cmH(2)O/ml OLV(post-RM) vs. 22.3+/-8.1 cmH(2)O/ml OLV(pre-RM)) (P<0.01). CONCLUSIONS During OLV in lateral decubitus for thoracic surgery, application to the dependent lung a recruiting strategy significantly recruits the dependent lung, improving arterial oxygenation and respiratory mechanics until the end of surgery. However, the transient haemodynamic derangement occurring during the RM should be taken into account.
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Affiliation(s)
- G Cinnella
- Dipartimento di Scienze Chirurgiche, Sezione di Anestesiologia e Rianimazione, Università degli Studi di Foggia, Policlinico Riuniti, Foggia, Italy.
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Kaditis AG, Motoyama EK, Zin W, Maekawa N, Nishio I, Imai T, Milic-Emili J. The Effect of Lung Expansion and Positive End-Expiratory Pressure on Respiratory Mechanics in Anesthetized Children. Anesth Analg 2008; 106:775-85, table of contents. [DOI: 10.1213/ane.0b013e318162c20a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Lutterbey G, Wattjes MP, Doerr D, Fischer NJ, Gieseke J, Schild HH. Atelectasis in children undergoing either propofol infusion or positive pressure ventilation anesthesia for magnetic resonance imaging. Paediatr Anaesth 2007; 17:121-5. [PMID: 17238882 DOI: 10.1111/j.1460-9592.2006.02045.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Atelectasis because of anesthesia is a recognized problem but may be affected by the anesthetic technique. We compared magnetic resonance images of atelectasis in children undergoing two types of anesthesia. METHODS Children requiring anesthesia for magnetic resonance imaging (MRI) had additional lung imaging sequences at the beginning and the end of anesthesia. Children had either i.v. propofol infusion (PI) without an artificial airway (n = 26) or positive pressure ventilation (PPV) via a tracheal tube (n = 20); the technique was chosen for clinical reasons. The extent of atelectasis was scored by two independent radiologists. RESULTS The median ages (range) for PI and PPV groups were 45 months (1-77 months) and 18 months (2-74 months), respectively. The proportion of children with atelectasis was different in the first lung scan (42% vs 80%), but in the second scan atelectasis was seen frequently in both groups (82% vs 94%) with a greater extent in the PPV group. The atelectasis score was higher in young children, but all children had normal oxygen requirements and saturations. CONCLUSIONS Many factors may influence the development of atelectasis but this study found less extensive atelectasis with PI than PPV. PI allows for sufficient motionlessness, required for high diagnostic image quality in pediatric MRI.
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Ratzenhofer-Komenda B, Offner A, Ofner P, Klemen H, Prause G, Smolle-Jüttner FM, Toller W. Arterial oxygen tension increase 2-3 h after hyperbaric oxygen therapy: a prospective observational study. Acta Anaesthesiol Scand 2007; 51:68-73. [PMID: 17229230 DOI: 10.1111/j.1399-6576.2006.01197.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Inhalation of hyperbaric oxygen (HBO) has been reported to decrease arterial oxygen tension (PaO(2)) in the early period after exposure. The current investigation aimed at evaluating whether and to what extent arterial blood gases were affected in mechanically ventilated intensive care patients within 6 h after HBO treatment. METHODS Arterial blood gases were measured in 11 ventilated subjects [nine males, two females, synchronized intermittent mandatory ventilation (SIMV) mode] undergoing HBO therapy for necrotizing soft tissue infection (seven patients), burn injury (two patients), crush injury (one patient) and major abdominal surgery (one patient). Blood gases were obtained with the patients in the supine position under continuous analgesia and sedation before the hyperbaric session (baseline), during isopression, after decompression, after each transport, and 1, 2, 3 and 6 h after exposure. Heart rates and blood pressures were recorded. Intensive care unit (ICU) ventilator settings remained unchanged. Transport and chamber ventilator settings were adjusted to baseline with maintenance of tidal volumes and positive end-expiratory pressure (PEEP) levels. The hyperbaric protocol consisted of 222.9 kPa (2.2 absolute atmospheres) and a 50-min isopression phase. The paired Wilcoxon's test was used. RESULTS Major findings (median values, 25%/75% quartiles) as per cent change of baseline: PaO(2) values decreased by 19.7% (7.0/31.7, P < 0.01) after 1 h and were elevated over baseline by 9.3% (1.5/13.7, P < 0.05) after 3 h. SaO(2), alveolar-arterial oxygen tension difference and PaO(2)/FiO(2) ratio behaved concomitantly. Acid-base status and carbon dioxide tension were unaffected. CONCLUSION Arterial oxygen tension declines transiently after HBO and subsequently improves over baseline in intensive care patients on volume-controlled mechanical ventilation. The effectiveness of other ventilation modes or a standardized recruitment manoeuvre has yet to be evaluated.
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Affiliation(s)
- B Ratzenhofer-Komenda
- Department of Anaesthesiology and Critical Care, University Medical School of Graz, Graz, Austria.
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Fassoulaki A, Petropoulos G, Kottis G, Sarantopoulos C. Pre-oxygenation enhances induction with sevoflurane as assessed using bispectral index monitoring. Acta Anaesthesiol Scand 2006; 50:475-80. [PMID: 16548860 DOI: 10.1111/j.1399-6576.2006.00981.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Several methods may enhance the inhalational induction of anesthesia. In this randomized double-blind study, we evaluated the speed of induction of anesthesia with sevoflurane with or without pre-oxygenation. METHODS Fifty-four patients scheduled for hysteroscopy received for 10 min air or 100% oxygen via a facemask followed by > or = 7% sevoflurane in 100% oxygen. During the first 300 s of sevoflurane administration, bispectral index (BIS) values were recorded every 30 s in all patients. In 14 patients, seven in each group, BIS, endtidal CO(2), tidal volume, respiratory rate, SpO(2), and heart rate were recorded every minute during the pre-induction period and every 30 s during the first 5 min of sevoflurane administration. RESULTS The BIS, endtidal CO(2), tidal volume and respiratory rate did not differ between the oxygen or air breathing groups (P = 0.696, P = 0.999, P = 0.388, and P = 0.875, respectively), though the oxygen group exhibited lower tidal volumes by 16-20%. The SpO(2) and heart rates were higher in the oxygen breathing group (P < 0.001 and P = 0.042, respectively). During sevoflurane administration, BIS values were lower in the oxygen group vs. the group breathing air, in particular at 90, 120, 150, 180 and 210 s (P = 0.001, P = 0.001, P = 0.001, P = 0.001 and P = 0.030, respectively). The endtidal CO(2) and the tidal volumes between the groups did not differ. The two groups differed in the SpO(2) and the heart rates during induction (P = 0.004 and 0.003, respectively). CONCLUSIONS Before sevoflurane administration, breathing 100% oxygen for 10 min enhances induction of anesthesia with sevoflurane.
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Affiliation(s)
- A Fassoulaki
- Department of Anesthesiology, Aretaieio Hospital, Medical School, University of Athens, Athens, Greece.
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Sinha PK, Neema PK, Unnikrishnan KP, Varma PK, Jaykumar K, Rathod RC. Effect of Lung Ventilation With 50% Oxygen in Air or Nitrous Oxide Versus 100% Oxygen on Oxygenation Index After Cardiopulmonary Bypass. J Cardiothorac Vasc Anesth 2006; 20:136-42. [PMID: 16616650 DOI: 10.1053/j.jvca.2005.11.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Indexed: 11/11/2022]
Abstract
OBJECTIVE This study was designed to assess the use of 100% oxygen or 50% oxygen in air or nitrous oxide after cardiopulmonary bypass (CPB) on atelectasis, as evidenced by the oxygenation index (PaO2/F(I)O2), after coronary artery bypass graft (CABG) surgery. DESIGN Prospective, randomized clinical study. SETTING University teaching hospital. PARTICIPANT Thirty-six adult patients undergoing CABG surgery. INTERVENTIONS Patients either received 50% O2 in air (50% O2 group), 50% O2 in N2O (50% N2O group), or 100% O2 (100% O2 group) after CPB. MEASUREMENTS AND MAIN RESULTS Apart from demographic and perioperative clinical data, extubation time, mediastinal drainage, and pulmonary complications were also recorded. After CPB, arterial blood gases done at various time points until 3 hours postextubation and oxygenation index were calculated. No significant differences were noted in demographic and perioperative data except preoperative hemoglobin and fluid use. Significant deterioration in arterial oxygenation was noted in the 100% O2 group from the baseline value, whereas significant improvement was seen in the 50% O2 group at 4 time points from baseline value and at all time points from the 100% O2 group. After initial deterioration in oxygenation, no further change was evident in the 50% N2O group. Furthermore, there was a greater increase in the oxygenation index as compared with the 100% O2 group. Time to extubation was also longer in the 100% O2 group than the 50% O2 group. CONCLUSION Significant deterioration in arterial oxygenation and an increase in the extubation time occurred with the use of 100% O2 after CPB, whereas better oxygenation was evident with the use of 50% O2 in air.
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Affiliation(s)
- Prabhat Kumar Sinha
- Department of Anaesthesiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, India.
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Whalen FX, Gajic O, Thompson GB, Kendrick ML, Que FL, Williams BA, Joyner MJ, Hubmayr RD, Warner DO, Sprung J. The effects of the alveolar recruitment maneuver and positive end-expiratory pressure on arterial oxygenation during laparoscopic bariatric surgery. Anesth Analg 2006; 102:298-305. [PMID: 16368847 DOI: 10.1213/01.ane.0000183655.57275.7a] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Abnormalities in gas exchange that occur during anesthesia are mostly caused by atelectasis, and these alterations are more pronounced in morbidly obese than in normal weight subjects. Sustained lung insufflation is capable of recruiting the collapsed areas and improving oxygenation in healthy patients of normal weight. We tested the effect of this ventilatory strategy on arterial oxygenation (Pao2) in patients undergoing laparoscopic bariatric surgery. After pneumoperitoneum was accomplished, the recruitment group received up to 4 sustained lung inflations with peak inspiratory pressures up to 50 cm H2O, which was followed by ventilation with 12 cm H2O positive end-expiratory pressure (PEEP). The patient's lungs in the control group were ventilated in a standard fashion with PEEP of 4 cm H2O. Variables related to gas exchange, respiratory mechanics, and hemodynamics were compared between recruitment and control groups. We found that alveolar recruitment effectively increased intraoperative Pao2 and temporarily increased respiratory system dynamic compliance (both P < 0.01). The effects of alveolar recruitment on oxygenation lasted as long as the trachea was intubated, and lungs were ventilated with high PEEP, but soon after tracheal extubation, all the beneficial effects on oxygenation disappeared. The mean number of vasopressor treatments given during surgery was larger in the recruitment group compared with the control group (3.0 versus 0.8; P = 0.04). In conclusion, our data suggest that the use of alveolar recruitment may be an effective mode of improving intraoperative oxygenation in morbidly obese patients. Our results showed the effect to be short lived and associated with more frequent intraoperative use of vasopressors.
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Affiliation(s)
- Francis X Whalen
- Department of Anesthesiology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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Marntell S, Nyman G, Hedenstierna G. High inspired oxygen concentrations increase intrapulmonary shunt in anaesthetized horses. Vet Anaesth Analg 2005; 32:338-47. [PMID: 16297043 DOI: 10.1111/j.1467-2995.2005.00199.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To compare pulmonary function and gas exchange in anaesthetized horses during and after breathing either O2-rich gas mixtures or air. ANIMALS Six healthy standard bred trotters (age range 3-12 years; mass range 423-520 kg), four geldings and two mares. Study design Randomized, cross-over experimental study. METHODS Horses were anaesthetized on two occasions with tiletamine-zolazepam after pre-anaesthetic medication with acepromazine, romifidine and butorphanol. After endotracheal intubation and positioning in left lateral recumbency, animals were allowed to breathe spontaneously. One of two, randomly allocated inspired gas treatments was provided: either i) room air (fractional concentration of inspired O2 [FIO2] = 0.21) provided throughout anaesthesia; or ii) an O2-rich gas mixture (FIO2 = >0.95) for 15 minutes, followed by room air. The alternative treatment was delivered at the second anaesthetic. Respiratory and haemodynamic variables and the distribution of ventilation-perfusion (VA/Q) ratios (using the multiple inert gas elimination technique) were determined in the standing conscious horse (baseline) after sedation and during anaesthesia. RESULTS Breathing O2-rich gas was associated with a decreased respiratory rate (p = 0.015) increased PaCO2 (p < 0.001) and increased PaO2 (p = 0.004) compared with breathing air. All horses developed intrapulmonary shunt during anaesthesia, but shunt was significantly greater (13 +/- 5%) when O2-rich gas was delivered compared with air breathing (5 +/- 2%; p = 0.013). Ten minutes after O2-rich gas was replaced by air, shunt remained larger in horses that had initially received oxygen compared with those breathing air (p = 0.042). Mixed venous oxygen tensions were significantly lower during sedation than at baseline (p < 0.001) and during anaesthesia (p < 0.001). CONCLUSIONS During dissociative anaesthesia, arterial oxygenation was greater when horses breathed gas containing more than 95% oxygen, compared with when they breathed air. However, breathing O2-rich gas increased intrapulmonary shunt and caused hypoventilation. The intrapulmonary shunt created during anaesthesia by high inspired O2 concentrations remained larger when FIO2 was reduced to 0.21, indicating that absorption atelectasis produced during O2-rich gas breathing persisted throughout anaesthesia. CLINICAL RELEVANCE In healthy horses undergoing short-term dissociative anaesthesia, air breathing ensures a level of oxygen delivery that meets tissue demand. There is no benefit to horses in breathing O2-rich gas after the gas supply is discontinued. On the contrary, the degree of shunt induced by breathing O2-rich gas persists. The clinical relevance of this during recovery requires investigation.
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Affiliation(s)
- Stina Marntell
- Department of Large Animal Clinical Sciences, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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Affiliation(s)
- S V Baudouin
- Department of Anaesthesia, Leazes Wing, Royal Victoria Infirmary, Newcastle upon Tyne, UK.
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Yoshino J, Akata T, Takahashi S. Intraoperative changes in arterial oxygenation during volume-controlled mechanical ventilation in modestly obese patients undergoing laparotomies with general anesthesia. Acta Anaesthesiol Scand 2003; 47:742-50. [PMID: 12803594 DOI: 10.1034/j.1399-6576.2003.00147.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND In obese patients, arterial oxygenation can be greatly impaired during general anesthesia. Both avoidance of denitrogenation and application of positive end-expiratory pressure (PEEP) during mechanical ventilation may be effective in preventing such impairment of arterial oxygenation. METHODS We studied 28 obese/overweight and seven non-obese (BMI < 25 kg x m-2) patients who underwent laparotomies with general anesthesia (i.e. isoflurane with or without nitrous oxide). During anesthesia, their lungs were mechanically ventilated at a rate of 10 breaths x min-1 with a constant flow, inspiratory-to-expiratory ratio 1 : 2, and tidal volume approximately 10 ml x kg-1. The obese/overweight patients were allocated to four different groups in terms of denitrogenation and application of PEEP (7 cm H2O) during the ventilation (n = 7 each). In the non-obese patients, their denitrogenated lungs were ventilated without application of PEEP. Arterial gas analyses were performed before induction of anesthesia, and 30, 90, 150 and 210 min after tracheal intubation. The ratio of PaO2 to FiO2 was calculated as an index of arterial oxygenation. RESULTS No significant changes in the PaO2/FiO2 ratio were observed throughout the study in the non-obese patients and in the obese/overweight patients whose non-denitrogenated lungs were ventilated with PEEP. In the obese/overweight patients whose lungs were ventilated after denitrogenation or without application of PEEP, significant decreases in the PaO2/FiO2 ratio were observed 30 and 90 min after tracheal intubation. CONCLUSIONS In obese or overweight patients under general anesthesia, it may be advisable to avoid denitrogenation and apply PEEP during mechanical ventilation in order to minimize the impairment of arterial oxygenation.
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Affiliation(s)
- J Yoshino
- Department of Anesthesiology and Critical Care Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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Affiliation(s)
- L Magnusson
- Department of Anaesthesiology, University Hospital, CHUV, CH-1011 Lausanne, Switzerland.
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Ratzenhofer-Komenda B, Offner A, Quehenberger F, Klemen H, Berger J, Fadai JH, Spernbauer P, Prause G, Smolle-Jüttner FM. Hemodynamic and oxygenation profiles in the early period after hyperbaric oxygen therapy: an observational study of intensive-care patients. Acta Anaesthesiol Scand 2003; 47:554-8. [PMID: 12699512 DOI: 10.1034/j.1399-6576.2003.00101.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND We studied whether hemodynamic and oxygenation profiles are altered in critically ill patients after exposure to hyperbaric oxygen (HBO). METHODS Ten intensive-care patients (two females, eight males) undergoing HBO treatment after major abdominal surgery, after burn injury and after CO poisoning were included. All subjects were put on mechanical ventilation and received continuous sedation, and had HBO treatment at 2.2 absolute atmospheres for 50 min. DESIGN Observational prospective study, and repeated measure design. RESULTS Hemodynamic and oxygen transport patterns were determined before (C0), 1 h (C1) and 2 h (C2) after HBO therapy with continuous cardiac output dual oximetry pulmonary arterial catheter, a central venous and radial arterial line. Data were analyzed with non-parametric repeated measure analysis. Key results are expressed as a percentage of baseline (C0 values correspond to 100%) at C1 and C2 (median values, lower and upper limit of confidence interval): cardiac index [C1: 105% (98-135), C2: 99% (91-117), P = 0.19], systemic (P = 0.62) and pulmonary vascular (P = 0.76) resistance indices were unchanged, but pulmonary venous admixture (Qs/Qt) increased [C1: 173% (112-298), C2: 140% (92-241), P = 0.00002)] and arterial oxygen tension decreased [C1: 76% (67-94), C2: 82% (72-112), P = 0.010]. CONCLUSION The hemodynamic profile remained unaffected. The increase in Qs/Qt and the decrease in PaO2 may be attributed to the inhalation of HBO, and both are reversible.
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Affiliation(s)
- B Ratzenhofer-Komenda
- Department of Anesthesiology and Critical Care Medicine, University Medical School of Graz, Graz, Austria.
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Claxton BA, Morgan P, McKeague H, Mulpur A, Berridge J. Alveolar recruitment strategy improves arterial oxygenation after cardiopulmonary bypass. Anaesthesia 2003; 58:111-6. [PMID: 12562405 DOI: 10.1046/j.1365-2044.2003.02892.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Atelectasis occurs during general anaesthesia. This is partly responsible for the impairment of gas exchange that occurs peri-operatively. During cardiopulmonary bypass, this atelectasis is exacerbated by the physical collapse of the lungs. As a result, poor arterial oxygenation is often seen postoperatively. We tested the effect of an 'alveolar recruitment strategy' on arterial oxygenation in a prospective randomised study of 78 patients undergoing cardiopulmonary bypass. Patients were divided equally into three groups of 26. Group 'no PEEP' received a standard post bypass manual lung inflation, and no positive end-expiratory pressure was applied until arrival at intensive care unit. Group '5 PEEP' received a standard post bypass manual inflation, and then 5 cmH2O of positive end-expiratory pressure was applied and maintained until extubation on intensive care. The third group, 'recruitment group', received a pressure-controlled stepwise increase in positive end-expiratory pressure up to 15 cmH2O and tidal volumes of up to 18 ml x kg(-1) until a peak inspiratory pressure of 40 cmH2O was reached. This was maintained for 10 cycles; the positive end-expiratory pressure of 5 cmH2O was maintained until extubation on intensive care. There was a significantly better oxygenation in the recruitment group at 30 min and 1 h post bypass when compared with the no PEEP and 5 PEEP groups. There was no significant difference in any of the groups beyond 1 h. Application of 5 cmH2O positive end-expiratory pressure alone had no significant effect on oxygenation. No complications due to the alveolar recruitment manoeuvre occurred. We conclude that the application of an alveolar recruitment strategy improves arterial oxygenation after cardiopulmonary bypass surgery.
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Affiliation(s)
- B A Claxton
- Department of Anaesthesia, St James's University Hospital, Beckett Street, Leeds, LS9 7TF, UK
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Purhonen S, Turunen M, Ruohoaho UM, Niskanen M, Hynynen M. Supplemental oxygen does not reduce the incidence of postoperative nausea and vomiting after ambulatory gynecologic laparoscopy. Anesth Analg 2003; 96:91-6, table of contents. [PMID: 12505931 DOI: 10.1097/00000539-200301000-00020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED Supplemental 80% oxygen administration halves the incidence of postoperative nausea and vomiting (PONV) in inpatients. Whether it prevents PONV after ambulatory surgery is unknown. We tested the efficacy of supplemental 80% oxygen in decreasing the incidence of PONV after ambulatory gynecologic laparoscopy. One hundred patients were given a standardized sevoflurane anesthetic. They were randomly assigned to two groups: routine oxygen administration with 30% oxygen, balance nitrogen (Group A); and supplemental oxygen with 80% oxygen, balance nitrogen (Group B). Oxygen was administered during surgery and up to 1 h after surgery. The incidence of nausea and vomiting and the need for rescue antiemetics did not differ between the groups in the postanesthesia care unit, in the Phase II unit, or during the 24-h follow-up. The overall incidence of nausea and vomiting during the first postoperative 24 h was 62% in Group A and 55% in Group B (P = 0.486). There were no differences in the recovery profiles and patient satisfaction between the groups. In this study, supplemental oxygen did not prevent PONV in patients undergoing ambulatory gynecologic laparoscopy. IMPLICATIONS Supplemental 80% oxygen administration during surgery and until 1 h after surgery compared with 30% oxygen administration did not prevent postoperative nausea and vomiting after ambulatory gynecologic laparoscopy.
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Affiliation(s)
- Sinikka Purhonen
- Department of Anesthesiology and Intensive Care, Kuopio University Hospital, Finland.
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Purhonen S, Turunen M, Ruohoaho UM, Niskanen M, Hynynen M. Supplemental Oxygen Does Not Reduce the Incidence of Postoperative Nausea and Vomiting After Ambulatory Gynecologic Laparoscopy. Anesth Analg 2003. [DOI: 10.1213/00000539-200301000-00020] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Loeckinger A, Kleinsasser A, Keller C, Schaefer A, Kolbitsch C, Lindner KH, Benzer A. Administration of oxygen before tracheal extubation worsens gas exchange after general anesthesia in a pig model. Anesth Analg 2002; 95:1772-6, table of contents. [PMID: 12456457 DOI: 10.1097/00000539-200212000-00057] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED Administration of 100% oxygen before tracheal extubation is common clinical practice. We determined the effect of this technique on postoperative gas exchange in a porcine model using the multiple inert gas elimination technique. After general anesthesia with mechanical ventilation for a period of 30 min (inspiratory fraction of oxygen of 0.3), anesthesia was discontinued, and the pigs were randomized to an inspiratory fraction of oxygen of 0.3 or 1.0 until they could be safely extubated. Thirty minutes after extubation while breathing air, blood flow to poorly ventilated units had significantly increased in pigs that had been administered 100% oxygen as compared with those receiving 30% oxygen (17% +/- 15% versus 7% +/- 5%; P = 0.009). We conclude that exposure to 100% oxygen before extubation may cause an undesirable alteration in gas exchange. IMPLICATIONS Blood flow to lung units with a low V(A)/Q ratio was significantly larger in pigs that had been exposed to 100% oxygen before extubation as compared with those exposed to 30% oxygen before extubation.
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Affiliation(s)
- Alexander Loeckinger
- Department of Anesthesiology, Critical Care and Emergency Medicine, The Leopold-Franzens University Innsbruck, Austria.
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Benoît Z, Wicky S, Fischer JF, Frascarolo P, Chapuis C, Spahn DR, Magnusson L. The effect of increased FIO(2) before tracheal extubation on postoperative atelectasis. Anesth Analg 2002; 95:1777-81, table of contents. [PMID: 12456458 DOI: 10.1097/00000539-200212000-00058] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED General anesthesia promotes pulmonary atelectasis, which can be eliminated by a vital capacity (VC) maneuver (inflation of the lungs to 40 cm H(2)O for 15 s). High-inspired oxygen concentration favors recurrence of atelectasis. Therefore, 100% oxygen before tracheal extubation may contribute to atelectasis. To evaluate whether the use of 100% oxygen before extubation increases the amount of postoperative atelectasis, we studied 30 adults scheduled for elective surgery of the extremities. Ten minutes before the presumed end of surgery, patients were randomly assigned to (a) a fraction of inspired oxygen (FIO(2)) = 1.0 (n = 10), (b) VC maneuver + FIO(2) = 1.0 (n = 10), or (c) VC maneuver + FIO(2) = 0.4 (n = 10). The amount of atelectasis was measured by computed tomography scan, and oxygenation was studied by arterial blood gas analysis. Data were analyzed by one-way analysis of variance with Bonferroni correction. Results are presented as mean +/- SD; P < 0.05 was considered significant. In the VC maneuver + FIO(2) = 0.4 group, postoperative atelectasis was smaller (2.6% +/- 1.1% of total lung surface, P < 0.05) than in the FIO(2) = 1.0 group (8.3% +/- 6.2%) and in the VC maneuver + FIO(2) = 1.0 group (6.8% +/- 3.4%). Oxygen 100% at the end of general anesthesia promotes postoperative atelectasis. A safety margin in terms of oxygenation during tracheal extubation is essential, and further studies should therefore evaluate whether atelectasis formation could be prevented despite the use of 100% oxygen. IMPLICATIONS For safety reasons, it is common to ventilate patients with 100% oxygen before tracheal extubation. This study demonstrates that this practice favors postoperative atelectasis.
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Affiliation(s)
- Zilgia Benoît
- Department of Anesthesiology, Centre Hospitalier Universitaire Vaudois, Lausanne, Suisse
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Murphy GS, Szokol JW, Curran RD, Votapka TV, Vender JS. Influence of a vital capacity maneuver on pulmonary gas exchange after cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2001; 15:336-40. [PMID: 11426365 DOI: 10.1053/jcan.2001.23287] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To investigate the effect of a single, vital capacity breath (vital capacity maneuver [VCM]), administered at the end of cardiopulmonary bypass (CPB), on pulmonary gas exchange in patients undergoing coronary artery bypass graft surgery. DESIGN Prospective, randomized, double-blind study. SETTING University-affiliated hospital. PARTICIPANTS Forty patients scheduled for elective coronary artery bypass graft surgery and early tracheal extubation. INTERVENTIONS Patients were randomized to 1 of 2 groups. VCM patients received a VCM at the conclusion of CPB. Control patients received no VCM. MEASUREMENTS AND MAIN RESULTS Intrapulmonary shunt (Q(S)/Q(T)), arterial oxygenation (PaO2), and alveolar-arterial oxygen gradients (P(A-a)O2) were measured after induction of anesthesia, CPB, intensive care unit (ICU) arrival, and extubation. The duration of postoperative intubation was recorded for each group. Q(S)/Q(T) increased significantly 30 minutes after CPB in the control group (15.7 +/- 1.8% to 27.4 +/- 2.6%; p = 0.01). In the VCM group, a small decrease in Q(S)/Q(T) occurred (16.1 +/- 2.0% to 14.9 +/- 2.0%). After ICU arrival and extubation, no significant difference in Q(S)/Q(T) existed between the 2 groups. With the exception of a higher P(A-a)O2 in the control group at induction of anesthesia, no differences in PaO2 or P(A-a)O2 were present between the 2 groups at any measurement interval. Patients who received a VCM were extubated earlier than the control group (6.5 +/- 2.1 hours v 9.4 +/- 4.2 hours; p = 0.01). CONCLUSION The use of a VCM prevented an increase in Q(S)/Q(T) from occurring in the operating room. Although a VCM did not influence pulmonary gas exchange in the ICU, its application in the operating room appears to exert a beneficial effect on tracheal extubation times after cardiac surgery.
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Affiliation(s)
- G S Murphy
- Departments of Anesthesia and Surgery, Evanston Northwestern Healthcare/Northwestern University, Evanston, IL, USA
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Perilli V, Sollazzi L, Bozza P, Modesti C, Chierichini A, Tacchino RM, Ranieri R. The effects of the reverse trendelenburg position on respiratory mechanics and blood gases in morbidly obese patients during bariatric surgery. Anesth Analg 2000; 91:1520-5. [PMID: 11094011 DOI: 10.1097/00000539-200012000-00041] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Anesthesia adversely affects respiratory function, particularly in morbidly obese patients. Although many studies have been performed to determine the optimal ventilatory settings in these patients, this question has not been answered. The aim of this study was to evaluate the effect of reverse Trendelenburg position (RTP) on gas exchange and respiratory mechanics in 15 obese patients undergoing biliopancreatic diversion. A standardized anesthetic regimen was used and patients were examined at standard times: 1) after tracheal intubation, 2) after laparotomy, 3) after positioning of subcostal retractors, 4) with retractors in RTP. The measurements of respiratory mechanics were repeated for a wide range of tidal volumes by using the technique of rapid occlusion during constant flow inflation. We noted a wide alveolar-arterial oxygen difference [P(A-a)O(2)] in all patients, particularly during Phase 3. When the patients were placed in RTP, P(A-a)O(2) showed a significant improvement and a return toward baseline values. As for mechanics, total respiratory system compliance was significantly higher in RTP than in the other phases. In conclusion, our data suggest that RTP is an appropriate intraoperative posture for obese subjects because it causes minimal arterial blood pressure changes and improves oxygenation.
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Affiliation(s)
- V Perilli
- Department of Anesthesiology and Surgery, Catholic University of Sacred Heart Rome, Rome, Italy
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Wetterslev J, Hansen EG, Kamp-Jensen M, Roikjaer O, Kanstrup IL. PaO2 during anaesthesia and years of smoking predict late postoperative hypoxaemia and complications after upper abdominal surgery in patients without preoperative cardiopulmonary dysfunction. Acta Anaesthesiol Scand 2000; 44:9-16. [PMID: 10669265 DOI: 10.1034/j.1399-6576.2000.440103.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND The incidence of late postoperative hypoxaemia and complications after upper abdominal surgery is 20-50% among cardiopulmonary healthy patients. Atelectasis development during anaesthesia and surgery is the main hypothesis to explain postoperative hypoxaemia. This study tested the predictive value of PaO2<19 kPa during combined general and thoracic epidural anaesthesia and the preoperative functional residual capacity (FRC) reduction in the 30 degree head tilt-down position for the development of late prolonged postoperative hypoxaemia, PaO2<8.5 kPa for a minimum of 3 out of 4 days, and other complications. Forty patients without cardiopulmonary morbidity, assessed by ECG, spirometry, FRC and diffusion capacity preoperatively, underwent upper abdominal surgery. PaO2 during anaesthesia and preoperative FRC reduction were compared to known risk factors for the development of hypoxaemia and complications: age, pack-years of smoking and duration of operation. The effect of optimizing pulmonary compliance with peroperative positive end-expiratory pressure (PEEP) on postoperative hypoxaemia and complications was evaluated in a blinded and randomized manner. RESULTS Late prolonged postoperative hypoxaemia and other complications were found in 37% and 38% of the patients, respectively. Patients with PaO2>19 kPa during anaesthesia with F(I)O2=0.33 exhibited a risk, irrespective of PEEP status, of suffering late prolonged hypoxaemia of 0% (0;23) and patients with PaO2<19 kPa a risk of 52% (32;71), P<0.005. Having smoked more than 20 pack-years was associated with a 47% (19;75) higher incidence of postoperative complications than having smoked less than 20 pack-years, P<0.006. CONCLUSIONS PaO2 during anaesthesia and smoked pack-years provide new tools evaluating patients undergoing upper abdominal surgery in order to predict the patients who develop late postoperative hypoxaemia and complications.
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Affiliation(s)
- J Wetterslev
- Department of Anaesthesiology and Intensive Care, Herlev University Hospital, Denmark
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Volta CA, Verri M, Righini ER, Ragazzi R, Pavoni V, Alvisi R, Gritti G. Respiratory mechanics during and after anaesthesia for major vascular surgery. Anaesthesia 1999; 54:1041-7. [PMID: 10540092 DOI: 10.1046/j.1365-2044.1999.01068.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To evaluate the effects of major vascular surgery on respiratory mechanics, 11 patients undergoing general anaesthesia for abdominal aortic surgery were studied. Before aortic cross-clamping, chest wall elastance and resistance both increased (by 126% and 58%, respectively) when surgical retractors were placed. After aortic cross-clamping, lung elastance increased by 29%, accompanied by a decrease in cardiac index (22%) and an increase in pulmonary (17%) and systemic (15%) vascular resistance. After aortic unclamping, lung elastance decreased, although it remained higher than baseline values (by 12%). All cardiovascular variables returned to the values obtained before aortic cross-clamping.
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Affiliation(s)
- C A Volta
- Department of Biomedical Science and Advanced Therapy, Section of Anaesthesia and Intensive Care, S. Anna Hospital, University of Ferrara, Italy
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