1
|
Sang L, Zhao Z, Lin Z, Liu X, Zhong N, Li Y. A narrative review of electrical impedance tomography in lung diseases with flow limitation and hyperinflation: methodologies and applications. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1688. [PMID: 33490200 PMCID: PMC7812189 DOI: 10.21037/atm-20-4984] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Electrical impedance tomography (EIT) is a functional radiation-free imaging technique that measures regional lung ventilation distribution by calculating the impedance changes in the corresponding regions. The aim of the present review was to summarize the current literature concerning the methodologies and applications of EIT in lung diseases with flow limitation and hyperinflation. PubMed was searched up to May 2020 to identify studies investigating the use of EIT in patients with asthma, bronchiectasis, bronchitis, bronchiolitis, chronic obstructive pulmonary disease, and cystic fibrosis. The extracted data included study design, EIT methodologies, interventions, validation and comparators, population characteristics, and key findings. Of the 44 included studies, seven were related to simulation, animal experimentation, or reconstruction algorithm development with evaluation on patients; 27 studies had the primary objective of validating EIT technique and measures including regional ventilation distribution, regional EIT-spirometry parameters, end-expiratory lung impedance, and regional time constants; and 10 studies had the primary objective of applying EIT to monitor the response to therapeutic interventions, including various ventilation supports, patient repositioning, and airway suctioning. In pediatric and adult patients, EIT has been successfully validated for assessing spatial and temporal ventilation distribution, measuring changes in lung volume and flow, and studying regional respiratory mechanics. EIT has also demonstrated potential as an alternative or supplement to well-established measurement modalities (e.g., conventional pulmonary function testing) to monitor the progression of obstructive lung diseases, although the existing literature lacks prediction values as references and lacks clinical outcome evidence.
Collapse
Affiliation(s)
- Ling Sang
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Zhanqi Zhao
- Department of Biomedical Engineering, Fourth Military Medical University, Xi'an, China.,Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Zhimin Lin
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Xiaoqing Liu
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Nanshan Zhong
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| | - Yimin Li
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Health, Guangzhou Medical University, the First Affiliated Hospital of Guangzhou Medical University, Department of Crit Care Med, Guangzhou, China
| |
Collapse
|
2
|
Mosing M, Waldmann AD, Sacks M, Buss P, Boesch JM, Zeiler GE, Hosgood G, Gleed RD, Miller M, Meyer LCR, Böhm SH. What hinders pulmonary gas exchange and changes distribution of ventilation in immobilized white rhinoceroses ( Ceratotherium simum) in lateral recumbency? J Appl Physiol (1985) 2020; 129:1140-1149. [PMID: 33054661 DOI: 10.1152/japplphysiol.00359.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
This study used electrical impedance tomography (EIT) measurements of regional ventilation and perfusion to elucidate the reasons for severe gas exchange impairment reported in rhinoceroses during opioid-induced immobilization. EIT values were compared with standard monitoring parameters to establish a new monitoring tool for conservational immobilization and future treatment options. Six male white rhinoceroses were immobilized using etorphine, and EIT ventilation variables, venous admixture, and dead space were measured 30, 40, and 50 min after becoming recumbent in lateral position. Pulmonary perfusion mapping using impedance-enhanced EIT was performed at the end of the study period. The measured impedance (∆Z) by EIT was compared between pulmonary regions using mixed linear models. Measurements of regional ventilation and perfusion revealed a pronounced disproportional shift of ventilation and perfusion toward the nondependent lung. Overall, the dependent lung was minimally ventilated and perfused, but remained aerated with minimal detectable lung collapse. Perfusion was found primarily around the hilum of the nondependent lung and was minimal in the periphery of the nondependent and the entire dependent lung. These shifts can explain the high amount of venous admixture and physiological dead space found in this study. Breath holding redistributed ventilation toward dependent and ventral lung areas. The findings of this study reveal important pathophysiological insights into the changes in lung ventilation and perfusion during immobilization of white rhinoceroses. These novel insights might induce a search for better therapeutic options and is establishing EIT as a promising monitoring tool for large animals in the field.NEW & NOTEWORTHY Electrical impedance tomography measurements of regional ventilation and perfusion applied to etorphine-immobilized white rhinoceroses in lateral recumbency revealed a pronounced disproportional shift of the measured ventilation and perfusion toward the nondependent lung. The dependent lung was minimally ventilated and perfused, but still aerated. Perfusion was found primarily around the hilum of the nondependent lung. These shifts can explain the gas exchange impairments found in this study. Breath holding can redistribute ventilation.
Collapse
Affiliation(s)
- Martina Mosing
- School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Australia
| | - Andreas D Waldmann
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
| | - Muriel Sacks
- School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Australia
| | - Peter Buss
- Veterinary Wildlife Services, South African National Parks, Kruger National Park, Skukuza, South Africa
| | - Jordyn M Boesch
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Gareth E Zeiler
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.,Centre for Veterinary Wildlife Studies and Department of Paraclinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Giselle Hosgood
- School of Veterinary Medicine, College of Science, Health, Engineering and Education, Murdoch University, Perth, Australia
| | - Robin D Gleed
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York
| | - Michele Miller
- Department of Science and Technology-National Research Foundation Centre of Excellence for Biomedical TB Research, South African Medical Research Council Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Leith C R Meyer
- Centre for Veterinary Wildlife Studies and Department of Paraclinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa
| | - Stephan H Böhm
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
| |
Collapse
|
3
|
Chemonges S. Cardiorespiratory physiological perturbations after acute smoke-induced lung injury and during extracorporeal membrane oxygenation support in sheep. F1000Res 2020; 9:769. [PMID: 32953091 PMCID: PMC7481850 DOI: 10.12688/f1000research.24927.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/14/2020] [Indexed: 01/19/2023] Open
Abstract
Background: Numerous successful therapies developed for human medicine involve animal experimentation. Animal studies that are focused solely on translational potential, may not sufficiently document unexpected outcomes. Considerable amounts of data from such studies could be used to advance veterinary science. For example, sheep are increasingly being used as models of intensive care and therefore, data arising from such models must be published. In this study, the hypothesis is that there is little information describing cardiorespiratory physiological data from sheep models of intensive care and the author aimed to analyse such data to provide biological information that is currently not available for sheep that received extracorporeal life support (ECLS) following acute smoke-induced lung injury. Methods: Nineteen mechanically ventilated adult ewes undergoing intensive care during evaluation of a form of ECLS (treatment) for acute lung injury were used to collate clinical observations. Eight sheep were injured by acute smoke inhalation prior to treatment (injured/treated), while another eight were not injured but treated (uninjured/treated). Two sheep were injured but not treated (injured/untreated), while one received room air instead of smoke as the injury and was not treated (placebo/untreated). The data were then analysed for 11 physiological categories and compared between the two treated groups. Results: Compared with the baseline, treatment contributed to and exacerbated the deterioration of pulmonary pathology by reducing lung compliance and the arterial oxygen partial pressure to fractional inspired oxygen (PaO 2/FiO 2) ratio. The oxygen extraction index changes mirrored those of the PaO 2/FiO 2 ratio. Decreasing coronary perfusion pressure predicted the severity of cardiopulmonary injury. Conclusions: These novel observations could help in understanding similar pathology such as that which occurs in animal victims of smoke inhalation from house or bush fires, aspiration pneumonia secondary to tick paralysis and in the management of the severe coronavirus disease 2019 (COVID-19) in humans.
Collapse
Affiliation(s)
- Saul Chemonges
- School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia
| |
Collapse
|
4
|
Platts DG, Shiino K, Chan J, Burstow DJ, Scalia GM, Fraser JF. Echocardiographic assessment of myocardial function and mechanics during veno-venous extracorporeal membrane oxygenation. Echo Res Pract 2019; 6:25-35. [PMID: 30959479 PMCID: PMC6499935 DOI: 10.1530/erp-18-0071] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 04/03/2019] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Transthoracic echocardiography (TTE) plays a fundamental role in the management of patients supported with extra-corporeal membrane oxygenation (ECMO). In light of fluctuating clinical states, serial monitoring of cardiac function is required. Formal quantification of ventricular parameters and myocardial mechanics offer benefit over qualitative assessment. The aim of this research was to compare unenhanced (UE) versus contrast-enhanced (CE) quantification of myocardial function and mechanics during ECMO in a validated ovine model. METHODS Twenty-four sheep were commenced on peripheral veno-venous ECMO. Acute smoke-induced lung injury was induced in 21 sheep (3 controls). CE-TTE with Definity using Cadence Pulse Sequencing was performed. Two readers performed image analysis with TomTec Arena. End diastolic area (EDA, cm2), end systolic area (ESA, cm2), fractional area change (FAC, %), endocardial global circumferential strain (EGCS, %), myocardial global circumferential strain (MGCS, %), endocardial rotation (ER, degrees) and global radial strain (GRD, %) were evaluated for UE-TTE and CE-TTE. RESULTS Full data sets are available in 22 sheep (92%). Mean CE EDA and ESA were significantly larger than in unenhanced images. Mean FAC was almost identical between the two techniques. There was no significant difference between UE and CE EGCS, MGCS and ER. There was significant difference in GRS between imaging techniques. Unenhanced inter-observer variability was from 0.48-0.70 but significantly improved to 0.71-0.89 for contrast imaging in all echocardiographic parameters. CONCLUSION Semi-automated methods of myocardial function and mechanics using CE-TTE during ECMO was feasible and similar to UE-TTE for all parameters except ventricular areas and global radial strain. Addition of contrast significantly decreased inter-observer variability of all measurements.
Collapse
Affiliation(s)
- David G Platts
- Department of Echocardiography, The Prince Charles Hospital, Brisbane, Queensland, Australia
- Critical Care Research Group, The Prince Charles Hospital, Brisbane, Queensland, Australia
- The University of Queensland, Brisbane, Queensland, Australia
| | - Kenji Shiino
- Department of Echocardiography, The Prince Charles Hospital, Brisbane, Queensland, Australia
- School of Medicine, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
- Fujita Health University, Toyoake, Japan
| | - Jonathan Chan
- Department of Echocardiography, The Prince Charles Hospital, Brisbane, Queensland, Australia
- School of Medicine, Menzies Health Institute Queensland, Griffith University, Gold Coast, Queensland, Australia
| | - Darryl J Burstow
- Department of Echocardiography, The Prince Charles Hospital, Brisbane, Queensland, Australia
- The University of Queensland, Brisbane, Queensland, Australia
| | - Gregory M Scalia
- Department of Echocardiography, The Prince Charles Hospital, Brisbane, Queensland, Australia
- The University of Queensland, Brisbane, Queensland, Australia
| | - John F Fraser
- Critical Care Research Group, The Prince Charles Hospital, Brisbane, Queensland, Australia
- The University of Queensland, Brisbane, Queensland, Australia
- Adult Intensive Care Service, The Prince Charles Hospital, Brisbane, Queensland, Australia
| |
Collapse
|
5
|
Cheng V, Abdul-Aziz MH, Roberts JA, Shekar K. Overcoming barriers to optimal drug dosing during ECMO in critically ill adult patients. Expert Opin Drug Metab Toxicol 2019; 15:103-112. [PMID: 30582435 DOI: 10.1080/17425255.2019.1563596] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
INTRODUCTION One major challenge to achieving optimal patient outcome in extracorporeal membrane oxygenation (ECMO) is the development of effective dosing strategies in this critically ill patient population. Suboptimal drug dosing impacts on patient outcome as patients on ECMO often require reversal of the underlying pathology with effective pharmacotherapy in order to be liberated of the life-support device. Areas covered: This article provides a concise review of the effective use of antibiotics, analgesics, and sedative by characterizing the specific changes in PK secondary to the introduction of the ECMO support. We also discuss the barriers to achieving optimal pharmacotherapy in patients on ECMO and also the current and potential research that can be undertaken to address these clinical challenges. Expert opinion: Decreased bioavailability due to sequestration of drugs in the ECMO circuit and ECMO induced PK alterations are both significant barriers to optimal drug dosing. Evidence-based drug choices may minimize sequestration in the circuit and would enable safety and efficacy to be maintained. More work to characterize ECMO related pharmacodynamic alterations such as effects of ECMO on hepatic cytochrome system are still needed. Novel techniques to increase target site concentrations should also be explored.
Collapse
Affiliation(s)
- Vesa Cheng
- a Faculty of Medicine , University of Queensland Centre for Clinical Research (UQCCR), The University of Queensland , Brisbane , Australia
| | - Mohd H Abdul-Aziz
- a Faculty of Medicine , University of Queensland Centre for Clinical Research (UQCCR), The University of Queensland , Brisbane , Australia.,b School of Pharmacy , International Islamic University Malaysia , Kuantan , Malaysia
| | - Jason A Roberts
- a Faculty of Medicine , University of Queensland Centre for Clinical Research (UQCCR), The University of Queensland , Brisbane , Australia.,c Department of Intensive Care Medicine , Royal Brisbane and Women's Hospital , Brisbane , Australia.,d Department of Pharmacy , Royal Brisbane and Women's Hospital , Brisbane , Australia.,e Centre for Translational Anti-infective Pharmacodynamics, School of Pharmacy , The University of Queensland , Brisbane , Australia
| | - Kiran Shekar
- f Adult Intensive Care Services , The Prince Charles Hospital , Chermside , Australia.,g Critical Care Research Group , Centre of Research Excellence for Advanced Cardio-respiratory Therapies Improving OrgaN Support (ACTIONS) and the University of Queensland , Brisbane , Australia.,h Faculty of Health Sciences and Medicine , Bond University , Gold Coast , Australia
| |
Collapse
|
6
|
Passmore MR, Fung YL, Simonova G, Foley SR, Diab SD, Dunster KR, Spanevello MM, McDonald CI, Tung JP, Pecheniuk NM, Hay K, Shekar K, Fraser JF. Evidence of altered haemostasis in an ovine model of venovenous extracorporeal membrane oxygenation support. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2017; 21:191. [PMID: 28754139 PMCID: PMC5534117 DOI: 10.1186/s13054-017-1788-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 07/05/2017] [Indexed: 12/12/2022]
Abstract
Background Extracorporeal membrane oxygenation (ECMO) is a life-saving modality used in the management of cardiopulmonary failure that is refractory to conventional medical and surgical therapies. The major problems clinicians face are bleeding and clotting, which can occur simultaneously. To discern the impact of pulmonary injury and ECMO on the host’s haemostatic response, we developed an ovine model of smoke-induced acute lung injury (S-ALI) and ECMO. The aims of this study were to determine if the ECMO circuit itself altered haemostasis and if this was augmented in a host with pulmonary injury. Methods Twenty-seven South African meat merino/Border Leicester Cross ewes underwent instrumentation. Animals received either sham injury (n = 12) or S-ALI (n = 15). Control animal groups consisted of healthy controls (ventilation only for 24 h) (n = 4), ECMO controls (ECMO only for 24 h) (n = 8) and S-ALI controls (S-ALI but no ECMO for 24 h) (n = 7). The test group comprised S-ALI sheep placed on ECMO (S-ALI + ECMO for 24 h) (n = 8). Serial blood samples were taken for rotational thromboelastometry, platelet aggregometry and routine coagulation laboratory tests. Animals were continuously monitored for haemodynamic, fluid and electrolyte balances and temperature. Pressure-controlled intermittent mandatory ventilation was used, and mean arterial pressure was augmented by protocolised use of pressors, inotropes and balanced fluid resuscitation to maintain mean arterial pressure >65 mmHg. Results Rotational thromboelastometry, platelet aggregometry and routine coagulation laboratory tests demonstrated that S-ALI and ECMO independently induced changes to platelet function, delayed clot formation and reduced clot firmness. This effect was augmented with the combination of S-ALI and ECMO, with evidence of increased collagen-induced platelet aggregation as well as changes in factor VIII (FVIII), factor XII and fibrinogen levels. Conclusions The introduction of an ECMO circuit itself increases collagen-induced platelet aggregation, decreases FVIII and von Willebrand factor, and induces a transient decrease in fibrinogen levels and function in the first 24 h. These changes to haemostasis are amplified when a host with a pre-existing pulmonary injury is placed on ECMO. Because patients are often on ECMO for extended periods, longer-duration studies are required to characterise ECMO-induced haemostatic changes over the long term. The utility of point-of-care tests for guiding haemostatic management during ECMO also warrants further exploration.
Collapse
Affiliation(s)
- Margaret R Passmore
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia.
| | - Yoke L Fung
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia.,School of Health and Sport Sciences, University of the Sunshine Coast, Sippy Downs, Australia
| | - Gabriela Simonova
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia.,Research and Development, Australian Red Cross Blood Service, Brisbane, Australia
| | - Samuel R Foley
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| | - Sara D Diab
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| | - Kimble R Dunster
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| | - Michelle M Spanevello
- Cancer Care Services, Royal Brisbane and Women's Hospital, Brisbane, Australia.,University of Queensland, Brisbane, Australia
| | - Charles I McDonald
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| | - John-Paul Tung
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia.,Research and Development, Australian Red Cross Blood Service, Brisbane, Australia
| | - Natalie M Pecheniuk
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia
| | - Karen Hay
- QIMR Berghofer Metro North Hospital and Health Service Statistics Unit, Brisbane, Australia
| | - Kiran Shekar
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| | - John F Fraser
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| |
Collapse
|
7
|
Passmore MR, Fung YL, Simonova G, Foley SR, Dunster KR, Diab SD, Tung JP, Minchinton RM, McDonald CI, Anstey CM, Shekar K, Fraser JF. Inflammation and lung injury in an ovine model of extracorporeal membrane oxygenation support. Am J Physiol Lung Cell Mol Physiol 2016; 311:L1202-L1212. [PMID: 27815258 DOI: 10.1152/ajplung.00296.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 11/02/2016] [Indexed: 02/01/2023] Open
Abstract
Extracorporeal membrane oxygenation (ECMO) is a life-saving treatment for patients with severe refractory cardiorespiratory failure. Exposure to the ECMO circuit is thought to trigger/exacerbate inflammation. Determining whether inflammation is the result of the patients' underlying pathologies or the ECMO circuit is difficult. To discern how different insults contribute to the inflammatory response, we developed an ovine model of lung injury and ECMO to investigate the impact of smoke-induced lung injury and ECMO in isolation and cumulatively on pulmonary and circulating inflammatory cells, cytokines, and tissue remodeling. Sheep receiving either smoke-induced acute lung injury (S-ALI) or sham injury were placed on veno-venous (VV) ECMO lasting either 2 or 24 h, with controls receiving conventional ventilation only. Lung tissue, bronchoalveolar fluid, and plasma were analyzed by RT-PCR, immunohistochemical staining, and zymography to assess inflammatory cells, cytokines, and matrix metalloproteinases. Pulmonary compliance decreased in sheep with S-ALI placed on ECMO with increased numbers of infiltrating neutrophils, monocytes, and alveolar macrophages compared with controls. Infiltration of neutrophils was also observed with S-ALI alone. RT-PCR studies showed higher expression of matrix metalloproteinases 2 and 9 in S-ALI plus ECMO, whereas IL-6 was elevated at 2 h. Zymography revealed higher levels of matrix metalloproteinase 2. Circulating plasma levels of IL-6 were elevated 1-2 h after commencement of ECMO alone. These data show that the inflammatory response is enhanced when a host with preexisting pulmonary injury is placed on ECMO, with increased infiltration of neutrophils and macrophages, the release of inflammatory cytokines, and upregulation of matrix metalloproteinases.
Collapse
Affiliation(s)
- Margaret R Passmore
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia;
| | - Yoke L Fung
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia.,School of Health and Sport Sciences, University of the Sunshine Coast, Sippy Downs, Australia
| | - Gabriela Simonova
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia.,Research and Development, Australian Red Cross Blood Service, Brisbane, Australia; and
| | - Samuel R Foley
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| | - Kimble R Dunster
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia.,Queensland University of Technology, Brisbane, Australia
| | - Sara D Diab
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| | - John-Paul Tung
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia.,Research and Development, Australian Red Cross Blood Service, Brisbane, Australia; and
| | - Robyn M Minchinton
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| | - Charles I McDonald
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| | - Chris M Anstey
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia.,Department of Critical Care Medicine, Nambour General Hospital, Nambour, Australia
| | - Kiran Shekar
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| | - John F Fraser
- Critical Care Research Group, University of Queensland and the Prince Charles Hospital, Brisbane, Australia
| |
Collapse
|
8
|
Ovine platelet function is unaffected by extracorporeal membrane oxygenation within the first 24 h. Blood Coagul Fibrinolysis 2016. [PMID: 26196193 DOI: 10.1097/mbc.0000000000000360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This study investigated platelet dysfunction during short-term extracorporeal membrane oxygenation (ECMO) and secondarily to determine if hyperoxaemia contributes to this dysfunction. Healthy sheep were anaesthetized and maintained on ECMO for either 2 or 24 h, with or without induction of smoke inhalation acute lung injury. A specialized animal-operating theatre was used to conduct the experimentation. Forty-three healthy female sheep were randomized into either a test or a control group. Following anaesthesia, test groups received ECMO ± smoke inhalation acute lung injury (SALI), whereas control groups were maintained with ventilation only ± SALI. Physiological, biochemical and coagulation data were obtained throughout via continuous monitoring and blood sampling. Platelet function was quantified through whole blood impedance aggregometry using Multiplate. Ovine platelet activity induced by adenosine diphosphate (ADP) and collagen was unaffected during the first 24 h of ECMO. However, progressive divergence of ADP-induced platelet activity was noted at cessation of the experiment. PaO2 was inversely related to ADP-dependent platelet activity in the ECMO groups--a relationship not identified in the control groups. ADP and collagen-dependent platelet activity are not significantly affected within the first 24 h of ECMO in sheep. However, dysfunction in ADP-dependent platelet activity may have continued to develop if observed beyond 24 h. Hyperoxaemia during ECMO does appear to affect how platelets react to ADP and may contribute to this developing dysfunction. Long-term animal models and investigation in clinical animals are warranted to fully investigate platelet function during ECMO.
Collapse
|
9
|
Vogt B, Zhao Z, Zabel P, Weiler N, Frerichs I. Regional lung response to bronchodilator reversibility testing determined by electrical impedance tomography in chronic obstructive pulmonary disease. Am J Physiol Lung Cell Mol Physiol 2016; 311:L8-L19. [DOI: 10.1152/ajplung.00463.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 05/17/2016] [Indexed: 01/01/2023] Open
Abstract
Patients with obstructive lung diseases commonly undergo bronchodilator reversibility testing during examination of their pulmonary function by spirometry. A positive response is defined by an increase in forced expiratory volume in 1 s (FEV1). FEV1 is a rather nonspecific criterion not allowing the regional effects of bronchodilator to be assessed. We employed the imaging technique of electrical impedance tomography (EIT) to visualize the spatial and temporal ventilation distribution in 35 patients with chronic obstructive pulmonary disease at baseline and 5, 10, and 20 min after bronchodilator inhalation. EIT scanning was performed during tidal breathing and forced full expiration maneuver in parallel with spirometry. Ventilation distribution was determined by EIT by calculating the image pixel values of FEV1, forced vital capacity (FVC), tidal volume, peak flow, and mean forced expiratory flow between 25 and 75% of FVC. The global inhomogeneity indexes of each measure and histograms of pixel FEV1/FVC values were then determined to assess the bronchodilator effect on spatial ventilation distribution. Temporal ventilation distribution was analyzed from pixel values of times needed to exhale 75 and 90% of pixel FVC. Based on spirometric FEV1, significant bronchodilator response was found in 17 patients. These patients exhibited higher postbronchodilator values of all regional EIT-derived lung function measures in contrast to nonresponders. Ventilation distribution was inhomogeneous in both groups. Significant improvements were noted for spatial distribution of pixel FEV1 and tidal volume and temporal distribution in responders. By providing regional data, EIT might increase the diagnostic and prognostic information derived from reversibility testing.
Collapse
Affiliation(s)
- Barbara Vogt
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Zhanqi Zhao
- Department of Biomedical Engineering, Furtwangen University, Villingen-Schwenningen, Germany; and
| | - Peter Zabel
- Department of Pneumology, Medical Clinic, Research Center Borstel, Germany
| | - Norbert Weiler
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Inéz Frerichs
- Department of Anesthesiology and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany
| |
Collapse
|
10
|
Can physicochemical properties of antimicrobials be used to predict their pharmacokinetics during extracorporeal membrane oxygenation? Illustrative data from ovine models. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2015; 19:437. [PMID: 26667471 PMCID: PMC4699331 DOI: 10.1186/s13054-015-1151-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 11/30/2015] [Indexed: 01/03/2023]
Abstract
Introduction Ex vivo experiments in extracorporeal membrane oxygenation (ECMO) circuits have identified octanol-water partition coefficient (logP, a marker of lipophilicity) and protein binding (PB) as key drug factors affecting pharmacokinetics (PK) during ECMO. Using ovine models, in this study we investigated whether these drug properties can be used to predict PK alterations of antimicrobial drugs during ECMO. Methods Single-dose PK sampling was performed in healthy sheep (HS, n = 7), healthy sheep on ECMO (E24H, n = 7) and sheep with smoke inhalation acute lung injury on ECMO (SE24H, n = 6). The sheep received eight study antimicrobials (ceftriaxone, gentamicin, meropenem, vancomycin, doripenem, ciprofloxacin, fluconazole, caspofungin) that exhibit varying degrees of logP and PB. Plasma drug concentrations were determined using validated chromatographic techniques. PK data obtained from a non-compartmental analysis were used in a linear regression model to predict PK parameters based on logP and PB. Results We found statistically significant differences in pH, haemodynamics, fluid balance and plasma proteins between the E24H and SE24H groups (p < 0.001). logP had a strong positive linear relationship with steady-state volume of distribution (Vss) in both the E24H and SE24H groups (p < 0.001) but not in the HS group (p = 0.9) and no relationship with clearance (CL) in all study groups. Although we observed an increase in CL for highly PB drugs in ECMO sheep, PB exhibited a weaker negative linear relationship with both CL (HS, p = 0.01; E24H, p < 0.001; SE24H, p < 0.001) and Vss (HS, p = 0.01; E24H, p = 0.004; SE24H, p =0.05) in the final model. Conclusions Lipophilic antimicrobials are likely to have an increased Vss and decreased CL during ECMO. Protein-bound antimicrobial agents are likely to have reductions both in CL and Vss during ECMO. The strong relationship between lipophilicity and Vss seen in both the E24H and SE24H groups indicates circuit sequestration of lipophilic drugs. These findings highlight the importance of drug factors in predicting antimicrobial drug PK during ECMO and should be a consideration when performing and interpreting population PK studies.
Collapse
|
11
|
McDonald CI, Fung YL, Shekar K, Diab SD, Dunster KR, Passmore MR, Foley SR, Simonova G, Platts D, Fraser JF. The impact of acute lung injury, ECMO and transfusion on oxidative stress and plasma selenium levels in an ovine model. J Trace Elem Med Biol 2015; 30:4-10. [PMID: 25744503 DOI: 10.1016/j.jtemb.2015.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Revised: 12/15/2014] [Accepted: 01/08/2015] [Indexed: 01/27/2023]
Abstract
The purpose of this study was to determine the effects of smoke induced acute lung injury (S-ALI), extracorporeal membrane oxygenation (ECMO) and transfusion on oxidative stress and plasma selenium levels. Forty ewes were divided into (i) healthy control (n=4), (ii) S-ALI control (n=7), (iii) ECMO control (n=7), (iv) S-ALI+ECMO (n=8) and (v) S-ALI+ECMO+packed red blood cell (PRBC) transfusion (n=14). Plasma thiobarbituric acid reactive substances (TBARS), selenium and glutathione peroxidase (GPx) activity were analysed at baseline, after smoke injury (or sham) and 0.25, 1, 2, 6, 7, 12 and 24h after initiation of ECMO. Peak TBARS levels were similar across all groups. Plasma selenium decreased by 54% in S-ALI sheep (1.36±0.20 to 0.63±0.27μmol/L, p<0.0001), and 72% in sheep with S-ALI+ECMO at 24h (1.36±0.20 to 0.38±0.19, p<0.0001). PRBC transfusion had no effect on TBARS, selenium levels or glutathione peroxidase activity in plasma. While ECMO independently increased TBARS in healthy sheep to levels which were similar to the S-ALI control, the addition of ECMO after S-ALI caused a negligible increase in TBARS. This suggests that the initial lung injury was the predominant feature in the TBARS response. In contrast, the addition of ECMO in S-ALI sheep exacerbated reductions in plasma selenium beyond that of S-ALI or ECMO alone. Clinical studies are needed to confirm the extent and duration of selenium loss associated with ECMO.
Collapse
Affiliation(s)
- Charles I McDonald
- Critical Care Research Group, The Prince Charles Hospital and The University of Queensland, Chermside, Queensland, Australia; Department of Anaesthesia and Perfusion, The Prince Charles Hospital, Chermside, Queensland, Australia.
| | - Yoke Lin Fung
- Critical Care Research Group, The Prince Charles Hospital and The University of Queensland, Chermside, Queensland, Australia; Inflammation and Healing Research Cluster, School of Health and Sport Sciences, University of the Sunshine Coast, Queensland, Australia.
| | - Kiran Shekar
- Critical Care Research Group, The Prince Charles Hospital and The University of Queensland, Chermside, Queensland, Australia; Adult Intensive Care Service, The Prince Charles Hospital, Chermside, Queensland, Australia.
| | - Sara D Diab
- Critical Care Research Group, The Prince Charles Hospital and The University of Queensland, Chermside, Queensland, Australia.
| | - Kimble R Dunster
- Critical Care Research Group, The Prince Charles Hospital and The University of Queensland, Chermside, Queensland, Australia; Biomedical Engineering and Medical Physics, Science and Engineering Faculty, Queensland University of Technology, Gardens Point, Brisbane, Queensland, Australia.
| | - Margaret R Passmore
- Critical Care Research Group, The Prince Charles Hospital and The University of Queensland, Chermside, Queensland, Australia.
| | - Samuel R Foley
- Critical Care Research Group, The Prince Charles Hospital and The University of Queensland, Chermside, Queensland, Australia.
| | - Gabriela Simonova
- Critical Care Research Group, The Prince Charles Hospital and The University of Queensland, Chermside, Queensland, Australia; Research and Development Division, Australian Red Cross Blood Service, Brisbane, Queensland, Australia.
| | - David Platts
- Critical Care Research Group, The Prince Charles Hospital and The University of Queensland, Chermside, Queensland, Australia; Department of Echocardiography, The Prince Charles Hospital, Chermside, Queensland, Australia.
| | - John F Fraser
- Critical Care Research Group, The Prince Charles Hospital and The University of Queensland, Chermside, Queensland, Australia; Adult Intensive Care Service, The Prince Charles Hospital, Chermside, Queensland, Australia.
| |
Collapse
|
12
|
Platts DG, Diab S, Dunster KR, Shekar K, Burstow DJ, Sim B, Tunbridge M, McDonald C, Chemonges S, Chan J, Fraser JF. Feasibility of perflutren microsphere contrast transthoracic echocardiography in the visualization of ventricular endocardium during venovenous extracorporeal membrane oxygenation in a validated ovine model. Echocardiography 2014; 32:548-56. [PMID: 25059883 DOI: 10.1111/echo.12695] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Transthoracic echocardiography (TTE) during extra corporeal membrane oxygenation (ECMO) is important but can be technically challenging. Contrast-specific TTE can improve imaging in suboptimal studies. These contrast microspheres are hydrodynamically labile structures. This study assessed the feasibility of contrast echocardiography (CE) during venovenous (VV) ECMO in a validated ovine model. METHOD Twenty-four sheep were commenced on VV ECMO. Parasternal long-axis (Plax) and short-axis (Psax) views were obtained pre- and postcontrast while on VV ECMO. Endocardial definition scores (EDS) per segment were graded: 1 = good, 2 = suboptimal 3 = not seen. Endocardial border definition score index (EBDSI) was calculated for each view. Endocardial length (EL) in the Plax view for the left ventricle (LV) and right ventricle (RV) was measured. RESULTS Summation EDS data for the LV and RV for unenhanced TTE (UE) versus CE TTE imaging: EDS 1 = 289 versus 346, EDS 2 = 38 versus 10, EDS 3 = 33 versus 4, respectively. Wilcoxon matched-pairs rank-sign tests showed a significant ranking difference (improvement) pre- and postcontrast for the LV (P < 0.0001), RV (P < 0.0001) and combined ventricular data (P < 0.0001). EBDSI for CE TTE was significantly lower than UE TTE for the LV (1.05 ± 0.17 vs. 1.22 ± 0.38, P = 0.0004) and RV (1.06 ± 0.22 vs. 1.42 ± 0.47, P = 0.0.0006) respectively. Visualized EL was significantly longer in CE versus UE for both the LV (58.6 ± 11.0 mm vs. 47.4 ± 11.7 mm, P < 0.0001) and the RV (52.3 ± 8.6 mm vs. 36.0 ± 13.1 mm, P < 0.0001), respectively. CONCLUSIONS Despite exposure to destructive hydrodynamic forces, CE is a feasible technique in an ovine ECMO model. CE results in significantly improved EDS and increased EL.
Collapse
Affiliation(s)
- David G Platts
- Department of Echocardiography, The Prince Charles Hospital, Brisbane, Australia; Critical Care Research Group, The Prince Charles Hospital, Brisbane, Australia; The University of Queensland, Brisbane, Australia
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Chemonges S, Shekar K, Tung JP, Dunster KR, Diab S, Platts D, Watts RP, Gregory SD, Foley S, Simonova G, McDonald C, Hayes R, Bellpart J, Timms D, Chew M, Fung YL, Toon M, Maybauer MO, Fraser JF. Optimal management of the critically ill: anaesthesia, monitoring, data capture, and point-of-care technological practices in ovine models of critical care. BIOMED RESEARCH INTERNATIONAL 2014; 2014:468309. [PMID: 24783206 PMCID: PMC3982457 DOI: 10.1155/2014/468309] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 01/21/2014] [Accepted: 02/10/2014] [Indexed: 12/18/2022]
Abstract
Animal models of critical illness are vital in biomedical research. They provide possibilities for the investigation of pathophysiological processes that may not otherwise be possible in humans. In order to be clinically applicable, the model should simulate the critical care situation realistically, including anaesthesia, monitoring, sampling, utilising appropriate personnel skill mix, and therapeutic interventions. There are limited data documenting the constitution of ideal technologically advanced large animal critical care practices and all the processes of the animal model. In this paper, we describe the procedure of animal preparation, anaesthesia induction and maintenance, physiologic monitoring, data capture, point-of-care technology, and animal aftercare that has been successfully used to study several novel ovine models of critical illness. The relevant investigations are on respiratory failure due to smoke inhalation, transfusion related acute lung injury, endotoxin-induced proteogenomic alterations, haemorrhagic shock, septic shock, brain death, cerebral microcirculation, and artificial heart studies. We have demonstrated the functionality of monitoring practices during anaesthesia required to provide a platform for undertaking systematic investigations in complex ovine models of critical illness.
Collapse
Affiliation(s)
- Saul Chemonges
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia ; Medical Engineering Research Facility (MERF), Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Kiran Shekar
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia ; Bond University, Gold Coast, QLD 4226, Australia
| | - John-Paul Tung
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; Research and Development, Australian Red Cross Blood Service, Kelvin Grove, Brisbane, QLD 4059, Australia
| | - Kimble R Dunster
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Sara Diab
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - David Platts
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Ryan P Watts
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; Department of Emergency Medicine, Princess Alexandra Hospital, 199 Ipswich Road, Woolloongabba, QLD 4102, Australia
| | - Shaun D Gregory
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia ; Innovative Cardiovascular Engineering and Technology Laboratory, The Prince Charles Hospital, Chermside, Brisbane, QLD 4032, Australia
| | - Samuel Foley
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Gabriela Simonova
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Charles McDonald
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Rylan Hayes
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Judith Bellpart
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Daniel Timms
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; Innovative Cardiovascular Engineering and Technology Laboratory, The Prince Charles Hospital, Chermside, Brisbane, QLD 4032, Australia
| | - Michelle Chew
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia
| | - Yoke L Fung
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Michael Toon
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia
| | - Marc O Maybauer
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - John F Fraser
- Critical Care Research Group Laboratory, The Prince Charles Hospital, Rode Road, Chermside, Brisbane, QLD 4032, Australia ; The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia ; Innovative Cardiovascular Engineering and Technology Laboratory, The Prince Charles Hospital, Chermside, Brisbane, QLD 4032, Australia
| |
Collapse
|
14
|
Shekar K, Davies AR, Mullany DV, Tiruvoipati R, Fraser JF. To ventilate, oscillate, or cannulate? J Crit Care 2013; 28:655-62. [PMID: 23827735 DOI: 10.1016/j.jcrc.2013.04.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 03/09/2013] [Accepted: 04/17/2013] [Indexed: 02/05/2023]
Abstract
Ventilatory management of acute respiratory distress syndrome has evolved significantly in the last few decades. The aims have shifted from optimal gas transfer without concern for iatrogenic risks to adequate gas transfer while minimizing lung injury. This change in focus, along with improved ventilator and multiorgan system management, has resulted in a significant improvement in patient outcomes. Despite this, a number of patients develop hypoxemic respiratory failure refractory to lung-protective ventilation (LPV). The intensivist then faces the dilemma of either persisting with LPV using adjuncts (neuromuscular blocking agents, prone positioning, recruitment maneuvers, inhaled nitric oxide, inhaled prostacyclin, steroids, and surfactant) or making a transition to rescue therapies such as high-frequency oscillatory ventilation (HFOV) and/or extracorporeal membrane oxygenation (ECMO) when both these modalities are at their disposal. The lack of quality evidence and potential harm reported in recent studies question the use of HFOV as a routine rescue option. Based on current literature, the role for venovenous (VV) ECMO is probably sequential as a salvage therapy to ensure ultraprotective ventilation in selected young patients with potentially reversible respiratory failure who fail LPV despite neuromuscular paralysis and prone ventilation. Given the risk profile and the economic impact, future research should identify the patients who benefit most from VV ECMO. These choices may be further influenced by the emerging novel extracorporeal carbon dioxide removal devices that can compliment LPV. Given the heterogeneity of acute respiratory distress syndrome, each of these modalities may play a role in an individual patient. Future studies comparing LPV, HFOV, and VV ECMO should not only focus on defining the patients who benefit most from each of these therapies but also consider long-term functional outcomes.
Collapse
Affiliation(s)
- Kiran Shekar
- Critical Care Research Group, Adult Intensive Care Services, The Prince Charles Hospital, The University of Queensland, Brisbane, Queensland, Australia.
| | | | | | | | | |
Collapse
|
15
|
Simonova G, Tung JP, Fraser JF, Do HL, Staib A, Chew MS, Dunster KR, Glenister KM, Jackson DE, Fung YL. A comprehensive ovine model of blood transfusion. Vox Sang 2013; 106:153-60. [PMID: 23992472 DOI: 10.1111/vox.12076] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 07/18/2013] [Accepted: 08/05/2013] [Indexed: 11/30/2022]
Abstract
BACKGROUND The growing awareness of transfusion-associated morbidity and mortality necessitates investigations into the underlying mechanisms. Small animals have been the dominant transfusion model but have associated limitations. This study aimed to develop a comprehensive large animal (ovine) model of transfusion encompassing: blood collection, processing and storage, compatibility testing right through to post-transfusion outcomes. MATERIALS AND METHODS Two units of blood were collected from each of 12 adult male Merino sheep and processed into 24 ovine-packed red blood cell (PRBC) units. Baseline haematological parameters of ovine blood and PRBC cells were analysed. Biochemical changes in ovine PRBCs were characterized during the 42-day storage period. Immunological compatibility of the blood was confirmed with sera from potential recipient sheep, using a saline and albumin agglutination cross-match. Following confirmation of compatibility, each recipient sheep (n = 12) was transfused with two units of ovine PRBC. RESULTS Procedures for collecting, processing, cross-matching and transfusing ovine blood were established. Although ovine red blood cells are smaller and higher in number, their mean cell haemoglobin concentration is similar to human red blood cells. Ovine PRBC showed improved storage properties in saline-adenine-glucose-mannitol (SAG-M) compared with previous human PRBC studies. Seventy-six compatibility tests were performed and 17·1% were incompatible. Only cross-match compatible ovine PRBC were transfused and no adverse reactions were observed. CONCLUSION These findings demonstrate the utility of the ovine model for future blood transfusion studies and highlight the importance of compatibility testing in animal models involving homologous transfusions.
Collapse
Affiliation(s)
- G Simonova
- Critical Care Research Group, The University of Queensland and The Prince Charles Hospital, Brisbane, Qld, Australia; Research and Development, Australian Red Cross Blood Service, Brisbane, Qld, Australia
| | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Shekar K, Roberts JA, Smith MT, Fung YL, Fraser JF. The ECMO PK Project: an incremental research approach to advance understanding of the pharmacokinetic alterations and improve patient outcomes during extracorporeal membrane oxygenation. BMC Anesthesiol 2013; 13:7. [PMID: 23517311 PMCID: PMC3643838 DOI: 10.1186/1471-2253-13-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 02/21/2013] [Indexed: 01/20/2023] Open
Abstract
Background Extracorporeal membrane oxygenation (ECMO) is a supportive therapy and its success depends on optimal drug therapy along with other supportive care. Emerging evidence suggests significant interactions between the drug and the device resulting in altered pharmacokinetics (PK) of vital drugs which may be further complicated by the PK changes that occur in the context of critical illness. Such PK alterations are complex and challenging to investigate in critically ill patients on ECMO and necessitate mechanistic research. The aim of this project is to investigate each of circuit, drug and critical illness factors that affect drug PK during ECMO. Methods/design An incremental research plan that encompasses ex vivo experiments for drug stability testing in fresh human and ovine whole blood, ex vivo drug disposition studies in standard and modified adult ECMO circuits primed with fresh human or ovine whole blood, PK studies in healthy and critically ill ovine models of ECMO with appropriate non ECMO controls and an international mutli-centre clinical population PK study will be utilised to comprehensively define the PK alterations that occur in the presence of ECMO. Novel drug assays that will allow quantification of multiple drugs in small volumes of plasma will also be developed. Mixed-effects regression models will be used to estimate the drug loss over time in ex vivo studies. Data from animal and clinical studies will be analysed using non-linear mixed-effects models. This will lead to generation of PK data that enables the development evidence based guidelines for antibiotic, sedative and analgesic drug therapy during ECMO. Discussion Systematic research that integrates both mechanistic and clinical research is desirable when investigating the complex area of pharmacokinetic alterations during ECMO. The above research approach will provide an advanced mechanistic understanding of PK during ECMO. The clinical study when complete will result in development robust guidelines for prescription of 18 commonly used antibiotic, sedative and analgesic drugs used in ECMO patients. This research may also pave the way for further refinements in circuitry, drug chemistry and drug prescriptions during ECMO. Trial registration ACTRN12612000559819.
Collapse
Affiliation(s)
- Kiran Shekar
- Critical Care Research Group, Adult Intensive Care Services, The Prince Charles, Hospital and The University of Queensland, Brisbane, QLD, 4032, Australia.
| | | | | | | | | |
Collapse
|
17
|
Fung YL, Diab S, Dunster K, Foley SR, McDonald CI, Passmore M, Platts D, Simonova G, Shekar K, Stewart D, Fraser JF. Extracorporeal lessons from sheep. ACTA ACUST UNITED AC 2012. [DOI: 10.1111/j.1751-2824.2012.01561.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
18
|
Avila MB, Mazzoli-Rocha F, Magalhães CB, Saldiva PHN, Carvalho AR, Faffe DS, Zin WA. Residual oil fly ash worsens pulmonary hyperreactivity in chronic allergic mice. Respir Physiol Neurobiol 2011; 179:151-7. [DOI: 10.1016/j.resp.2011.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 07/06/2011] [Accepted: 07/19/2011] [Indexed: 12/17/2022]
|
19
|
Comparison of airway pressure release ventilation to conventional mechanical ventilation in the early management of smoke inhalation injury in swine. Crit Care Med 2011; 39:2314-21. [PMID: 21705889 DOI: 10.1097/ccm.0b013e318225b5b3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVE The role of airway pressure release ventilation in the management of early smoke inhalation injury has not been studied. We compared the effects of airway pressure release ventilation and conventional mechanical ventilation on oxygenation in a porcine model of acute respiratory distress syndrome induced by wood smoke inhalation. DESIGN Prospective animal study. SETTING Government laboratory animal intensive care unit. PATIENTS Thirty-three Yorkshire pigs. INTERVENTIONS Smoke inhalation injury. MEASUREMENTS AND MAIN RESULTS Anesthetized female Yorkshire pigs (n = 33) inhaled room-temperature pine-bark smoke. Before injury, the pigs were randomized to receive conventional mechanical ventilation (n = 15) or airway pressure release ventilation (n = 12) for 48 hrs after smoke inhalation. As acute respiratory distress syndrome developed (PaO2/Fio2 ratio <200), plateau pressures were limited to <35 cm H2O. Six uninjured pigs received conventional mechanical ventilation for 48 hrs and served as time controls. Changes in PaO2/Fio2 ratio, tidal volume, respiratory rate, mean airway pressure, plateau pressure, and hemodynamic variables were recorded. Survival was assessed using Kaplan-Meier analysis. PaO2/Fio2 ratio was lower in airway pressure release ventilation vs. conventional mechanical ventilation pigs at 12, 18, and 24 hrs (p < .05) but not at 48 hrs. Tidal volumes were lower in conventional mechanical ventilation animals between 30 and 48 hrs post injury (p < .05). Respiratory rates were lower in airway pressure release ventilation at 24, 42, and 48 hrs (p < .05). Mean airway pressures were higher in airway pressure release ventilation animals between 6 and 48 hrs (p < .05). There was no difference in plateau pressures, hemodynamic variables, or survival between conventional mechanical ventilation and airway pressure release ventilation pigs. CONCLUSIONS In this model of acute respiratory distress syndrome caused by severe smoke inhalation in swine, airway pressure release ventilation-treated animals developed acute respiratory distress syndrome faster than conventional mechanical ventilation-treated animals, showing a lower PaO2/Fio2 ratio at 12, 18, and 24 hrs after injury. At other time points, PaO2/Fio2 ratio was not different between conventional mechanical ventilation and airway pressure release ventilation.
Collapse
|
20
|
Tung JP, Fung YL, Nataatmadja M, Colebourne KI, Esmaeel HM, Wilson K, Barnett AG, Wood P, Silliman CC, Fraser JF. A novel in vivo ovine model of transfusion-related acute lung injury (TRALI). Vox Sang 2011; 100:219-30. [PMID: 20667072 DOI: 10.1111/j.1423-0410.2010.01381.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND AND OBJECTIVES Even with the introduction of specific risk-reduction strategies, transfusion-related acute lung injury (TRALI) continues to be a leading cause of transfusion-related morbidity and mortality. Existing small animal models have not yet investigated TRALI resulting from the infusion of heat-treated supernatant from whole blood platelet concentrates. In this study, our objective was the development of a novel in vivo two-event model of TRALI in sheep. MATERIALS AND METHODS Lipopolysaccharide (LPS; 15 μg/kg) as a first event, modelled clinical infection. Transfusion (estimated at 10% of total blood volume) of heat-treated pooled supernatant from date-of-expire human whole blood platelet concentrates (d5-PLT-S/N) was used as a second event. TRALI was defined by both hypoxaemia that developed either during the transfusion or within two hours of its completion and post-mortem histological evidence of pulmonary oedema. RESULTS LPS infusion did not cause lung injury itself, but did result in decreased circulating levels of lymphocytes and neutrophils with evidence of the latter becoming sequestered in the lungs. Sheep that received LPS (first event) followed by d5-PLT-S/N (second event) displayed decreased pulmonary compliance, decreased end tidal CO(2) and increased arterial partial pressure of CO(2) relative to control sheep, and 80% of these sheep developed TRALI. CONCLUSIONS This novel ovine two-event TRALI model presents a new tool for the investigation of TRALI pathogenesis. It represents the first description of an in vivo large animal model of TRALI and the first description of TRALI caused by transfusion with heat-treated pooled supernatant from human whole blood platelet concentrates.
Collapse
Affiliation(s)
- J P Tung
- Research and Development Laboratory, Australian Red Cross Blood Service, Brisbane, Qld, Australia.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Grant CA, Pham T, Hough J, Riedel T, Stocker C, Schibler A. Measurement of ventilation and cardiac related impedance changes with electrical impedance tomography. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2011; 15:R37. [PMID: 21266025 PMCID: PMC3222074 DOI: 10.1186/cc9985] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 11/03/2010] [Accepted: 01/25/2011] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Electrical impedance tomography (EIT) has been shown to be able to distinguish both ventilation and perfusion. With adequate filtering the regional distributions of both ventilation and perfusion and their relationships could be analysed. Several methods of separation have been suggested previously, including breath holding, electrocardiograph (ECG) gating and frequency filtering. Many of these methods require interventions inappropriate in a clinical setting. This study therefore aims to extend a previously reported frequency filtering technique to a spontaneously breathing cohort and assess the regional distributions of ventilation and perfusion and their relationship. METHODS Ten healthy adults were measured during a breath hold and while spontaneously breathing in supine, prone, left and right lateral positions. EIT data were analysed with and without filtering at the respiratory and heart rate. Profiles of ventilation, perfusion and ventilation/perfusion related impedance change were generated and regions of ventilation and pulmonary perfusion were identified and compared. RESULTS Analysis of the filtration technique demonstrated its ability to separate the ventilation and cardiac related impedance signals without negative impact. It was, therefore, deemed suitable for use in this spontaneously breathing cohort.Regional distributions of ventilation, perfusion and the combined ΔZV/ΔZQ were calculated along the gravity axis and anatomically in each position. Along the gravity axis, gravity dependence was seen only in the lateral positions in ventilation distribution, with the dependent lung being better ventilated regardless of position. This gravity dependence was not seen in perfusion.When looking anatomically, differences were only apparent in the lateral positions. The lateral position ventilation distributions showed a difference in the left lung, with the right lung maintaining a similar distribution in both lateral positions. This is likely caused by more pronounced anatomical changes in the left lung when changing positions. CONCLUSIONS The modified filtration technique was demonstrated to be effective in separating the ventilation and perfusion signals in spontaneously breathing subjects. Gravity dependence was seen only in ventilation distribution in the left lung in lateral positions, suggesting gravity based shifts in anatomical structures. Gravity dependence was not seen in any perfusion distributions.
Collapse
Affiliation(s)
- Caroline A Grant
- Paediatric Critical Care Research Group, Paediatric Intensive Care Unit, Mater Children's Hospital, 550 Stanley Street, South Brisbane, Queensland 4101, Australia.
| | | | | | | | | | | |
Collapse
|
22
|
HUANG PM, SYRKINA O, YU L, DEDAJ R, ZHAO H, SHIEDLIN A, LIU YY, GARG H, QUINN DA, HALES CA. High MW hyaluronan inhibits smoke inhalation-induced lung injury and improves survival. Respirology 2010; 15:1131-9. [DOI: 10.1111/j.1440-1843.2010.01829.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
23
|
Ballard-Croft C, Sumpter LR, Broaddus R, Alexander J, Wang D, Zwischenberger JB. Ovine smoke/burn ARDS model: a new ventilator-controlled smoke delivery system. J Surg Res 2010; 164:e155-62. [PMID: 20828741 DOI: 10.1016/j.jss.2010.05.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 05/06/2010] [Accepted: 05/17/2010] [Indexed: 11/30/2022]
Abstract
BACKGROUND Our current ovine smoke/burn acute respiratory distress syndrome (ARDS) model utilizes a manual bee smoker. This smoke delivery system lacks standardization and reproducibility, with 20% of sheep failing to meet ARDS criteria. Time to reach ARDS criteria and survival time are also variable. The mild volutrauma (15 mL/kg) applied after smoke/burn injury may also fail to induce ARDS within 24 h. We hypothesized that these inconsistencies were associated with the bee smoker and the mild volutrauma. In the current study, we addressed these problems to improve the consistency of the smoke/burn ARDS model. METHODS Adult female sheep (n = 10) were given a 40% total body surface area third degree cutaneous burn and 48 breaths (4 × 12) of cotton smoke under general anesthesia. A modified ventilator was then used to deliver a precise and consistent smoke volume (tidal volume) to the sheep. Additional barotrauma was induced by pressure control ventilation (40 cm H(2)0). When ARDS criteria (PaO(2)/FiO(2) < 200) were met, the ARDS Network low tidal volume ventilation protocol (6-8 mL/kg ideal body weight) was used. RESULTS Carboxyhemoglobin levels were 81.4% ± 5.6% immediately following smoke injury. All sheep met ARDS criteria within 24 h (12.5 ± 4.9 h). Mean survival time post-injury was 62.1 ± 26.4 h. White blood cells and granulocytes were significantly elevated at 24 h post-smoke/burn injury. Lung tissue at necropsy was consistent with ARDS. CONCLUSIONS The refinements made to the original ovine smoke/burn ARDS model produce a more reliable time to ARDS onset, injury severity, and time of death.
Collapse
|
24
|
Esechie A, Enkhbaatar P, Traber DL, Jonkam C, Lange M, Hamahata A, Djukom C, Whorton EB, Hawkins HK, Traber LD, Szabo C. Beneficial effect of a hydrogen sulphide donor (sodium sulphide) in an ovine model of burn- and smoke-induced acute lung injury. Br J Pharmacol 2009; 158:1442-53. [PMID: 19845680 DOI: 10.1111/j.1476-5381.2009.00411.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE The present study investigated whether the pathophysiological changes induced by burn and smoke inhalation are modulated by parenteral administration of Na(2)S, a H(2)S donor. EXPERIMENTAL APPROACH The study used a total of 16 chronically instrumented, adult female sheep. Na(2)S was administered 1 h post injury, as a bolus injection at a dose of 0.5 mg.kg(-1) and subsequently, as a continuous infusion at a rate of 0.2 mg.kg(-1).h(-1) for 24 h. Cardiopulmonary variables (mean arterial and pulmonary arterial blood pressure, cardiac output, ventricular stroke work index, vascular resistance) and arterial and mixed venous blood gases were measured. Lung wet-to-dry ratio and myeloperoxidase content and protein oxidation and nitration were also measured. In addition, lung inducible nitric oxide synthase expression and cytochrome c were measured in lung homogenates via Western blotting and enzyme-linked immunosorbent assay (elisa) respectively. KEY RESULTS The H(2)S donor decreased mortality during the 96 h experimental period, improved pulmonary gas exchange and lowered further increase in inspiratory pressure and fluid accumulation associated with burn- and smoke-induced acute lung injury. Further, the H(2)S donor treatment reduced the presence of protein oxidation and 3-nitrotyrosine formation following burn and smoke inhalation injury. CONCLUSIONS AND IMPLICATIONS Parenteral administration of the H(2)S donor ameliorated the pulmonary pathophysiological changes associated with burn- and smoke-induced acute lung injury. Based on the effect of H(2)S observed in this clinically relevant model of disease, we propose that treatment with H(2)S or its donors may represent a potential therapeutic strategy in managing patients with acute lung injury.
Collapse
Affiliation(s)
- Aimalohi Esechie
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, 77550, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Rooney D, Friese M, Fraser JF, R Dunster K, Schibler A. Gravity-dependent ventilation distribution in rats measured with electrical impedance tomography. Physiol Meas 2009; 30:1075-85. [PMID: 19738318 DOI: 10.1088/0967-3334/30/10/008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ventilation in larger animals and humans is gravity dependent and mainly distributed to the dependent lung. Little is known of the effect of gravity on ventilation distribution in small animals such as rodents. The aim of this study was to investigate gravity-dependent ventilation distribution and regional filling characteristics in rats. Ventilation distribution and regional lung filling were measured in six rats using electrical impedance tomography (EIT). Measurements were performed in four body positions (supine, prone, left and right lateral), and all animals were ventilated with increasing tidal volumes from 3 to 8 mL kg(-1). The effect of gravity on regional ventilation distribution was assessed with profiles of relative impedance change and calculation of the geometric centre. Regional filling was measured by calculating the slope of the plot of regional versus global relative impedance change on a breath-by-breath basis. Ventilation was significantly distributed to the non-dependent lung regardless of body position and tidal volume used. The geometric centre was located in the dependent lung in all but prone position. The regional filling characteristics followed an anatomical pattern with the posterior and the right lung generally filling faster. Gravity had little impact on regional filling. Ventilation distribution in rats is gravity dependent, whereas regional filling characteristics are dependent on anatomy.
Collapse
Affiliation(s)
- Daniel Rooney
- Paediatric Critical Care Research Group, Paediatric Intensive Care Unit, Mater Children's Hospital, South Brisbane QLD, Australia
| | | | | | | | | |
Collapse
|
26
|
Pulletz S, Elke G, Zick G, Schädler D, Scholz J, Weiler N, Frerichs I. Performance of electrical impedance tomography in detecting regional tidal volumes during one-lung ventilation. Acta Anaesthesiol Scand 2008; 52:1131-9. [PMID: 18840115 DOI: 10.1111/j.1399-6576.2008.01706.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Electrical impedance tomography (EIT) is becoming a new medical imaging modality for continuous monitoring of regional lung function in the intensive care unit or operating room. The aim of our study was to evaluate the performance of EIT in detecting regional tidal volumes in patients during volume-controlled mechanical ventilation of one or both lungs. METHODS Ten adult patients undergoing elective thoracic surgery were included. EIT measurements were performed with the Goe-MF II EIT system. Data were collected before surgery during ventilation of both, the right and left lungs. Tidal volumes of 800 and 400 ml were applied during bilateral and unilateral ventilation, respectively. RESULTS Ventilation-related impedance changes determined in the whole chest cross-section during the right and left lung ventilation did not significantly differ from each other and were equal to 47.6+/-5.6% and 48.5+/-7.8% (mean+/-SD) of the value determined during bilateral ventilation. During unilateral ventilation, EIT clearly separated the ventilated and non-ventilated lung regions; nevertheless, ventilation-related impedance changes were also detected at the non-ventilated sides in areas corresponding to 3.4+/-4.1% and 12.4+/-6.9% of the scan halves during ventilation of the left and right lung, respectively. Changes in global tidal volumes were adequately detected by EIT during both bilateral and unilateral lung ventilation. CONCLUSION Although good separation of the ventilated and non-ventilated sides of the chest was possible, the data indicate that reliable quantification of regional tidal volumes during asymmetric or inhomogeneous distribution patterns requires regions-of-interest analysis.
Collapse
Affiliation(s)
- S Pulletz
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Center of Schleswig-Holstein, Campus Kiel, Kiel, Germany.
| | | | | | | | | | | | | |
Collapse
|
27
|
Steinvall I, Bak Z, Sjoberg F. Acute respiratory distress syndrome is as important as inhalation injury for the development of respiratory dysfunction in major burns. Burns 2008; 34:441-51. [DOI: 10.1016/j.burns.2007.10.007] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Accepted: 10/26/2007] [Indexed: 01/31/2023]
|