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Cronin JN, Crockett DC, Perchiazzi G, Farmery AD, Camporota L, Formenti F. Intra-tidal PaO 2 oscillations associated with mechanical ventilation: a pilot study to identify discrete morphologies in a porcine model. Intensive Care Med Exp 2023; 11:60. [PMID: 37672140 PMCID: PMC10482813 DOI: 10.1186/s40635-023-00544-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/28/2023] [Indexed: 09/07/2023] Open
Abstract
BACKGROUND Within-breath oscillations in arterial oxygen tension (PaO2) can be detected using fast responding intra-arterial oxygen sensors in animal models. These PaO2 signals, which rise in inspiration and fall in expiration, may represent cyclical recruitment/derecruitment and, therefore, a potential clinical monitor to allow titration of ventilator settings in lung injury. However, in hypovolaemia models, these oscillations have the potential to become inverted, such that they decline, rather than rise, in inspiration. This inversion suggests multiple aetiologies may underlie these oscillations. A correct interpretation of the various PaO2 oscillation morphologies is essential to translate this signal into a monitoring tool for clinical practice. We present a pilot study to demonstrate the feasibility of a new analysis method to identify these morphologies. METHODS Seven domestic pigs (average weight 31.1 kg) were studied under general anaesthesia with muscle relaxation and mechanical ventilation. Three underwent saline-lavage lung injury and four were uninjured. Variations in PEEP, tidal volume and presence/absence of lung injury were used to induce different morphologies of PaO2 oscillation. Functional principal component analysis and k-means clustering were employed to separate PaO2 oscillations into distinct morphologies, and the cardiorespiratory physiology associated with these PaO2 morphologies was compared. RESULTS PaO2 oscillations from 73 ventilatory conditions were included. Five functional principal components were sufficient to explain ≥ 95% of the variance of the recorded PaO2 signals. From these, five unique morphologies of PaO2 oscillation were identified, ranging from those which increased in inspiration and decreased in expiration, through to those which decreased in inspiration and increased in expiration. This progression was associated with the estimates of the first functional principal component (P < 0.001, R2 = 0.88). Intermediate morphologies demonstrated waveforms with two peaks and troughs per breath. The progression towards inverted oscillations was associated with increased pulse pressure variation (P = 0.03). CONCLUSIONS Functional principal component analysis and k-means clustering are appropriate to identify unique morphologies of PaO2 waveform associated with distinct cardiorespiratory physiology. We demonstrated novel intermediate morphologies of PaO2 waveform, which may represent a development of zone 2 physiologies within the lung. Future studies of PaO2 oscillations and modelling should aim to understand the aetiologies of these morphologies.
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Affiliation(s)
- John N Cronin
- Department of Anaesthesia and Perioperative Medicine, St. Thomas' Hospital, Guy's and St. Thomas' NHS Foundation Trust, Westminster Bridge Road, London, SE1 7EH, UK.
- Faculty of Life Sciences and Medicine, King's College London, London, UK.
| | - Douglas C Crockett
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Gaetano Perchiazzi
- Hedenstierna Laboratory, Department of Surgical Sciences, University of Uppsala, Uppsala, Sweden
| | - Andrew D Farmery
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Luigi Camporota
- Faculty of Life Sciences and Medicine, King's College London, London, UK
- Department of Intensive Care, Guy's and St. Thomas' NHS Foundation Trust, London, UK
| | - Federico Formenti
- Faculty of Life Sciences and Medicine, King's College London, London, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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Nieman GF, Kaczka DW, Andrews PL, Ghosh A, Al-Khalisy H, Camporota L, Satalin J, Herrmann J, Habashi NM. First Stabilize and then Gradually Recruit: A Paradigm Shift in Protective Mechanical Ventilation for Acute Lung Injury. J Clin Med 2023; 12:4633. [PMID: 37510748 PMCID: PMC10380509 DOI: 10.3390/jcm12144633] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/15/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) is associated with a heterogeneous pattern of injury throughout the lung parenchyma that alters regional alveolar opening and collapse time constants. Such heterogeneity leads to atelectasis and repetitive alveolar collapse and expansion (RACE). The net effect is a progressive loss of lung volume with secondary ventilator-induced lung injury (VILI). Previous concepts of ARDS pathophysiology envisioned a two-compartment system: a small amount of normally aerated lung tissue in the non-dependent regions (termed "baby lung"); and a collapsed and edematous tissue in dependent regions. Based on such compartmentalization, two protective ventilation strategies have been developed: (1) a "protective lung approach" (PLA), designed to reduce overdistension in the remaining aerated compartment using a low tidal volume; and (2) an "open lung approach" (OLA), which first attempts to open the collapsed lung tissue over a short time frame (seconds or minutes) with an initial recruitment maneuver, and then stabilize newly recruited tissue using titrated positive end-expiratory pressure (PEEP). A more recent understanding of ARDS pathophysiology identifies regional alveolar instability and collapse (i.e., hidden micro-atelectasis) in both lung compartments as a primary VILI mechanism. Based on this understanding, we propose an alternative strategy to ventilating the injured lung, which we term a "stabilize lung approach" (SLA). The SLA is designed to immediately stabilize the lung and reduce RACE while gradually reopening collapsed tissue over hours or days. At the core of SLA is time-controlled adaptive ventilation (TCAV), a method to adjust the parameters of the airway pressure release ventilation (APRV) modality. Since the acutely injured lung at any given airway pressure requires more time for alveolar recruitment and less time for alveolar collapse, SLA adjusts inspiratory and expiratory durations and inflation pressure levels. The TCAV method SLA reverses the open first and stabilize second OLA method by: (i) immediately stabilizing lung tissue using a very brief exhalation time (≤0.5 s), so that alveoli simply do not have sufficient time to collapse. The exhalation duration is personalized and adaptive to individual respiratory mechanical properties (i.e., elastic recoil); and (ii) gradually recruiting collapsed lung tissue using an inflate and brake ratchet combined with an extended inspiratory duration (4-6 s) method. Translational animal studies, clinical statistical analysis, and case reports support the use of TCAV as an efficacious lung protective strategy.
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Affiliation(s)
- Gary F. Nieman
- Department of Surgery, Upstate Medical University, Syracuse, NY 13210, USA;
| | - David W. Kaczka
- Departments of Anesthesia, Radiology and Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Penny L. Andrews
- Department of Medicine, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD 21201, USA
| | - Auyon Ghosh
- Department of Medicine, Upstate Medical University, Syracuse, NY 13210, USA
| | - Hassan Al-Khalisy
- Brody School of Medicine, Department of Internal Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Luigi Camporota
- Department of Adult Critical Care, Guy’s and St Thomas’ NHS Foundation Trust, King’s Partners, St Thomas’ Hospital, London SE1 7EH, UK
| | - Joshua Satalin
- Department of Surgery, Upstate Medical University, Syracuse, NY 13210, USA;
| | - Jacob Herrmann
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Nader M. Habashi
- Department of Medicine, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD 21201, USA
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Nieman G, Kollisch-Singule M, Ramcharran H, Satalin J, Blair S, Gatto LA, Andrews P, Ghosh A, Kaczka DW, Gaver D, Bates J, Habashi NM. Unshrinking the baby lung to calm the VILI vortex. Crit Care 2022; 26:242. [PMID: 35934707 PMCID: PMC9357329 DOI: 10.1186/s13054-022-04105-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 07/12/2022] [Indexed: 02/07/2023] Open
Abstract
A hallmark of ARDS is progressive shrinking of the ‘baby lung,’ now referred to as the ventilator-induced lung injury (VILI) ‘vortex.’ Reducing the risk of the VILI vortex is the goal of current ventilation strategies; unfortunately, this goal has not been achieved nor has mortality been reduced. However, the temporal aspects of a mechanical breath have not been considered. A brief expiration prevents alveolar collapse, and an extended inspiration can recruit the atelectatic lung over hours. Time-controlled adaptive ventilation (TCAV) is a novel ventilator approach to achieve these goals, since it considers many of the temporal aspects of dynamic lung mechanics.
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Affiliation(s)
- Gary Nieman
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - Michaela Kollisch-Singule
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - Harry Ramcharran
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - Joshua Satalin
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA.
| | - Sarah Blair
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - Louis A Gatto
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - Penny Andrews
- Department of Medicine, University of Maryland, Baltimore, MD, USA
| | - Auyon Ghosh
- Department of Surgery, SUNY Upstate Medical Center, SUNY Upstate, 750 East Adams St., Syracuse, NY, 13210, USA
| | - David W Kaczka
- Departments of Anesthesia, Biomedical Engineering, and Radiology, University of Iowa, Iowa City, IA, USA
| | - Donald Gaver
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
| | - Jason Bates
- Department of Medicine, University of Vermont, Burlington, VT, USA
| | - Nader M Habashi
- Department of Medicine, University of Maryland, Baltimore, MD, USA
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Andrews P, Shiber J, Madden M, Nieman GF, Camporota L, Habashi NM. Myths and Misconceptions of Airway Pressure Release Ventilation: Getting Past the Noise and on to the Signal. Front Physiol 2022; 13:928562. [PMID: 35957991 PMCID: PMC9358044 DOI: 10.3389/fphys.2022.928562] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/21/2022] [Indexed: 12/16/2022] Open
Abstract
In the pursuit of science, competitive ideas and debate are necessary means to attain knowledge and expose our ignorance. To quote Murray Gell-Mann (1969 Nobel Prize laureate in Physics): "Scientific orthodoxy kills truth". In mechanical ventilation, the goal is to provide the best approach to support patients with respiratory failure until the underlying disease resolves, while minimizing iatrogenic damage. This compromise characterizes the philosophy behind the concept of "lung protective" ventilation. Unfortunately, inadequacies of the current conceptual model-that focuses exclusively on a nominal value of low tidal volume and promotes shrinking of the "baby lung" - is reflected in the high mortality rate of patients with moderate and severe acute respiratory distress syndrome. These data call for exploration and investigation of competitive models evaluated thoroughly through a scientific process. Airway Pressure Release Ventilation (APRV) is one of the most studied yet controversial modes of mechanical ventilation that shows promise in experimental and clinical data. Over the last 3 decades APRV has evolved from a rescue strategy to a preemptive lung injury prevention approach with potential to stabilize the lung and restore alveolar homogeneity. However, several obstacles have so far impeded the evaluation of APRV's clinical efficacy in large, randomized trials. For instance, there is no universally accepted standardized method of setting APRV and thus, it is not established whether its effects on clinical outcomes are due to the ventilator mode per se or the method applied. In addition, one distinctive issue that hinders proper scientific evaluation of APRV is the ubiquitous presence of myths and misconceptions repeatedly presented in the literature. In this review we discuss some of these misleading notions and present data to advance scientific discourse around the uses and misuses of APRV in the current literature.
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Affiliation(s)
- Penny Andrews
- R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Joseph Shiber
- University of Florida College of Medicine, Jacksonville, FL, United States
| | - Maria Madden
- R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Gary F. Nieman
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Luigi Camporota
- Department of Adult Critical Care, Guy’s and St Thomas’ NHS Foundation Trust, Health Centre for Human and Applied Physiological Sciences, London, United Kingdom
| | - Nader M. Habashi
- R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, MD, United States
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Crockett DC, Cronin JN, Bommakanti N, Chen R, Hahn CEW, Hedenstierna G, Larsson A, Farmery AD, Formenti F. Tidal changes in PaO 2 and their relationship to cyclical lung recruitment/derecruitment in a porcine lung injury model. Br J Anaesth 2018; 122:277-285. [PMID: 30686314 PMCID: PMC6354046 DOI: 10.1016/j.bja.2018.09.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 08/21/2018] [Accepted: 09/10/2018] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Tidal recruitment/derecruitment (R/D) of collapsed regions in lung injury has been presumed to cause respiratory oscillations in the partial pressure of arterial oxygen (PaO2). These phenomena have not yet been studied simultaneously. We examined the relationship between R/D and PaO2 oscillations by contemporaneous measurement of lung-density changes and PaO2. METHODS Five anaesthetised pigs were studied after surfactant depletion via a saline-lavage model of R/D. The animals were ventilated with a mean fraction of inspired O2 (FiO2) of 0.7 and a tidal volume of 10 ml kg-1. Protocolised changes in pressure- and volume-controlled modes, inspiratory:expiratory ratio (I:E), and three types of breath-hold manoeuvres were undertaken. Lung collapse and PaO2 were recorded using dynamic computed tomography (dCT) and a rapid PaO2 sensor. RESULTS During tidal ventilation, the expiratory lung collapse increased when I:E <1 [mean (standard deviation) lung collapse=15.7 (8.7)%; P<0.05], but the amplitude of respiratory PaO2 oscillations [2.2 (0.8) kPa] did not change during the respiratory cycle. The expected relationship between respiratory PaO2 oscillation amplitude and R/D was therefore not clear. Lung collapse increased during breath-hold manoeuvres at end-expiration and end-inspiration (14% vs 0.9-2.1%; P<0.0001). The mean change in PaO2 from beginning to end of breath-hold manoeuvres was significantly different with each type of breath-hold manoeuvre (P<0.0001). CONCLUSIONS This study in a porcine model of collapse-prone lungs did not demonstrate the expected association between PaO2 oscillation amplitude and the degree of recruitment/derecruitment. The results suggest that changes in pulmonary ventilation are not the sole determinant of changes in PaO2 during mechanical ventilation in lung injury.
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Affiliation(s)
- D C Crockett
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK.
| | - J N Cronin
- Centre for Human and Applied Physiological Sciences, King's College, London, UK
| | - N Bommakanti
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK; Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - R Chen
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK
| | - C E W Hahn
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK
| | - G Hedenstierna
- Hedenstierna Laboratory, Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - A Larsson
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - A D Farmery
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK
| | - F Formenti
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK; Centre for Human and Applied Physiological Sciences, King's College, London, UK; Department of Biomechanics, University of Nebraska Omaha, Omaha, NE, USA.
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7
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Boehme S, Toemboel FPR, Hartmann EK, Bentley AH, Weinheimer O, Yang Y, Achenbach T, Hagmann M, Kaniusas E, Baumgardner JE, Markstaller K. Detection of inspiratory recruitment of atelectasis by automated lung sound analysis as compared to four-dimensional computed tomography in a porcine lung injury model. Crit Care 2018; 22:50. [PMID: 29475456 PMCID: PMC6389194 DOI: 10.1186/s13054-018-1964-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 01/24/2018] [Indexed: 11/21/2022] Open
Abstract
Background Cyclic recruitment and de-recruitment of atelectasis (c-R/D) is a contributor to ventilator-induced lung injury (VILI). Bedside detection of this dynamic process could improve ventilator management. This study investigated the potential of automated lung sound analysis to detect c-R/D as compared to four-dimensional computed tomography (4DCT). Methods In ten piglets (25 ± 2 kg), acoustic measurements from 34 thoracic piezoelectric sensors (Meditron ASA, Norway) were performed, time synchronized to 4DCT scans, at positive end-expiratory pressures of 0, 5, 10, and 15 cmH2O during mechanical ventilation, before and after induction of c-R/D by surfactant washout. 4DCT was post-processed for within-breath variation in atelectatic volume (Δ atelectasis) as a measure of c-R/D. Sound waveforms were evaluated for: 1) dynamic crackle energy (dCE): filtered crackle sounds (600–700 Hz); 2) fast Fourier transform area (FFT area): spectral content above 500 Hz in frequency and above −70 dB in amplitude in proportion to the total amount of sound above −70 dB amplitude; and 3) dynamic spectral coherence (dSC): variation in acoustical homogeneity over time. Parameters were analyzed for global, nondependent, central, and dependent lung areas. Results In healthy lungs, negligible values of Δ atelectasis, dCE, and FFT area occurred. In lavage lung injury, the novel dCE parameter showed the best correlation to Δ atelectasis in dependent lung areas (R2 = 0.88) where c-R/D took place. dCE was superior to FFT area analysis for each lung region examined. The analysis of dSC could predict the lung regions where c-R/D originated. Conclusions c-R/D is associated with the occurrence of fine crackle sounds as demonstrated by dCE analysis. Standardized computer-assisted analysis of dCE and dSC seems to be a promising method for depicting c-R/D. Electronic supplementary material The online version of this article (10.1186/s13054-018-1964-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stefan Boehme
- Department of Anesthesia, General Intensive Care Medicine and Pain Management, Medical University Vienna, Waehringer Guertel, 18-20, Vienna, Austria. .,Department of Anesthesiology, Medical Center of the Johannes-Gutenberg University Mainz, Mainz, Germany.
| | - Frédéric P R Toemboel
- Department of Anesthesia, General Intensive Care Medicine and Pain Management, Medical University Vienna, Waehringer Guertel, 18-20, Vienna, Austria
| | - Erik K Hartmann
- Department of Anesthesiology, Medical Center of the Johannes-Gutenberg University Mainz, Mainz, Germany
| | - Alexander H Bentley
- Department of Anesthesiology, Medical Center of the Johannes-Gutenberg University Mainz, Mainz, Germany
| | - Oliver Weinheimer
- Department of Diagnostic and Interventional Radiology, Medical Center of the Johannes-Gutenberg University Mainz, Mainz, Germany.,Department of Diagnostic and Interventional Radiology, University Hospital of Heidelberg, Heidelberg, Germany.,Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), Heidelberg, Germany
| | - Yang Yang
- Department of Diagnostic and Interventional Radiology, Medical Center of the Johannes-Gutenberg University Mainz, Mainz, Germany
| | - Tobias Achenbach
- Department of Diagnostic and Interventional Radiology, Medical Center of the Johannes-Gutenberg University Mainz, Mainz, Germany.,Institute of Diagnostic and Interventional Radiology, St. Vinzenz Hospital, Cologne, Germany
| | - Michael Hagmann
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University Vienna, Vienna, Austria
| | - Eugenijus Kaniusas
- Institute of Electrodynamics, Microwave and Circuit Engineering, Vienna University of Technology, Vienna, Austria
| | - James E Baumgardner
- Department of Anesthesiology, University of Pittsburgh Medical Center, Pittsburgh, PA, 15261, USA
| | - Klaus Markstaller
- Department of Anesthesia, General Intensive Care Medicine and Pain Management, Medical University Vienna, Waehringer Guertel, 18-20, Vienna, Austria.,Department of Anesthesiology, Medical Center of the Johannes-Gutenberg University Mainz, Mainz, Germany
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Formenti F, Bommakanti N, Chen R, Cronin JN, McPeak H, Holopherne-Doran D, Hedenstierna G, Hahn CEW, Larsson A, Farmery AD. Respiratory oscillations in alveolar oxygen tension measured in arterial blood. Sci Rep 2017; 7:7499. [PMID: 28878215 PMCID: PMC5587703 DOI: 10.1038/s41598-017-06975-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 06/20/2017] [Indexed: 01/02/2023] Open
Abstract
Arterial oxygen partial pressure can increase during inspiration and decrease during expiration in the presence of a variable shunt fraction, such as with cyclical atelectasis, but it is generally presumed to remain constant within a respiratory cycle in the healthy lung. We measured arterial oxygen partial pressure continuously with a fast intra-vascular sensor in the carotid artery of anaesthetized, mechanically ventilated pigs, without lung injury. Here we demonstrate that arterial oxygen partial pressure shows respiratory oscillations in the uninjured pig lung, in the absence of cyclical atelectasis (as determined with dynamic computed tomography), with oscillation amplitudes that exceeded 50 mmHg, depending on the conditions of mechanical ventilation. These arterial oxygen partial pressure respiratory oscillations can be modelled from a single alveolar compartment and a constant oxygen uptake, without the requirement for an increased shunt fraction during expiration. Our results are likely to contribute to the interpretation of arterial oxygen respiratory oscillations observed during mechanical ventilation in the acute respiratory distress syndrome.
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Affiliation(s)
- Federico Formenti
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, United Kingdom. .,Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom.
| | - Nikhil Bommakanti
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, United Kingdom
| | - Rongsheng Chen
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, United Kingdom
| | - John N Cronin
- Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Hanne McPeak
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, United Kingdom
| | | | | | - Clive E W Hahn
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, United Kingdom
| | - Anders Larsson
- Department of Surgical Sciences, University of Uppsala, Uppsala, Sweden
| | - Andrew D Farmery
- Nuffield Division of Anaesthetics, University of Oxford, Oxford, United Kingdom
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Cyclic PaO 2 oscillations assessed in the renal microcirculation: correlation with tidal volume in a porcine model of lung lavage. BMC Anesthesiol 2017; 17:92. [PMID: 28693425 PMCID: PMC5504855 DOI: 10.1186/s12871-017-0382-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 06/30/2017] [Indexed: 01/08/2023] Open
Abstract
Background Oscillations of the arterial partial pressure of oxygen induced by varying shunt fractions occur during cyclic alveolar recruitment within the injured lung. Recently, these were proposed as a pathomechanism that may be relevant for remote organ injury following acute respiratory distress syndrome. This study examines the transmission of oxygen oscillations to the renal tissue and their tidal volume dependency. Methods Lung injury was induced by repetitive bronchoalveolar lavage in eight anaesthetized pigs. Cyclic alveolar recruitment was provoked by high tidal volume ventilation. Oscillations of the arterial partial pressure of oxygen were measured in real-time in the macrocirculation by multi-frequency phase fluorimetry and in the renal microcirculation by combined white-light spectrometry and laser-Doppler flowmetry during tidal volume down-titration. Results Significant respiratory-dependent oxygen oscillations were detected in the macrocirculation and transmitted to the renal microcirculation in a substantial extent. The amplitudes of these oscillations significantly correlate to the applied tidal volume and are minimized during down-titration. Conclusions In a porcine model oscillations of the arterial partial pressure of oxygen are induced by cyclic alveolar recruitment and transmitted to the renal microcirculation in a tidal volume-dependent fashion. They might play a role in organ crosstalk and remote organ damage following lung injury.
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Brander L, Moerer O, Hedenstierna G, Beck J, Takala J, Slutsky AS, Sinderby C. Neural control of ventilation prevents both over-distension and de-recruitment of experimentally injured lungs. Respir Physiol Neurobiol 2016; 237:57-67. [PMID: 28013057 DOI: 10.1016/j.resp.2016.12.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 10/25/2016] [Accepted: 12/20/2016] [Indexed: 01/24/2023]
Abstract
BACKGROUND Endogenous pulmonary reflexes may protect the lungs during mechanical ventilation. We aimed to assess integration of continuous neurally adjusted ventilatory assist (cNAVA), delivering assist in proportion to diaphragm's electrical activity during inspiration and expiration, and Hering-Breuer inflation and deflation reflexes on lung recruitment, distension, and aeration before and after acute lung injury (ALI). METHODS In 7 anesthetised rabbits with bilateral pneumothoraces, we identified adequate cNAVA level (cNAVAAL) at the plateau in peak ventilator pressure during titration procedures before (healthy lungs with endotracheal tube, [HLETT]) and after ALI (endotracheal tube [ALIETT] and during non-invasive ventilation [ALINIV]). Following titration, cNAVAAL was maintained for 5min. In 2 rabbits, procedures were repeated after vagotomy (ALIETT+VAG). In 3 rabbits delivery of assist was temporarily modulated to provide assist on inspiration only. Computed tomography was performed before intubation, before ALI, during cNAVA titration, and after maintenance at cNAVAAL. RESULTS During ALIETT and ALINIV, normally aerated lung-regions doubled and poorly aerated lung-regions decreased to less than a third (p<0.05) compared to HLETT; no over-distension was observed. Tidal volumes were<5ml/kg throughout. Removing assist during expiration resulted in lung de-recruitment during ALIETT, but not during ALINIV. During ALIETT+VAG the expiratory portion of EAdi disappeared, resulting in cyclic lung collapse and recruitment. CONCLUSIONS When using cNAVA in ALI, vagally mediated reflexes regulated lung recruitment preventing both lung over-distension and atelectasis. During non-invasive cNAVA the upper airway muscles play a role in preventing atelectasis. Future studies should be performed to compare these findings with conventional lung-protective approaches.
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Affiliation(s)
- Lukas Brander
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Department of Critical Care Medicine, St. Michael's Hospital, Toronto, Canada; Department of Intensive Care Medicine, Cantonal Hospital of Lucerne, Switzerland.
| | - Onnen Moerer
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Department of Critical Care Medicine, St. Michael's Hospital, Toronto, Canada; Department of Anaesthesiology, Emergency and Critical Care Medicine, University of Göttingen, Germany
| | - Göran Hedenstierna
- Department of Medical Sciences, Clinical Physiology, University of Uppsala, Uppsala, Sweden
| | - Jennifer Beck
- Department of Pediatrics, University of Toronto, Toronto, Canada; Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Canada; Institute for Biomedical Engineering and Science Technology (iBEST) at Ryerson University and St. Michael's Hospital, Toronto, Canada
| | - Jukka Takala
- Department of Intensive Care Medicine, Bern University Hospital - Inselspital, and University of Bern, Switzerland
| | - Arthur S Slutsky
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Department of Critical Care Medicine, St. Michael's Hospital, Toronto, Canada; Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Canada
| | - Christer Sinderby
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Department of Critical Care Medicine, St. Michael's Hospital, Toronto, Canada; Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, Canada; Institute for Biomedical Engineering and Science Technology (iBEST) at Ryerson University and St. Michael's Hospital, Toronto, Canada
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Jauncey-Cooke J, Schibler A, Bogossian F, Gibbons K, Grant CA, East CE. Lung recruitment manoeuvres in mechanically ventilated children for reducing respiratory morbidity. Hippokratia 2016. [DOI: 10.1002/14651858.cd008866.pub2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Andreas Schibler
- Mater Children’s Hospital; Paediatric Critical Care Research Group; South Brisbane Queensland Australia 4101
| | - Fiona Bogossian
- School of Nursing and Midwifery; The University of Queensland; Herston Australia
| | - Kristen Gibbons
- Mater Research Institute; South Brisbane Queensland Australia 4101
| | - Caroline A Grant
- Mater Children's Hospital; Paediatric Intensive Care Unit; Raymond Terrace South Brisbane Queensland Australia 4001
| | - Christine E East
- Monash University/Monash Health; School of Nursing and Midwifery/Maternity Services; 246 Clayton Road Clayton Victoria Australia 3168
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12
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Schreiter D, Carvalho NC, Katscher S, Mende L, Reske AP, Spieth PM, Carvalho AR, Beda A, Lachmann B, Amato MBP, Wrigge H, Reske AW. Experimental blunt chest trauma--cardiorespiratory effects of different mechanical ventilation strategies with high positive end-expiratory pressure: a randomized controlled study. BMC Anesthesiol 2016; 16:3. [PMID: 26757894 PMCID: PMC4709895 DOI: 10.1186/s12871-015-0166-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 12/09/2015] [Indexed: 02/01/2023] Open
Abstract
Background Uncertainty persists regarding the optimal ventilatory strategy in trauma patients developing acute respiratory distress syndrome (ARDS). This work aims to assess the effects of two mechanical ventilation strategies with high positive end-expiratory pressure (PEEP) in experimental ARDS following blunt chest trauma. Methods Twenty-six juvenile pigs were anesthetized, tracheotomized and mechanically ventilated. A contusion was applied to the right chest using a bolt-shot device. Ninety minutes after contusion, animals were randomized to two different ventilation modes, applied for 24 h: Twelve pigs received conventional pressure-controlled ventilation with moderately low tidal volumes (VT, 8 ml/kg) and empirically chosen high external PEEP (16cmH2O) and are referred to as the HP-CMV-group. The other group (n = 14) underwent high-frequency inverse-ratio pressure-controlled ventilation (HFPPV) involving respiratory rate of 65breaths · min−1, inspiratory-to-expiratory-ratio 2:1, development of intrinsic PEEP and recruitment maneuvers, compatible with the rationale of the Open Lung Concept. Hemodynamics, gas exchange and respiratory mechanics were monitored during 24 h. Computed tomography and histology were analyzed in subgroups. Results Comparing changes which occurred from randomization (90 min after chest trauma) over the 24-h treatment period, groups differed statistically significantly (all P values for group effect <0.001, General Linear Model analysis) for the following parameters (values are mean ± SD for randomization vs. 24-h): PaO2 (100 % O2) (HFPPV 186 ± 82 vs. 450 ± 59 mmHg; HP-CMV 249 ± 73 vs. 243 ± 81 mmHg), venous admixture (HFPPV 34 ± 9.8 vs. 11.2 ± 3.7 %; HP-CMV 33.9 ± 10.5 vs. 21.8 ± 7.2 %), PaCO2 (HFPPV 46.9 ± 6.8 vs. 33.1 ± 2.4 mmHg; HP-CMV 46.3 ± 11.9 vs. 59.7 ± 18.3 mmHg) and normally aerated lung mass (HFPPV 42.8 ± 11.8 vs. 74.6 ± 10.0 %; HP-CMV 40.7 ± 8.6 vs. 53.4 ± 11.6 %). Improvements occurring after recruitment in the HFPPV-group persisted throughout the study. Peak airway pressure and VT did not differ significantly. HFPPV animals had lower atelectasis and inflammation scores in gravity-dependent lung areas. Conclusions In this model of ARDS following unilateral blunt chest trauma, HFPPV ventilation improved respiratory function and fulfilled relevant ventilation endpoints for trauma patients, i.e. restoration of oxygenation and lung aeration while avoiding hypercapnia and respiratory acidosis.
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Affiliation(s)
- Dierk Schreiter
- Helios Park Clinic, Department of Intensive Care Medicine, Leipzig, Germany.
| | - Nadja C Carvalho
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Leipzig, Liebigstr. 20, D-04103, Leipzig, Germany. .,Department of Electronic Engineering, Federal University of Minas Gerais, Belo Horizonte, Brazil.
| | - Sebastian Katscher
- Sana Kliniken Leipziger Land, Department of Orthopedic, Trauma and Hand Surgery, Borna, Germany.
| | - Ludger Mende
- Intensive Care Unit, Sana Kliniken Leipziger Land, Borna, Germany.
| | - Alexander P Reske
- Anesthesiology and Intensive Care Medicine, Fachkrankenhaus Coswig, Coswig, Sachsen, Germany.
| | - Peter M Spieth
- Pulmonary Engineering Group, Department of Anesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus, Dresden, Germany.
| | - Alysson R Carvalho
- Carlos Chagas Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
| | - Alessandro Beda
- Department of Electronic Engineering, Federal University of Minas Gerais, Belo Horizonte, Brazil.
| | - Burkhard Lachmann
- Department of Anesthesiology and Intensive Care Medicine, Charité, Berlin Medical University, Berlin, Germany.
| | - Marcelo B P Amato
- Cardio-Pulmonary Department, Pulmonary Division, Hospital das Clínicas, University of São Paulo, São Paulo, Brazil.
| | - Hermann Wrigge
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Leipzig, Liebigstr. 20, D-04103, Leipzig, Germany.
| | - Andreas W Reske
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Leipzig, Liebigstr. 20, D-04103, Leipzig, Germany.
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Nieman GF, Gatto LA, Habashi NM. Reducing acute respiratory distress syndrome occurrence using mechanical ventilation. World J Respirol 2015; 5:188-198. [DOI: 10.5320/wjr.v5.i3.188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 07/01/2015] [Accepted: 07/17/2015] [Indexed: 02/06/2023] Open
Abstract
The standard treatment for acute respiratory distress syndrome (ARDS) is supportive in the form of low tidal volume ventilation applied after significant lung injury has already developed. Nevertheless, ARDS mortality remains unacceptably high (> 40%). Indeed, once ARDS is established it becomes refractory to treatment, and therefore avoidance is key. However, preventive techniques and therapeutics to reduce the incidence of ARDS in patients at high-risk have not been validated clinically. This review discusses the current data suggesting that preemptive application of the properly adjusted mechanical breath can block progressive acute lung injury and significantly reduce the occurrence of ARDS.
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Jauncey-Cooke J, East CE, Bogossian F. Paediatric lung recruitment: a review of the clinical evidence. Paediatr Respir Rev 2015; 16:127-32. [PMID: 24680638 DOI: 10.1016/j.prrv.2014.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 02/13/2014] [Accepted: 02/15/2014] [Indexed: 12/21/2022]
Abstract
Lung recruitment is used as an adjunct to lung protective ventilation strategies. Lung recruitment is a brief, deliberate elevation of transpulmonary pressures beyond what is achieved during tidal ventilation levels. The aim of lung recruitment is to maximise the number of alveoli participating in gas exchange particularly in distal and dependant regions of the lung. This may improve oxygenation and end expiratory levels. Restoration of end expiratory levels and stabilisation of the alveoli may reduce the incidence of ventilator induced lung injury (VILI). Various methods of lung recruitment have been studied in adult and experimental populations. This review aims to establish the evidence for lung recruitment in the pediatric population.
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Affiliation(s)
- Jacqui Jauncey-Cooke
- School of Nursing & Midwifery, The University of Queensland, Australia; Paediatric Critical Care Research Group, PICU, Mater Children's Hospital, Brisbane, Australia.
| | - Chris E East
- School of Nursing and Midwifery/Maternity Services, Monash University/Southern Health, Clayton, Victoria and the School of Nursing & Midwifery, The University of Queensland, Australia.
| | - Fiona Bogossian
- School of Nursing & Midwifery, The University of Queensland, Australia.
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15
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Formenti F, Chen R, McPeak H, Murison PJ, Matejovic M, Hahn CEW, Farmery AD. Intra-breath arterial oxygen oscillations detected by a fast oxygen sensor in an animal model of acute respiratory distress syndrome. Br J Anaesth 2015; 114:683-8. [PMID: 25631471 PMCID: PMC4364062 DOI: 10.1093/bja/aeu407] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background There is considerable interest in oxygen partial pressure (Po2) monitoring in physiology, and in tracking Po2 changes dynamically when it varies rapidly. For example, arterial Po2 (PaO2) can vary within the respiratory cycle in cyclical atelectasis (CA), where PaO2 is thought to increase and decrease during inspiration and expiration, respectively. A sensor that detects these PaO2 oscillations could become a useful diagnostic tool of CA during acute respiratory distress syndrome (ARDS). Methods We developed a fibreoptic Po2 sensor (<200 µm diameter), suitable for human use, that has a fast response time, and can measure Po2 continuously in blood. By altering the inspired fraction of oxygen (FIO2) from 21 to 100% in four healthy animal models, we determined the linearity of the sensor's signal over a wide range of PaO2 values in vivo. We also hypothesized that the sensor could measure rapid intra-breath PaO2 oscillations in a large animal model of ARDS. Results In the healthy animal models, PaO2 responses to changes in FIO2 were in agreement with conventional intermittent blood-gas analysis (n=39) for a wide range of PaO2 values, from 10 to 73 kPa. In the animal lavage model of CA, the sensor detected PaO2 oscillations, also at clinically relevant PaO2 levels close to 9 kPa. Conclusions We conclude that these fibreoptic PaO2 sensors have the potential to become a diagnostic tool for CA in ARDS.
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Affiliation(s)
- F Formenti
- Nuffield Department of Clinical Neurosciences, Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK
| | - R Chen
- Nuffield Department of Clinical Neurosciences, Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK
| | - H McPeak
- Nuffield Department of Clinical Neurosciences, Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK
| | - P J Murison
- School of Veterinary Sciences, University of Bristol, Bristol, UK
| | - M Matejovic
- Biomedical Centre, Charles University in Prague, Faculty of Medicine in Pilsen, alej Svobody 80, 304 60 Pilsen, Czech Republic First Medical Department, Charles University in Prague, Faculty of Medicine in Pilsen, alej Svobody 80, 304 60 Pilsen, Czech Republic
| | - C E W Hahn
- Nuffield Department of Clinical Neurosciences, Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK
| | - A D Farmery
- Nuffield Department of Clinical Neurosciences, Nuffield Division of Anaesthetics, University of Oxford, Oxford, UK
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Large changes in PaO2 oscillation amplitude with respiratory rate are not measurement artifact. Respir Physiol Neurobiol 2014; 195:59. [PMID: 24456732 DOI: 10.1016/j.resp.2014.01.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 01/12/2014] [Indexed: 11/21/2022]
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Formenti F, Chen R, McPeak H, Matejovic M, Farmery AD, Hahn CEW. A fibre optic oxygen sensor that detects rapid PO2 changes under simulated conditions of cyclical atelectasis in vitro. Respir Physiol Neurobiol 2013; 191:1-8. [PMID: 24184746 PMCID: PMC3906517 DOI: 10.1016/j.resp.2013.10.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 10/11/2013] [Accepted: 10/14/2013] [Indexed: 12/02/2022]
Abstract
Real time detection of cyclical atelectasis is fundamental for individualised mechanical-ventilation therapy in ARDS. Intra-arterial oxygen sensors could be used to detect the breath-by-breath oscillations in PO2 during cyclical atelectasis. The fidelity with which oxygen sensors can detect these arterial PO2 oscillations depends on the sensors’ speed of response. We present a system for testing fast-response fibre optic oxygen sensors under simulated conditions of cyclical atelectasis. We show that a prototype fibre optic oxygen sensor, compatible with clinical use, can detect rapid PO2 changes in vitro.
Two challenges in the management of Acute Respiratory Distress Syndrome are the difficulty in diagnosing cyclical atelectasis, and in individualising mechanical ventilation therapy in real-time. Commercial optical oxygen sensors can detect PaO2 oscillations associated with cyclical atelectasis, but are not accurate at saturation levels below 90%, and contain a toxic fluorophore. We present a computer-controlled test rig, together with an in-house constructed ultra-rapid sensor to test the limitations of these sensors when exposed to rapidly changing PO2 in blood in vitro. We tested the sensors’ responses to simulated respiratory rates between 10 and 60 breaths per minute. Our sensor was able to detect the whole amplitude of the imposed PO2 oscillations, even at the highest respiratory rate. We also examined our sensor's resistance to clot formation by continuous in vivo deployment in non-heparinised flowing animal blood for 24 h, after which no adsorption of organic material on the sensor's surface was detectable by scanning electron microscopy.
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Affiliation(s)
- Federico Formenti
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
| | - Rongsheng Chen
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Hanne McPeak
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Martin Matejovic
- Biomedical Centre, Charles University in Prague, Faculty of Medicine in Pilsen, alej Svobody 80, 304 60 Pilsen, Czech Republic; First Medical Department, Charles University in Prague, Faculty of Medicine in Pilsen, alej Svobody 80, 304 60 Pilsen, Czech Republic
| | - Andrew D Farmery
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Clive E W Hahn
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.
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Cyclic recruitment of atelectasis – Are there implications for our clinical practice? TRENDS IN ANAESTHESIA AND CRITICAL CARE 2013. [DOI: 10.1016/j.tacc.2013.02.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Jauncey-Cooke J, Bogossian F, Hough JL, Schibler A, Davies MW, Grant CA, Gibbons K, East CE. Lung recruitment manoeuvres for reducing respiratory morbidity in mechanically ventilated neonates. Hippokratia 2012. [DOI: 10.1002/14651858.cd009969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Fiona Bogossian
- School of Nursing and Midwifery; The University of Queensland; Herston Australia
| | - Judith L Hough
- Mater Medical Research Institute; South Brisbane Queensland Australia 4101
| | - Andreas Schibler
- Mater Children's Hospital; Paediatric Intensive Care Unit; Raymond Terrace South Brisbane Queensland Australia 4101
| | - Mark W Davies
- Department of Paediatrics & Child Health, The University of Queensland; Grantley Stable Neonatal Unit, Royal Brisbane and Women's Hospital; Butterfield St Herston Brisbane Queensland Australia 4029
| | - Caroline A Grant
- Mater Children's Hospital; Paediatric Intensive Care Unit; Raymond Terrace South Brisbane Queensland Australia 4101
| | - Kristen Gibbons
- Mater Medical Research Institute; Clinical Research Support Unit; Level 3, Quarters Building Raymond Terrace South Brisbane Queensland Australia 4101
| | - Christine E East
- School of Nursing and Midwifery, Monash University / Southern Health; School of Nursing and Midwifery, University of Queensland; 246 Clayton Rd Clayton Victoria Australia 3168
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Chen R, Hahn CEW, Farmery AD. A flowing liquid test system for assessing the linearity and time-response of rapid fibre optic oxygen partial pressure sensors. Respir Physiol Neurobiol 2012; 183:100-7. [PMID: 22688018 DOI: 10.1016/j.resp.2012.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 05/31/2012] [Accepted: 06/02/2012] [Indexed: 11/16/2022]
Abstract
The development of a methodology for testing the time response, linearity and performance characteristics of ultra fast fibre optic oxygen sensors in the liquid phase is presented. Two standard medical paediatric oxygenators are arranged to provide two independent extracorporeal circuits. Flow from either circuit can be diverted over the sensor under test by means of a system of rapid cross-over solenoid valves exposing the sensor to an abrupt change in oxygen partial pressure, P O2. The system is also capable of testing the oxygen sensor responses to changes in temperature, carbon dioxide partial pressure P CO2 and pH in situ. Results are presented for a miniature fibre optic oxygen sensor constructed in-house with a response time ≈ 50 ms and a commercial fibre optic sensor (Ocean Optics Foxy), when tested in flowing saline and stored blood.
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Affiliation(s)
- R Chen
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
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Hartmann EK, Boehme S, Bentley A, Duenges B, Klein KU, Elsaesser A, Baumgardner JE, David M, Markstaller K. Influence of respiratory rate and end-expiratory pressure variation on cyclic alveolar recruitment in an experimental lung injury model. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2012; 16:R8. [PMID: 22248044 PMCID: PMC3396238 DOI: 10.1186/cc11147] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 12/04/2011] [Accepted: 01/16/2012] [Indexed: 01/11/2023]
Abstract
Introduction Cyclic alveolar recruitment/derecruitment (R/D) is an important mechanism of ventilator-associated lung injury. In experimental models this process can be measured with high temporal resolution by detection of respiratory-dependent oscillations of the paO2 (ΔpaO2). A previous study showed that end-expiratory collapse can be prevented by an increased respiratory rate in saline-lavaged rabbits. The current study compares the effects of increased positive end-expiratory pressure (PEEP) versus an individually titrated respiratory rate (RRind) on intra-tidal amplitude of Δ paO2 and on average paO2 in saline-lavaged pigs. Methods Acute lung injury was induced by bronchoalveolar lavage in 16 anaesthetized pigs. R/D was induced and measured by a fast-responding intra-aortic probe measuring paO2. Ventilatory interventions (RRind (n = 8) versus extrinsic PEEP (n = 8)) were applied for 30 minutes to reduce Δ paO2. Haemodynamics, spirometry and Δ paO2 were monitored and the Ventilation/Perfusion distributions were assessed by multiple inert gas elimination. The main endpoints average and Δ paO2 following the interventions were analysed by Mann-Whitney-U-Test and Bonferroni's correction. The secondary parameters were tested in an explorative manner. Results Both interventions reduced Δ paO2. In the RRind group, ΔpaO2 was significantly smaller (P < 0.001). The average paO2 continuously decreased following RRind and was significantly higher in the PEEP group (P < 0.001). A sustained difference of the ventilation/perfusion distribution and shunt fractions confirms these findings. The RRind application required less vasopressor administration. Conclusions Different recruitment kinetics were found compared to previous small animal models and these differences were primarily determined by kinetics of end-expiratory collapse. In this porcine model, respiratory rate and increased PEEP were both effective in reducing the amplitude of paO2 oscillations. In contrast to a recent study in a small animal model, however, increased respiratory rate did not maintain end-expiratory recruitment and ultimately resulted in reduced average paO2 and increased shunt fraction.
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Affiliation(s)
- Erik K Hartmann
- Department of Anaesthesiology, Medical Center of the Johannes Gutenberg-University, Mainz 55131, Germany.
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Abstract
PURPOSE OF REVIEW Hypoxemia during one-lung ventilation (OLV) has become less common; however, it may still occur in about 10% of cases. We review recent developments which may affect the incidence and treatment of hypoxemia during OLV. RECENT FINDINGS Changes in surgical techniques are affecting oxygenation during OLV. The increased use of the supine position may adversely affect the prevalence of hypoxemia, whereas the increased application of thoracoscopic techniques is limiting the treatment options. Treatment options such as global or selective recruitment maneuvers and drug effects of dexmedetomidine and epoprostenol on arterial oxygenation during OLV are discussed. Capnometry prior to, or early during OLV, may in fact be able to predict the degree of hypoxemia during OLV. Persistent controversies surrounding the effect of epidural anesthesia, ventilatory modalities and gravity are reviewed. SUMMARY Interesting concepts have emerged from case reports and small studies on the treatment and prediction of hypoxemia during OLV. Definitive studies on the most effective ventilatory mode remain elusive. End-organ effects of OLV are an exciting new concept that may shape clinical practice and research going forward.
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Shi C, Boehme S, Hartmann EK, Markstaller K. Novel technologies to detect atelectotrauma in the injured lung. Exp Lung Res 2010; 37:18-25. [PMID: 20860539 DOI: 10.3109/01902148.2010.501402] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cyclical recruitment and derecruitment of lung parenchyma (R/D) remains a serious problem in ALI/ARDS patients, defined as atelectotrauma. Detection of cyclical R/D to titrate the optimal respiratory settings is of high clinical importance. Image-based technologies that are capable of detecting changes of lung ventilation within a respiratory cycle include dynamic computed tomography (dCT), synchrotron radiation computed tomography (SRCT), and electrical impedance tomography (EIT). Time-dependent intra-arterial oxygen tension monitoring represents an alternative approach to detect cyclical R/D, as cyclical R/D can result in oscillations of PaO₂ within a respiratory cycle. Continuous, ultrafast, on-line in vivo measurement of PaO₂ can be provided by an indwelling PaO₂ probe. In addition, monitoring of fast changes in SaO₂ by pulse oximetry technology at the bedside could also be used to detect those fast changes in oxygenation.
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Affiliation(s)
- Chang Shi
- Department of Anesthesiology, Medical Center of the Johannes-Gutenberg-University, Mainz, Germany.
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Bodenstein M, Wang H, Boehme S, Baumgardner JE, Duenges B, Vogt A, David M, Markstaller K. Observation of ventilation-induced Spo(2) oscillations in pigs: first step to noninvasive detection of cyclic recruitment of atelectasis? Exp Lung Res 2010; 36:270-6. [PMID: 20497021 DOI: 10.3109/01902140903575971] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
High arterial partial oxygen pressure (Pao(2)) oscillations within the respiratory cycle were described recently in experimental acute lung injury. This phenomenon has been related to cyclic recruitment of atelectasis and varying pulmonary shunt fractions. Noninvasive detection of Spo(2) (oxygen saturation measured by pulse oximetry) as an indicator of cyclic collapse of atelectasis, instead of recording Pao(2) oscillations, could be of clinical interest in critical care. Spo(2) oscillations were recorded continuously in three different cases of lung damage to demonstrate the technical feasibility of this approach. To deduce Pao(2) from Spo(2), a mathematical model of the hemoglobin dissociation curve including left and right shifts was derived from the literature and adapted to the dynamic changes of oxygenation. Calculated Pao(2) amplitudes (derived from Spo(2) measurements) were compared to simultaneously measured fast changes of Pao(2), using a current standard method (fluorescence quenching of ruthenium). Peripheral hemoglobin saturation was capable to capture changes of Spo(2) within each respiratory cycle. For the first time, Spo(2) oscillations due to cyclic recruitment of atelectasis within a respiratory cycle were determined by photoplethysmography, a technology that can be readily applied noninvasively in clinical routine. A mathematic model to calculate the respective Pao(2) changes was developed and its applicability tested.
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Affiliation(s)
- Marc Bodenstein
- Department of Anaesthesiology, University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany.
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A Numerical Model of the Respiratory Modulation of Pulmonary Shunt and PaO2 Oscillations for Acute Lung Injury. Ann Biomed Eng 2009; 38:993-1006. [DOI: 10.1007/s10439-009-9862-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Accepted: 11/26/2009] [Indexed: 01/27/2023]
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Jauncey-Cooke JI, Bogossian F, East CE. Lung recruitment--a guide for clinicians. Aust Crit Care 2009; 22:155-62. [PMID: 19679490 DOI: 10.1016/j.aucc.2009.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 05/12/2009] [Accepted: 06/04/2009] [Indexed: 12/31/2022] Open
Abstract
Recruitment manoeuvres play an important role in minimising ventilator associated lung injury (VALI) particularly when lung protective ventilation strategies are employed and as such clinicians should consider their application. This paper provides evidence-based recommendations for clinical practice with regard to alveolar recruitment. It includes recommendations for timing of recruitment, strategies of recruitment and methods of measuring the efficacy of recruitment manoeuvres and contributes to knowledge about the risks associated with recruitment manoeuvres. There are a range of methods for recruiting alveoli, most notably by manipulating positive end expiratory pressure (PEEP) and peak inspiratory pressure (PIP) with consensus as to the most effective not yet determined. A number of studies have demonstrated that improvement in oxygenation is rarely sustained following a recruitment manoeuvre and it is questionable whether improved oxygenation should be the clinician's goal. Transient haemodynamic compromise has been noted in a number of studies with a few studies reporting persistent, harmful sequelae to recruitment manoeuvres. No studies have been located that assess the impact of recruitment manoeuvres on length of ventilation, length of stay, morbidity or mortality. Recruitment manoeuvres restore end expiratory lung volume by overcoming threshold opening pressures and are most effective when applied after circuit disconnection and airway suction. Whether this ultimately improves outcomes in adult or paediatric populations is unknown.
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Koefoed-Nielsen J, Andersen G, Barklin A, Bach A, Lunde S, Tønnesen E, Larsson A. Maximal hysteresis: a new method to set positive end-expiratory pressure in acute lung injury? Acta Anaesthesiol Scand 2008; 52:641-9. [PMID: 18419718 DOI: 10.1111/j.1399-6576.2008.01600.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND No methods are superior when setting positive end-expiratory pressure (PEEP) in acute lung injury (ALI). In ALI, the vertical distance (hysteresis) between the inspiratory and expiratory limbs of a static pressure-volume (PV) loop mainly indicates lung recruitment. We hypothesized that PEEP set at the pressure where hysteresis is 90% of its maximum (90%MH) would give similar oxygenation, but less cardiovascular depression than PEEP set at the pressure at lower inflection point (LIP) on the inspiratory limb or at the point of maximal curvature (PMC) on the expiratory limb in ALI. METHODS In 12 mechanically ventilated pigs, ALI was induced in a randomized fashion by lung lavage, lung lavage plus injurious ventilation, or by oleic acid. From a static PV loop obtained by an interrupted low-flow method, the pressures at LIP [25 (25, 25) cmH(2)O, mean and 25, 75 percentiles], at PMC [24 (20, 24) cmH(2)O], and at 90% MH [19 (18, 19) cmH(2)O] were determined and used for the PEEP-settings. We measured lung inflation (by computed tomography), end-expiratory lung volume (EELV), airway pressures, compliance of the respiratory system (Crs), blood gases, cardiac output and arterial blood pressure. RESULTS There were no differences between the PEEP settings in EELV or oxygenation, but the 90%MH setting gave lower end-inspiratory pause pressure (P<0.025), higher Crs (P<0.025), less hyper-aeration (P<0.025) and better maintained hemodynamics. CONCLUSION In this porcine lung injury model, PEEP set at 90% MH gave better lung mechanics and hemodynamics, than PEEP set at PMC or LIP.
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Enekvist BJ, Luttropp HH, Johansson A. The effect of increased apparatus dead space and tidal volumes on carbon dioxide elimination and oxygen saturations in a low-flow anesthesia system. J Clin Anesth 2008; 20:170-4. [DOI: 10.1016/j.jclinane.2007.09.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 09/04/2007] [Accepted: 09/21/2007] [Indexed: 10/22/2022]
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Otto CM, Markstaller K, Kajikawa O, Karmrodt J, Syring RS, Pfeiffer B, Good VP, Frevert CW, Baumgardner JE. Spatial and temporal heterogeneity of ventilator-associated lung injury after surfactant depletion. J Appl Physiol (1985) 2008; 104:1485-94. [PMID: 18323462 DOI: 10.1152/japplphysiol.01089.2007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Volutrauma and atelectrauma have been proposed as mechanisms of ventilator-associated lung injury, but few studies have compared their relative importance in mediating lung injury. The objective of our study was to compare the injury produced by stretch (volutrauma) vs. cyclical recruitment (atelectrauma) after surfactant depletion. In saline-lavaged rabbits, we used high tidal volume, low respiratory rate, and low positive end-expiratory pressure to produce stretch injury in nondependent lung regions and cyclical recruitment in dependent lung regions. Tidal changes in shunt fraction were assessed by measuring arterial Po(2) oscillations. After ventilating for times ranging from 0 to 6 h, lungs were excised, sectioned gravitationally, and assessed for regional injury by evaluation of edema formation, chemokine expression, upregulation of inflammatory enzyme activity, and alveolar neutrophil accumulation. Edema formation, lung tissue interleukin-8 expression, and alveolar neutrophil accumulation progressed more rapidly in dependent lung regions, whereas macrophage chemotactic protein-1 expression progressed more rapidly in nondependent lung regions. Temporal and regional heterogeneity of lung injury were substantial. In this surfactant depletion model of acute lung injury, cyclical recruitment produced more injury than stretch.
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Affiliation(s)
- Cynthia M Otto
- Departmrnt of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
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Costa E, Amato M. Maintenance of end-expiratory recruitment with increased respiratory rate after saline-lavage lung injury. J Appl Physiol (1985) 2007; 102:2414; author reply 2415. [PMID: 17551113 DOI: 10.1152/japplphysiol.00154.2007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Pavone LA, Albert S, Carney D, Gatto LA, Halter JM, Nieman GF. Injurious mechanical ventilation in the normal lung causes a progressive pathologic change in dynamic alveolar mechanics. Crit Care 2007; 11:R64. [PMID: 17565688 PMCID: PMC2206429 DOI: 10.1186/cc5940] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 04/04/2007] [Accepted: 06/12/2007] [Indexed: 01/11/2023] Open
Abstract
INTRODUCTION Acute respiratory distress syndrome causes a heterogeneous lung injury, and without protective mechanical ventilation a secondary ventilator-induced lung injury can occur. To ventilate noncompliant lung regions, high inflation pressures are required to 'pop open' the injured alveoli. The temporal impact, however, of these elevated pressures on normal alveolar mechanics (that is, the dynamic change in alveolar size and shape during ventilation) is unknown. In the present study we found that ventilating the normal lung with high peak pressure (45 cmH(2)0) and low positive end-expiratory pressure (PEEP of 3 cmH(2)O) did not initially result in altered alveolar mechanics, but alveolar instability developed over time. METHODS Anesthetized rats underwent tracheostomy, were placed on pressure control ventilation, and underwent sternotomy. Rats were then assigned to one of three ventilation strategies: control group (n = 3, P control = 14 cmH(2)O, PEEP = 3 cmH(2)O), high pressure/low PEEP group (n = 6, P control = 45 cmH(2)O, PEEP = 3 cmH(2)O), and high pressure/high PEEP group (n = 5, P control = 45 cmH(2)O, PEEP = 10 cmH(2)O). In vivo microscopic footage of subpleural alveolar stability (that is, recruitment/derecruitment) was taken at baseline and than every 15 minutes for 90 minutes following ventilator adjustments. Alveolar recruitment/derecruitment was determined by measuring the area of individual alveoli at peak inspiration (I) and end expiration (E) by computer image analysis. Alveolar recruitment/derecruitment was quantified by the percentage change in alveolar area during tidal ventilation (%I - E Delta). RESULTS Alveoli were stable in the control group for the entire experiment (low %I - E Delta). Alveoli in the high pressure/low PEEP group were initially stable (low %I - E Delta), but with time alveolar recruitment/derecruitment developed. The development of alveolar instability in the high pressure/low PEEP group was associated with histologic lung injury. CONCLUSION A large change in lung volume with each breath will, in time, lead to unstable alveoli and pulmonary damage. Reducing the change in lung volume by increasing the PEEP, even with high inflation pressure, prevents alveolar instability and reduces injury. We speculate that ventilation with large changes in lung volume over time results in surfactant deactivation, which leads to alveolar instability.
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Affiliation(s)
- Lucio A Pavone
- Department of Surgery, SUNY Upstate Medical University, 750 East Adams St Syracuse, NY 13210, USA
| | - Scott Albert
- Department of Surgery, SUNY Upstate Medical University, 750 East Adams St Syracuse, NY 13210, USA
| | - David Carney
- Memorial Health University Medical Center, 4700 Waters Ave Savannah, GA 31404, USA
| | - Louis A Gatto
- Department of Biological Sciences, SUNY Cortland, P.O. Box 2000 Cortland, NY 13045, USA
| | - Jeffrey M Halter
- Department of Surgery, SUNY Upstate Medical University, 750 East Adams St Syracuse, NY 13210, USA
| | - Gary F Nieman
- Department of Surgery, SUNY Upstate Medical University, 750 East Adams St Syracuse, NY 13210, USA
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