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Camporota L, Rose L, Andrews PL, Nieman GF, Habashi NM. Airway pressure release ventilation for lung protection in acute respiratory distress syndrome: an alternative way to recruit the lungs. Curr Opin Crit Care 2024; 30:76-84. [PMID: 38085878 DOI: 10.1097/mcc.0000000000001123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
PURPOSE OF REVIEW Airway pressure release ventilation (APRV) is a modality of ventilation in which high inspiratory continuous positive airway pressure (CPAP) alternates with brief releases. In this review, we will discuss the rationale for APRV as a lung protective strategy and then provide a practical introduction to initiating APRV using the time-controlled adaptive ventilation (TCAV) method. RECENT FINDINGS APRV using the TCAV method uses an extended inspiratory time and brief expiratory release to first stabilize and then gradually recruit collapsed lung (over hours/days), by progressively 'ratcheting' open a small volume of collapsed tissue with each breath. The brief expiratory release acts as a 'brake' preventing newly recruited units from re-collapsing, reversing the main drivers of ventilator-induced lung injury (VILI). The precise timing of each release is based on analysis of expiratory flow and is set to achieve termination of expiratory flow at 75% of the peak expiratory flow. Optimization of the release time reflects the changes in elastance and, therefore, is personalized (i.e. conforms to individual patient pathophysiology), and adaptive (i.e. responds to changes in elastance over time). SUMMARY APRV using the TCAV method is a paradigm shift in protective lung ventilation, which primarily aims to stabilize the lung and gradually reopen collapsed tissue to achieve lung homogeneity eliminating the main mechanistic drivers of VILI.
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Affiliation(s)
- Luigi Camporota
- Department of Critical Care, Guy's & St Thomas' NHS Foundation Trust
- Centre for Human & Applied Physiological Sciences, School of Basic & Medical Biosciences
| | - Louise Rose
- Department of Critical Care, Guy's & St Thomas' NHS Foundation Trust
- Florence Nightingale Faculty of Nursing, Midwifery, and Palliative Care, King's College London, London, UK
| | - Penny L Andrews
- Department of Critical Care, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, Maryland
| | - Gary F Nieman
- Department of Surgery, Upstate Medical University, Syracuse, New York, USA
| | - Nader M Habashi
- Department of Critical Care, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, Maryland
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2
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Gogniat E, Madorno M, Rodriguez PO, Dianti J, Otero PE, Krukewitt L, Böhm SH, Roman ES, Tusman G. Dynamic Relative Regional Lung Strain Estimated by Electrical Impedance Tomography in an Experimental Model of ARDS. Respir Care 2022; 67:906-913. [PMID: 35610029 PMCID: PMC9994153 DOI: 10.4187/respcare.09682] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND To analyze the role of PEEP on dynamic relative regional strain (DRRS) in a model of ARDS, respective maps were generated by electrical impedance tomography (EIT). METHODS Eight ARDS pigs submitted to PEEP steps of 0, 5, 10, and 15 cm H2O at fixed ventilation were evaluated by EIT images. DRRS was calculated as (VT-EIT/EELI)/(VT-EIT[15PEEP]/EELI[15PEEP]), where the tidal volume (VT)-EIT and end-expiratory lung impedance (EELI) are the tidal and end-expiratory change in lung impedance, respectively. The measurement at 15 PEEP was taken as reference (end-expiratory transpulmonary pressure > 0 cm H2O). The relationship between EIT variables (center of ventilation, EELI, and DRRS) and airway pressures was assessed with mixed-effects models using EIT measurements as dependent variables and PEEP as fixed-effect variable. RESULTS At constant ventilation, respiratory compliance increased progressively with PEEP (lowest value at zero PEEP 10 ± 3 mL/cm H2O and highest value at 15 PEEP 16 ± 6 mL/cm H2O; P < .001), whereas driving pressure decreased with PEEP (highest value at zero PEEP 34 ± 6 cm H2O and lowest value at 15 PEEP 21 ± 4 cm H2O; P < .001). The mixed-effect regression models showed that the center of ventilation moved to dorsal lung areas with a slope of 1.81 (1.44-2.18) % points by each cm H2O of PEEP; P < .001. EELI increased with a slope of 0.05 (0.02-0.07) (arbitrary units) for each cm H2O of PEEP; P < .001. DRRS maps showed that local strain in ventral lung areas decreased with a slope of -0.02 (-0.24 to 0.15) with each cm H2O increase of PEEP; P < .001. CONCLUSIONS EIT-derived DRRS maps showed high strain in ventral lung zones at low levels of PEEP. The findings suggest overdistention of the baby lung.
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Affiliation(s)
- Emiliano Gogniat
- Department of Intensive Care Medicine, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina; and Instituto Tecnológico Buenos Aires, Buenos Aires, Argentina
| | - Matías Madorno
- Instituto Tecnológico Buenos Aires, Buenos Aires, Argentina; and MBMed SA, Buenos Aires, Argentina
| | - Pablo O Rodriguez
- Pulmonary and Critical Care Medicine, Instituto Universitario CEMIC (Centro de Educación Médica e Investigaciones Clínicas), Buenos Aires, Argentina
| | - José Dianti
- Department of Intensive Care Medicine, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Pablo E Otero
- Anesthesia Department, Veterinary School, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Lisa Krukewitt
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
| | - Stephan H Böhm
- Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany
| | - Eduardo San Roman
- Department of Intensive Care Medicine, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
| | - Gerardo Tusman
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina.
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Abstract
Pulmonary atelectasis is common in the perioperative period. Physiologically, it is produced when collapsing forces derived from positive pleural pressure and surface tension overcome expanding forces from alveolar pressure and parenchymal tethering. Atelectasis impairs blood oxygenation and reduces lung compliance. It is increasingly recognized that it can also induce local tissue biologic responses, such as inflammation, local immune dysfunction, and damage of the alveolar-capillary barrier, with potential loss of lung fluid clearance, increased lung protein permeability, and susceptibility to infection, factors that can initiate or exaggerate lung injury. Mechanical ventilation of a heterogeneously aerated lung (e.g., in the presence of atelectatic lung tissue) involves biomechanical processes that may precipitate further lung damage: concentration of mechanical forces, propagation of gas-liquid interfaces, and remote overdistension. Knowledge of such pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should guide optimal clinical management.
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Musch G. New Frontiers in Functional and Molecular Imaging of the Acutely Injured Lung: Pathophysiological Insights and Research Applications. Front Physiol 2021; 12:762688. [PMID: 34955883 PMCID: PMC8696200 DOI: 10.3389/fphys.2021.762688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 11/17/2021] [Indexed: 11/13/2022] Open
Abstract
This review focuses on the advances in the understanding of the pathophysiology of ventilator-induced and acute lung injury that have been afforded by technological development of imaging methods over the last decades. Examples of such advances include the establishment of regional lung mechanical strain as a determinant of ventilator-induced lung injury, the relationship between alveolar recruitment and overdistension, the regional vs. diffuse nature of pulmonary involvement in acute respiratory distress syndrome (ARDS), the identification of the physiological determinants of the response to recruitment interventions, and the pathophysiological significance of metabolic alterations in the acutely injured lung. Taken together, these advances portray multimodality imaging as the next frontier to both advance knowledge of the pathophysiology of these conditions and to tailor treatment to the individual patient's condition.
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Affiliation(s)
- Guido Musch
- Department of Anesthesiology and Perioperative Medicine, University of Massachusetts Medical School, Worcester, MA, United States
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5
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Over-distension prediction via hysteresis loop analysis and patient-specific basis functions in a virtual patient model. Comput Biol Med 2021; 141:105022. [PMID: 34801244 DOI: 10.1016/j.compbiomed.2021.105022] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 11/02/2021] [Accepted: 11/04/2021] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND OBJECTIVE Recruitment maneuvers (RMs) with subsequent positive-end-expiratory-pressure (PEEP) have proven effective in recruiting lung volume and preventing alveolar collapse. However, a suboptimal PEEP could induce undesired injury in lungs by insufficient or excessive breath support. Thus, a predictive model for patient response under PEEP changes could improve clinical care and lower risks. METHODS This research adds novel elements to a virtual patient model to identify and predict patient-specific lung distension to optimise and personalise care. Model validity and accuracy are validated using data from 18 volume-controlled ventilation (VCV) patients at 7 different baseline PEEP levels (0-12cmH2O), yielding 623 prediction cases. Predictions were made up to ΔPEEP = 12cmH2O ahead covering 6x2cmH2O PEEP steps. RESULTS Using the proposed lung distension model, 90% of absolute peak inspiratory pressure (PIP) prediction errors compared to clinical measurement are within 3.95cmH2O, compared with 4.76cmH2O without this distension term. Comparing model-predicted and clinically measured distension had high correlation increasing to R2 = 0.93-0.95 if maximum ΔPEEP ≤ 6cmH2O. Predicted dynamic functional residual capacity (Vfrc) changes as PEEP rises yield 0.013L median prediction error for both prediction groups and overall R2 of 0.84. CONCLUSIONS Overall results demonstrate nonlinear distension mechanics are accurately captured in virtual lung mechanics patients for mechanical ventilation, for the first time. This result can minimise the risk of lung injury by predicting its potential occurrence of distension before changing ventilator settings. The overall outcomes significantly extend and more fully validate this virtual mechanical ventilation patient model.
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6
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Pourfathi M, Xin Y, Rosalino M, Cereda M, Kadlecek S, Duncan I, Profka H, Hamedani H, Siddiqui S, Ruppert K, Chatterjee S, Rizi RR. Pulmonary pyruvate metabolism as an index of inflammation and injury in a rat model of acute respiratory distress syndrome. NMR IN BIOMEDICINE 2020; 33:e4380. [PMID: 32681670 DOI: 10.1002/nbm.4380] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 06/15/2020] [Accepted: 06/29/2020] [Indexed: 06/11/2023]
Abstract
Increased pulmonary lactate production is correlated with severity of lung injury and outcome in acute respiratory distress syndrome (ARDS) patients. This study was conducted to investigate the relative contributions of inflammation and hypoxia to the lung's metabolic shift to glycolysis in an experimental animal model of ARDS using hyperpolarized (HP) 13 C MRI. Fifty-three intubated and mechanically ventilated male rats were imaged using HP 13 C MRI before, and 1, 2.5 and 4 hours after saline (sham) or hydrochloric acid (HCl; 0.5 ml/kg) instillation in the trachea, followed by protective and nonprotective mechanical ventilation (HCl-PEEP and HCl-ZEEP) or the start of moderate or severe hypoxia (Hyp90 and Hyp75 groups). Pulmonary and cardiac HP lactate-to-pyruvate ratios were compared among groups for different time points. Postmortem histology and immunofluorescence were used to assess lung injury severity and quantify the expression of innate inflammatory markers and local tissue hypoxia. HP pulmonary lactate-to-pyruvate ratio progressively increased in rats with lung injury and moderate hypoxia (HCl-ZEEP), with no significant change in pulmonary lactate-to-pyruvate ratio in noninjured but moderately hypoxic rats (Hyp90). Pulmonary lactate-to-pyruvate ratio was elevated in otherwise healthy lung tissue only in severe systemic hypoxia (Hyp75 group). ex vivo histological and immunopathological assessment further confirmed the link between elevated glycolysis and the recruitment into and presence of activated neutrophils in injured lungs. HP lactate-to-pyruvate ratio is elevated in injured lungs predominantly as a result of increased glycolysis in activated inflammatory cells, but can also increase due to severe inflammation-induced hypoxia.
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Affiliation(s)
- Mehrdad Pourfathi
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yi Xin
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael Rosalino
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Maurizio Cereda
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Stephen Kadlecek
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ian Duncan
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Harrilla Profka
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hooman Hamedani
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sarmad Siddiqui
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kai Ruppert
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Shampa Chatterjee
- Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Rahim R Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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7
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Albert K, Krischer JM, Pfaffenroth A, Wilde S, Lopez-Rodriguez E, Braun A, Smith BJ, Knudsen L. Hidden Microatelectases Increase Vulnerability to Ventilation-Induced Lung Injury. Front Physiol 2020; 11:530485. [PMID: 33071807 PMCID: PMC7530907 DOI: 10.3389/fphys.2020.530485] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 08/28/2020] [Indexed: 11/13/2022] Open
Abstract
Mechanical ventilation of lungs suffering from microatelectases may trigger the development of acute lung injury (ALI). Direct lung injury by bleomycin results in surfactant dysfunction and microatelectases at day 1 while tissue elastance and oxygenation remain normal. Computational simulations of alveolar micromechanics 1-day post-bleomycin predict persisting microatelectases throughout the respiratory cycle and increased alveolar strain during low positive end-expiratory pressure (PEEP) ventilation. As such, we hypothesize that mechanical ventilation in presence of microatelectases, which occur at low but not at higher PEEP, aggravates and unmasks ALI in the bleomycin injury model. Rats were randomized and challenged with bleomycin (B) or not (H = healthy). One day after bleomycin instillation the animals were ventilated for 3 h with PEEP 1 (PEEP1) or 5 cmH2O (PEEP5) and a tidal volume of 10 ml/kg bodyweight. Tissue elastance was repetitively measured after a recruitment maneuver to investigate the degree of distal airspace instability. The right lung was subjected to bronchoalveolar lavage (BAL), the left lung was fixed for design-based stereology at light- and electron microscopic level. Prior to mechanical ventilation, lung tissue elastance did not differ. During mechanical ventilation tissue elastance increased in bleomycin-injured lungs ventilated with PEEP = 1 cmH2O but remained stable in all other groups. Measurements at the conclusion of ventilation showed the largest time-dependent increase in tissue elastance after recruitment in B/PEEP1, indicating increased instability of distal airspaces. These lung mechanical findings correlated with BAL measurements including elevated BAL neutrophilic granulocytes as well as BAL protein and albumin in B/PEEP1. Moreover, the increased septal wall thickness and volume of peri-bronchiolar-vascular connective tissue in B/PEEP1 suggested aggravation of interstitial edema by ventilation in presence of microatelectases. At the electron microscopic level, the largest surface area of injured alveolar epithelial was observed in bleomycin-challenged lungs after PEEP = 1 cmH2O ventilation. After bleomycin treatment cellular markers of endoplasmic reticulum stress (p-Perk and p-EIF-2α) were positive within the septal wall and ventilation with PEEP = 1 cmH2O ventilation increased the surface area stained positively for p-EIF-2α. In conclusion, hidden microatelectases are linked with an increased pulmonary vulnerability for mechanical ventilation characterized by an aggravation of epithelial injury.
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Affiliation(s)
- Karolin Albert
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany
| | - Jeanne-Marie Krischer
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany
| | - Alexander Pfaffenroth
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany
| | - Sabrina Wilde
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany
| | - Elena Lopez-Rodriguez
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany.,Institute for Functional Anatomy, Charité, Berlin, Germany
| | - Armin Braun
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany
| | - Bradford J Smith
- Department of Bioengineering, College of Engineering, Design and Computing, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, United States
| | - Lars Knudsen
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hanover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hanover, Germany
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8
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Radiographic Manifestations of Diffuse Pulmonary Alveolar Derecruitment. J Thorac Imaging 2020; 34:362-366. [PMID: 30994518 DOI: 10.1097/rti.0000000000000414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Pulmonary alveolar derecruitment is a process of alveolar collapse that occurs in critically ill patients. While the entity and its physiological manifestations are described in the anesthesiology and critical care literature, the radiographic manifestations of alveolar derecruitment have not yet been thoroughly described. This phenomenon can have a similar appearance to pulmonary edema; however, patients often have severe intravascular volume depletion. As the treatment for these 2 entities is essentially contradictory, it is important to be familiar with alveolar derecruitment and consider it as a differential diagnosis when clinically appropriate.
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9
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Nieman GF, Al-Khalisy H, Kollisch-Singule M, Satalin J, Blair S, Trikha G, Andrews P, Madden M, Gatto LA, Habashi NM. A Physiologically Informed Strategy to Effectively Open, Stabilize, and Protect the Acutely Injured Lung. Front Physiol 2020; 11:227. [PMID: 32265734 PMCID: PMC7096584 DOI: 10.3389/fphys.2020.00227] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 02/27/2020] [Indexed: 12/16/2022] Open
Abstract
Acute respiratory distress syndrome (ARDS) causes a heterogeneous lung injury and remains a serious medical problem, with one of the only treatments being supportive care in the form of mechanical ventilation. It is very difficult, however, to mechanically ventilate the heterogeneously damaged lung without causing secondary ventilator-induced lung injury (VILI). The acutely injured lung becomes time and pressure dependent, meaning that it takes more time and pressure to open the lung, and it recollapses more quickly and at higher pressure. Current protective ventilation strategies, ARDSnet low tidal volume (LVt) and the open lung approach (OLA), have been unsuccessful at further reducing ARDS mortality. We postulate that this is because the LVt strategy is constrained to ventilating a lung with a heterogeneous mix of normal and focalized injured tissue, and the OLA, although designed to fully open and stabilize the lung, is often unsuccessful at doing so. In this review we analyzed the pathophysiology of ARDS that renders the lung susceptible to VILI. We also analyzed the alterations in alveolar and alveolar duct mechanics that occur in the acutely injured lung and discussed how these alterations are a key mechanism driving VILI. Our analysis suggests that the time component of each mechanical breath, at both inspiration and expiration, is critical to normalize alveolar mechanics and protect the lung from VILI. Animal studies and a meta-analysis have suggested that the time-controlled adaptive ventilation (TCAV) method, using the airway pressure release ventilation mode, eliminates the constraints of ventilating a lung with heterogeneous injury, since it is highly effective at opening and stabilizing the time- and pressure-dependent lung. In animal studies it has been shown that by “casting open” the acutely injured lung with TCAV we can (1) reestablish normal expiratory lung volume as assessed by direct observation of subpleural alveoli; (2) return normal parenchymal microanatomical structural support, known as alveolar interdependence and parenchymal tethering, as assessed by morphometric analysis of lung histology; (3) facilitate regeneration of normal surfactant function measured as increases in surfactant proteins A and B; and (4) significantly increase lung compliance, which reduces the pathologic impact of driving pressure and mechanical power at any given tidal volume.
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Affiliation(s)
- Gary F Nieman
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Hassan Al-Khalisy
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States.,Department of Medicine, SUNY Upstate Medical University, Syracuse, NY, United States
| | | | - Joshua Satalin
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Sarah Blair
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Girish Trikha
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States.,Department of Medicine, SUNY Upstate Medical University, Syracuse, NY, United States
| | - Penny Andrews
- Department of Trauma Critical Care Medicine, R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Maria Madden
- Department of Trauma Critical Care Medicine, R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Louis A Gatto
- Department of Surgery, SUNY Upstate Medical University, Syracuse, NY, United States.,Department of Biological Sciences, SUNY Cortland, Cortland, NY, United States
| | - Nader M Habashi
- Department of Trauma Critical Care Medicine, R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, MD, United States
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10
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Abstract
Acute respiratory distress syndrome (ARDS) consists of acute hypoxemic respiratory failure characterized by massive and heterogeneously distributed loss of lung aeration caused by diffuse inflammation and edema present in interstitial and alveolar spaces. It is defined by consensus criteria, which include diffuse infiltrates on chest imaging-either plain radiography or computed tomography. This review will summarize how imaging sciences can inform modern respiratory management of ARDS and continue to increase the understanding of the acutely injured lung. This review also describes newer imaging methodologies that are likely to inform future clinical decision-making and potentially improve outcome. For each imaging modality, this review systematically describes the underlying principles, technology involved, measurements obtained, insights gained by the technique, emerging approaches, limitations, and future developments. Finally, integrated approaches are considered whereby multimodal imaging may impact management of ARDS.
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11
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Tan JJ, Boudreault F, Adam D, Brochiero E, Grygorczyk R. Type 2 secretory cells are primary source of ATP release in mechanically stretched lung alveolar cells. Am J Physiol Lung Cell Mol Physiol 2019; 318:L49-L58. [PMID: 31596106 DOI: 10.1152/ajplung.00321.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Extracellular ATP and its metabolites are potent paracrine modulators of lung alveolar cell function, including surfactant secretion and fluid transport, but the sources and mechanism of intra-alveolar ATP release remain unclear. To determine the contribution of gas-exchanging alveolar type 1 (AT1) and surfactant-secreting type 2 (AT2) cells to stretch-induced ATP release, we used quantitative real-time luminescence ATP imaging and rat primary alveolar cells cultured on silicon substrate for 2-7 days. When cultured on solid support, primary AT2 cells progressively transdifferentiated into AT1-like cells with ~20% of cells showing AT1 phenotype by day 2-3 (AT2:AT1 ≈ 4:1), while on day 7, the AT2:AT1 cell ratio was reversed with up to 80% of the cells displaying characteristics of AT1 cells. Stretch (1 s, 5-35%) induced ATP release from AT2/AT1 cell cultures, and it was highest on days 2 and 3 but declined in older cultures. ATP release tightly correlated with the number of remaining AT2 cells in culture, consistent with ~10-fold lower ATP release by AT1 than AT2 cells. ATP release was unaffected by inhibitors of putative ATP channels carbenoxolone and probenecid but was significantly diminished in cells loaded with calcium chelator BAPTA. These pharmacological modulators had similar effects on stretch-induced intracellular Ca2+ responses measured by Fura2 fluorescence. The study revealed that AT2 cells are the primary source of stretch-induced ATP release in heterocellular AT2/AT1 cell cultures, suggesting similar contribution in intact alveoli. Our results support a role for calcium-regulated mechanism but not ATP-conducting channels in ATP release by alveolar epithelial cells.
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Affiliation(s)
- Ju Jing Tan
- Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada.,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Francis Boudreault
- Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada
| | - Damien Adam
- Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada.,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Emmanuelle Brochiero
- Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada.,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Ryszard Grygorczyk
- Centre de recherche du Centre hospitalier de l'Université de Montréal, Montreal, Quebec, Canada.,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
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12
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Yehya N. Lessons learned in acute respiratory distress syndrome from the animal laboratory. ANNALS OF TRANSLATIONAL MEDICINE 2019; 7:503. [PMID: 31728356 DOI: 10.21037/atm.2019.09.33] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Since the description of the acute respiratory distress syndrome (ARDS) in 1967, investigators have struggled to reproduce the syndrome in the animal laboratory. While several different models of experimental acute lung injury (ALI) have been developed, none completely capture the inciting etiologies, initial inflammation, heterogeneity, and resolution of human ARDS. This potentially has contributed to the poor translation of potential therapeutics between animal ALI models and human ARDS. It was only recently that standardized criteria were suggested for what makes an ALI model comparable to human ARDS. Nevertheless, despite model heterogeneity, these models have contributed substantially to our understanding of the syndrome. From the initial studies identifying the risks of mechanical ventilation to the identification of potentially targetable inflammatory mediators, to modern studies focusing on regional heterogeneity and novel molecular pathways, animal models continue to inform our understanding of ARDS. This review will cover several major lessons learned from animal models of ALI, and provide some direction for future studies in this field.
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Affiliation(s)
- Nadir Yehya
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA, USA
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13
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A Window on the Lung: Molecular Imaging as a Tool to Dissect Pathophysiologic Mechanisms of Acute Lung Disease. CONTRAST MEDIA & MOLECULAR IMAGING 2019; 2019:1510507. [PMID: 31531003 PMCID: PMC6732639 DOI: 10.1155/2019/1510507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 05/08/2019] [Indexed: 11/21/2022]
Abstract
In recent years, imaging has given a fundamental contribution to our understanding of the pathophysiology of acute lung diseases. Several methods have been developed based on computed tomography (CT), positron emission tomography (PET), and magnetic resonance (MR) imaging that allow regional, in vivo measurement of variables such as lung strain, alveolar size, metabolic activity of inflammatory cells, ventilation, and perfusion. Because several of these methods are noninvasive, they can be successfully translated from animal models to patients. The aim of this paper is to review the advances in knowledge that have been accrued with these imaging modalities on the pathophysiology of acute respiratory distress syndrome (ARDS), ventilator-induced lung injury (VILI), asthma and chronic obstructive pulmonary disease (COPD).
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14
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Grygorczyk R, Boudreault F, Tan JJ, Ponomarchuk O, Sokabe M, Furuya K. Mechanosensitive ATP release in the lungs: New insights from real-time luminescence imaging studies. CURRENT TOPICS IN MEMBRANES 2019; 83:45-76. [PMID: 31196610 DOI: 10.1016/bs.ctm.2019.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Extracellular ATP and other nucleotides are important autocrine/paracrine mediators that stimulate purinergic receptors and regulate diverse processes in the normal lungs. They are also associated with pathogenesis of a number of respiratory diseases and clinical complications including acute respiratory distress syndrome and ventilator induced lung injury. Mechanical forces are major stimuli for cellular ATP release but precise mechanisms responsible for this release are still debated. The present review intends to provide the current state of knowledge of the mechanisms of ATP release in the lung. Putative pathways of the release, including the contribution of cell membrane injury and cell lysis are discussed addressing their strength, weaknesses and missing evidence that requires future study. We also provide an overview of the recent technical advances in studying cellular ATP release in vitro and ex vivo. Special attention is given to new insights into lung ATP release obtained with the real-time luminescence ATP imaging. This includes recent data on stretch-induced mechanosensitive ATP release in a model and primary cells of lung alveoli in vitro as well as inflation-induced ATP release in airspaces and pulmonary blood vessels of lungs, ex vivo.
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Affiliation(s)
- Ryszard Grygorczyk
- Department of Medicine, Université de Montréal, Montréal, QC, Canada; Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.
| | - Francis Boudreault
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | - Ju Jing Tan
- Department of Medicine, Université de Montréal, Montréal, QC, Canada; Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | - Olga Ponomarchuk
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada; Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University, Graduate School of Medicine, Nagoya, Japan
| | - Kishio Furuya
- Mechanobiology Laboratory, Nagoya University, Graduate School of Medicine, Nagoya, Japan
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Motta-Ribeiro G, Winkler T, Hashimoto S, Vidal Melo MF. Spatial Heterogeneity of Lung Strain and Aeration and Regional Inflammation During Early Lung Injury Assessed with PET/CT. Acad Radiol 2019; 26:313-325. [PMID: 30057194 PMCID: PMC6612262 DOI: 10.1016/j.acra.2018.02.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/20/2018] [Accepted: 02/27/2018] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Spatial heterogeneity of lung aeration and strain (change volume/resting volume) occurs at microscopic levels and contributes to lung injury. Yet, it is mostly assessed with histograms or large regions-of-interest. Spatial heterogeneity could also influence regional gene expression. We used positron emission tomography (PET)/computed tomography (CT) to assess the contribution of different length-scales to mechanical heterogeneity and to direct lung injury biological pathway identification. MATERIALS AND METHODS Sheep exposed to mild (n = 5, supine and n = 3, prone) and moderate (n = 6, supine) systemic endotoxemia were protectively ventilated. At baseline, 6 hours and 20 hours length-scale analysis was applied to aeration in CT (mild groups) and PET transmission (moderate group) scans; and voxel-level strain derived from image registration of end-inspiratory and end-expiratory CTs (mild). 2-deoxy-2-[(18)F]fluoro-d-glucose (18F-FDG)-PET kinetics parameters in ventral and dorsal regions were correlated with tissue microarray gene expression (moderate). RESULTS While aeration and strain heterogeneity were highest at 5-10 mm length-scales, larger length-scales contained a higher fraction of strain than aeration heterogeneity. Contributions of length-scales >5-10 mm to aeration and strain heterogeneity increased as lung injury progressed (p < 0.001) and were higher in supine than prone animals. Genes expressed with regional correlation to 18F-FDG-PET kinetics (|r| = 0.81 [0.78-0.85]) yielded pathways associated with immune system activation and fluid clearance. CONCLUSION Normal spatial heterogeneity of aeration and strain suggest larger anatomical and functional determinants of lung strain than aeration heterogeneity. Lung injury and supine position increase the contribution of larger length-scales. 18F-FDG-PET-based categorization of gene expression results in known and novel biological pathways relevant to lung injury.
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Affiliation(s)
- Gabriel Motta-Ribeiro
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Boston, MA 02114.
| | - Tilo Winkler
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Boston, MA 02114.
| | - Soshi Hashimoto
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Boston, MA 02114.
| | - Marcos F Vidal Melo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, 55 Fruit St, Boston, MA 02114.
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16
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Xin Y, Cereda M, Hamedani H, Pourfathi M, Siddiqui S, Meeder N, Kadlecek S, Duncan I, Profka H, Rajaei J, Tustison NJ, Gee JC, Kavanagh BP, Rizi RR. Unstable Inflation Causing Injury. Insight from Prone Position and Paired Computed Tomography Scans. Am J Respir Crit Care Med 2018; 198:197-207. [PMID: 29420904 PMCID: PMC6058981 DOI: 10.1164/rccm.201708-1728oc] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 02/08/2018] [Indexed: 01/16/2023] Open
Abstract
RATIONALE It remains unclear how prone positioning improves survival in acute respiratory distress syndrome. Using serial computed tomography (CT), we previously reported that "unstable" inflation (i.e., partial aeration with large tidal density swings, indicating increased local strain) is associated with injury progression. OBJECTIVES We prospectively tested whether prone position contains the early propagation of experimental lung injury by stabilizing inflation. METHODS Injury was induced by tracheal hydrochloric acid in rats; after randomization to supine or prone position, injurious ventilation was commenced using high tidal volume and low positive end-expiratory pressure. Paired end-inspiratory (EI) and end-expiratory (EE) CT scans were acquired at baseline and hourly up to 3 hours. Each sequential pair (EI, EE) of CT images was superimposed in parametric response maps to analyze inflation. Unstable inflation was then measured in each voxel in both dependent and nondependent lung. In addition, five pigs were imaged (EI and EE) prone versus supine, before and (1 hour) after hydrochloric acid aspiration. MEASUREMENTS AND MAIN RESULTS In rats, prone position limited lung injury propagation and increased survival (11/12 vs. 7/12 supine; P = 0.01). EI-EE densities, respiratory mechanics, and blood gases deteriorated more in supine versus prone rats. At baseline, more voxels with unstable inflation occurred in dependent versus nondependent regions when supine (41 ± 6% vs. 18 ± 7%; P < 0.01) but not when prone. In supine pigs, unstable inflation predominated in dorsal regions and was attenuated by prone positioning. CONCLUSIONS Prone position limits the radiologic progression of early lung injury. Minimizing unstable inflation in this setting may alleviate the burden of acute respiratory distress syndrome.
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Affiliation(s)
- Yi Xin
- Department of Radiology and
| | - Maurizio Cereda
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | | | | | - Natalie Meeder
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | | | | | | | - Nicholas J. Tustison
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia; and
| | | | - Brian P. Kavanagh
- Department of Critical Care Medicine and
- Department of Anesthesia, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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17
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Ferrando C, Tusman G, Suarez-Sipmann F, León I, Pozo N, Carbonell J, Puig J, Pastor E, Gracia E, Gutiérrez A, Aguilar G, Belda FJ, Soro M. Individualized lung recruitment maneuver guided by pulse-oximetry in anesthetized patients undergoing laparoscopy: a feasibility study. Acta Anaesthesiol Scand 2018; 62:608-619. [PMID: 29377061 DOI: 10.1111/aas.13082] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 12/21/2017] [Accepted: 01/02/2018] [Indexed: 01/27/2023]
Abstract
BACKGROUND We conducted this study to test whether pulse-oximetry hemoglobin saturation (SpO2 ) can personalize the implementation of an open-lung approach during laparoscopy. Thirty patients with SpO2 ≥ 97% on room-air before anesthesia were studied. After anesthesia and capnoperitoneum the FIO2 was reduced to 0.21. Those patients whose SpO2 decreased below 97% - an indication of shunt related to atelectasis - completed the following phases: (1) First recruitment maneuver (RM), until reaching lung's opening pressure, defined as the inspiratory pressure level yielding a SpO2 ≥ 97%; (2) decremental positive end-expiratory (PEEP) titration trial until reaching lung's closing pressure defined as the PEEP level yielding a SpO2 < 97%; (3) second RM and, (4) ongoing ventilation with PEEP adjusted above the detected closing pressure. RESULTS When breathing air, in 24 of 30 patients SpO2 was < 97%, PaO2 /FIO2 ˂ 53.3 kPa and negative end-expiratory transpulmonary pressure (PTP-EE ). The mean (SD) opening pressures were found at 40 (5) and 33 (4) cmH2 O during the first and second RM, respectively (P < 0.001; 95% CI: 3.2-7.7). The closing pressure was found at 11 (5) cmH2 O. This SpO2 -guided approach increased PTP-EE (from -6.4 to 1.2 cmH2 O, P < 0.001) and PaO2 /FIO2 (from 30.3 to 58.1 kPa, P < 0.001) while decreased driving pressure (from 18 to 10 cmH2 O, P < 0.001). SpO2 discriminated the lung's opening and closing pressures with accuracy taking the reference parameter PTP-EE (area under the receiver-operating-curve of 0.89, 95% CI: 0.80-0.99). CONCLUSION The non-invasive SpO2 monitoring can help to individualize an open-lung approach, including all involved steps, from the identification of those patients who can benefit from recruitment, the identification of opening and closing pressures to the subsequent monitoring of an open-lung condition.
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Affiliation(s)
- C. Ferrando
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
- CIBER de Enfermedades Respiratorias; Instituto de Salud Carlos III; Madrid Spain
| | - G. Tusman
- Department of Anesthesiology; Hospital Privado de Comunidad Mar de Plata; Mar de Plata Argentina
| | - F. Suarez-Sipmann
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
- Deparment of Intensive Care; Hospital Universitario La Princesa; Madrid Spain
| | - I. León
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
| | - N. Pozo
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
| | - J. Carbonell
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
| | - J. Puig
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
| | - E. Pastor
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
| | - E. Gracia
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
| | - A. Gutiérrez
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
| | - G. Aguilar
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
| | - F. J. Belda
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
| | - M. Soro
- Department of Anaesthesiology and Critical Care; Hospital Clínico Universitario; Valencia Spain
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18
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Pourfathi M, Cereda M, Chatterjee S, Xin Y, Kadlecek S, Duncan I, Hamedani H, Siddiqui S, Profka H, Ehrich J, Ruppert K, Rizi RR. Lung Metabolism and Inflammation during Mechanical Ventilation; An Imaging Approach. Sci Rep 2018; 8:3525. [PMID: 29476083 PMCID: PMC5824838 DOI: 10.1038/s41598-018-21901-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 02/13/2018] [Indexed: 12/20/2022] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a major cause of mortality in critically ill patients. Patients are currently managed by protective ventilation and alveolar recruitment using positive-end expiratory pressure (PEEP). However, the PEEP's effect on both pulmonary metabolism and regional inflammation is poorly understood. Here, we demonstrate the effect of PEEP on pulmonary anaerobic metabolism in mechanically ventilated injured rats, using hyperpolarized carbon-13 imaging. Pulmonary lactate-to-pyruvate ratio was measured in 21 rats; 14 rats received intratracheal instillation of hydrochloric-acid, while 7 rats received sham saline. 1 hour after acid/saline instillation, PEEP was lowered to 0 cmH2O in 7 injured rats (ZEEP group) and in all sham rats; PEEP was continued in the remaining 7 injured rats (PEEP group). Pulmonary compliance, oxygen saturation, histological injury scores, ICAM-1 expression and myeloperoxidase expression were measured. Lactate-to-pyruvate ratio progressively increased in the dependent lung during mechanical ventilation at ZEEP (p < 0.001), but remained unchanged in PEEP and sham rats. Lactate-to-pyruvate ratio was correlated with hyaline membrane deposition (r = 0.612), edema severity (r = 0.663), ICAM-1 (r = 0.782) and myeloperoxidase expressions (r = 0.817). Anaerobic pulmonary metabolism increases during lung injury progression and is contained by PEEP. Pulmonary lactate-to-pyruvate ratio may indicate in-vivo neutrophil activity due to atelectasis.
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Affiliation(s)
- Mehrdad Pourfathi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- Department Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Maurizio Cereda
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Shampa Chatterjee
- Department of Physiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Yi Xin
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Stephen Kadlecek
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ian Duncan
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hooman Hamedani
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Sarmad Siddiqui
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Harrilla Profka
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jason Ehrich
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Kai Ruppert
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Rahim R Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA.
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Su Z, Liu S, Oto J, Chenelle CT, Sulemanji D, Kacmarek RM, Jiang Y. Effects of Positive End-Expiratory Pressure on the Risk of Postoperative Pulmonary Complications in Patients Undergoing Elective Craniotomy. World Neurosurg 2017; 112:e39-e49. [PMID: 29253690 DOI: 10.1016/j.wneu.2017.12.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND Intraoperative use of positive end-expiratory pressure (PEEP) has a protective effect in patients with acute lung injury and is recommended during anesthesia to minimize postoperative pulmonary complications. However, high levels of pressure might also cause harm to the lung because of overdistension. This retrospective study was designed to compare the effect of low and high levels of PEEP on the risk of postoperative pulmonary complications in patients with normal lung function who were undergoing an elective craniotomy. METHODS Two thousand four hundred thirty-seven patients without any pre-existing respiratory disease, who underwent an elective craniotomy, were hospitalized from January 1, 2008, to December 31, 2012. The patients were divided into 2 groups according to the application of an intraoperative PEEP < 5 or ≥ 5 cm H2O, referred as low and high groups. Primary outcome was the odds of postoperative pneumonia and the requirement for either noninvasive ventilation (NIV) or reintubation and mechanical ventilation (MV). RESULTS One thousand twenty-three (42%) of 2437 patients were in the low group, and 1414 patients (58%) were in the high group. Patients in the low group did not show any difference in the incidence of postoperative pneumonia (P = 0.523) or the requirement of postoperative reintubation and MV (P = 0.999) compared with those in the high group. The incidence of reintubation and MV is significantly associated with postoperative pneumonia (P < 0.001). CONCLUSIONS Low and high levels of PEEP show similar incidences of postoperative pneumonia and requirement of postoperative NIV or invasive MV in patients with normal function of the lungs undergoing elective craniotomy.
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Affiliation(s)
- Zhenbo Su
- Department of Anesthesia, China-Japan Union Hospital of Jilin University, Changchun, China; Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Respiratory Care Services, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Shujie Liu
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Respiratory Care Services, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Anesthesia, the First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Jun Oto
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Respiratory Care Services, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Emergency and Disaster Medicine, Tokushima University Hospital, Tokushima, Japan
| | - Christopher T Chenelle
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Respiratory Care Services, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Demet Sulemanji
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Respiratory Care Services, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Robert M Kacmarek
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Respiratory Care Services, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Yandong Jiang
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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20
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Sahetya SK, Goligher EC, Brower RG. Fifty Years of Research in ARDS. Setting Positive End-Expiratory Pressure in Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med 2017; 195:1429-1438. [PMID: 28146639 PMCID: PMC5470753 DOI: 10.1164/rccm.201610-2035ci] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 02/01/2017] [Indexed: 11/16/2022] Open
Abstract
Positive end-expiratory pressure (PEEP) has been used during mechanical ventilation since the first description of acute respiratory distress syndrome (ARDS). In the subsequent decades, many different strategies for optimally titrating PEEP have been proposed. Higher PEEP can improve arterial oxygenation, reduce tidal lung stress and strain, and promote more homogenous ventilation by preventing alveolar collapse at end expiration. However, PEEP may also cause circulatory depression and contribute to ventilator-induced lung injury through alveolar overdistention. The overall effect of PEEP is primarily related to the balance between the number of alveoli that are recruited to participate in ventilation and the amount of lung that is overdistended when PEEP is applied. Techniques to assess lung recruitment from PEEP may help to direct safer and more effective PEEP titration. Some PEEP titration strategies attempt to weigh beneficial effects on arterial oxygenation and on prevention of cyclic alveolar collapse with the harmful potential of overdistention. One method for PEEP titration is a PEEP/FiO2 table that prioritizes support for arterial oxygenation. Other methods set PEEP based on mechanical parameters, such as the plateau pressure, respiratory system compliance, or transpulmonary pressure. No single method of PEEP titration has been shown to improve clinical outcomes compared with other approaches of setting PEEP. Future trials should focus on identifying individuals who respond to higher PEEP with recruitment and on clinically important outcomes (e.g., mortality).
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Affiliation(s)
- Sarina K. Sahetya
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Ewan C. Goligher
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada; and
- Department of Medicine, Division of Respirology, University Health Network and Mount Sinai Hospital, Toronto, Canada
| | - Roy G. Brower
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
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21
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Ferrando C, Suarez-Sipmann F, Tusman G, León I, Romero E, Gracia E, Mugarra A, Arocas B, Pozo N, Soro M, Belda FJ. Open lung approach versus standard protective strategies: Effects on driving pressure and ventilatory efficiency during anesthesia - A pilot, randomized controlled trial. PLoS One 2017; 12:e0177399. [PMID: 28493943 PMCID: PMC5426745 DOI: 10.1371/journal.pone.0177399] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 04/24/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Low tidal volume (VT) during anesthesia minimizes lung injury but may be associated to a decrease in functional lung volume impairing lung mechanics and efficiency. Lung recruitment (RM) can restore lung volume but this may critically depend on the post-RM selected PEEP. This study was a randomized, two parallel arm, open study whose primary outcome was to compare the effects on driving pressure of adding a RM to low-VT ventilation, with or without an individualized post-RM PEEP in patients without known previous lung disease during anesthesia. METHODS Consecutive patients scheduled for major abdominal surgery were submitted to low-VT ventilation (6 ml·kg-1) and standard PEEP of 5 cmH2O (pre-RM, n = 36). After 30 min estabilization all patients received a RM and were randomly allocated to either continue with the same PEEP (RM-5 group, n = 18) or to an individualized open-lung PEEP (OL-PEEP) (Open Lung Approach, OLA group, n = 18) defined as the level resulting in maximal Cdyn during a decremental PEEP trial. We compared the effects on driving pressure and lung efficiency measured by volumetric capnography. RESULTS OL-PEEP was found at 8±2 cmH2O. 36 patients were included in the final analysis. When compared with pre-RM, OLA resulted in a 22% increase in compliance and a 28% decrease in driving pressure when compared to pre-RM. These parameters did not improve in the RM-5. The trend of the DP was significantly different between the OLA and RM-5 groups (p = 0.002). VDalv/VTalv was significantly lower in the OLA group after the RM (p = 0.035). CONCLUSIONS Lung recruitment applied during low-VT ventilation improves driving pressure and lung efficiency only when applied as an open-lung strategy with an individualized PEEP in patients without lung diseases undergoing major abdominal surgery. TRIAL REGISTRATION ClinicalTrials.gov NCT02798133.
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Affiliation(s)
- Carlos Ferrando
- Department of Anesthesiology and Critical Care, Hospital Clínico Universitario, Valencia, Spain
- * E-mail:
| | - Fernando Suarez-Sipmann
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University Hospital Uppsala, Sweden
| | - Gerardo Tusman
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar de Plata, Argentina
| | - Irene León
- Department of Anesthesiology and Critical Care, Hospital Clínico Universitario, Valencia, Spain
| | - Esther Romero
- Department of Anesthesiology and Critical Care, Hospital Clínico Universitario, Valencia, Spain
| | - Estefania Gracia
- Department of Anesthesiology and Critical Care, Hospital Clínico Universitario, Valencia, Spain
| | - Ana Mugarra
- Department of Anesthesiology and Critical Care, Hospital Clínico Universitario, Valencia, Spain
| | - Blanca Arocas
- Department of Anesthesiology and Critical Care, Hospital Clínico Universitario, Valencia, Spain
| | - Natividad Pozo
- INCLIVA Clinical Research Institute, Hospital Clínico Universitario, Valencia, Spain
| | - Marina Soro
- Department of Anesthesiology and Critical Care, Hospital Clínico Universitario, Valencia, Spain
| | - Francisco J. Belda
- Department of Anesthesiology and Critical Care, Hospital Clínico Universitario, Valencia, Spain
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Xin Y, Cereda M, Kadlecek S, Emami K, Hamedani H, Duncan I, Rajaei J, Hughes L, Meeder N, Naji J, Profka H, Bolognese BJ, Foley JP, Podolin PL, Rizi RR. Hyperpolarized gas diffusion MRI of biphasic lung inflation in short- and long-term emphysema models. Am J Physiol Lung Cell Mol Physiol 2017; 313:L305-L312. [PMID: 28473321 DOI: 10.1152/ajplung.00048.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/28/2017] [Accepted: 04/29/2017] [Indexed: 11/22/2022] Open
Abstract
During lung inflation, airspace dimensions are affected nonlinearly by both alveolar expansion and recruitment, potentially confounding the identification of emphysematous lung by hyperpolarized helium-3 diffusion magnetic resonance imaging (HP MRI). This study aimed to characterize lung inflation over a broad range of inflation volume and pressure values in two different models of emphysema, as well as in normal lungs. Elastase-treated rats (n = 7) and healthy controls (n = 7) were imaged with HP MRI. Gradual inflation was achieved by incremental changes to both inflation volume and airway pressure. The apparent diffusion coefficient (ADC) was measured at each level of inflation and fitted to the corresponding airway pressures as the second-order response equation, with minimizing residue (χ2 < 0.001). A biphasic ADC response was detected, with an initial ADC increase followed by a decrease at airway pressures >18 cmH2O. Discrimination between treated and control rats was optimal when airway pressure was intermediate (between 10 and 11 cmH2O). Similar findings were confirmed in mice following long-term exposure to cigarette smoke, where optimal discrimination between treated and healthy mice occurred at a similar airway pressure as in the rats. We subsequently explored the evolution of ADC measured at the intermediate inflation level in mice after prolonged smoke exposure and found a significant increase (P < 0.01) in ADC over time. Our results demonstrate that measuring ADC at intermediate inflation enhances the distinction between healthy and diseased lungs, thereby establishing a model that may improve the diagnostic accuracy of future HP gas diffusion studies.
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Affiliation(s)
- Yi Xin
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Maurizio Cereda
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Stephen Kadlecek
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Hooman Hamedani
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ian Duncan
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Liam Hughes
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Natalie Meeder
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Joseph Naji
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Harrilla Profka
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Joseph P Foley
- Glaxosmithkline, Incorpoarted, King of Prussia, Pennsylvania
| | | | - Rahim R Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania;
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Kollisch-Singule M, Jain SV, Satalin J, Andrews P, Searles Q, Liu Z, Zhou Y, Wang G, Meier AH, Gatto LA, Nieman GF, Habashi NM. Limiting ventilator-associated lung injury in a preterm porcine neonatal model. J Pediatr Surg 2017; 52:50-55. [PMID: 27837992 DOI: 10.1016/j.jpedsurg.2016.10.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 10/20/2016] [Indexed: 01/28/2023]
Abstract
PURPOSE Preterm infants are prone to respiratory distress syndrome (RDS), with severe cases requiring mechanical ventilation for support. However, there are no clear guidelines regarding the optimal ventilation strategy. We hypothesized that airway pressure release ventilation (APRV) would mitigate lung injury in a preterm porcine neonatal model. METHODS Preterm piglets were delivered on gestational day 98 (85% of 115day term), instrumented, and randomized to volume guarantee (VG; n=10) with low tidal volumes (5.5cm3kg-1) and PEEP 4cmH2O or APRV (n=10) with initial ventilator settings: PHigh 18cmH2O, PLow 0cmH2O, THigh 1.30s, TLow 0.15s. Ventilator setting changes were made in response to clinical parameters in both groups. Animals were monitored continuously for 24hours. RESULTS The mortality rates between the two groups were not significantly different (p>0.05). The VG group had relatively increased oxygen requirements (FiO2 50%±9%) compared with the APRV group (FiO2 28%±5%; p>0.05) and a decrease in PaO2/FiO2 ratio (VG 162±33mmHg; APRV 251±45mmHg; p<0.05). The compliance of the VG group (0.51±0.07L·cmH2O-1) was significantly less than the APRV group (0.90±0.06L·cmH2O-1; p<0.05). CONCLUSION This study demonstrates that APRV improves oxygenation and compliance as compared with VG. This preliminary work suggests further study into the clinical uses of APRV in the neonate is warranted. LEVEL OF EVIDENCE Not Applicable (Basic Science Animal Study).
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Affiliation(s)
| | - Sumeet V Jain
- Department of Surgery, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA.
| | - Joshua Satalin
- Department of Surgery, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA.
| | - Penny Andrews
- Department of Trauma Critical Care Medicine, R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, 22 S. Greene St., Baltimore, MD, 21201, USA.
| | - Quinn Searles
- Department of Surgery, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA.
| | - Zhiyong Liu
- Department of Surgery, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA.
| | - Yan Zhou
- Department of Surgery, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA.
| | - Guirong Wang
- Department of Surgery, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA.
| | - Andreas H Meier
- Department of Surgery, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA.
| | - Louis A Gatto
- Department of Surgery, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA; Department of Biological Sciences, SUNY Cortland, 22 Graham Ave, Cortland, NY, 13045, USA.
| | - Gary F Nieman
- Department of Surgery, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA.
| | - Nader M Habashi
- Department of Trauma Critical Care Medicine, R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, 22 S. Greene St., Baltimore, MD, 21201, USA.
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Abstract
Prevention of ventilator-induced lung injury (VILI) can attenuate multiorgan failure and improve survival in at-risk patients. Clinically significant VILI occurs from volutrauma, barotrauma, atelectrauma, biotrauma, and shear strain. Differences in regional mechanics are important in VILI pathogenesis. Several interventions are available to protect against VILI. However, most patients at risk of lung injury do not develop VILI. VILI occurs most readily in patients with concomitant physiologic insults. VILI prevention strategies must balance risk of lung injury with untoward side effects from the preventive effort, and may be most effective when targeted to subsets of patients at increased risk.
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Furuya K, Tan JJ, Boudreault F, Sokabe M, Berthiaume Y, Grygorczyk R. Real-time imaging of inflation-induced ATP release in the ex vivo rat lung. Am J Physiol Lung Cell Mol Physiol 2016; 311:L956-L969. [PMID: 27638905 DOI: 10.1152/ajplung.00425.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 09/13/2016] [Indexed: 12/25/2022] Open
Abstract
Extracellular ATP and other nucleotides are important autocrine/paracrine mediators that regulate diverse processes critical for lung function, including mucociliary clearance, surfactant secretion, and local blood flow. Cellular ATP release is mechanosensitive; however, the impact of physical stimuli on ATP release during breathing has never been tested in intact lungs in real time and remains elusive. In this pilot study, we investigated inflation-induced ATP release in rat lungs ex vivo by real-time luciferin-luciferase (LL) bioluminescence imaging coupled with simultaneous infrared tissue imaging to identify ATP-releasing sites. With LL solution introduced into air spaces, brief inflation of such edematous lung (1 s, ∼20 cmH2O) induced transient (<30 s) ATP release in a limited number of air-inflated alveolar sacs during their recruitment/opening. Released ATP reached concentrations of ∼10-6 M, relevant for autocrine/paracrine signaling, but it remained spatially restricted to single alveolar sacs or their clusters. ATP release was stimulus dependent: prolonged (100 s) inflation evoked long-lasting ATP release that terminated upon alveoli deflation/derecruitment while cyclic inflation/suction produced cyclic ATP release. With LL introduced into blood vessels, inflation induced transient ATP release in many small patchlike areas the size of alveolar sacs. Findings suggest that inflation induces ATP release in both alveoli and the surrounding blood capillary network; the functional units of ATP release presumably consist of alveolar sacs or their clusters. Our study demonstrates the feasibility of real-time ATP release imaging in ex vivo lungs and provides the first direct evidence of inflation-induced ATP release in lung air spaces and in pulmonary blood capillaries, highlighting the importance of purinergic signaling in lung function.
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Affiliation(s)
- Kishio Furuya
- Mechanobiology Laboratory, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Ju Jing Tan
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Francis Boudreault
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Yves Berthiaume
- Department of Medicine, Université de Montréal, Montreal, Quebec, Canada; and.,Institut de recherches cliniques de Montréal (IRCM), Quebec, Canada
| | - Ryszard Grygorczyk
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada; .,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada; and
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Abstract
BACKGROUND Mechanical ventilation worsens acute respiratory distress syndrome, but this secondary "ventilator-associated" injury is variable and difficult to predict. The authors aimed to visualize the propagation of such ventilator-induced injury, in the presence (and absence) of a primary underlying lung injury, and to determine the predictors of propagation. METHODS Anesthetized rats (n = 20) received acid aspiration (hydrochloric acid) followed by ventilation with moderate tidal volume (V(T)). In animals surviving ventilation for at least 2 h, propagation of injury was quantified by using serial computed tomography. Baseline lung status was assessed by oxygenation, lung weight, and lung strain (V(T)/expiratory lung volume). Separate groups of rats without hydrochloric acid aspiration were ventilated with large (n = 10) or moderate (n = 6) V(T). RESULTS In 15 rats surviving longer than 2 h, computed tomography opacities spread outward from the initial site of injury. Propagation was associated with higher baseline strain (propagation vs. no propagation [mean ± SD]: 1.52 ± 0.13 vs. 1.16 ± 0.20, P < 0.01) but similar oxygenation and lung weight. Propagation did not occur where baseline strain was less than 1.29. In healthy animals, large V(T) caused injury that was propagated inward from the lung periphery; in the absence of preexisting injury, propagation did not occur where strain was less than 2.0. CONCLUSIONS Compared with healthy lungs, underlying injury causes propagation to occur at a lower strain threshold and it originates at the site of injury; this suggests that tissue around the primary lesion is more sensitive. Understanding how injury is propagated may ultimately facilitate a more individualized monitoring or management.
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Pesenti A, Musch G, Lichtenstein D, Mojoli F, Amato MBP, Cinnella G, Gattinoni L, Quintel M. Imaging in acute respiratory distress syndrome. Intensive Care Med 2016; 42:686-698. [DOI: 10.1007/s00134-016-4328-1] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 03/11/2016] [Indexed: 11/30/2022]
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Cereda M, Xin Y, Hamedani H, Clapp J, Kadlecek S, Meeder N, Zeng J, Profka H, Kavanagh BP, Rizi RR. Mild loss of lung aeration augments stretch in healthy lung regions. J Appl Physiol (1985) 2015; 120:444-54. [PMID: 26662053 DOI: 10.1152/japplphysiol.00734.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/07/2015] [Indexed: 11/22/2022] Open
Abstract
Inspiratory stretch by mechanical ventilation worsens lung injury. However, it is not clear whether and how the ventilator damages lungs in the absence of preexisting injury. We hypothesized that subtle loss of lung aeration during general anesthesia regionally augments ventilation and distension of ventilated air spaces. In eight supine anesthetized and intubated rats, hyperpolarized gas MRI was performed after a recruitment maneuver following 1 h of volume-controlled ventilation with zero positive end-expiratory pressure (ZEEP), FiO2 0.5, and tidal volume 10 ml/kg, and after a second recruitment maneuver. Regional fractional ventilation (FV), apparent diffusion coefficient (ADC) of (3)He (a measurement of ventilated peripheral air space dimensions), and gas volume were measured in lung quadrants of ventral and dorsal regions of the lungs. In six additional rats, computed tomography (CT) images were obtained at each time point. Ventilation with ZEEP decreased total lung gas volume and increased both FV and ADC in all studied regions. Increases in FV were more evident in the dorsal slices. In each lung quadrant, higher ADC was predicted by lower gas volume and by increased mean values (and heterogeneity) of FV distribution. CT scans documented 10% loss of whole-lung aeration and increased density in the dorsal lung, but no macroscopic atelectasis. Loss of pulmonary gas at ZEEP increased fractional ventilation and inspiratory dimensions of ventilated peripheral air spaces. Such regional changes could help explain a propensity for mechanical ventilation to contribute to lung injury in previously uninjured lungs.
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Affiliation(s)
- Maurizio Cereda
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania;
| | - Yi Xin
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Hooman Hamedani
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Justin Clapp
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Stephen Kadlecek
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Natalie Meeder
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Johnathan Zeng
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Harrilla Profka
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Brian P Kavanagh
- Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Rahim R Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania; and
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Pathophysiology and Prevention of Intraoperative Atelectasis: A Review of the Literature. J Perianesth Nurs 2015; 30:516-527. [DOI: 10.1016/j.jopan.2014.03.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 03/17/2014] [Accepted: 03/23/2014] [Indexed: 11/23/2022]
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Yehya N, Xin Y, Oquendo Y, Cereda M, Rizi RR, Margulies SS. Cecal ligation and puncture accelerates development of ventilator-induced lung injury. Am J Physiol Lung Cell Mol Physiol 2014; 308:L443-51. [PMID: 25550313 DOI: 10.1152/ajplung.00312.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sepsis is a leading cause of respiratory failure requiring mechanical ventilation, but the interaction between sepsis and ventilation is unclear. While prior studies demonstrated a priming role with endotoxin, actual septic animal models have yielded conflicting results regarding the role of preceding sepsis on development of subsequent ventilator-induced lung injury (VILI). Using a rat cecal ligation and puncture (CLP) model of sepsis and subsequent injurious ventilation, we sought to determine if sepsis affects development of VILI. Adult male Sprague-Dawley rats were subject to CLP or sham operation and, after 12 h, underwent injurious mechanical ventilation (tidal volume 30 ml/kg, positive end-expiratory pressure 0 cmH2O) for either 0, 60, or 120 min. Biochemical and physiological measurements, as well as computed tomography, were used to assess injury at 0, 60, and 120 min of ventilation. Before ventilation, CLP rats had higher levels of alveolar neutrophils and interleukin-1β. After 60 min of ventilation, CLP rats had worse injury as evidenced by increased alveolar inflammation, permeability, respiratory static compliance, edema, oxygenation, and computed tomography. By 120 min, CLP and sham rats had comparable levels of lung injury as assessed by many, but not all, of these metrics. CLP rats had an accelerated and worse loss of end-expiratory lung volume relative to sham, and consistently higher levels of alveolar interleukin-1β. Loss of aeration and progression of edema was more pronounced in dependent lung regions. We conclude that CLP initiated pulmonary inflammation in rats, and accelerated the development of subsequent VILI.
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Affiliation(s)
- Nadir Yehya
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania;
| | - Yi Xin
- Department of Radiology, Hospital of the University of Pennsylvania, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Yousi Oquendo
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Maurizio Cereda
- Department of Radiology, Hospital of the University of Pennsylvania, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and Department of Anesthesiology and Critical Care Medicine, Hospital of the University of Pennsylvania, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rahim R Rizi
- Department of Radiology, Hospital of the University of Pennsylvania, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Susan S Margulies
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
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Cereda M, Xin Y, Kadlecek S, Hamedani H, Rajaei J, Clapp J, Rizi RR. Hyperpolarized gas diffusion MRI for the study of atelectasis and acute respiratory distress syndrome. NMR IN BIOMEDICINE 2014; 27:1468-78. [PMID: 24920074 PMCID: PMC4232982 DOI: 10.1002/nbm.3136] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/03/2014] [Accepted: 04/21/2014] [Indexed: 06/03/2023]
Abstract
Considerable uncertainty remains about the best ventilator strategies for the mitigation of atelectasis and associated airspace stretch in patients with acute respiratory distress syndrome (ARDS). In addition to several immediate physiological effects, atelectasis increases the risk of ventilator-associated lung injury, which has been shown to significantly worsen ARDS outcomes. A number of lung imaging techniques have made substantial headway in clarifying the mechanisms of atelectasis. This paper reviews the contributions of computed tomography, positron emission tomography, and conventional MRI to understanding this phenomenon. In doing so, it also reveals several important shortcomings inherent to each of these approaches. Once these shortcomings have been made apparent, we describe how hyperpolarized (HP) gas MRI--a technique that is uniquely able to assess responses to mechanical ventilation and lung injury in peripheral airspaces--is poised to fill several of these knowledge gaps. The HP-MRI-derived apparent diffusion coefficient (ADC) quantifies the restriction of (3) He diffusion by peripheral airspaces, thereby obtaining pulmonary structural information at an extremely small scale. Lastly, this paper reports the results of a series of experiments that measured ADC in mechanically ventilated rats in order to investigate (i) the effect of atelectasis on ventilated airspaces, (ii) the relationship between positive end-expiratory pressure (PEEP), hysteresis, and the dimensions of peripheral airspaces, and (iii) the ability of PEEP and surfactant to reduce airspace dimensions after lung injury. An increase in ADC was found to be a marker of atelectasis-induced overdistension. With recruitment, higher airway pressures were shown to reduce stretch rather than worsen it. Moving forward, HP MRI has significant potential to shed further light on the atelectatic processes that occur during mechanical ventilation.
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Affiliation(s)
- Maurizio Cereda
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA, USA
| | - Yi Xin
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Stephen Kadlecek
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hooman Hamedani
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jennia Rajaei
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Justin Clapp
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Rahim R. Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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Ma LQ, Pan CS, Yang N, Liu YY, Yan L, Sun K, Wei XH, He K, Xiao MM, Fan JY, Han JY. Posttreatment with Ma-Xing-Shi-Gan-Tang, a Chinese Medicine Formula, Ameliorates Lipopolysaccharide-Induced Lung Microvessel Hyperpermeability and Inflammatory Reaction in Rat. Microcirculation 2014; 21:649-63. [DOI: 10.1111/micc.12144] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 05/01/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Li-Qian Ma
- Department of Integration of Chinese and Western Medicine; School of Basic Medical Sciences; Peking University; Beijing China
- Tasly Microcirculation Research Center; Peking University Health Science Center; Beijing China
- Key Laboratory of Microcirculation; State Administration of Traditional Chinese Medicine of China; Beijing China
- Key Laboratory of Stasis and Phlegm; State Administration of Traditional Chinese Medicine of China; Beijing China
| | - Chun-Shui Pan
- Tasly Microcirculation Research Center; Peking University Health Science Center; Beijing China
- Key Laboratory of Microcirculation; State Administration of Traditional Chinese Medicine of China; Beijing China
- Key Laboratory of Stasis and Phlegm; State Administration of Traditional Chinese Medicine of China; Beijing China
| | - Ning Yang
- Tasly Microcirculation Research Center; Peking University Health Science Center; Beijing China
- Key Laboratory of Microcirculation; State Administration of Traditional Chinese Medicine of China; Beijing China
- Key Laboratory of Stasis and Phlegm; State Administration of Traditional Chinese Medicine of China; Beijing China
| | - Yu-Ying Liu
- Tasly Microcirculation Research Center; Peking University Health Science Center; Beijing China
- Key Laboratory of Microcirculation; State Administration of Traditional Chinese Medicine of China; Beijing China
- Key Laboratory of Stasis and Phlegm; State Administration of Traditional Chinese Medicine of China; Beijing China
| | - Li Yan
- Tasly Microcirculation Research Center; Peking University Health Science Center; Beijing China
- Key Laboratory of Microcirculation; State Administration of Traditional Chinese Medicine of China; Beijing China
- Key Laboratory of Stasis and Phlegm; State Administration of Traditional Chinese Medicine of China; Beijing China
| | - Kai Sun
- Tasly Microcirculation Research Center; Peking University Health Science Center; Beijing China
- Key Laboratory of Microcirculation; State Administration of Traditional Chinese Medicine of China; Beijing China
- Key Laboratory of Stasis and Phlegm; State Administration of Traditional Chinese Medicine of China; Beijing China
| | - Xiao-Hong Wei
- Tasly Microcirculation Research Center; Peking University Health Science Center; Beijing China
- Key Laboratory of Microcirculation; State Administration of Traditional Chinese Medicine of China; Beijing China
- Key Laboratory of Stasis and Phlegm; State Administration of Traditional Chinese Medicine of China; Beijing China
| | - Ke He
- Department of Integration of Chinese and Western Medicine; School of Basic Medical Sciences; Peking University; Beijing China
- Tasly Microcirculation Research Center; Peking University Health Science Center; Beijing China
- Key Laboratory of Microcirculation; State Administration of Traditional Chinese Medicine of China; Beijing China
- Key Laboratory of Stasis and Phlegm; State Administration of Traditional Chinese Medicine of China; Beijing China
| | - Meng-Meng Xiao
- Department of Integration of Chinese and Western Medicine; School of Basic Medical Sciences; Peking University; Beijing China
- Tasly Microcirculation Research Center; Peking University Health Science Center; Beijing China
- Key Laboratory of Microcirculation; State Administration of Traditional Chinese Medicine of China; Beijing China
- Key Laboratory of Stasis and Phlegm; State Administration of Traditional Chinese Medicine of China; Beijing China
| | - Jing-Yu Fan
- Tasly Microcirculation Research Center; Peking University Health Science Center; Beijing China
- Key Laboratory of Microcirculation; State Administration of Traditional Chinese Medicine of China; Beijing China
- Key Laboratory of Stasis and Phlegm; State Administration of Traditional Chinese Medicine of China; Beijing China
| | - Jing-Yan Han
- Department of Integration of Chinese and Western Medicine; School of Basic Medical Sciences; Peking University; Beijing China
- Tasly Microcirculation Research Center; Peking University Health Science Center; Beijing China
- Key Laboratory of Microcirculation; State Administration of Traditional Chinese Medicine of China; Beijing China
- Key Laboratory of Stasis and Phlegm; State Administration of Traditional Chinese Medicine of China; Beijing China
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Retamal J, Bergamini BC, Carvalho AR, Bozza FA, Borzone G, Borges JB, Larsson A, Hedenstierna G, Bugedo G, Bruhn A. Non-lobar atelectasis generates inflammation and structural alveolar injury in the surrounding healthy tissue during mechanical ventilation. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:505. [PMID: 25200702 PMCID: PMC4172813 DOI: 10.1186/s13054-014-0505-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 08/22/2014] [Indexed: 12/16/2022]
Abstract
Introduction When alveoli collapse the traction forces exerted on their walls by adjacent expanded units may increase and concentrate. These forces may promote its re-expansion at the expense of potentially injurious stresses at the interface between the collapsed and the expanded units. We developed an experimental model to test the hypothesis that a local non-lobar atelectasis can act as a stress concentrator, contributing to inflammation and structural alveolar injury in the surrounding healthy lung tissue during mechanical ventilation. Methods A total of 35 rats were anesthetized, paralyzed and mechanically ventilated. Atelectasis was induced by bronchial blocking: after five minutes of stabilization and pre-oxygenation with FIO2 = 1.0, a silicon cylinder blocker was wedged in the terminal bronchial tree. Afterwards, the animals were randomized between two groups: 1) Tidal volume (VT) = 10 ml/kg and positive end-expiratory pressure (PEEP) = 3 cmH2O (VT10/PEEP3); and 2) VT = 20 ml/kg and PEEP = 0 cmH2O (VT20/zero end-expiratory pressure (ZEEP)). The animals were then ventilated during 180 minutes. Three series of experiments were performed: histological (n = 12); tissue cytokines (n = 12); and micro-computed tomography (microCT; n = 2). An additional six, non-ventilated, healthy animals were used as controls. Results Atelectasis was successfully induced in the basal region of the lung of 26 out of 29 animals. The microCT of two animals revealed that the volume of the atelectasis was 0.12 and 0.21 cm3. There were more alveolar disruption and neutrophilic infiltration in the peri-atelectasis region than the corresponding contralateral lung (control) in both groups. Edema was higher in the peri-atelectasis region than the corresponding contralateral lung (control) in the VT20/ZEEP than VT10/PEEP3 group. The volume-to-surface ratio was higher in the peri-atelectasis region than the corresponding contralateral lung (control) in both groups. We did not find statistical difference in tissue interleukin-1β and cytokine-induced neutrophil chemoattractant-1 between regions. Conclusions The present findings suggest that a local non-lobar atelectasis acts as a stress concentrator, generating structural alveolar injury and inflammation in the surrounding lung tissue.
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Cereda M, Xin Y, Emami K, Huang J, Rajaei J, Profka H, Han B, Mongkolwisetwara P, Kadlecek S, Kuzma NN, Pickup S, Kavanagh BP, Deutschman CS, Rizi RR. Positive end-expiratory pressure increments during anesthesia in normal lung result in hysteresis and greater numbers of smaller aerated airspaces. Anesthesiology 2013; 119:1402-9. [PMID: 24025616 PMCID: PMC3987989 DOI: 10.1097/aln.0b013e3182a9b0c1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Although it is recognized that pulmonary hysteresis can influence the effects of positive end-expiratory pressure (PEEP), the extent to which expansion of previously opened (vs. newly opening) peripheral airspaces contribute to increased lung volume is unknown. METHODS Following a recruitment maneuver, rats were ventilated with constant tidal volumes and imaged during ascending and descending ramps of PEEP. RESULTS The authors estimated peripheral airspace dimensions by measuring the apparent diffusion coefficient of He in 10 rats. In a separate group (n = 5) undergoing a similar protocol, the authors used computerized tomography to quantify lung volume. Hysteresis was confirmed by larger end-inspiratory lung volume (mean ± SD; all PEEP levels included): 8.4 ± 2.8 versus 6.8 ± 2.0 ml (P < 0.001) and dynamic compliance: 0.52 ± 0.12 versus 0.42 ± 0.09 ml/cm H2O (P < 0.001) during descending versus ascending PEEP ramps. Apparent diffusion coefficient increased with PEEP, but it was smaller during the descending versus ascending ramps for corresponding levels of PEEP: 0.168 ± 0.019 versus 0.183 ± 0.019 cm/s (P < 0.001). Apparent diffusion coefficient was smaller in the posterior versus anterior lung regions, but the effect of PEEP and hysteresis on apparent diffusion coefficient was greater in the posterior regions. CONCLUSIONS The authors' study results suggest that in healthy lungs, larger lung volumes due to hysteresis are associated with smaller individual airspaces. This may be explained by opening of previously nonaerated peripheral airspaces rather than expansion of those already aerated. Setting PEEP on a descending ramp may minimize distension of individual airspaces.
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Affiliation(s)
- Maurizio Cereda
- Assistant Professor, Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Yi Xin
- Research Specialist, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kiarash Emami
- Project Manager, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jessie Huang
- Student, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jennia Rajaei
- Student, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Harrilla Profka
- Research Specialist, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Biao Han
- Research Specialist, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Stephen Kadlecek
- Research Assistant Professor, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nicholas N. Kuzma
- Research Assistant Professor, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Stephen Pickup
- Technical Director, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Brian P. Kavanagh
- Professor, Departments of Critical Care Medicine and Anesthesia, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Clifford S. Deutschman
- Professor, Department of Anesthesiology and Critical Care and Stavropoulos Sepsis Research Program, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rahim R. Rizi
- Professor, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
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Derosa S, Borges JB, Segelsjö M, Tannoia A, Pellegrini M, Larsson A, Perchiazzi G, Hedenstierna G. Reabsorption atelectasis in a porcine model of ARDS: regional and temporal effects of airway closure, oxygen, and distending pressure. J Appl Physiol (1985) 2013; 115:1464-73. [DOI: 10.1152/japplphysiol.00763.2013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Little is known about the small airways dysfunction in acute respiratory distress syndrome (ARDS). By computed tomography (CT) imaging in a porcine experimental model of early ARDS, we aimed at studying the location and magnitude of peripheral airway closure and alveolar collapse under high and low distending pressures and high and low inspiratory oxygen fraction (FIO2). Six piglets were mechanically ventilated under anesthesia and muscle relaxation. Four animals underwent saline-washout lung injury, and two served as healthy controls. Beyond the site of assumed airway closure, gas was expected to be trapped in the injured lungs, promoting alveolar collapse. This was tested by ventilation with an FIO2 of 0.25 and 1 in sequence during low and high distending pressures. In the most dependent regions, the gas/tissue ratio of end-expiratory CT, after previous ventilation with FIO2 0.25 low-driving pressure, was significantly higher than after ventilation with FIO2 1; with high-driving pressure, this difference disappeared. Also, significant reduction in poorly aerated tissue and a correlated increase in nonaerated tissue in end-expiratory CT with FIO2 1 low-driving pressure were seen. When high-driving pressure was applied or after previous ventilation with FIO2 0.25 and low-driving pressure, this pattern disappeared. The findings suggest that low distending pressures produce widespread dependent airway closure and with high FIO2, subsequent absorption atelectasis. Low FIO2 prevented alveolar collapse during the study period because of slow absorption of gas behind closed airways.
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Affiliation(s)
- Savino Derosa
- Department of Emergency and Organ Transplant, Bari University, Bari, Italy
- Hedenstierna Laboratory, Department of Surgical Sciences, Section of Anaesthesiology and Critical Care, Uppsala University, Uppsala, Sweden
| | - João Batista Borges
- Hedenstierna Laboratory, Department of Surgical Sciences, Section of Anaesthesiology and Critical Care, Uppsala University, Uppsala, Sweden
- Pulmonary Divison, Heart Institute (Incor), Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
| | - Monica Segelsjö
- Department of Radiology, Oncology and Radiation Science, Section of Radiology, Uppsala University, Uppsala, Sweden; and
| | - Angela Tannoia
- Department of Emergency and Organ Transplant, Bari University, Bari, Italy
| | | | - Anders Larsson
- Hedenstierna Laboratory, Department of Surgical Sciences, Section of Anaesthesiology and Critical Care, Uppsala University, Uppsala, Sweden
| | - Gaetano Perchiazzi
- Department of Emergency and Organ Transplant, Bari University, Bari, Italy
| | - Göran Hedenstierna
- Hedenstierna Laboratory, Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden
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