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Al-Khalisy H, Nieman GF, Kollisch-Singule M, Andrews P, Camporota L, Shiber J, Manougian T, Satalin J, Blair S, Ghosh A, Herrmann J, Kaczka DW, Gaver DP, Bates JHT, Habashi NM. Time-Controlled Adaptive Ventilation (TCAV): a personalized strategy for lung protection. Respir Res 2024; 25:37. [PMID: 38238778 PMCID: PMC10797864 DOI: 10.1186/s12931-023-02615-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 11/25/2023] [Indexed: 01/22/2024] Open
Abstract
Acute respiratory distress syndrome (ARDS) alters the dynamics of lung inflation during mechanical ventilation. Repetitive alveolar collapse and expansion (RACE) predisposes the lung to ventilator-induced lung injury (VILI). Two broad approaches are currently used to minimize VILI: (1) low tidal volume (LVT) with low-moderate positive end-expiratory pressure (PEEP); and (2) open lung approach (OLA). The LVT approach attempts to protect already open lung tissue from overdistension, while simultaneously resting collapsed tissue by excluding it from the cycle of mechanical ventilation. By contrast, the OLA attempts to reinflate potentially recruitable lung, usually over a period of seconds to minutes using higher PEEP used to prevent progressive loss of end-expiratory lung volume (EELV) and RACE. However, even with these protective strategies, clinical studies have shown that ARDS-related mortality remains unacceptably high with a scarcity of effective interventions over the last two decades. One of the main limitations these varied interventions demonstrate to benefit is the observed clinical and pathologic heterogeneity in ARDS. We have developed an alternative ventilation strategy known as the Time Controlled Adaptive Ventilation (TCAV) method of applying the Airway Pressure Release Ventilation (APRV) mode, which takes advantage of the heterogeneous time- and pressure-dependent collapse and reopening of lung units. The TCAV method is a closed-loop system where the expiratory duration personalizes VT and EELV. Personalization of TCAV is informed and tuned with changes in respiratory system compliance (CRS) measured by the slope of the expiratory flow curve during passive exhalation. Two potentially beneficial features of TCAV are: (i) the expiratory duration is personalized to a given patient's lung physiology, which promotes alveolar stabilization by halting the progressive collapse of alveoli, thereby minimizing the time for the reopened lung to collapse again in the next expiration, and (ii) an extended inspiratory phase at a fixed inflation pressure after alveolar stabilization gradually reopens a small amount of tissue with each breath. Subsequently, densely collapsed regions are slowly ratcheted open over a period of hours, or even days. Thus, TCAV has the potential to minimize VILI, reducing ARDS-related morbidity and mortality.
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Affiliation(s)
| | - Gary F Nieman
- SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA
| | | | - Penny Andrews
- R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD, USA
| | - Luigi Camporota
- Health Centre for Human and Applied Physiological Sciences, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Joseph Shiber
- University of Florida College of Medicine, Jacksonville, FL, USA
| | | | - Joshua Satalin
- SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA.
| | - Sarah Blair
- SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA
| | - Auyon Ghosh
- SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY, 13210, USA
| | | | | | | | | | - Nader M Habashi
- R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD, USA
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Camporesi A, Pierucci UM, Paladini G, Gentile A, Buonsenso D, Pelizzo G. Lung ultrasound-guided best positive end-expiratory pressure in neonatal anesthesia: a proposed randomized, controlled study. Pediatr Res 2024; 95:393-396. [PMID: 37648746 DOI: 10.1038/s41390-023-02730-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/27/2023] [Accepted: 06/01/2023] [Indexed: 09/01/2023]
Abstract
BACKGROUND Atelectasis is a common complication in neonatal anesthesia. Lung ultrasound (LUS) can be used intraoperatively to evaluate and recognize atelectatic lung areas. Hypotheses for the study are: (1) The use of LUS to guide choice of best positive end-expiratory pressure (PEEP) can lead to reduction of FiO2 to achieve same saturations of oxygen (SpO2). (2) In a less de-recruited lung, there will be less postoperative pulmonary complications. (3) Static respiratory system compliance could be different. (4) Hemodynamic parameters and amount of fluids infused or need for vasopressors intraoperatively could be different. METHODS We propose a randomized controlled trial that compares standard PEEP settings with LUS-guided PEEP choice in patients under 2 months of age undergoing general anesthesia. RESULTS The primary aim is to determine whether LUS-guided PEEP choice in neonatal anesthesia, compared to standard PEEP choice, can lead to reduction of FiO2 applied to the ventilatory setting in order to maintain same SpO2s. Secondary aims are to determine whether patients treated with LUS-guided PEEP will develop less postoperative pulmonary complications, will have a significant difference in hemodynamic parameters and amount of fluids or vasopressors infused, and in static respiratory system compliance. CONCLUSIONS We expect a significant reduction of FiO2 in LUS-guided ventilation. IMPACT Lung atelectasis is extremely common in neonatal anesthesia, because of the physiology of the neonatal lung and chest wall and leads to hypoxemia, being a lung area with a perfusion/ventilation mismatch. Raising inspired fraction of oxygen can overcome temporarily hypoxemia but oxygen is a toxic compound for newborns. Lung ultrasound (LUS) can detect atelectasis at bedside and be used to optimize ventilator settings including choice of positive end-expiratory pressure (PEEP). This randomized controlled trial (RCT) aims at demonstrating that LUS-guided choice of best PEEP during neonatal anesthesia can lead to reduction of inspired fractions of oxygen to keep same peripheral saturations SpO2.
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Affiliation(s)
- Anna Camporesi
- Department of Pediatric Anesthesia and Intensive Care, Buzzi Children's Hospital, Milan, Italy.
| | | | - Giuseppe Paladini
- Department of Pediatric Anesthesia and Intensive Care, Buzzi Children's Hospital, Milan, Italy
| | - Andrea Gentile
- Department of Medical-Surgical Physiopathology and Transplants, University of Milan, Milan, Italy
| | - Danilo Buonsenso
- Department of Woman and Child Health and Public Health, Fondazione Policlinico Universitario "A. Gemelli", Roma, Italy
| | - Gloria Pelizzo
- Pediatric Surgery Department, Buzzi Children's Hospital, Milan, Italy
- Department of Biomedical and Clinical Science, Luigi Sacco University Hospital, Milan, Italy
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Kim YJ, Kim BR, Kim HW, Jung JY, Cho HY, Seo JH, Kim WH, Kim HS, Hwangbo S, Yoon HK. Effect of driving pressure-guided positive end-expiratory pressure on postoperative pulmonary complications in patients undergoing laparoscopic or robotic surgery: a randomised controlled trial. Br J Anaesth 2023; 131:955-965. [PMID: 37679285 DOI: 10.1016/j.bja.2023.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 07/27/2023] [Accepted: 08/01/2023] [Indexed: 09/09/2023] Open
Abstract
BACKGROUND Individualised positive end-expiratory pressure (PEEP) improves respiratory mechanics. However, whether PEEP reduces postoperative pulmonary complications (PPCs) remains unclear. We investigated whether driving pressure-guided PEEP reduces PPCs after laparoscopic/robotic abdominal surgery. METHODS This single-centre, randomised controlled trial enrolled patients at risk for PPCs undergoing laparoscopic or robotic lower abdominal surgery. The individualised group received driving pressure-guided PEEP, whereas the comparator group received 5 cm H2O fixed PEEP during surgery. Both groups received a tidal volume of 8 ml kg-1 ideal body weight. The primary outcome analysed per protocol was a composite of pulmonary complications (defined by pre-specified clinical and radiological criteria) within 7 postoperative days after surgery. RESULTS Some 384 patients (median age: 67 yr [inter-quartile range: 61-73]; 66 [18%] female) were randomised. Mean (standard deviation) PEEP in patients randomised to individualised PEEP (n=178) was 13.6 cm H2O (2.1). Individualised PEEP resulted in lower mean driving pressures (14.7 cm H2O [2.6]), compared with 185 patients randomised to standard PEEP (18.4 cm H2O [3.2]; mean difference: -3.7 cm H2O [95% confidence interval (CI): -4.3 to -3.1 cm H2O]; P<0.001). There was no difference in the incidence of pulmonary complications between individualised (25/178 [14.0%]) vs standard PEEP (36/185 [19.5%]; risk ratio [95% CI], 0.72 [0.45-1.15]; P=0.215). Pulmonary complications as a result of desaturation were less frequent in patients randomised to individualised PEEP (8/178 [4.5%], compared with standard PEEP (30/185 [16.2%], risk ratio [95% CI], 0.28 [0.13-0.59]; P=0.001). CONCLUSIONS Driving pressure-guided PEEP did not decrease the incidence of pulmonary complications within 7 days of laparoscopic or robotic lower abdominal surgery, although uncertainty remains given the lower than anticipated event rate for the primary outcome. CLINICAL TRIAL REGISTRATION KCT0004888 (http://cris.nih.go.kr, registration date: April 6, 2020).
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Affiliation(s)
- Yoon Jung Kim
- Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Bo Rim Kim
- Department of Anesthesiology and Pain Medicine, Korea University College of Medicine, Korea University Guro Hospital, Seoul, Republic of Korea
| | - Hee Won Kim
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Ji-Yoon Jung
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Hye-Yeon Cho
- Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jeoung-Hwa Seo
- Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Won Ho Kim
- Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Hee-Soo Kim
- Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Suhyun Hwangbo
- Department of Genomic Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Hyun-Kyu Yoon
- Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea; Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
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Nieman GF, Kaczka DW, Andrews PL, Ghosh A, Al-Khalisy H, Camporota L, Satalin J, Herrmann J, Habashi NM. First Stabilize and then Gradually Recruit: A Paradigm Shift in Protective Mechanical Ventilation for Acute Lung Injury. J Clin Med 2023; 12:4633. [PMID: 37510748 PMCID: PMC10380509 DOI: 10.3390/jcm12144633] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/15/2023] [Accepted: 06/21/2023] [Indexed: 07/30/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) is associated with a heterogeneous pattern of injury throughout the lung parenchyma that alters regional alveolar opening and collapse time constants. Such heterogeneity leads to atelectasis and repetitive alveolar collapse and expansion (RACE). The net effect is a progressive loss of lung volume with secondary ventilator-induced lung injury (VILI). Previous concepts of ARDS pathophysiology envisioned a two-compartment system: a small amount of normally aerated lung tissue in the non-dependent regions (termed "baby lung"); and a collapsed and edematous tissue in dependent regions. Based on such compartmentalization, two protective ventilation strategies have been developed: (1) a "protective lung approach" (PLA), designed to reduce overdistension in the remaining aerated compartment using a low tidal volume; and (2) an "open lung approach" (OLA), which first attempts to open the collapsed lung tissue over a short time frame (seconds or minutes) with an initial recruitment maneuver, and then stabilize newly recruited tissue using titrated positive end-expiratory pressure (PEEP). A more recent understanding of ARDS pathophysiology identifies regional alveolar instability and collapse (i.e., hidden micro-atelectasis) in both lung compartments as a primary VILI mechanism. Based on this understanding, we propose an alternative strategy to ventilating the injured lung, which we term a "stabilize lung approach" (SLA). The SLA is designed to immediately stabilize the lung and reduce RACE while gradually reopening collapsed tissue over hours or days. At the core of SLA is time-controlled adaptive ventilation (TCAV), a method to adjust the parameters of the airway pressure release ventilation (APRV) modality. Since the acutely injured lung at any given airway pressure requires more time for alveolar recruitment and less time for alveolar collapse, SLA adjusts inspiratory and expiratory durations and inflation pressure levels. The TCAV method SLA reverses the open first and stabilize second OLA method by: (i) immediately stabilizing lung tissue using a very brief exhalation time (≤0.5 s), so that alveoli simply do not have sufficient time to collapse. The exhalation duration is personalized and adaptive to individual respiratory mechanical properties (i.e., elastic recoil); and (ii) gradually recruiting collapsed lung tissue using an inflate and brake ratchet combined with an extended inspiratory duration (4-6 s) method. Translational animal studies, clinical statistical analysis, and case reports support the use of TCAV as an efficacious lung protective strategy.
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Affiliation(s)
- Gary F. Nieman
- Department of Surgery, Upstate Medical University, Syracuse, NY 13210, USA;
| | - David W. Kaczka
- Departments of Anesthesia, Radiology and Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Penny L. Andrews
- Department of Medicine, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD 21201, USA
| | - Auyon Ghosh
- Department of Medicine, Upstate Medical University, Syracuse, NY 13210, USA
| | - Hassan Al-Khalisy
- Brody School of Medicine, Department of Internal Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Luigi Camporota
- Department of Adult Critical Care, Guy’s and St Thomas’ NHS Foundation Trust, King’s Partners, St Thomas’ Hospital, London SE1 7EH, UK
| | - Joshua Satalin
- Department of Surgery, Upstate Medical University, Syracuse, NY 13210, USA;
| | - Jacob Herrmann
- Department of Biomedical Engineering, University of Iowa, Iowa City, IA 52242, USA
| | - Nader M. Habashi
- Department of Medicine, R Adams Cowley Shock Trauma Center, University of Maryland Medical Center, Baltimore, MD 21201, USA
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Park M, Yoon S, Nam JS, Ahn HJ, Kim H, Kim HJ, Choi H, Kim HK, Blank RS, Yun SC, Lee DK, Yang M, Kim JA, Song I, Kim BR, Bahk JH, Kim J, Lee S, Choi IC, Oh YJ, Hwang W, Lim BG, Heo BY. Driving pressure-guided ventilation and postoperative pulmonary complications in thoracic surgery: a multicentre randomised clinical trial. Br J Anaesth 2023; 130:e106-e118. [PMID: 35995638 DOI: 10.1016/j.bja.2022.06.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/30/2022] [Accepted: 06/16/2022] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Airway driving pressure, easily measured as plateau pressure minus PEEP, is a surrogate for alveolar stress and strain. However, the effect of its targeted reduction remains unclear. METHODS In this multicentre trial, patients undergoing lung resection surgery were randomised to either a driving pressure group (n=650) receiving an alveolar recruitment/individualised PEEP to deliver the lowest driving pressure or to a conventional protective ventilation group (n=650) with fixed PEEP of 5 cm H2O. The primary outcome was a composite of pulmonary complications within 7 days postoperatively. RESULTS The modified intention-to-treat analysis included 1170 patients (mean [standard deviation, sd]; age, 63 [10] yr; 47% female). The mean driving pressure was 7.1 cm H2O in the driving pressure group vs 9.2 cm H2O in the protective ventilation group (mean difference [95% confidence interval, CI]; -2.1 [-2.4 to -1.9] cm H2O; P<0.001). The incidence of pulmonary complications was not different between the two groups: driving pressure group (233/576, 40.5%) vs protective ventilation group (254/594, 42.8%) (risk difference -2.3%; 95% CI, -8.0% to 3.3%; P=0.42). Intraoperatively, lung compliance (mean [sd], 42.7 [12.4] vs 33.5 [11.1] ml cm H2O-1; P<0.001) and Pao2 (median [inter-quartile range], 21.5 [14.5 to 30.4] vs 19.5 [13.5 to 29.1] kPa; P=0.03) were higher and the need for rescue ventilation was less frequent (6.8% vs 10.8%; P=0.02) in the driving pressure group. CONCLUSIONS In lung resection surgery, a driving pressure-guided ventilation improved pulmonary mechanics intraoperatively, but did not reduce the incidence of postoperative pulmonary complications compared with a conventional protective ventilation. CLINICAL TRIAL REGISTRATION NCT04260451.
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Affiliation(s)
- MiHye Park
- Department of Anaesthesiology and Pain Medicine, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Susie Yoon
- Department of Anaesthesiology and Pain Medicine, Seoul National University Hospital, University of Seoul National College of Medicine, Seoul, South Korea
| | - Jae-Sik Nam
- Department of Anaesthesiology and Pain Medicine, Asan Medical Centre, University of Ulsan College of Medicine, Seoul, South Korea
| | - Hyun Joo Ahn
- Department of Anaesthesiology and Pain Medicine, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, South Korea.
| | - Heezoo Kim
- Department of Anaesthesiology and Pain Medicine, Korea University Guro Hospital, Korea University College of Medicine, Seoul, South Korea
| | - Hye Jin Kim
- Department of Anaesthesiology and Pain Medicine, and Anaesthesia and Pain Research Institute, Yonsei University College of Medicine, South Korea
| | - Hoon Choi
- Department of Anaesthesiology and Pain Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Hong Kwan Kim
- Department of Thoracic and Cardiovascular Surgery, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Randal S Blank
- Department of Anaesthesiology, University of Virginia Health System, Charlottesville, VA, USA
| | - Sung-Cheol Yun
- Department of Biostatistics, Asan Medical Centre, University of Ulsan College of Medicine, Seoul, South Korea
| | - Dong Kyu Lee
- Department of Anaesthesiology and Pain Medicine, Dongguk University Hospital, Goyang-si, South Korea
| | - Mikyung Yang
- Department of Anaesthesiology and Pain Medicine, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Jie Ae Kim
- Department of Anaesthesiology and Pain Medicine, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Insun Song
- Department of Anaesthesiology and Pain Medicine, Seoul National University Hospital, University of Seoul National College of Medicine, Seoul, South Korea
| | - Bo Rim Kim
- Department of Anaesthesiology and Pain Medicine, Seoul National University Hospital, University of Seoul National College of Medicine, Seoul, South Korea
| | - Jae-Hyon Bahk
- Department of Anaesthesiology and Pain Medicine, Seoul National University Hospital, University of Seoul National College of Medicine, Seoul, South Korea
| | - Juyoun Kim
- Department of Anaesthesiology and Pain Medicine, Asan Medical Centre, University of Ulsan College of Medicine, Seoul, South Korea
| | - Sangho Lee
- Department of Anaesthesiology and Pain Medicine, Asan Medical Centre, University of Ulsan College of Medicine, Seoul, South Korea
| | - In-Cheol Choi
- Department of Anaesthesiology and Pain Medicine, Asan Medical Centre, University of Ulsan College of Medicine, Seoul, South Korea
| | - Young Jun Oh
- Department of Anaesthesiology and Pain Medicine, and Anaesthesia and Pain Research Institute, Yonsei University College of Medicine, South Korea
| | - Wonjung Hwang
- Department of Anaesthesiology and Pain Medicine, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Byung Gun Lim
- Department of Anaesthesiology and Pain Medicine, Korea University Guro Hospital, Korea University College of Medicine, Seoul, South Korea
| | - Burn Young Heo
- Department of Anaesthesiology and Pain Medicine, Samsung Medical Centre, Sungkyunkwan University School of Medicine, Seoul, South Korea
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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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7
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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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8
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Szabari MV, Takahashi K, Feng Y, Locascio JJ, Chao W, Carter EA, Vidal Melo MF, Musch G. Relation between Respiratory Mechanics, Inflammation, and Survival in Experimental Mechanical Ventilation. Am J Respir Cell Mol Biol 2019; 60:179-188. [PMID: 30199644 DOI: 10.1165/rcmb.2018-0100oc] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Low-tidal volume (Vt) ventilation might protect healthy lungs from volutrauma but lead to inflammation resulting from other mechanisms, namely alveolar derecruitment and the ensuing alveolar collapse and tidal reexpansion. We hypothesized that the different mechanisms of low- and high-volume injury would be reflected in different mechanical properties being associated with development of pulmonary inflammation and mortality: an increase of hysteresis, reflecting progressive alveolar derecruitment, at low Vt; an increase of elastance, as a result of overdistension, at higher Vt. Mice were allocated to "protective" (6 ml/kg) or "injurious" (15-20 ml/kg) Vt groups and ventilated for 16 hours or until death. We measured elastance and hysteresis; pulmonary IL-6, IL-1β, and MIP-2 (macrophage inflammatory protein 2); wet-to-dry ratio; and blood gases. Survival was greater in the protective group (60%) than in the injurious group (25%). Nonsurvivors showed increased pulmonary cytokines, particularly in the injurious group, with the increase of elastance reflecting IL-6 concentration. Survivors instead showed only modest increases of cytokines, independent of Vt and unrelated to the increase of elastance. No single lung strain threshold could discriminate survivors from nonsurvivors. Hysteresis increased faster in the protective group, but, contrary to our hypothesis, its change was inversely related to the concentration of cytokines. In this model, significant mortality associated with pulmonary inflammation occurred even for strain values as low as about 0.8. Low Vt improved survival. The accompanying increase of hysteresis was not associated with greater inflammation.
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Affiliation(s)
- Margit V Szabari
- 1 Department of Anesthesia, Critical Care and Pain Medicine.,2 Department of Medicine
| | | | - Yan Feng
- 1 Department of Anesthesia, Critical Care and Pain Medicine.,4 Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | | | - Wei Chao
- 1 Department of Anesthesia, Critical Care and Pain Medicine.,4 Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Edward A Carter
- 6 Department of Pediatrics, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | | | - Guido Musch
- 1 Department of Anesthesia, Critical Care and Pain Medicine.,7 Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri
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9
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Cereda M, Xin Y, Goffi A, Herrmann J, Kaczka DW, Kavanagh BP, Perchiazzi G, Yoshida T, Rizi RR. Imaging the Injured Lung: Mechanisms of Action and Clinical Use. Anesthesiology 2019; 131:716-749. [PMID: 30664057 PMCID: PMC6692186 DOI: 10.1097/aln.0000000000002583] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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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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
| | - Alberto Goffi
- Interdepartmental Division of Critical Care Medicine and Department of Medicine, University of Toronto, ON, Canada
| | - Jacob Herrmann
- Departments of Anesthesia and Biomedical Engineering, University of Iowa, IA
| | - David W. Kaczka
- Departments of Anesthesia, Radiology, and Biomedical Engineering, University of Iowa, IA
| | | | - Gaetano Perchiazzi
- Hedenstierna Laboratory and Uppsala University Hospital, Uppsala University, Sweden
| | - Takeshi Yoshida
- Hospital for Sick Children, University of Toronto, ON, Canada
| | - Rahim R. Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
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10
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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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11
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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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12
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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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13
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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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14
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Xin Y, Song G, Cereda M, Kadlecek S, Hamedani H, Jiang Y, Rajaei J, Clapp J, Profka H, Meeder N, Wu J, Tustison NJ, Gee JC, Rizi RR. Semiautomatic segmentation of longitudinal computed tomography images in a rat model of lung injury by surfactant depletion. J Appl Physiol (1985) 2014; 118:377-85. [PMID: 25640150 DOI: 10.1152/japplphysiol.00627.2014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Quantitative analysis of computed tomography (CT) is essential to the study of acute lung injury. However, quantitative CT is made difficult by poor lung aeration, which complicates the critical step of image segmentation. To overcome this obstacle, this study sought to develop and validate a semiautomated, multilandmark, registration-based scheme for lung segmentation that is effective in conditions of poor aeration. Expiratory and inspiratory CT images were obtained in rats (n = 8) with surfactant depletion of incremental severity to mimic worsening aeration. Trained operators manually delineated the images to provide a comparative landmark. Semiautomatic segmentation originated from a single, previously segmented reference image obtained at healthy baseline. Deformable registration of the target images (after surfactant depletion) was performed using the symmetric diffeomorphic transformation model with B-spline regularization. Registration used multiple landmarks (i.e., rib cage, spine, and lung parenchyma) to minimize the effect of poor aeration. Then target images were automatically segmented by applying the calculated transformation function to the reference image contour. Semiautomatically and manually segmented contours proved to be highly similar in all aeration conditions, including those characterized by more severe surfactant depletion and expiration. The Dice similarity coefficient was over 0.9 in most conditions, confirming high agreement, irrespective of poor aeration. Furthermore, CT density-based measurements of gas volume, tissue mass, and lung aeration distribution were minimally affected by the method of segmentation. Moving forward, multilandmark registration has the potential to streamline quantitative CT analysis by enabling semiautomatic image segmentation of lungs with a broad range of injury severity.
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Affiliation(s)
- Yi Xin
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Gang Song
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Maurizio Cereda
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Stephen Kadlecek
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hooman Hamedani
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Yunqing Jiang
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jennia Rajaei
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Justin Clapp
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Harrilla Profka
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Natalie Meeder
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jue Wu
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nicholas J Tustison
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia
| | - James C Gee
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Rahim R Rizi
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania
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