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Valle N, Eapen MS, Pillai K, Morris R, Akhter J, Mekkawy AH, Morris DL, Valle SJ. Impact of Nebulized BromAc ® on Mucus Plug Clearance in a Mechanically Ventilated Ex Vivo Ovine Lung Model of Obstructive Respiratory Conditions. Life (Basel) 2024; 14:1111. [PMID: 39337895 PMCID: PMC11433166 DOI: 10.3390/life14091111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 08/15/2024] [Accepted: 08/26/2024] [Indexed: 09/30/2024] Open
Abstract
Mucus plugging of the respiratory tract occurs in airway diseases, including asthma, chronic obstructive pulmonary disease, and cystic fibrosis. It can cause blockage of the airways, leading to breathlessness and lung failure. Here, we used a ventilatory setup to demonstrate the effect of BromAc® in dissolving mucus plugs in a novel ex vivo ovine obstructive lung model. Mucus simulant was filled into the trachea of freshly slaughtered ovine lungs and ventilated via an endotracheal tube (ETT) using Continuous Mandatory Ventilation. Predetermined single or repeated doses of Bromelain, Acetylcysteine (Ac), BromAc®, and saline control were administered via an Aerogen® vibrating nebulizer and ventilated for 30 or 60 min. Ventilatory recording of resistance, compliance, and tidal volume was conducted, and rheology pre- and post-treatment were measured. A significant decline in airway resistance (p < 0.0001) compared to the saline control was observed when treated with Bromelain, Ac, and BromAc®, with the latter showing a stronger mucolytic effect than single agents. The decline in resistance was also effective in shorter time points (p < 0.05) at lower doses of the drugs. Changes in compliance, peak pressure, and tidal volume were not observed after administration of the drugs. Rheology measurements revealed that BromAc®TM significantly reduced the viscosity of the mucin at the end of 30 min and 60 min time points (p < 0.001) compared to the saline control. BromAc® showed complete dissolution of the respiratory mucus simulant and improved ventilatory airflow parameters in the ex vivo ovine model.
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Affiliation(s)
- Nicole Valle
- Mucpharm Pty Ltd., Sydney, NSW 2217, Australia; (N.V.); (K.P.); (J.A.); (A.H.M.); (D.L.M.)
| | - Mathew Suji Eapen
- Mucpharm Pty Ltd., Sydney, NSW 2217, Australia; (N.V.); (K.P.); (J.A.); (A.H.M.); (D.L.M.)
| | - Krishna Pillai
- Mucpharm Pty Ltd., Sydney, NSW 2217, Australia; (N.V.); (K.P.); (J.A.); (A.H.M.); (D.L.M.)
| | - Richard Morris
- Intensive Care Unit, Shoalhaven District Memorial Hospital, Nowra, NSW 2541, Australia;
| | - Javed Akhter
- Mucpharm Pty Ltd., Sydney, NSW 2217, Australia; (N.V.); (K.P.); (J.A.); (A.H.M.); (D.L.M.)
| | - Ahmed H. Mekkawy
- Mucpharm Pty Ltd., Sydney, NSW 2217, Australia; (N.V.); (K.P.); (J.A.); (A.H.M.); (D.L.M.)
| | - David L. Morris
- Mucpharm Pty Ltd., Sydney, NSW 2217, Australia; (N.V.); (K.P.); (J.A.); (A.H.M.); (D.L.M.)
- Department of Surgery, St George Hospital, Sydney, NSW 2217, Australia
- St George and Sutherland Clinical School of Medicine, University of New South Wales, Sydney, NSW 2052, Australia
| | - Sarah J. Valle
- Mucpharm Pty Ltd., Sydney, NSW 2217, Australia; (N.V.); (K.P.); (J.A.); (A.H.M.); (D.L.M.)
- St George and Sutherland Clinical School of Medicine, University of New South Wales, Sydney, NSW 2052, Australia
- Intensive Care Unit, St George Hospital, Sydney, NSW 2217, Australia
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Bhalla AK, Klein MJ, Hotz J, Kwok J, Bonilla-Cartagena JE, Baron DA, Kohler K, Bornstein D, Chang D, Vu K, Armenta-Quiroz A, Nelson LP, Newth CJL, Khemani RG. Noninvasive Surrogate for Physiologic Dead Space Using the Carbon Dioxide Ventilatory Equivalent: Testing in a Single-Center Cohort, 2017-2023. Pediatr Crit Care Med 2024; 25:784-794. [PMID: 38771137 PMCID: PMC11379541 DOI: 10.1097/pcc.0000000000003539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
OBJECTIVES We sought to evaluate the association between the carbon dioxide ( co2 ) ventilatory equivalent (VEq co2 = minute ventilation/volume of co2 produced per min), a marker of dead space that does not require a blood gas measurement, and mortality risk. We compared the strength of this association to that of physiologic dead space fraction (V D /V t = [Pa co2 -mixed-expired P co2 ]/Pa co2 ) as well as to other commonly used markers of dead space (i.e., the end-tidal alveolar dead space fraction [AVDSf = (Pa co2 -end-tidal P co2 )/Pa co2 ], and ventilatory ratio [VR = (minute ventilation × Pa co2 )/(age-adjusted predicted minute ventilation × 37.5)]). DESIGN Retrospective cohort data, 2017-2023. SETTING Quaternary PICU. PATIENTS One hundred thirty-one children with acute respiratory distress syndrome. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS All dead space markers were calculated at the same 1-minute timepoint for each patient within the first 72 hours of using invasive mechanical ventilation. The 131 children had a median (interquartile range, IQR) age of 5.8 (IQR 1.4, 12.6) years, oxygenation index (OI) of 7.5 (IQR 4.6, 14.3), V D /V t of 0.47 (IQR 0.38, 0.61), and mortality was 17.6% (23/131). Higher VEq co2 ( p = 0.003), V D /V t ( p = 0.002), and VR ( p = 0.013) were all associated with greater odds of mortality in multivariable models adjusting for OI, immunosuppressive comorbidity, and overall severity of illness. We failed to identify an association between AVDSf and mortality in the multivariable modeling. Similarly, we also failed to identify an association between OI and mortality after controlling for any dead space marker in the modeling. For the 28-day ventilator-free days outcome, we failed to identify an association between V D /V t and the dead space markers in multivariable modeling, although OI was significant. CONCLUSIONS VEq co2 performs similarly to V D /V t and other surrogate dead space markers, is independently associated with mortality risk, and may be a reasonable noninvasive surrogate for V D /V t .
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Affiliation(s)
- Anoopindar K Bhalla
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
- Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Margaret J Klein
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
| | - Justin Hotz
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
| | - Jeni Kwok
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
| | | | - David A Baron
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
| | - Kristen Kohler
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
| | - Dinnel Bornstein
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
| | - Daniel Chang
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
| | - Kennedy Vu
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
| | - Anabel Armenta-Quiroz
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
| | - Lara P Nelson
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
- Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Christopher J L Newth
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
- Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA
| | - Robinder G Khemani
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital Los Angeles, Los Angeles, CA
- Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA
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Klein-Blommert R, Markhorst DG, Bem RA. Exhaled CO2: No Volume to Waste. Pediatr Crit Care Med 2024; 25:860-863. [PMID: 39240665 DOI: 10.1097/pcc.0000000000003570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/07/2024]
Affiliation(s)
- Rozalinde Klein-Blommert
- Pediatric Intensive Care Unit, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | - Dick G Markhorst
- Pediatric Intensive Care Unit, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | - Reinout A Bem
- Pediatric Intensive Care Unit, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
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4
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Liu PH, Casillas P, Alismail A. Evaluation of ventilatory ratio in airway pressure release ventilation (APRV) in patients with acute respiratory failure: Brief communication. Respir Med 2023; 219:107423. [PMID: 37827292 DOI: 10.1016/j.rmed.2023.107423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/03/2023] [Accepted: 10/06/2023] [Indexed: 10/14/2023]
Affiliation(s)
- Ping-Hui Liu
- Department of Cardiopulmonary Science, Loma Linda University, USA; Division of Respiratory Care, Cincinnati Children's Hospital, USA.
| | - Paul Casillas
- Department of Cardiopulmonary Science, Loma Linda University, USA
| | - Abdullah Alismail
- Department of Cardiopulmonary Science, Loma Linda University, USA; Department of Medicine, Loma Linda University, USA
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Jayasimhan D, Chieng J, Kolbe J, Sidebotham DA. Dead-Space Ventilation Indices and Mortality in Acute Respiratory Distress Syndrome: A Systematic Review and Meta-Analysis. Crit Care Med 2023; 51:1363-1372. [PMID: 37204257 DOI: 10.1097/ccm.0000000000005921] [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: 05/20/2023]
Abstract
OBJECTIVES Acute respiratory distress syndrome (ARDS) is associated with high ventilation-perfusion heterogeneity and dead-space ventilation. However, whether the degree of dead-space ventilation is associated with outcomes is uncertain. In this systematic review and meta-analysis, we evaluated the ability of dead-space ventilation measures to predict mortality in patients with ARDS. DATA SOURCES MEDLINE, CENTRAL, and Google Scholar from inception to November 2022. STUDY SELECTION Studies including adults with ARDS reporting a dead-space ventilation index and mortality. DATA EXTRACTION Two reviewers independently identified eligible studies and extracted data. We calculated pooled effect estimates using a random effects model for both adjusted and unadjusted results. The quality and strength of evidence were assessed using the Quality in Prognostic Studies and Grading of Recommendations, Assessment, Development, and Evaluation, respectively. DATA SYNTHESIS We included 28 studies in our review, 21 of which were included in our meta-analysis. All studies had a low risk of bias. A high pulmonary dead-space fraction was associated with increased mortality (odds ratio [OR], 3.52; 95% CI, 2.22-5.58; p < 0.001; I2 = 84%). After adjusting for other confounding variables, every 0.05 increase in pulmonary-dead space fraction was associated with an increased odds of death (OR, 1.23; 95% CI, 1.13-1.34; p < 0.001; I2 = 57%). A high ventilatory ratio was also associated with increased mortality (OR, 1.55; 95% CI, 1.33-1.80; p < 0.001; I2 = 48%). This association was independent of common confounding variables (OR, 1.33; 95% CI, 1.12-1.58; p = 0.001; I2 = 66%). CONCLUSIONS Dead-space ventilation indices were independently associated with mortality in adults with ARDS. These indices could be incorporated into clinical trials and used to identify patients who could benefit from early institution of adjunctive therapies. The cut-offs identified in this study should be prospectively validated.
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Affiliation(s)
- Dilip Jayasimhan
- Cardiothoracic and Vascular Intensive Care Unit, Te Whatu Ora Te Toka Tumai Auckland, Auckland, New Zealand
- Respiratory Services, Te Whatu Ora Te Toka Tumai Auckland, Auckland, New Zealand
| | - Jennifer Chieng
- Respiratory Services, Te Whatu Ora Te Toka Tumai Auckland, Auckland, New Zealand
| | - John Kolbe
- Respiratory Services, Te Whatu Ora Te Toka Tumai Auckland, Auckland, New Zealand
- Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - David A Sidebotham
- Cardiothoracic and Vascular Intensive Care Unit, Te Whatu Ora Te Toka Tumai Auckland, Auckland, New Zealand
- Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
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6
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Beloncle FM, Richard JC, Merdji H, Desprez C, Pavlovsky B, Yvin E, Piquilloud L, Olivier PY, Chean D, Studer A, Courtais A, Campfort M, Rahmani H, Lesimple A, Meziani F, Mercat A. Advanced respiratory mechanics assessment in mechanically ventilated obese and non-obese patients with or without acute respiratory distress syndrome. Crit Care 2023; 27:343. [PMID: 37667379 PMCID: PMC10476380 DOI: 10.1186/s13054-023-04623-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/22/2023] [Indexed: 09/06/2023] Open
Abstract
BACKGROUND Respiratory mechanics is a key element to monitor mechanically ventilated patients and guide ventilator settings. Besides the usual basic assessments, some more complex explorations may allow to better characterize patients' respiratory mechanics and individualize ventilation strategies. These advanced respiratory mechanics assessments including esophageal pressure measurements and complete airway closure detection may be particularly relevant in critically ill obese patients. This study aimed to comprehensively assess respiratory mechanics in obese and non-obese ICU patients with or without ARDS and evaluate the contribution of advanced respiratory mechanics assessments compared to basic assessments in these patients. METHODS All intubated patients admitted in two ICUs for any cause were prospectively included. Gas exchange and respiratory mechanics including esophageal pressure and end-expiratory lung volume (EELV) measurements and low-flow insufflation to detect complete airway closure were assessed in standardized conditions (tidal volume of 6 mL kg-1 predicted body weight (PBW), positive end-expiratory pressure (PEEP) of 5 cmH2O) within 24 h after intubation. RESULTS Among the 149 analyzed patients, 52 (34.9%) were obese and 90 (60.4%) had ARDS (65.4% and 57.8% of obese and non-obese patients, respectively, p = 0.385). A complete airway closure was found in 23.5% of the patients. It was more frequent in obese than in non-obese patients (40.4% vs 14.4%, p < 0.001) and in ARDS than in non-ARDS patients (30% vs. 13.6%, p = 0.029). Respiratory system and lung compliances and EELV/PBW were similarly decreased in obese patients without ARDS and obese or non-obese patients with ARDS. Chest wall compliance was not impacted by obesity or ARDS, but end-expiratory esophageal pressure was higher in obese than in non-obese patients. Chest wall contribution to respiratory system compliance differed widely between patients but was not predictable by their general characteristics. CONCLUSIONS Most respiratory mechanics features are similar in obese non-ARDS and non-obese ARDS patients, but end-expiratory esophageal pressure is higher in obese patients. A complete airway closure can be found in around 25% of critically ill patients ventilated with a PEEP of 5 cmH2O. Advanced explorations may allow to better characterize individual respiratory mechanics and adjust ventilation strategies in some patients. Trial registration NCT03420417 ClinicalTrials.gov (February 5, 2018).
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Affiliation(s)
- François M Beloncle
- Medical ICU, University Hospital of Angers, Vent'Lab, University of Angers, 4 Rue Larrey, 49933, Angers Cedex 9, France.
- CNRS, INSERM 1083, MITOVASC, University of Angers, Angers, France.
| | - Jean-Christophe Richard
- Medical ICU, University Hospital of Angers, Vent'Lab, University of Angers, 4 Rue Larrey, 49933, Angers Cedex 9, France
- Med2Lab, ALMS, Antony, France
| | - Hamid Merdji
- Medical ICU, University Hospital of Strasbourg, University of Strasbourg, Strasbourg, France
- UMR 1260, Regenerative Nanomedicine (RNM), FMTS, INSERM (French National Institute of Health and Medical Research), Strasbourg, France
| | - Christophe Desprez
- Medical ICU, University Hospital of Angers, Vent'Lab, University of Angers, 4 Rue Larrey, 49933, Angers Cedex 9, France
| | - Bertrand Pavlovsky
- Medical ICU, University Hospital of Angers, Vent'Lab, University of Angers, 4 Rue Larrey, 49933, Angers Cedex 9, France
| | - Elise Yvin
- Medical ICU, University Hospital of Angers, Vent'Lab, University of Angers, 4 Rue Larrey, 49933, Angers Cedex 9, France
| | - Lise Piquilloud
- Adult Intensive Care Unit, University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Pierre-Yves Olivier
- Medical ICU, University Hospital of Angers, Vent'Lab, University of Angers, 4 Rue Larrey, 49933, Angers Cedex 9, France
| | - Dara Chean
- Medical ICU, University Hospital of Angers, Vent'Lab, University of Angers, 4 Rue Larrey, 49933, Angers Cedex 9, France
| | - Antoine Studer
- Medical ICU, University Hospital of Strasbourg, University of Strasbourg, Strasbourg, France
| | - Antonin Courtais
- Medical ICU, University Hospital of Angers, Vent'Lab, University of Angers, 4 Rue Larrey, 49933, Angers Cedex 9, France
| | - Maëva Campfort
- Medical ICU, University Hospital of Angers, Vent'Lab, University of Angers, 4 Rue Larrey, 49933, Angers Cedex 9, France
| | - Hassene Rahmani
- Medical ICU, University Hospital of Strasbourg, University of Strasbourg, Strasbourg, France
| | - Arnaud Lesimple
- CNRS, INSERM 1083, MITOVASC, University of Angers, Angers, France
- Med2Lab, ALMS, Antony, France
| | - Ferhat Meziani
- Medical ICU, University Hospital of Strasbourg, University of Strasbourg, Strasbourg, France
- UMR 1260, Regenerative Nanomedicine (RNM), FMTS, INSERM (French National Institute of Health and Medical Research), Strasbourg, France
| | - Alain Mercat
- Medical ICU, University Hospital of Angers, Vent'Lab, University of Angers, 4 Rue Larrey, 49933, Angers Cedex 9, France
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7
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Letter to the editor: "Increased respiratory dead space could associate with coagulation activation and poor outcomes in COVID-19 ARDS". J Crit Care 2023; 73:154214. [PMID: 36443127 PMCID: PMC9692210 DOI: 10.1016/j.jcrc.2022.154214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/31/2022] [Indexed: 11/27/2022]
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Graf J, Pérez R, López R. Increased respiratory dead space could associate with coagulation activation and poor outcomes in COVID-19 ARDS. J Crit Care 2022; 71:154095. [PMID: 35724445 PMCID: PMC9212801 DOI: 10.1016/j.jcrc.2022.154095] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 05/17/2022] [Accepted: 06/04/2022] [Indexed: 01/08/2023]
Abstract
PURPOSE To determine whether VDPhys/VT is associated with coagulation activation and outcomes. MATERIALS AND METHODS We enrolled patients with COVID-19 pneumonia who were supported by invasive mechanical ventilation and were monitored using volumetric capnography. Measurements were performed during the first 24 h of mechanical ventilation. The primary endpoint was the likelihood of being discharge alive on day 28. RESULTS Sixty patients were enrolled, of which 25 (42%) had high VDPhys/VT (>57%). Patients with high vs. low VDPhys/VT had higher APACHE II (10[8-13] vs. 8[6-9] points, p = 0.002), lower static compliance of the respiratory system (35[24-46] mL/cmH2O vs. 42[37-45] mL/cmH2O, p = 0.005), and higher D-dimer levels (1246[1050-1594] ng FEU/mL vs. 792[538-1159] ng FEU/mL, p = 0.001), without differences in P/F ratio (157[112-226] vs. 168[136-226], p = 0.719). Additionally, D-dimer levels correlated with VDPhys/VT (r = 0.530, p < 0.001), but not with the P/F ratio (r = -0.103, p = 0.433). Patients with high VDPhys/VT were less likely to be discharged alive on day 28 (32% vs. 71%, aHR = 3.393[1.161-9.915], p = 0.026). CONCLUSIONS In critically ill COVID-19 patients, increased VDPhys/VT was associated with high D-dimer levels and a lower likelihood of being discharged alive. Dichotomic VDPhys/VT could help identify a high-risk subgroup of patients neglected by the P/F ratio.
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Affiliation(s)
- Jerónimo Graf
- Departamento de Paciente Crítico, Clínica Alemana de Santiago, Avenida Vitacura 5951, Vitacura, Santiago Zip Code 7650568, Chile,Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Av. Plaza 680, San Carlos de Apoquindo, Las Condes, Santiago Zip Code 7550000, Chile
| | - Rodrigo Pérez
- Departamento de Paciente Crítico, Clínica Alemana de Santiago, Avenida Vitacura 5951, Vitacura, Santiago Zip Code 7650568, Chile,Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Av. Plaza 680, San Carlos de Apoquindo, Las Condes, Santiago Zip Code 7550000, Chile
| | - René López
- Departamento de Paciente Crítico, Clínica Alemana de Santiago, Avenida Vitacura 5951, Vitacura, Santiago Zip Code 7650568, Chile; Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Av. Plaza 680, San Carlos de Apoquindo, Las Condes, Santiago Zip Code 7550000, Chile.
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9
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Godbole R, Church SB, Abolhoda A, Porszasz J, Sassoon CSH. Resting Physiologic Dead Space as Predictor of Postoperative Pulmonary Complications After Robotic-Assisted Lung Resection: A Pilot Study. Front Physiol 2022; 13:803641. [PMID: 35923226 PMCID: PMC9340204 DOI: 10.3389/fphys.2022.803641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 06/17/2022] [Indexed: 11/13/2022] Open
Abstract
Lung resection surgery carries significant risks of postoperative pulmonary complications (PPC). Cardiopulmonary exercise testing (CPET) is performed to predict risk of PPC in patients with severely reduced predicted postoperative forced expiratory volume in one second (FEV1) and diffusion of carbon monoxide (DLCO). Recently, resting end-tidal partial pressure of carbon dioxide (PETCO2) has been shown as a good predictor for increased risk of PPC. However, breath-breath breathing pattern significantly affects PETCO2. Resting physiologic dead space (VD), and physiologic dead space to tidal volume ratio (VD/VT), may be a better predictor of PPC than PETCO2. The objective of this study was to prospectively determine the utility of resting measurements of VD and VD/VT in predicting PPC in patients who underwent robotic-assisted lung resection for suspected or biopsy-proven lung malignancy. Thirty-five consecutive patients were included in the study. Patients underwent preoperative pulmonary function testing, symptom-limited CPET, and a 6-min walk test. In the first 2 min prior to the exercise portion of the CPET, we obtained resting VT, minute ventilation (V˙E), VD (less instrument dead space), VD/VT, PETCO2, and arterial blood gases. PPC within 90 days were recorded. Fourteen (40%) patients had one or more PPC. Patients with PPC had significantly elevated resting VD compared to those without (0.318 ± 0.028 L vs. 0.230 ± 0.017 L (± SE), p < 0.006), and a trend toward increased VD/VT (0.35 ± 0.02 vs. 0.31 ± 0.02, p = 0.051). Area under the receiver operating characteristic (ROC) for VD was 0.81 (p < 0.002), VD/VT was 0.68 (p = 0.077), and PETCO2 was 0.52 (p = 0.840). Peak V˙O2, V˙E/ V˙CO2 slope, pulmonary function tests, 6-min walk distance and arterial blood gases were similar between the two groups. Intensive care unit and total hospital length of stay was significantly longer in those with PPC. In conclusion, preoperative resting VD was significantly elevated in patients with PPC. The observed increase in resting VD may be a potentially useful predictor of PPC in patients undergoing robotic-assisted lung resection surgery for suspected or biopsy-proven lung malignancy. A large prospective study is needed for confirmation.
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Affiliation(s)
- Rohit Godbole
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California, Irvine, CA, United States
| | - Sanford B. Church
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California, Irvine, CA, United States
| | - Amir Abolhoda
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California, Irvine, CA, United States
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, VA Long Beach Healthcare System, Long Beach, CA, United States
| | - Janos Porszasz
- The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, United States
| | - Catherine S. H. Sassoon
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of California, Irvine, CA, United States
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, VA Long Beach Healthcare System, Long Beach, CA, United States
- *Correspondence: Catherine S. H. Sassoon,
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10
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Rezoagli E, Laffey JG, Bellani G. Monitoring Lung Injury Severity and Ventilation Intensity during Mechanical Ventilation. Semin Respir Crit Care Med 2022; 43:346-368. [PMID: 35896391 DOI: 10.1055/s-0042-1748917] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Acute respiratory distress syndrome (ARDS) is a severe form of respiratory failure burden by high hospital mortality. No specific pharmacologic treatment is currently available and its ventilatory management is a key strategy to allow reparative and regenerative lung tissue processes. Unfortunately, a poor management of mechanical ventilation can induce ventilation induced lung injury (VILI) caused by physical and biological forces which are at play. Different parameters have been described over the years to assess lung injury severity and facilitate optimization of mechanical ventilation. Indices of lung injury severity include variables related to gas exchange abnormalities, ventilatory setting and respiratory mechanics, ventilation intensity, and the presence of lung hyperinflation versus derecruitment. Recently, specific indexes have been proposed to quantify the stress and the strain released over time using more comprehensive algorithms of calculation such as the mechanical power, and the interaction between driving pressure (DP) and respiratory rate (RR) in the novel DP multiplied by four plus RR [(4 × DP) + RR] index. These new parameters introduce the concept of ventilation intensity as contributing factor of VILI. Ventilation intensity should be taken into account to optimize protective mechanical ventilation strategies, with the aim to reduce intensity to the lowest level required to maintain gas exchange to reduce the potential for VILI. This is further gaining relevance in the current era of phenotyping and enrichment strategies in ARDS.
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Affiliation(s)
- Emanuele Rezoagli
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Department of Emergency and Intensive Care, San Gerardo University Hospital, Monza, Italy
| | - John G Laffey
- School of Medicine, National University of Ireland, Galway, Ireland.,Department of Anaesthesia and Intensive Care Medicine, Galway University Hospitals, Saolta University Hospital Group, Galway, Ireland.,Lung Biology Group, Regenerative Medicine Institute (REMEDI) at CÚRAM Centre for Research in Medical Devices, National University of Ireland Galway, Galway, Ireland
| | - Giacomo Bellani
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Department of Emergency and Intensive Care, San Gerardo University Hospital, Monza, Italy
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11
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Derespina KR, Medar SS, Aydin SI, Kaushik S, Al-Subu A, Ofori-Amanfo G. Volumetric Capnography in Pediatric Extracorporeal Membrane Oxygenation: A Case Series. J Pediatr Intensive Care 2022; 11:109-113. [DOI: 10.1055/s-0040-1718375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 08/30/2020] [Indexed: 10/23/2022] Open
Abstract
AbstractThe kinetics of carbon dioxide elimination (VCO2) may be used as a surrogate for pulmonary blood flow. As such, we can apply a novel use of volumetric capnography to assess hemodynamic stability in patients requiring extracorporeal membrane oxygenation (ECMO). We report our experience of pediatric patients requiring ECMO support who were monitored using volumetric capnography. We describe the use of VCO2 and its association with successful decannulation. This is a prospective observational study of pediatric patients requiring ECMO support at The Children's Hospital at Montefiore from 2017 to 2019. A Respironics NM3 monitor was applied to each patient. Demographics, hemodynamic data, blood gases, and VCO2 (mL/min) data were collected. Data were collected immediately prior to and after decannulation. Over the course of the study period, seven patients were included. Predecannulation VCO2 was higher among patients who were successfully decannulated than nonsurvivors (109 [35, 230] vs. 12.4 [7.6, 17.2] mL/min), though not statistically significant. Four patients (57%) survived without further mechanical support; two (29%) died, and one (14%) was decannulated to Berlin. Predecannulation VCO2 appears to correlate with hemodynamic stability following decannulation. This case series adds to the growing literature describing the use of volumetric capnography in critical care medicine, particularly pediatric patients requiring ECMO. Prospective studies are needed to further elucidate the use of volumetric capnography and optimal timing for ECMO decannulation.
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Affiliation(s)
- Kim R. Derespina
- Division of Pediatric Critical Care Medicine, The Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Shivanand S. Medar
- Division of Pediatric Critical Care Medicine, The Children's Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Scott I. Aydin
- Division of Pediatric Critical Care Medicine, Mount Sinai Kravis Children's Hospital, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Shubhi Kaushik
- Division of Pediatric Critical Care Medicine, Mount Sinai Kravis Children's Hospital, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Awni Al-Subu
- Division of Pediatric Critical Care Medicine, American Family Children's Hospital, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States
| | - George Ofori-Amanfo
- Division of Pediatric Critical Care Medicine, Mount Sinai Kravis Children's Hospital, Icahn School of Medicine at Mount Sinai, New York, United States
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12
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Balmain BN, Tomlinson AR, MacNamara JP, Sarma S, Levine BD, Hynan LS, Babb TG. Physiological dead space during exercise in patients with heart failure with preserved ejection fraction. J Appl Physiol (1985) 2022; 132:632-640. [PMID: 35112932 PMCID: PMC8897014 DOI: 10.1152/japplphysiol.00786.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heart failure with preserved ejection fraction (HFpEF) is associated with cardiopulmonary abnormalities that may increase physiological dead space to tidal volume (VD/VT) during exercise. However, studies have not corrected VD/VT for apparatus mechanical dead space (VDM), which may confound the accurate calculation of VD/VT. We evaluated whether calculating physiological dead space with (VD/VTVDM) and without (VD/VT) correcting for VDM impacts the interpretation of gas exchange efficiency during exercise in HFpEF. Fifteen HFpEF (age: 69 ± 6 yr; V̇o2peak: 1.34 ± 0.45 L/min) and 12 controls (70 ± 3 yr; V̇o2peak: 1.70 ± 0.51 L/min) were studied. Pulmonary gas exchange and arterial blood gases were analyzed at rest, submaximal (20 W for HFpEF and 40 W for controls), and peak exercise. VD/VT was calculated as [Formula: see text] - [Formula: see text]/[Formula: see text]. VD/VTVDM was calculated as [Formula: see text] - [Formula: see text]/[Formula: see text] - VDM/VT. VD/VT decreased from rest (HFpEF: 0.54 ± 0.07; controls: 0.32 ± 0.07) to submaximal exercise (HFpEF: 0.46 ± 0.07; controls: 0.25 ± 0.06) in both groups (P < 0.05), but remained stable (P > 0.05) thereafter to peak exercise (HFpEF: 0.46 ± 0.09; controls: 0.22 ± 0.05). In HFpEF, VD/VTVDM did not change (P = 0.58) from rest (0.29 ± 0.07) to submaximal exercise (0.29 ± 0.06), but increased (P = 0.02) thereafter to peak exercise (0.33 ± 0.06). In controls, VD/VTVDM remained stable such that no change was observed (P > 0.05) from rest (0.17 ± 0.06) to submaximal exercise (0.14 ± 0.06), or thereafter to peak exercise (0.14 ± 0.05). Calculating physiological dead space with and without a VDM correction yields quantitively and qualitatively different results, which could have impact on the interpretation of gas exchange efficiency in HFpEF. Further investigation is required to uncover the clinical consequences and the mechanism(s) explaining the increase in VD/VTVDM during exercise in HFpEF.NEW & NOTEWORTHY Calculating VD/VT with and without correcting for VDM yields quantitively and qualitatively different results, which could have an important impact on the interpretation of V/Q mismatch in HFpEF. The finding that V/Q mismatch and gas exchange efficiency worsened, as reflected by an increase in VD/VTVDM during exercise, has not been previously demonstrated in HFpEF. Thus, further studies are needed to investigate the mechanisms explaining the increase in VD/VTVDM during exercise in patients with HFpEF.
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Affiliation(s)
- Bryce N. Balmain
- 1Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas,2Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Andrew R. Tomlinson
- 1Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas,2Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - James P. MacNamara
- 1Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas,2Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Satyam Sarma
- 1Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas,2Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Benjamin D. Levine
- 1Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas,2Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Linda S. Hynan
- 3Department of Population and Data Sciences (Biostatistics) & Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Tony G. Babb
- 1Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas,2Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
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13
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Ghorbi M, Rashidi M, Olapour A, Javaherforooshzadeh F, Akhondzadeh R. Effect of N-Acetylcysteine on the treatment of acute respiratory distress syndrome in mechanically ventilated patients admitted to the intensive care unit. Med J Islam Repub Iran 2021; 35:87. [PMID: 34291011 PMCID: PMC8285549 DOI: 10.47176/mjiri.35.87] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Indexed: 02/03/2023] Open
Abstract
Background: N-acetylcysteine (NAC) is an antioxidant derived from the amino acid cysteine and is one of the drugs used in the treatment of respiratory diseases. The aim of this study was to investigate the effect of NAC on the treatment of acute respiratory distress syndrome in mechanically ventilated patients admitted to the intensive care unit. Methods: This study was a randomized clinical trial. Patients under mechanical ventilation admitted to the intensive care unit were examined. Patients in the intervention group received daily 150 mg/kg of NAC on the first day of admission and then 50 mg/kg up to the fourth day of admission. Patients in the control group received routine care. The vital signs, level of consciousness, and other important variables were recorded. Data were analyzed using statistical tests and SPSS software version 24. Results: There was no significant difference between MAP, heart rate, respiratory rate, O2Sat, APACHE II score, and pulmonary capacity of the patients in the two groups on the first, second, third and fourth days after the intervention (p>0.05 ). There was no significant difference between the level of consciousness (according to GCS criteria), respiratory index (PAO2/FIO2) and PEEP of patients in the two study groups within 1 to 2 days after the intervention (p>0.05). There was a significant difference between the level of consciousness (based on GCS criteria), respiratory index (PAO2/FIO2) and PEEP of patients in the two study groups within 3 to 4 days after the intervention (p<0.05). There was no significant difference between the duration of hospitalization in the ICU, the time required for mechanical ventilation and the mortality rate of the patients in the two groups (p>0.05). Conclusion: It seems that N-acetylcysteine has a positive effect on the treatment of acute respiratory distress syndrome in mechanically ventilated patients admitted to the intensive care unit.
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Affiliation(s)
- Mojtaba Ghorbi
- Department of Anesthesia, Ahvaz Anesthesiology and Pain Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mahbobe Rashidi
- Department of Anesthesia, Ahvaz Anesthesiology and Pain Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Alireza Olapour
- Department of Anesthesia, Ahvaz Anesthesiology and Pain Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Fatemeh Javaherforooshzadeh
- Department of Anesthesia, Ahvaz Anesthesiology and Pain Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Reza Akhondzadeh
- Department of Anesthesia, Ahvaz Anesthesiology and Pain Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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14
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Spinelli E, Kircher M, Stender B, Ottaviani I, Basile MC, Marongiu I, Colussi G, Grasselli G, Pesenti A, Mauri T. Unmatched ventilation and perfusion measured by electrical impedance tomography predicts the outcome of ARDS. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2021; 25:192. [PMID: 34082795 PMCID: PMC8173510 DOI: 10.1186/s13054-021-03615-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 05/21/2021] [Indexed: 12/30/2022]
Abstract
Background In acute respiratory distress syndrome (ARDS), non-ventilated perfused regions coexist with non-perfused ventilated regions within lungs. The number of unmatched regions might reflect ARDS severity and affect the risk of ventilation-induced lung injury. Despite pathophysiological relevance, unmatched ventilation and perfusion are not routinely assessed at the bedside. The aims of this study were to quantify unmatched ventilation and perfusion at the bedside by electrical impedance tomography (EIT) investigating their association with mortality in patients with ARDS and to explore the effects of positive end-expiratory pressure (PEEP) on unmatched ventilation and perfusion in subgroups of patients with different ARDS severity based on PaO2/FiO2 and compliance. Methods Prospective observational study in 50 patients with mild (36%), moderate (46%), and severe (18%) ARDS under clinical ventilation settings. EIT was applied to measure the regional distribution of ventilation and perfusion using central venous bolus of saline 5% during end-inspiratory pause. We defined unmatched units as the percentage of only ventilated units plus the percentage of only perfused units. Results Percentage of unmatched units was significantly higher in non-survivors compared to survivors (32[27–47]% vs. 21[17–27]%, p < 0.001). Percentage of unmatched units was an independent predictor of mortality (OR 1.22, 95% CI 1.07–1.39, p = 0.004) with an area under the ROC curve of 0.88 (95% CI 0.79–0.97, p < 0.001). The percentage of ventilation to the ventral region of the lung was higher than the percentage of ventilation to the dorsal region (32 [27–38]% vs. 18 [13–21]%, p < 0.001), while the opposite was true for perfusion (28 [22–38]% vs. 36 [32–44]%, p < 0.001). Higher percentage of only perfused units was correlated with lower dorsal ventilation (r = − 0.486, p < 0.001) and with lower PaO2/FiO2 ratio (r = − 0.293, p = 0.039). Conclusions EIT allows bedside assessment of unmatched ventilation and perfusion in mechanically ventilated patients with ARDS. Measurement of unmatched units could identify patients at higher risk of death and could guide personalized treatment.
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Affiliation(s)
- Elena Spinelli
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Michael Kircher
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | | | - Irene Ottaviani
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Maria C Basile
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Ines Marongiu
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Giulia Colussi
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Giacomo Grasselli
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy.,Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Antonio Pesenti
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy.,Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Tommaso Mauri
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy. .,Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.
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15
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Morales-Quinteros L, Neto AS, Artigas A, Blanch L, Botta M, Kaufman DA, Schultz MJ, Tsonas AM, Paulus F, Bos LD. Dead space estimates may not be independently associated with 28-day mortality in COVID-19 ARDS. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2021; 25:171. [PMID: 34001222 PMCID: PMC8127435 DOI: 10.1186/s13054-021-03570-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/08/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND Estimates for dead space ventilation have been shown to be independently associated with an increased risk of mortality in the acute respiratory distress syndrome and small case series of COVID-19-related ARDS. METHODS Secondary analysis from the PRoVENT-COVID study. The PRoVENT-COVID is a national, multicenter, retrospective observational study done at 22 intensive care units in the Netherlands. Consecutive patients aged at least 18 years were eligible for participation if they had received invasive ventilation for COVID-19 at a participating ICU during the first month of the national outbreak in the Netherlands. The aim was to quantify the dynamics and determine the prognostic value of surrogate markers of wasted ventilation in patients with COVID-19-related ARDS. RESULTS A total of 927 consecutive patients admitted with COVID-19-related ARDS were included in this study. Estimations of wasted ventilation such as the estimated dead space fraction (by Harris-Benedict and direct method) and ventilatory ratio were significantly higher in non-survivors than survivors at baseline and during the following days of mechanical ventilation (p < 0.001). The end-tidal-to-arterial PCO2 ratio was lower in non-survivors than in survivors (p < 0.001). As ARDS severity increased, mortality increased with successive tertiles of dead space fraction by Harris-Benedict and by direct estimation, and with an increase in the VR. The same trend was observed with decreased levels in the tertiles for the end-tidal-to-arterial PCO2 ratio. After adjustment for a base risk model that included chronic comorbidities and ventilation- and oxygenation-parameters, none of the dead space estimates measured at the start of ventilation or the following days were significantly associated with 28-day mortality. CONCLUSIONS There is significant impairment of ventilation in the early course of COVID-19-related ARDS but quantification of this impairment does not add prognostic information when added to a baseline risk model. TRIAL REGISTRATION ISRCTN04346342. Registered 15 April 2020. Retrospectively registered.
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Affiliation(s)
- Luis Morales-Quinteros
- Intensive Care Unit, Hospital Universitari General de Catalunya, Grupo Quironsalud, Carrer Pedro i Pons, 1, 08195, Sant Cugat del Vallès, Barcelona, Spain. .,Universidad Autonoma de Barcelona, Barcelona, Spain. .,Institut D'Investigació, Innovació Parc Taulí I3PT, Sabadell, Spain.
| | - Ary Serpa Neto
- Department of Intensive Care & Laboratory of Experimental Intensive Care and Anaesthesiology (L·E·I·C·A), Amsterdam UMC Location AMC, Amsterdam, The Netherlands.,Department of Critical Care Medicine, Hospital Israelita Albert Einstein, São Paulo, Brazil.,Australian and New Zealand Intensive Care Research Centre (ANZIC-RC), Monash University, Melbourne, Australia.,Data Analytics Research and Evaluation (DARE) Centre, Austin Hospital and University of Melbourne, Melbourne, Australia
| | - Antonio Artigas
- Universidad Autonoma de Barcelona, Barcelona, Spain.,Institut D'Investigació, Innovació Parc Taulí I3PT, Sabadell, Spain.,Critical Care Center, Corporacion Sanitaria Universitaria Parc Taulí, Sabadell, Spain.,CIBER Enfermedades Respiratorias (ISCiii), Madrid, Spain
| | - Lluis Blanch
- Universidad Autonoma de Barcelona, Barcelona, Spain.,Institut D'Investigació, Innovació Parc Taulí I3PT, Sabadell, Spain.,Critical Care Center, Corporacion Sanitaria Universitaria Parc Taulí, Sabadell, Spain.,CIBER Enfermedades Respiratorias (ISCiii), Madrid, Spain
| | - Michela Botta
- Department of Intensive Care & Laboratory of Experimental Intensive Care and Anaesthesiology (L·E·I·C·A), Amsterdam UMC Location AMC, Amsterdam, The Netherlands
| | - David A Kaufman
- Division of Pulmonary, Critical Care, and Sleep Medicine, NYU School of Medicine, New York, NY, USA
| | - Marcus J Schultz
- Department of Intensive Care & Laboratory of Experimental Intensive Care and Anaesthesiology (L·E·I·C·A), Amsterdam UMC Location AMC, Amsterdam, The Netherlands.,Nuffield Department of Medicine, Oxford University, Oxford, UK.,Mahidol-Oxford Tropical Medicine Research Unit (MORU), Mahidol University, Bangkok, Thailand
| | - Anissa M Tsonas
- Department of Intensive Care & Laboratory of Experimental Intensive Care and Anaesthesiology (L·E·I·C·A), Amsterdam UMC Location AMC, Amsterdam, The Netherlands
| | - Frederique Paulus
- Department of Intensive Care & Laboratory of Experimental Intensive Care and Anaesthesiology (L·E·I·C·A), Amsterdam UMC Location AMC, Amsterdam, The Netherlands
| | - Lieuwe D Bos
- Department of Intensive Care & Laboratory of Experimental Intensive Care and Anaesthesiology (L·E·I·C·A), Amsterdam UMC Location AMC, Amsterdam, The Netherlands
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16
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Caviedes I, Soto R, Torres A. Pulmonary Angiopathy in Severe COVID-19: Physiological Conclusions Derived from Ventilatory Ratio? Am J Respir Crit Care Med 2021; 203:258-259. [PMID: 33085901 PMCID: PMC7874412 DOI: 10.1164/rccm.202009-3446le] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Affiliation(s)
- Iván Caviedes
- Faculty of Medicine, Clínica Alemana-Universidad del Desarrollo Santiago, Chile
| | - Rodrigo Soto
- Faculty of Medicine, Clínica Alemana-Universidad del Desarrollo Santiago, Chile
| | - Antoni Torres
- Hospital Clinic, University of Barcelona Barcelona, Spain and.,CIBERESUCICOVID Barcelona, Spain
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17
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Beda A, Winkler T, Wellman TJ, De Prost N, Tucci M, Melo MFV. Physiological mechanism and spatial distribution of increased alveolar dead-space in early ARDS: An experimental study. Acta Anaesthesiol Scand 2021; 65:100-108. [PMID: 32931610 PMCID: PMC9846860 DOI: 10.1111/aas.13702] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/03/2020] [Accepted: 08/25/2020] [Indexed: 01/21/2023]
Abstract
BACKGROUND We aimed to investigate the physiological mechanism and spatial distribution of increased physiological dead-space, an early marker of ARDS mortality, in the initial stages of ARDS. We hypothesized that: increased dead-space results from the spatial redistribution of pulmonary perfusion, not ventilation; such redistribution is not related to thromboembolism (ie, areas with perfusion = 0 and infinite ventilation-perfusion ratio, V ˙ / Q ˙ ), but rather to moderate shifts of perfusion increasing V ˙ / Q ˙ in non-dependent regions. METHODS Five healthy anesthetized sheep received protective ventilation for 20 hours, while endotoxin was continuously infused. Maps of voxel-level lung ventilation, perfusion, V ˙ / Q ˙ , CO2 partial pressures, and alveolar dead-space fraction were estimated from positron emission tomography at baseline and 20 hours. RESULTS Alveolar dead-space fraction increased during the 20 hours (+0.05, P = .031), mainly in non-dependent regions (+0.03, P = .031). This was mediated by perfusion redistribution away from non-dependent regions (-5.9%, P = .031), while the spatial distribution of ventilation did not change, resulting in increased V ˙ / Q ˙ in non-dependent regions. The increased alveolar dead-space derived mostly from areas with intermediate V ˙ / Q ˙ (0.5≤ V ˙ / Q ˙ ≤10), not areas of nearly "complete" dead-space ( V ˙ / Q ˙ >10). CONCLUSIONS In this early ARDS model, increases in alveolar dead-space occur within 20 hours due to the regional redistribution of perfusion and not ventilation. This moderate redistribution suggests changes in the interplay between active and passive perfusion redistribution mechanisms (including hypoxic vasoconstriction and gravitational effects), not the appearance of thromboembolism. Hence, the association between mortality and increased dead-space possibly arises from the former, reflecting gas-exchange inefficiency due to perfusion heterogeneity. Such heterogeneity results from the injury and exhaustion of compensatory mechanisms for perfusion redistribution.
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Affiliation(s)
- Alessandro Beda
- Postgraduate Program of Electrical Engineering, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Tilo Winkler
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Tyler J. Wellman
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Nicolas De Prost
- Medical Intensive Care Unit, Hôpital Henri Mondor, Assistance Publique - Hôpitaux de Paris, Créteil, France
| | - Mauro Tucci
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA,Divisao de Pneumologia, Instituto do Coracao; Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brazil
| | - Marcos F. Vidal Melo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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18
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Vaporidi K, Akoumianaki E, Telias I, Goligher EC, Brochard L, Georgopoulos D. Respiratory Drive in Critically Ill Patients. Pathophysiology and Clinical Implications. Am J Respir Crit Care Med 2020; 201:20-32. [DOI: 10.1164/rccm.201903-0596so] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Katerina Vaporidi
- Department of Intensive Care Medicine, University Hospital of Heraklion, Medical School University of Crete, Heraklion, Greece
| | - Evangelia Akoumianaki
- Department of Intensive Care Medicine, University Hospital of Heraklion, Medical School University of Crete, Heraklion, Greece
| | - Irene Telias
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
- Keenan Research Center and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
| | - Ewan C. Goligher
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Medicine, University Health Network, Toronto, Ontario, Canada; and
- Toronto General Hospital Research Institute, Toronto, Ontario, Canada
| | - Laurent Brochard
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
- Keenan Research Center and Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
| | - Dimitris Georgopoulos
- Department of Intensive Care Medicine, University Hospital of Heraklion, Medical School University of Crete, Heraklion, Greece
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19
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Wu X, Zheng R, Zhuang Z. Effect of transpulmonary pressure-guided positive end-expiratory pressure titration on lung injury in pigs with acute respiratory distress syndrome. J Clin Monit Comput 2019; 34:151-159. [PMID: 30903412 PMCID: PMC6946758 DOI: 10.1007/s10877-019-00267-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 01/25/2019] [Indexed: 01/17/2023]
Abstract
To investigate the effect of positive end-expiratory pressure (PEEP) guided by transpulmonary pressure or with maximum oxygenation-directed PEEP on lung injury in a porcine model of acute respiratory distress syndrome (ARDS). The porcine model of ARDS was induced in 12 standard pigs by intratracheal infusion with normal saline. The pigs were then randomly divided into two groups who were ventilated with the lung-protective strategy of low tidal volume (VT) (6 ml/kg), using different methods to titrate PEEP level: transpulmonary pressure (TP group; n = 6) or maximum oxygenation (MO group; n = 6). Gas exchange, pulmonary mechanics, and hemodynamics were determined and pulmonary inflammatory response indices were measured after 4 h of ventilation. The titrated PEEP level in the TP group (6.12 ± 0.89 cmH2O) was significantly lower than that in the MO group (11.33 ± 2.07 cmH2O) (P < 0.05). The PaO2/FiO2 (P/F) after PEEP titration both improved in the TP and MO groups as compared with that at T0 (when the criteria for ARDS were obtained). The P/F in the TP group did not differ significantly from that in the MO group during the 4 h of ventilation (P > 0.05). Respiratory system compliance and lung compliance were significantly improved in the TP group compared to the MO group (P < 0.05). The VD/VT in the TP group was significantly lower than that in the MO group after 4 h of ventilation (P < 0.05). Central venous pressure increased and the cardiac index decreased significantly in the MO group as compared with the TP group (P < 0.05), whereas oxygen delivery did not differ significantly between the groups (P > 0.05). The pulmonary vascular permeability index and the extravascular lung water index in the TP group were significantly lower than those in the MO group (P < 0.05). The TP group had a lower lung wet to dry weight ratio, lung injury score, and MPO, TNF-, and IL-8 concentrations than the MO group (P < 0.05). In summary, in a pig model of ARDS, ventilation with low VT and transpulmonary pressure-guided PEEP adjustment was associated with improved compliance, reduced dead space ventilation, increased cardiac output, and relieved lung injury, as compared to maximum oxygenation-guide PEEP adjustment.
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Affiliation(s)
- Xiaoyan Wu
- Department of Critical Care Medicine, Clinical Medical College, YangZhou University, Northern Jiangsu People's Hospital, Yangzhou, 225001, Jiangsu, China
| | - Ruiqiang Zheng
- Department of Critical Care Medicine, Clinical Medical College, YangZhou University, Northern Jiangsu People's Hospital, Yangzhou, 225001, Jiangsu, China.
| | - Zhiqing Zhuang
- Department of Neurology, Clinical Medical College, Wutaishan Hospital, YangZhou University, Yangzhou, 225001, Jiangsu, China
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Sinha P, Calfee CS, Beitler JR, Soni N, Ho K, Matthay MA, Kallet RH. Physiologic Analysis and Clinical Performance of the Ventilatory Ratio in Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med 2019; 199:333-341. [PMID: 30211618 PMCID: PMC6363976 DOI: 10.1164/rccm.201804-0692oc] [Citation(s) in RCA: 182] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 09/10/2018] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Pulmonary dead space fraction (Vd/Vt) is an independent predictor of mortality in acute respiratory distress syndrome (ARDS). Yet, it is seldom used in practice. The ventilatory ratio is a simple bedside index that can be calculated using routinely measured respiratory variables and is a measure of impaired ventilation. Ventilatory ratio is defined as [minute ventilation (ml/min) × PaCO2 (mm Hg)]/(predicted body weight × 100 × 37.5). OBJECTIVES To determine the relation of ventilatory ratio with Vd/Vt in ARDS. METHODS First, in a single-center, prospective observational study of ARDS, we tested the association of Vd/Vt with ventilatory ratio. With in-hospital mortality as the primary outcome and ventilator-free days as the secondary outcome, we tested the role of ventilatory ratio as an outcome predictor. The findings from this study were further verified in secondary analyses of two NHLBI ARDS Network randomized controlled trials. MEASUREMENTS AND MAIN RESULTS Ventilatory ratio positively correlated with Vd/Vt. Ordinal groups of ventilatory ratio had significantly higher Vd/Vt. Ventilatory ratio was independently associated with increased risk of mortality after adjusting for PaO2/FiO2, and positive end-expiratory pressure (odds ratio, 1.51; P = 0.024) and after adjusting for Acute Physiologic Assessment and Chronic Health Evaluation II score (odds ratio, 1.59; P = 0.04). These findings were further replicated in secondary analyses of two separate NHLBI randomized controlled trials. CONCLUSIONS Ventilatory ratio correlates well with Vd/Vt in ARDS, and higher values at baseline are associated with increased risk of adverse outcomes. These results are promising for the use of ventilatory ratio as a simple bedside index of impaired ventilation in ARDS.
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Affiliation(s)
- Pratik Sinha
- Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, Department of Medicine
| | - Carolyn S. Calfee
- Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, Department of Medicine
- Department of Anesthesia, and
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California
| | - Jeremy R. Beitler
- Division of Pulmonary and Critical Care Medicine, University of California, San Diego, San Diego, California
| | - Neil Soni
- Magill Department of Anaesthesia, Intensive Care Medicine and Pain Management, Chelsea and Westminster Hospital, London, United Kingdom; and
| | - Kelly Ho
- Respiratory Care Services, Department of Anesthesia and Perioperative Care, University of California, San Francisco at Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, California
| | - Michael A. Matthay
- Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, Department of Medicine
- Department of Anesthesia, and
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California
| | - Richard H. Kallet
- Respiratory Care Services, Department of Anesthesia and Perioperative Care, University of California, San Francisco at Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, California
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King MR, Feldman JM. Optimal management of apparatus dead space in the anesthetized infant. Paediatr Anaesth 2017; 27:1185-1192. [PMID: 29044830 DOI: 10.1111/pan.13254] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/23/2017] [Indexed: 11/28/2022]
Abstract
Mechanical ventilation of the anesthetized infant requires careful attention to equipment and ventilator settings to assure optimal gas exchange and minimize the potential for lung injury. Apparatus dead space, defined as dead space resulting from devices placed between the endotracheal tube and the Y-piece of the breathing circuit, is the primary source of dead space controlled by the clinician. Due to the small tidal volumes required by infants and neonates, it is easy to create excessive apparatus dead space resulting in unintended hypercarbia or increased minute ventilation in an effort to achieve a desirable PCO2 . The goal of this review was to evaluate the apparatus that are commonly added to the breathing circuit during anesthesia care, and develop recommendations to guide the clinician in selecting apparatus that are best matched to the clinical goals and the patient's size. We include specific recommendations for apparatus that are best suited for different size pediatric patients, with a particular focus on patients <5 kg.
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Affiliation(s)
- Michael R King
- Ann and Robert H. Lurie Children's Hospital of Chicago and Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Jeffrey M Feldman
- The Children's Hospital of Philadelphia and the University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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Zhang Y, Ding S, Li C, Wang Y, Chen Z, Wang Z. Effects of N-acetylcysteine treatment in acute respiratory distress syndrome: A meta-analysis. Exp Ther Med 2017; 14:2863-2868. [PMID: 28928799 PMCID: PMC5590037 DOI: 10.3892/etm.2017.4891] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 04/28/2017] [Indexed: 01/06/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a serious complication of acute lung injury. Severe systemic inflammation is the main cause of multiple organ dysfunction and high mortality. Removal of reactive oxygen species by anti-oxidants has been applied in clinical practice. N-acetylcysteine (NAC) is the most commonly used anti-oxidant. However, the benefit of anti-oxidant therapy was not consistently demonstrated by previous studies. In the present study, a meta-analysis was performed to evaluate the effects of NAC for adult patients with ARDS. The PubMed, Cochrane and EMBASE databases were searched to retrieve all of the available randomized controlled trials (RCTs) published until October 2015. Quality evaluation of included studies was performed according to the modified Jadad scale score. The Cochrane Collaboration Review Manager 5.3 software was used to perform the meta-analysis. Five RCTs comprising 183 patients were found to be eligible for inclusion in the meta-analysis. Pooled analysis showed that NAC did not contribute to reduce short-term mortality [risk ratio (RR)=0.73; 95% confidence interval (CI): 0.50–1.07; P=0.10] or 30-day mortality (RR=0.72; 95% CI: 0.44–1.19; P=0.20) when compared with those in the control group. However, duration of intensive care unit (ICU) stay in the NAC group was shortened [weighted mean difference (WMD), −4.56; 95% CI: (−7.32 to −1.80); P=0.001]. There was no significant difference in the ratio of partial arterial oxygen pressure to the fraction of inspired oxygen between the two groups [WMD, 54.34; 95% CI: (−30.50 to 139.17); P=0.21]. No severe adverse reactions were observed in the patients included. Although the duration of ICU stay was shortened, the clinical benefits of NAC were limited for ARDS based on the present meta-analysis. As the number of included trials and patients was small, additional trials are required to provide sufficient evidence for the efficacy of NAC in ARDS.
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Affiliation(s)
- Ying Zhang
- Intensive Care Unit, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Shaoxue Ding
- Department of Hematology, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Caifeng Li
- Intensive Care Unit, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Yifeng Wang
- Intensive Care Unit, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Zhe Chen
- Department of Cadre Health, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Zhiqiang Wang
- Intensive Care Unit, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
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Minute ventilation to carbon dioxide production ratio is a simple and non-invasive index of ventilatory inefficiency in mechanically ventilated patients: proof of concept. Intensive Care Med 2017; 43:1542-1543. [PMID: 28567572 DOI: 10.1007/s00134-017-4844-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/12/2017] [Indexed: 10/19/2022]
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The Neglected Variable. Pediatr Crit Care Med 2017; 18:282-283. [PMID: 28257368 DOI: 10.1097/pcc.0000000000001101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Can Transcutaneous CO2 Tension Be Used to Calculate Ventilatory Dead Space? A Pilot Study. Crit Care Res Pract 2016; 2016:9874150. [PMID: 27688911 PMCID: PMC5027368 DOI: 10.1155/2016/9874150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 08/07/2016] [Accepted: 08/16/2016] [Indexed: 11/18/2022] Open
Abstract
Dead space fraction (Vd/Vt) measurement performed using volumetric capnography requires arterial blood gas (ABG) sampling to estimate the partial pressure of carbon dioxide (PaCO2). In recent years, transcutaneous capnography (PtcCO2) has emerged as a noninvasive method of estimating PaCO2. We hypothesized that PtcCO2 can be used as a substitute for PaCO2 in the calculation of Vd/Vt. In this prospective pilot comparison study, 30 consecutive postcardiac surgery mechanically ventilated patients had Vd/Vt calculated separately using volumetric capnography by substituting PtcCO2 for PaCO2. The mean Vd/Vt calculated using PaCO2 and PtcCO2 was 0.48 ± 0.09 and 0.53 ± 0.08, respectively, with a strong positive correlation between the two methods of calculation (Pearson's correlation = 0.87, p < 0.05). Bland-Altman analysis showed a mean difference of −0.05 (95% CI: −0.01 to −0.09) between the two methods. PtcCO2 measurements can provide a noninvasive means to measure Vd/Vt, thus accessing important physiologic information and prognostic assessment in patients receiving mechanical ventilation.
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Abstract
OBJECTIVES In this review, we discuss hemodynamic monitoring modalities, including their application, the interpretation of data, limitations, and impact on outcomes. DATA SOURCE MEDLINE, PubMed. CONCLUSIONS One of the tenets of critical care medicine is to ensure adequate tissue oxygenation. This assessment must be timely and accurate to optimize outcomes. The clinical assessment of cardiac function, cardiac output, and tissue oxygenation based on the physical examination and standard hemodynamic variables, although an indispensable part of this exercise, has significant limitations. The use of adjunctive hemodynamic monitoring modalities provides a much more objective, accurate, and timely assessment of the patient's hemodynamic profile and is invaluable for assessing the patient's clinical status, clinical trajectory, and response to interventions.
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Verscheure S, Massion PB, Verschuren F, Damas P, Magder S. Volumetric capnography: lessons from the past and current clinical applications. Crit Care 2016; 20:184. [PMID: 27334879 PMCID: PMC4918076 DOI: 10.1186/s13054-016-1377-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Dead space is an important component of ventilation–perfusion abnormalities. Measurement of dead space has diagnostic, prognostic and therapeutic applications. In the intensive care unit (ICU) dead space measurement can be used to guide therapy for patients with acute respiratory distress syndrome (ARDS); in the emergency department it can guide thrombolytic therapy for pulmonary embolism; in peri-operative patients it can indicate the success of recruitment maneuvers. A newly available technique called volumetric capnography (Vcap) allows measurement of physiological and alveolar dead space on a regular basis at the bedside. We discuss the components of dead space, explain important differences between the Bohr and Enghoff approaches, discuss the clinical significance of arterial to end-tidal CO2 gradient and finally summarize potential clinical indications for Vcap measurements in the emergency room, operating room and ICU.
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Affiliation(s)
- Sara Verscheure
- Department of Critical Care Medicine, University of McGill, Montreal, Quebec, Canada.,Department of General Intensive Care, University Hospital of Liege, Liege, Belgium
| | - Paul B Massion
- Department of General Intensive Care, University Hospital of Liege, Liege, Belgium
| | - Franck Verschuren
- Department of Emergency Medicine, Cliniques universitaire Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Pierre Damas
- Department of General Intensive Care, University Hospital of Liege, Liege, Belgium
| | - Sheldon Magder
- Department of Critical Care Medicine, University of McGill, Montreal, Quebec, Canada.
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Estimating dead-space fraction for secondary analyses of acute respiratory distress syndrome clinical trials. Crit Care Med 2015; 43:1026-35. [PMID: 25738857 DOI: 10.1097/ccm.0000000000000921] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Pulmonary dead-space fraction is one of few lung-specific independent predictors of mortality from acute respiratory distress syndrome. However, it is not measured routinely in clinical trials and thus altogether ignored in secondary analyses that shape future research directions and clinical practice. This study sought to validate an estimate of dead-space fraction for use in secondary analyses of clinical trials. DESIGN Analysis of patient-level data pooled from acute respiratory distress syndrome clinical trials. Four approaches to estimate dead-space fraction were evaluated: three required estimating metabolic rate; one estimated dead-space fraction directly. SETTING U.S. academic teaching hospitals. PATIENTS Data from 210 patients across three clinical trials were used to compare performance of estimating equations with measured dead-space fraction. A second cohort of 3,135 patients from six clinical trials without measured dead-space fraction was used to confirm whether estimates independently predicted mortality. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Dead-space fraction estimated using the unadjusted Harris-Benedict equation for energy expenditure was unbiased (mean ± SD Harris-Benedict, 0.59 ± 0.13; measured, 0.60 ± 0.12). This estimate predicted measured dead-space fraction to within ±0.10 in 70% of patients and ±0.20 in 95% of patients. Measured dead-space fraction independently predicted mortality (odds ratio, 1.36 per 0.05 increase in dead-space fraction; 95% CI, 1.10-1.68; p < 0.01). The Harris-Benedict estimate closely approximated this association with mortality in the same cohort (odds ratio, 1.55; 95% CI, 1.21-1.98; p < 0.01) and remained independently predictive of death in the larger Acute Respiratory Distress Syndrome Network cohort. Other estimates predicted measured dead-space fraction or its association with mortality less well. CONCLUSIONS Dead-space fraction should be measured in future acute respiratory distress syndrome clinical trials to facilitate incorporation into secondary analyses. For analyses where dead-space fraction was not measured, the Harris-Benedict estimate can be used to estimate dead-space fraction and adjust for its association with mortality.
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Abstract
PURPOSE OF REVIEW Volumetric capnography (VCap) measures the kinetics of carbon dioxide (CO2) elimination on a breath-by-breath basis. A volumetric capnogram contains extensive physiological information about metabolic production, circulatory transport and CO2 elimination within the lungs. VCap is also the best clinical tool to measure dead spaces allowing a detailed analysis of the functional components of each tidal volume, thereby providing clinically useful hints about the lung's efficiency of gas exchange. Difficulties in its bedside measurement, oversimplifications of its interpretation along with prevailing misconceptions regarding dead space analysis have, however, limited its adoption as a routine tool for monitoring mechanically ventilated patients. RECENT FINDINGS Improvements in CO2 measuring technologies and more advanced algorithms for faster and more accurate analysis of volumetric capnograms have increased our physiological understanding and thus the clinical usefulness of VCap. The recently validated VCap-based method for estimating alveolar partial pressure of CO2 provided a breakthrough for a fully noninvasive breath-by-breath measurement of physiological dead space. SUMMARY Recent advances in VCap and our improved understanding of its clinical implications may help in overcoming the known limitations and reluctances to include expired CO2 kinetics and dead space analysis in routine bedside monitoring. It is about time to start using this powerful monitoring tool to support decision making in the intensive care environment.
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One-year mortality and predictors of death among hospital survivors of acute respiratory distress syndrome. Intensive Care Med 2014; 40:388-96. [PMID: 24435201 PMCID: PMC3943651 DOI: 10.1007/s00134-013-3186-3] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 12/02/2013] [Indexed: 01/20/2023]
Abstract
PURPOSE Advances in supportive care and ventilator management for acute respiratory distress syndrome (ARDS) have resulted in declines in short-term mortality, but risks of death after survival to hospital discharge have not been well described. Our objective was to quantify the difference between short-term and long-term mortality in ARDS and to identify risk factors for death and causes of death at 1 year among hospital survivors. METHODS This multi-intensive care unit, prospective cohort included patients with ARDS enrolled between January 2006 and February 2010. We determined the clinical characteristics associated with in-hospital and 1-year mortality among hospital survivors and utilized death certificate data to identify causes of death. RESULTS Of 646 patients hospitalized with ARDS, mortality at 1 year was substantially higher (41 %, 95% CI 37-45%) than in-hospital mortality (24%, 95% CI 21-27%), P < 0.0001. Among 493 patients who survived to hospital discharge, the 110 (22%) who died in the subsequent year were older (P < 0.001) and more likely to have been discharged to a nursing home, other hospital, or hospice compared to patients alive at 1 year (P < 0.001). Important predictors of death among hospital survivors were comorbidities present at the time of ARDS, and not living at home prior to admission. ARDS-related measures of severity of illness did not emerge as independent predictors of mortality in hospital survivors. CONCLUSIONS Despite improvements in short-term ARDS outcomes, 1-year mortality is high, mostly because of the large burden of comorbidities, which are prevalent in patients with ARDS.
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Dassow C, Schwenninger D, Runck H, Guttmann J. Time and volume dependence of dead space in healthy and surfactant-depleted rat lungs during spontaneous breathing and mechanical ventilation. J Appl Physiol (1985) 2013; 115:1268-74. [DOI: 10.1152/japplphysiol.00299.2013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Volumetric capnography is a standard method to determine pulmonary dead space. Hereby, measured carbon dioxide (CO2) in exhaled gas volume is analyzed using the single-breath diagram for CO2. Unfortunately, most existing CO2 sensors do not work with the low tidal volumes found in small animals. Therefore, in this study, we developed a new mainstream capnograph designed for the utilization in small animals like rats. The sensor was used for determination of dead space volume in healthy and surfactant-depleted rats ( n = 62) during spontaneous breathing (SB) and mechanical ventilation (MV) at three different tidal volumes: 5, 8, and 11 ml/kg. Absolute dead space and wasted ventilation (dead space volume in relation to tidal volume) were determined over a period of 1 h. Dead space increase and reversibility of the increase was investigated during MV with different tidal volumes and during SB. During SB, the dead space volume was 0.21 ± 0.14 ml and increased significantly at MV to 0.39 ± 0.03 ml at a tidal volume of 5 ml/kg and to 0.6 ± 0.08 ml at a tidal volume of 8 and 11 ml/kg. Dead space and wasted ventilation during MV increased with tidal volume. This increase was mostly reversible by switching back to SB. Surfactant depletion had no further influence on the dead space increase during MV, but impaired the reversibility of the dead space increase.
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Affiliation(s)
- Constanze Dassow
- Department of Anesthesiology, Division for Experimental Anesthesiology, University Medical Center, Freiburg, Germany
| | - David Schwenninger
- Department of Anesthesiology, Division for Experimental Anesthesiology, University Medical Center, Freiburg, Germany
| | - Hanna Runck
- Department of Anesthesiology, Division for Experimental Anesthesiology, University Medical Center, Freiburg, Germany
| | - Josef Guttmann
- Department of Anesthesiology, Division for Experimental Anesthesiology, University Medical Center, Freiburg, Germany
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A mathematical model for carbon dioxide elimination: an insight for tuning mechanical ventilation. Eur J Appl Physiol 2013; 114:165-75. [PMID: 24162130 DOI: 10.1007/s00421-013-2754-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/10/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE The aim is to provide better understanding of carbon dioxide (CO2) elimination during ventilation for both the healthy and atelectatic condition, derived in a pressure-controlled mode. Therefore, we present a theoretical analysis of CO2 elimination of healthy and diseased lungs. METHODS Based on a single-compartment model, CO2 elimination is mathematically modeled and its contours were plotted as a function of temporal settings and driving pressure. The model was validated within some level of tolerance on an average of 4.9% using porcine dynamics. RESULTS CO2 elimination is affected by various factors, including driving pressure, temporal variables from mechanical ventilator settings, lung mechanics and metabolic rate. CONCLUSION During respiratory care, CO2 elimination is a key parameter for bedside monitoring, especially for patients with pulmonary disease. This parameter provides valuable insight into the status of an atelectatic lung and of cardiopulmonary pathophysiology. Therefore, control of CO2 elimination should be based on the fine tuning of the driving pressure and temporal ventilator settings. However, for critical condition of hypercapnia, airway resistance during inspiration and expiration should be additionally measured to determine the optimal percent inspiratory time (%TI) to maximize CO2 elimination for treating patients with hypercapnia.
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Sinha P, Singh S, Hardman JG, Bersten AD, Soni N. Evaluation of the physiological properties of ventilatory ratio in a computational cardiopulmonary model and its clinical application in an acute respiratory distress syndrome population. Br J Anaesth 2013; 112:96-101. [PMID: 24067330 PMCID: PMC9585654 DOI: 10.1093/bja/aet283] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Owing to complexities of measuring dead space, ventilatory failure is difficult to quantify in critical care. A simple, novel index called ventilatory ratio (VR) can quantify ventilatory efficiency at the bedside. The study objectives were to evaluate physiological properties of VR and examine its clinical applicability in acute respiratory distress syndrome (ARDS) patients. METHODS A validated computational model of cardiopulmonary physiology [Nottingham Physiology Simulator (NPS)] was used to evaluate VR ex vivo in three virtual patients with varying degrees of gas exchange defects. Arterial P(CO₂) and mixed expired P(CO₂) were obtained from the simulator while either dead space or CO₂ production was altered in isolation. VR and deadspace fraction was calculated using these values. A retrospective analysis of a previously presented prospective ARDS database was then used to evaluate the clinical utility of VR. Basic characteristics of VR and its association with mortality were examined. RESULTS The NPS showed that VR behaved in an intuitive manner as would be predicted by its physiological properties. When CO₂ production was constant, there was strong positive correlation between dead space and VR (modified Pearson's r 0.98, P<0.01). The ARDS database had a mean VR of 1.47 (standard deviation 0.58). Non-survivors had a significantly higher VR compared with survivors [1.70 vs 1.34, mean difference 0.35, 95% confidence interval (CI) 0.16-0.56, P<0.01]. VR was an independent predictor of mortality (odds ratio 3.05, CI 1.35-6.91, P<0.01). CONCLUSIONS VR is influenced by dead space and CO₂ production. In ARDS, high VR was associated with increased mortality.
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Affiliation(s)
- P Sinha
- Magill Department of Anaesthesia, Intensive Care Medicine and Pain Management Chelsea and Westminster Hospital, 369 Fulham Road, London, UK
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Corrections of Enghoff's dead space formula for shunt effects still overestimate Bohr's dead space. Respir Physiol Neurobiol 2013; 189:99-105. [PMID: 23827851 DOI: 10.1016/j.resp.2013.06.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 05/19/2013] [Accepted: 06/24/2013] [Indexed: 12/28/2022]
Abstract
Dead space ratio is determined using Enghoff's modification (VD(B-E)/VT) of Bohr's formula (VD(Bohr)/VT) in which arterial is used as a surrogate of alveolar PCO₂. In presence of intrapulmonary shunt Enghoff's approach overestimates dead space. In 40 lung-lavaged pigs we evaluated the Kuwabara's and Niklason's algorithms to correct for shunt effects and hypothesized that corrected VD(B-E)/VT should provide similar values as VD(Bohr)/VT. We analyzed 396 volumetric capnograms and arterial and mixed-venous blood samples to calculate VD(Bohr)/VT and VD(B-E)/VT. Thereafter, we corrected the latter for shunt effects using Kuwabara's (K) VD(B-E)/VT and Niklason's (N) VD(B-E)/VT algorithms. Uncorrected VD(B-E)/VT (mean ± SD of 0.70 ± 0.10) overestimated VD(Bohr)/VT (0.59 ± 0.12) (p < 0.05), over the entire range of shunts. Mean (K) VD(B-E)/VT was significantly higher than VD(Bohr)/VT (0.67 ± 0.08, bias -0.085, limits of agreement -0.232 to 0.085; p < 0.05) whereas (N)VD(B-E)/VT showed a better correction for shunt effects (0.64 ± 0.09, bias 0.048, limits of agreement -0.168 to 0.072; p < 0.05). Neither Kuwabara's nor Niklason's algorithms were able to correct Enghoff's dead space formula for shunt effects.
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Sinha P, Sanders RD, Soni N, Vukoja MK, Gajic O. Acute Respiratory Distress Syndrome: The Prognostic Value of Ventilatory Ratio—A Simple Bedside Tool to Monitor Ventilatory Efficiency. Am J Respir Crit Care Med 2013; 187:1150-3. [DOI: 10.1164/rccm.201211-2037le] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Sinha P, Fauvel NJ, Singh P, Soni N. Analysis of ventilatory ratio as a novel method to monitor ventilatory adequacy at the bedside. Crit Care 2013; 17:R34. [PMID: 23445563 PMCID: PMC4057449 DOI: 10.1186/cc12541] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 02/05/2013] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Due to complexities in its measurement, adequacy of ventilation is seldom used to categorize disease severity and guide ventilatory strategies. Ventilatory ratio (VR) is a novel index to monitor ventilatory adequacy at the bedside. VR=(VEmeasured × PaCO₂measured)/(VEpredicted × PaCO₂ideal). VEpredicted is 100 mL.Kg-1.min-1 and PaCO₂ideal is 5 kPa. Physiological analysis shows that VR is influenced by dead space (VD/VT) and CO₂ production (VCO₂). Two studies were conducted to explore the physiological properties of VR and assess its use in clinical practice. METHODS Both studies were conducted in adult mechanically ventilated ICU patients. In Study 1, volumetric capnography was used to estimate daily VD/VT and measure VCO₂ in 48 patients. Simultaneously, ventilatory ratio was calculated using arterial blood gas measurements alongside respiratory and ventilatory variables. This data was used to explore the physiological properties of VR. In Study 2, 224 ventilated patients had daily VR and other respiratory variables, baseline characteristics, and outcome recorded. The database was used to examine the prognostic value of VR. RESULTS Study 1 showed that there was significant positive correlation between VR and VD/VT (modified r = 0.71) and VCO₂ (r = 0.14). The correlation between VR and VD/VT was stronger in mandatory ventilation compared to spontaneous ventilation. Linear regression analysis showed that VD/VT had a greater influence on VR than VCO₂ (standardized regression coefficient 1/1-VD/VT: 0.78, VCO₂: 0.44). Study 2 showed that VR was significantly higher in non-survivors compared to survivors (1.55 vs. 1.32; P < 0.01). Univariate logistic regression showed that higher VR was associated with mortality (OR 2.3, P < 0.01), this remained the case after adjusting for confounding variables (OR 2.34, P = 0.04). CONCLUSIONS VR is an easy to calculate bedside index of ventilatory adequacy and appears to yield clinically useful information.
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Comparison of volumetric capnography and mixed expired gas methods to calculate physiological dead space in mechanically ventilated ICU patients. Intensive Care Med 2012; 38:1712-7. [PMID: 22893221 DOI: 10.1007/s00134-012-2670-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 07/19/2012] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Physiological dead space should be a routine measurement in ventilated patients but measuring dead space using the Douglas bag (DB) method is cumbersome and requires corrections for compressed ventilator gas. These factors make this method impractical in the critical care setting. Volumetric capnography (VCAP) offers a relatively simple solution to calculating dead space. Few studies have been conducted to directly compare dead space measured by VCAP and the DB method in critically unwell adults. METHOD Prospective observational study of 48 mechanically ventilated adults ICU patients. Dead space was calculated simultaneously using VCAP (CO(2)SMO) and the Bohr-Enghoff equation. In total, 168 paired readings were taken. Single-breath CO(2) waveform areas under the curve were computed automatically by software to calculate physiological dead space. The calculated value of P(Ē(CO(2))) was also recorded from the CO(2)SMO device. Exhaust ventilator gas was collected in a 10-l mixing chamber. P(Ē(CO(2))) was measured in the chamber following correction for compressed gas. RESULTS The study demonstrated good agreement between physiological V(D)/V(T) calculated by VCAP and corrected (mean bias 0.03), and uncorrected (mean bias 0.02) Bohr-Enghoff method. There was good correlation between the two methods of measurement (VCAP vs corrected r(2) = 0.90 P < 0.001, VCAP vs uncorrected r(2) = 0.90, P < 0.001). There was good correlation between [Formula: see text] calculated by the CO(2)SMO and in the exhaust collected gas (mean bias 0.08). CONCLUSIONS VCAP shows good agreement with Douglas Bag method in measuring physiological V(D)/V(T) over a wide range of dead space fractions.
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Year in review in Intensive Care Medicine 2011: III. ARDS and ECMO, weaning, mechanical ventilation, noninvasive ventilation, pediatrics and miscellanea. Intensive Care Med 2012; 38:542-56. [PMID: 22349425 PMCID: PMC3308008 DOI: 10.1007/s00134-012-2508-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 01/24/2012] [Indexed: 12/17/2022]
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