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Torsani V, Cardoso PFG, Borges JB, Gomes S, Moriya HT, Cruz AFD, Santiago RRDS, Nagao CK, Fitipaldi MF, Beraldo MDA, Junior MHV, Mlček M, Pego-Fernandes PM, Amato MBP. First real-time imaging of bronchoscopic lung volume reduction by electrical impedance tomography. Respir Res 2024; 25:264. [PMID: 38965590 PMCID: PMC11225379 DOI: 10.1186/s12931-024-02877-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Accepted: 06/11/2024] [Indexed: 07/06/2024] Open
Abstract
BACKGROUND Bronchoscopic lung volume reduction (BLVR) with one-way endobronchial valves (EBV) has better outcomes when the target lobe has poor collateral ventilation, resulting in complete lobe atelectasis. High-inspired oxygen fraction (FIO2) promotes atelectasis through faster gas absorption after airway occlusion, but its application during BLVR with EBV has been poorly understood. We aimed to investigate the real-time effects of FIO2 on regional lung volumes and regional ventilation/perfusion by electrical impedance tomography (EIT) during BLVR with EBV. METHODS Six piglets were submitted to left lower lobe occlusion by a balloon-catheter and EBV valves with FIO2 0.5 and 1.0. Regional end-expiratory lung impedances (EELI) and regional ventilation/perfusion were monitored. Local pocket pressure measurements were obtained (balloon occlusion method). One animal underwent simultaneous acquisitions of computed tomography (CT) and EIT. Regions-of-interest (ROIs) were right and left hemithoraces. RESULTS Following balloon occlusion, a steep decrease in left ROI-EELI with FIO2 1.0 occurred, 3-fold greater than with 0.5 (p < 0.001). Higher FIO2 also enhanced the final volume reduction (ROI-EELI) achieved by each valve (p < 0.01). CT analysis confirmed the denser atelectasis and greater volume reduction achieved by higher FIO2 (1.0) during balloon occlusion or during valve placement. CT and pocket pressure data agreed well with EIT findings, indicating greater strain redistribution with higher FIO2. CONCLUSIONS EIT demonstrated in real-time a faster and more complete volume reduction in the occluded lung regions under high FIO2 (1.0), as compared to 0.5. Immediate changes in the ventilation and perfusion of ipsilateral non-target lung regions were also detected, providing better estimates of the full impact of each valve in place. TRIAL REGISTRATION Not applicable.
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Affiliation(s)
- Vinicius Torsani
- Divisao de Pneumologia, Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brasil
| | - Paulo Francisco Guerreiro Cardoso
- Division of Thoracic Surgery, Thoracic Surgery Research Laboratory (LIM 61), Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brasil
| | - João Batista Borges
- Institute of Physiology, First Faculty of Medicine, Charles University, Albertov 5, Prague, 128 00, Czech Republic.
| | - Susimeire Gomes
- Divisao de Pneumologia, Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brasil
| | - Henrique Takachi Moriya
- Biomedical Engineering Laboratory, Escola Politecnica da Universidade de Sao Paulo, Sao Paulo, Brasil
| | - Andrea Fonseca da Cruz
- Biomedical Engineering Laboratory, Escola Politecnica da Universidade de Sao Paulo, Sao Paulo, Brasil
| | | | - Cristopher Kengo Nagao
- Division of Thoracic Surgery, Thoracic Surgery Research Laboratory (LIM 61), Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brasil
| | - Mariana Fernandes Fitipaldi
- Division of Thoracic Surgery, Thoracic Surgery Research Laboratory (LIM 61), Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brasil
| | - Marcelo do Amaral Beraldo
- Divisao de Pneumologia, Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brasil
| | - Marcus Henrique Victor Junior
- Divisao de Pneumologia, Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brasil
| | - Mikuláš Mlček
- Institute of Physiology, First Faculty of Medicine, Charles University, Albertov 5, Prague, 128 00, Czech Republic
| | - Paulo Manuel Pego-Fernandes
- Division of Thoracic Surgery, Thoracic Surgery Research Laboratory (LIM 61), Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brasil
| | - Marcelo Britto Passos Amato
- Divisao de Pneumologia, Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, Brasil
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Longhini F, Bruni A, Saraco G, Garofalo E, Conti G. Should high-flow through nasal cannula be used during bronchoscopy in critically ill patients with hypoxemic acute respiratory failure? JOURNAL OF ANESTHESIA, ANALGESIA AND CRITICAL CARE 2021. [PMCID: PMC8418281 DOI: 10.1186/s44158-021-00001-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Flexible fiberoptic bronchoscopy (FOB) is an invasive procedure with diagnostic and/or therapeutic purposes commonly used in critically ill patients. FOB may be complicated by desaturation, onset or worsening of the respiratory failure, and hemodynamic instability due to cardio-respiratory alterations occurring during the procedure. Increasing evidences suggest the use of high-flow through nasal cannula (HFNC) over conventional oxygen therapy (COT) in critically ill patients with acute respiratory failure (ARF). Indeed, HFNC has a rationale and possible physiologic advantages, even during FOB. However, to date, evidences in favor of HFNC over COT or continuous positive airway pressure (CPAP) or non-invasive ventilation (NIV) during FOB are still weak. Nonetheless, in critically ill patients with hypoxemic ARF, the choice of the oxygenation strategy during a FOB is challenging. Based on a review of the literature, HFNC may be preferred over COT in patients with mild to moderate hypoxemic ARF, without cardiac failure or hemodynamic instability. On the opposite, in critically ill patients with more severe hypoxemic ARF or in the presence of cardiac failure or hemodynamic instability, CPAP or NIV, applied with specifically designed interfaces, may be preferred over HFNC.
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Matthay MA, Arabi YM, Siegel ER, Ware LB, Bos LDJ, Sinha P, Beitler JR, Wick KD, Curley MAQ, Constantin JM, Levitt JE, Calfee CS. Phenotypes and personalized medicine in the acute respiratory distress syndrome. Intensive Care Med 2020; 46:2136-2152. [PMID: 33206201 PMCID: PMC7673253 DOI: 10.1007/s00134-020-06296-9] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 10/13/2020] [Indexed: 12/15/2022]
Abstract
Although the acute respiratory distress syndrome (ARDS) is well defined by the development of acute hypoxemia, bilateral infiltrates and non-cardiogenic pulmonary edema, ARDS is heterogeneous in terms of clinical risk factors, physiology of lung injury, microbiology, and biology, potentially explaining why pharmacologic therapies have been mostly unsuccessful in treating ARDS. Identifying phenotypes of ARDS and integrating this information into patient selection for clinical trials may increase the chance for efficacy with new treatments. In this review, we focus on classifying ARDS by the associated clinical disorders, physiological data, and radiographic imaging. We consider biologic phenotypes, including plasma protein biomarkers, gene expression, and common causative microbiologic pathogens. We will also discuss the issue of focusing clinical trials on the patient's phase of lung injury, including prevention, administration of therapy during early acute lung injury, and treatment of established ARDS. A more in depth understanding of the interplay of these variables in ARDS should provide more success in designing and conducting clinical trials and achieving the goal of personalized medicine.
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Affiliation(s)
- Michael A Matthay
- Department of Anesthesia, University of California San Francisco, San Francisco, CA, USA.
- Cardiovascular Research Institute, University of California, San Francisco, USA.
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California, San Francisco, USA.
| | - Yaseen M Arabi
- King Saud Bin Abdulaziz University for Health Sciences and King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Emily R Siegel
- Cardiovascular Research Institute, University of California, San Francisco, USA
| | - Lorraine B Ware
- Division of Allergy, Pulmonary and Critical Care, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lieuwe D J Bos
- Department of Respiratory Medicine, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Infection and Immunity, Amsterdam, The Netherlands
| | - Pratik Sinha
- Department of Anesthesiology, Washington University, Saint Louis, MO, USA
| | - Jeremy R Beitler
- Division of Pulmonary, Allergy, and Critical Care Medicine, Center for Acute Respiratory Failure, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Katherine D Wick
- Cardiovascular Research Institute, University of California, San Francisco, USA
| | - Martha A Q Curley
- School of Nursing, University of Pennsylvania, Philadelphia, PA, USA
| | - Jean-Michel Constantin
- Department of Anesthesia and Critical Care, La Pitié Salpetriere Hospital, University Paris-Sorbonne, Paris, France
| | - Joseph E Levitt
- Department of Medicine, Stanford University, Stanford, CA, USA
| | - Carolyn S Calfee
- Department of Anesthesia, University of California San Francisco, San Francisco, CA, USA
- Cardiovascular Research Institute, University of California, San Francisco, USA
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California, San Francisco, USA
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Longhini F, Bruni A, Garofalo E, Ronco C, Gusmano A, Cammarota G, Pasin L, Frigerio P, Chiumello D, Navalesi P. Chest physiotherapy improves lung aeration in hypersecretive critically ill patients: a pilot randomized physiological study. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2020; 24:479. [PMID: 32746877 PMCID: PMC7396943 DOI: 10.1186/s13054-020-03198-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 07/22/2020] [Indexed: 12/11/2022]
Abstract
Background Besides airway suctioning, patients undergoing invasive mechanical ventilation (iMV) benefit of different combinations of chest physiotherapy techniques, to improve mucus removal. To date, little is known about the clearance effects of oscillating devices on patients with acute respiratory failure undergoing iMV. This study aimed to assess (1) the effects of high-frequency chest wall oscillation (HFCWO) on lung aeration and ventilation distribution, as assessed by electrical impedance tomography (EIT), and (2) the effect of the association of HFCWO with recruitment manoeuvres (RM). Methods Sixty critically ill patients, 30 classified as normosecretive and 30 as hypersecretive, who received ≥ 48 h of iMV, underwent HFCWO; patients from both subgroups were randomized to receive RM or not, according to two separated randomization sequences. We therefore obtained four arms of 15 patients each. After baseline record (T0), HFCWO was applied for 10 min. At the end of the treatment (T1) or after 1 (T2) and 3 h (T3), EIT data were recorded. At the beginning of each step, closed tracheobronchial suctioning was performed. In the RM subgroup, tracheobronchial suctioning was followed by application of 30 cmH2O to the patient’s airway for 30 s. At each step, we assessed the change in end-expiratory lung impedance (ΔEELI) and in tidal impedance variation (ΔTIV), and the center of gravity (COG) through EIT. We also analysed arterial blood gases (ABGs). Results ΔTIV and COG did not differ between normosecretive and hypersecretive patients. Compared to T0, ΔEELI significantly increased in hypersecretive patients at T2 and T3, irrespective of the RM; on the contrary, no differences were observed in normosecretive patients. No differences of ABGs were recorded. Conclusions In hypersecretive patients, HFCWO significantly improved aeration of the dorsal lung region, without affecting ABGs. The application of RM did not provide any further improvements. Trial registration Prospectively registered at the Australian New Zealand Clinical Trial Registry (www.anzctr.org.au; number of registration: ACTRN12615001257550; date of registration: 17th November 2015).
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Affiliation(s)
- Federico Longhini
- Anesthesia and Intensive Care Unit, Department of Medical and Surgical Sciences, University Hospital Mater Domini, Magna Graecia University, Catanzaro, Italy
| | - Andrea Bruni
- Anesthesia and Intensive Care Unit, Department of Medical and Surgical Sciences, University Hospital Mater Domini, Magna Graecia University, Catanzaro, Italy
| | - Eugenio Garofalo
- Anesthesia and Intensive Care Unit, Department of Medical and Surgical Sciences, University Hospital Mater Domini, Magna Graecia University, Catanzaro, Italy
| | - Chiara Ronco
- Anesthesia and Intensive Care, Sant'Andrea Hospital, ASL VC, Vercelli, Italy
| | - Andrea Gusmano
- Anesthesia and Intensive Care, Sant'Andrea Hospital, ASL VC, Vercelli, Italy
| | - Gianmaria Cammarota
- Department of Anesthesia and Intensive Care, "Maggiore della carità" University Hospital, Novara, Italy
| | - Laura Pasin
- Department of Anesthesia and Intensive Care, Azienda Ospedaliera-Università di Padova, Padua, Italy
| | | | - Davide Chiumello
- SC Anestesia e Rianimazione, Ospedale San Paolo - Polo Universitario, ASST Santi Paolo e Carlo, Milan, Italy.,Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy.,Centro Ricerca Coordinata di Insufficienza Respiratoria, Università degli Studi di Milano, Milan, Italy
| | - Paolo Navalesi
- Department of Anesthesia and Intensive Care, Azienda Ospedaliera-Università di Padova, Padua, Italy. .,Dipartimento di Medicina-DIMED, Università degli Studi di Padova, Via Giustiniani, 2 -, 35128, Padova, Italy.
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Frerichs I, Dargaville PA, Rimensberger PC. Regional pulmonary effects of bronchoalveolar lavage procedure determined by electrical impedance tomography. Intensive Care Med Exp 2019; 7:11. [PMID: 30771111 PMCID: PMC6377686 DOI: 10.1186/s40635-019-0225-6] [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: 08/22/2018] [Accepted: 02/06/2019] [Indexed: 12/13/2022] Open
Abstract
Background The provision of guidance in ventilator therapy by continuous monitoring of regional lung ventilation, aeration and respiratory system mechanics is the main clinical benefit of electrical impedance tomography (EIT). A new application was recently described in critically ill patients undergoing diagnostic bronchoalveolar lavage (BAL) with the intention of using EIT to identify the region where sampling was performed. Increased electrical bioimpedance was reported after fluid instillation. To verify the accuracy of these findings, contradicting the current EIT knowledge, we have systematically analysed chest EIT data acquired under controlled experimental conditions in animals undergoing a large number of BAL procedures. Methods One hundred thirteen BAL procedures were performed in 13 newborn piglets positioned both supine and prone. EIT data was obtained at 13 images before, during and after each BAL. The data was analysed at three time points: (1) after disconnection from the ventilator before the fluid instillation and by the ends of fluid (2) instillation and (3) recovery by suction and compared with the baseline measurements before the procedure. Functional EIT images were generated, and changes in pixel electrical bioimpedance were calculated relative to baseline. The data was examined in the whole image and in three (ventral, middle, dorsal) regions-of-interest per lung. Results Compared with the baseline phase, chest electrical bioimpedance fell after the disconnection from the ventilator in all animals in both postures during all procedures. The fluid instillation further decreased electrical bioimpedance. During fluid recovery, electrical bioimpedance increased, but not to baseline values. All effects were highly significant (p < 0.001). The fractional changes in individual regions-of-interest were posture-dependent. The regional fall in electrical bioimpedance was smaller in the ventral and larger in the dorsal regions after the fluid instillation than after the initial disconnection to ambient pressure in supine animals (p < 0.001) whereas these changes were of comparable amplitude in prone position. Conclusions The results of this study show a regionally dissimilar initial fall in electrical bioimpedance caused by non-uniform aeration loss at the beginning of the BAL procedure. They also confirm a further pronounced fall in bioimpedance during fluid instillation, incomplete recovery after suction and a posture-dependent distribution pattern of these effects. Electronic supplementary material The online version of this article (10.1186/s40635-019-0225-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Inéz Frerichs
- Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3, 24105, Kiel, Germany.
| | - Peter A Dargaville
- Neonatal and Paediatric Intensive Care Unit, Royal Hobart Hospital, Hobart, Australia.,Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia
| | - Peter C Rimensberger
- Pediatric and Neonatal Intensive Care Unit, Children's Hospital, University of Geneva, Geneva, Switzerland
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6
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Smeijsters KMG, Bijkerk RM, Daniels JMA, van de Ven PM, Girbes ARJ, Heunks LMA, Spijkstra JJ, Tuinman PR. Effect of Bronchoscopy on Gas Exchange and Respiratory Mechanics in Critically Ill Patients With Atelectasis: An Observational Cohort Study. Front Med (Lausanne) 2018; 5:301. [PMID: 30483505 PMCID: PMC6243639 DOI: 10.3389/fmed.2018.00301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/11/2018] [Indexed: 11/29/2022] Open
Abstract
Background: Atelectasis frequently develops in critically ill patients and may result in impaired gas exchange among other complications. The long-term effects of bronchoscopy on gas exchange and the effects on respiratory mechanics are largely unknown. Objective: To evaluate the effect of bronchoscopy on gas exchange and respiratory mechanics in intensive care unit (ICU) patients with atelectasis. Methods: A retrospective, single-center cohort study of patients with clinical indication for bronchoscopy because of atelectasis diagnosed on chest X-ray (CXR). Results: In total, 101 bronchoscopies were performed in 88 ICU patients. Bronchoscopy improved oxygenation (defined as an increase of PaO2/FiO2 ratio > 20 mmHg) and ventilation (defined as a decrease of > 2 mmHg in partial pressure of CO2 in arterial blood) in 76 and 59% of procedures, respectively, for at least 24 h. Patients with a low baseline value of PaO2/FiO2 ratio and a high baseline value of PaCO2 were most likely to benefit from bronchoscopy. In addition, in intubated and pressure control ventilated patients, respiratory mechanics improved after bronchoscopy for up to 24 h. Mild complications, and in particular desaturation between 80 and 90%, were reported in 13% of the patients. Conclusions: In selected critically ill patients with atelectasis, bronchoscopy improves oxygenation, ventilation, and respiratory mechanics for at least 24 h.
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Affiliation(s)
- Kim M G Smeijsters
- Department of Intensive Care, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.,Department of Anesthesiology, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Ronald M Bijkerk
- Department of Intensive Care, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.,Department of Anesthesiology, Noordwest Ziekenhuisgroep, Alkmaar, Netherlands
| | - Johannes M A Daniels
- Department of Pulmonary Diseases, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Peter M van de Ven
- Department of Epidemiology and Biostatistics, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Armand R J Girbes
- Department of Intensive Care, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.,Research VUmc Intensive Care (REVIVE), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, Netherlands
| | - Leo M A Heunks
- Department of Intensive Care, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.,Research VUmc Intensive Care (REVIVE), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, Netherlands
| | - Jan Jaap Spijkstra
- Department of Intensive Care, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.,Research VUmc Intensive Care (REVIVE), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, Netherlands
| | - Pieter R Tuinman
- Department of Intensive Care, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.,Research VUmc Intensive Care (REVIVE), Amsterdam University Medical Centers, Vrije Universiteit, Amsterdam, Netherlands
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Ergan B, Nava S. The use of bronchoscopy in critically ill patients: considerations and complications. Expert Rev Respir Med 2018; 12:651-663. [PMID: 29958019 DOI: 10.1080/17476348.2018.1494576] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Flexible bronchoscopy has been well established for diagnostic and therapeutic purposes in critically ill patients. Areas covered: This review outlines the clinical evidence of the utility and safety of flexible bronchoscopy in the intensive care unit, as well as specific considerations, including practical points and potential complications, in critically ill patients. Expert commentary: Its ease to learn and perform and its capacity for bedside application with relatively few complications make flexible bronchoscopy an indispensable tool in the intensive care unit setting. The main indications for flexible bronchoscopy in the intensive care unit are the visualization of the airways, sampling for diagnostic purposes and management of the artificial airways. The decision to perform flexible bronchoscopy can only be made by trade-offs between potential risks and benefits because of the fragile nature of the critically ill. Flexible bronchoscopy-associated serious adverse events are inevitable in cases of a lack of expertise or appropriate precautions.
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Affiliation(s)
- Begum Ergan
- a Department of Pulmonary and Critical Care , School of Medicine, Dokuz Eylul University , Izmir , Turkey
| | - Stefano Nava
- b Department of Clinical , Integrated and Experimental Medicine (DIMES), Respiratory and Critical Care Unit, S. Orsola-Malpighi Hospital, Alma Mater University , Bologna , Italy
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Lobo B, Hermosa C, Abella A, Gordo F. Electrical impedance tomography. ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:26. [PMID: 29430443 PMCID: PMC5799136 DOI: 10.21037/atm.2017.12.06] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 11/30/2017] [Indexed: 11/06/2022]
Abstract
Continuous assessment of respiratory status is one of the cornerstones of modern intensive care unit (ICU) monitoring systems. Electrical impedance tomography (EIT), although with some constraints, may play the lead as a new diagnostic and guiding tool for an adequate optimization of mechanical ventilation in critically ill patients. EIT may assist in defining mechanical ventilation settings, assess distribution of tidal volume and of end-expiratory lung volume (EELV) and contribute to titrate positive end-expiratory pressure (PEEP)/tidal volume combinations. It may also quantify gains (recruitment) and losses (overdistention or derecruitment), granting a more realistic evaluation of different ventilator modes or recruitment maneuvers, and helping in the identification of responders and non-responders to such maneuvers. Moreover, EIT also contributes to the management of life-threatening lung diseases such as pneumothorax, and aids in guiding fluid management in the critical care setting. Lastly, assessment of cardiac function and lung perfusion through electrical impedance is on the way.
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Affiliation(s)
- Beatriz Lobo
- Intensive Care Unit, Henares University Hospital, Coslada-Madrid, Spain
- Grupo de Investigación en Patología Crítica, Facultad de Ciencias de la Salud, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Madrid, Spain
| | - Cecilia Hermosa
- Intensive Care Unit, Henares University Hospital, Coslada-Madrid, Spain
- Grupo de Investigación en Patología Crítica, Facultad de Ciencias de la Salud, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Madrid, Spain
| | - Ana Abella
- Intensive Care Unit, Henares University Hospital, Coslada-Madrid, Spain
- Grupo de Investigación en Patología Crítica, Facultad de Ciencias de la Salud, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Madrid, Spain
| | - Federico Gordo
- Intensive Care Unit, Henares University Hospital, Coslada-Madrid, Spain
- Grupo de Investigación en Patología Crítica, Facultad de Ciencias de la Salud, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Madrid, Spain
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Defining a Ventilation Strategy for Flexible Bronchoscopy on Mechanically Ventilated Patients in the Medical Intensive Care Unit. J Bronchology Interv Pulmonol 2017; 24:206-210. [PMID: 28696966 DOI: 10.1097/lbr.0000000000000367] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Flexible bronchoscopy (FB) in intubated patients on mechanical ventilation increases airway resistance. During FB, two ventilatory strategies are possible: maintaining tidal volume (VT) while maintaining baseline CO2 or allowing reduction of VT. The former strategy carries risk of hyperinflation due to expiratory flow limitation with FB. The aim of the authors was too study end expiratory lung volume (EELV) during FB of intubated subjects while limiting VT. METHODS We studied 16 subjects who were intubated on mechanical ventilation and required FB. Changes in EELV were measured by respiratory inductance plethysmography. Ventilator mechanics, EELV, and arterial blood gases, were measured. RESULTS FB insertions decreased EELV in 64% of cases (-325±371 mL) and increased it in 32% of cases (65±59 mL). Suctioning decreased EELV in 76% of cases (-120±104 mL) and increased it in 16% of cases (29±33 mL). Respiratory mechanics were unchanged. Pre-FB and post-FB, PaO2 decreased by 61±96 mm Hg and PaCO2 increased by 15±7 mm Hg. CONCLUSIONS There was no clinically significant increase in EELV in any subject during FB. Decreases in EELV coincided with FB-suctioning maneuvers. Peak pressure limiting ventilation protected the subject against hyperinflation with a consequent, well-tolerated reduction in VT, and hypercapnea. Suctioning should be limited, especially in patients vulnerable to derecruitment effect.
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Nakstad ER, Opdahl H, Heyerdahl F, Borchsenius F, Skjønsberg OH. Manual ventilation and open suction procedures contribute to negative pressures in a mechanical lung model. BMJ Open Respir Res 2017; 4:e000176. [PMID: 28725445 PMCID: PMC5501241 DOI: 10.1136/bmjresp-2016-000176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/22/2017] [Accepted: 03/03/2017] [Indexed: 11/03/2022] Open
Abstract
INTRODUCTION Removal of pulmonary secretions in mechanically ventilated patients usually requires suction with closed catheter systems or flexible bronchoscopes. Manual ventilation is occasionally performed during such procedures if clinicians suspect inadequate ventilation. Suctioning can also be performed with the ventilator entirely disconnected from the endotracheal tube (ETT). The aim of this study was to investigate if these two procedures generate negative airway pressures, which may contribute to atelectasis. METHODS The effects of device insertion and suctioning in ETTs were examined in a mechanical lung model with a pressure transducer inserted distal to ETTs of 9 mm, 8 mm and 7 mm internal diameter (ID). A 16 Fr bronchoscope and 12, 14 and 16 Fr suction catheters were used at two different vacuum levels during manual ventilation and with the ETTs disconnected. RESULTS During manual ventilation with ETTs of 9 mm, 8 mm and 7 mm ID, and bronchoscopic suctioning at moderate suction level, peak pressure (PPEAK) dropped from 23, 22 and 24.5 cm H2O to 16, 16 and 15 cm H2O, respectively. Maximum suction reduced PPEAK to 20, 17 and 11 cm H2O, respectively, and the end-expiratory pressure fell from 5, 5.5 and 4.5 cm H2O to -2, -6 and -17 cm H2O. Suctioning through disconnected ETTs (open suction procedure) gave negative model airway pressures throughout the duration of the procedures. CONCLUSIONS Manual ventilation and open suction procedures induce negative end-expiratory pressure during endotracheal suctioning, which may have clinical implications in patients who need high PEEP (positive end-expiratory pressure).
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Affiliation(s)
- Espen Rostrup Nakstad
- Department of Acute Medicine, Oslo University Hospital, Ullevaal, Norway.,Department of Pulmonary Medicine, Oslo University Hospital, Ullevaal, Norway
| | - Helge Opdahl
- Department of Acute Medicine, Oslo University Hospital, Ullevaal, Norway
| | - Fridtjof Heyerdahl
- Department of Anesthesiology, Oslo University Hospital, Ullevaal, Norway
| | - Fredrik Borchsenius
- Department of Pulmonary Medicine, Oslo University Hospital, Ullevaal, Norway
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Nakstad ER, Opdahl H, Heyerdahl F, Borchsenius F, Skjønsberg OH. Can ventilator settings reduce the negative effects of endotracheal suctioning? Investigations in a mechanical lung model. BMC Anesthesiol 2016; 16:30. [PMID: 27350249 PMCID: PMC4924309 DOI: 10.1186/s12871-016-0196-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 05/13/2016] [Indexed: 11/17/2022] Open
Abstract
Background The insertion of suction devices through endotracheal tubes (ETTs) increases airway resistance and the subsequent suctioning may reduce airway pressures and facilitate atelectasis. The aim of this study was to investigate how airway pressures and tidal volumes change when different combinations of suction equipment and ETT sizes are used, and to what extent unfavorable effects can be ameliorated by choice of ventilator settings. Methods A mechanical ventilator was connected to a lung model by ETTs of 9 mm, 8 mm or 7 mm internal diameter (ID) with a pressure transducer inserted distal to the ETT. The effects of suction procedures with bronchoscope and closed catheter systems were investigated during pressure controlled ventilation (PCV) and volume controlled ventilation (VCV). In each mode, the effects of changes in inspiration:expiration (I:E) ratio, trigger sensitivity and suction pressure were examined. Results The variables that contributed most to negative model airway pressures and loss of tidal volume during suctioning were (in descending order); 1) Small-size ETTs (7–8 mm ID) combined with large diameter suction devices (14–16 Fr); 2) inverse I:E ratio ventilation (in VCV); 3) negative ventilator trigger sensitivity; and 4) strong suction pressure. The pressure changes observed distal to the ETTs were not identical to those detected by the ventilator. Conclusions Negative model airway pressure was induced by suctioning through small-size ETTs. The most extreme pressure and volume changes were ameliorated when conventional ventilator settings were used, such as PCV mode with short inspiration time and a trigger function sensitive to flow changes. Electronic supplementary material The online version of this article (doi:10.1186/s12871-016-0196-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Espen R Nakstad
- Department of Acute Medicine, Oslo University Hospital, Ullevaal, Oslo, Norway. .,Department of Pulmonary Medicine, Oslo University Hospital, Ullevaal, Oslo, Norway.
| | - Helge Opdahl
- Department of Acute Medicine, Oslo University Hospital, Ullevaal, Oslo, Norway
| | - Fridtjof Heyerdahl
- Department of Acute Medicine, Oslo University Hospital, Ullevaal, Oslo, Norway
| | - Fredrik Borchsenius
- Department of Pulmonary Medicine, Oslo University Hospital, Ullevaal, Oslo, Norway
| | - Ole H Skjønsberg
- Department of Pulmonary Medicine, Oslo University Hospital, Ullevaal, Oslo, Norway.,University of Oslo, Oslo, Norway
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Kobylianskii J, Murray A, Brace D, Goligher E, Fan E. Electrical impedance tomography in adult patients undergoing mechanical ventilation: A systematic review. J Crit Care 2016; 35:33-50. [PMID: 27481734 DOI: 10.1016/j.jcrc.2016.04.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/25/2016] [Accepted: 04/27/2016] [Indexed: 01/20/2023]
Abstract
PURPOSE The purpose of the study is to systematically review and summarize current literature concerning the validation and application of electrical impedance tomography (EIT) in mechanically ventilated adult patients. MATERIALS AND METHODS An electronic search of MEDLINE, EMBASE, CINAHL, Cochrane Central Register of Controlled Trials, and the Web of Science was performed up to June 2014. Studies investigating the use of EIT in an adult human patient population treated with mechanical ventilation (MV) were included. Data extracted included study objectives, EIT details, interventions, MV protocol, validation and comparators, population characteristics, and key findings. RESULTS Of the 67 included studies, 35 had the primary objective of validating EIT measures including regional ventilation distribution, lung volume, regional respiratory mechanics, and nonventilatory parameters. Thirty-two studies had the primary objective of applying EIT to monitor the response to therapeutic MV interventions including change in ventilation mode, patient repositioning, endotracheal suctioning, recruitment maneuvers, and change in positive end-expiratory pressure. CONCLUSIONS In adult patients, EIT has been successfully validated for assessing ventilation distribution, measuring changes in lung volume, studying regional respiratory mechanics, and investigating nonventilatory parameters. Electrical impedance tomography has also been demonstrated to be useful in monitoring regional respiratory system changes during MV interventions, although existing literature lacks clinical outcome evidence.
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Affiliation(s)
- Jane Kobylianskii
- School of Medicine, Queen's University, Kingston, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada
| | - Alistair Murray
- Schulich School of Medicine & Dentistry, Western University, London, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada
| | - Debbie Brace
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada
| | - Ewan Goligher
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada
| | - Eddy Fan
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada.
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Nay MA, Mankikian J, Auvet A, Dequin PF, Guillon A. The effect of fibreoptic bronchoscopy in acute respiratory distress syndrome: experimental evidence from a lung model. Anaesthesia 2015; 71:185-91. [DOI: 10.1111/anae.13274] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2015] [Indexed: 11/27/2022]
Affiliation(s)
- M.-A. Nay
- Centre Hospitalier Régional Universitaire de Tours; Service de Réanimation Polyvalente; Tours France
| | - J. Mankikian
- Centre Hospitalier Régional Universitaire de Tours; Service de Réanimation Polyvalente; Tours France
| | - A. Auvet
- Centre Hospitalier Régional Universitaire de Tours; Service de Réanimation Polyvalente; Tours France
- French Institute of Health and Medical Research; Centre d'Etude des Pathologies Respiratoires; Tours France
| | - P.-F. Dequin
- French Institute of Health and Medical Research; Centre d'Etude des Pathologies Respiratoires; Tours France
- Centre Hospitalier Régional Universitaire de Tours; Service de Réanimation Polyvalente; Tours France
| | - A. Guillon
- Centre Hospitalier Régional Universitaire de Tours; Service de Réanimation Polyvalente; Tours France
- French Institute of Health and Medical Research; Centre d'Etude des Pathologies Respiratoires; Tours France
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Caruana LR, Paratz J, Chang AT, Fraser JF. Electrical impedance tomography in the clinical assessment of lung volumes following recruitment manoeuvres. PHYSICAL THERAPY REVIEWS 2013. [DOI: 10.1179/1743288x10y.0000000021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Electrical impedance tomography: the holy grail of ventilation and perfusion monitoring? Intensive Care Med 2012; 38:1917-29. [DOI: 10.1007/s00134-012-2684-z] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 08/08/2012] [Indexed: 01/08/2023]
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16
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Leonhardt S, Pikkemaat R, Stenqvist O, Lundin S. Electrical Impedance Tomography for hemodynamic monitoring. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2012:122-125. [PMID: 23365847 DOI: 10.1109/embc.2012.6345886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Electrical Impedance Tomography (EIT) is a known technique to monitor impedance changes in a cross-section of a body segment, which recently gained increasing interest for regional ventilation monitoring. In this paper, we focus on hemodynamic monitoring using EIT. Past and ongoing research activities to obtain cardiac related signals and regional perfusion information from EIT image streams are summarized. Finally, we present some preliminary results on stroke volume estimation using EIT.
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Affiliation(s)
- Steffen Leonhardt
- Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, D-52074 Aachen, Germany
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Antonelli M. The feasibility and safety of fiberoptic bronchoscopy during noninvasive ventilation in patients with established acute lung injury: another small brick in the wall. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2011; 15:191. [PMID: 22027334 PMCID: PMC3334728 DOI: 10.1186/cc10342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
In hypoxemic patients needing fiberoptic bronchoscopy (FOB), noninvasive ventilation (NIV) has been used to prevent gas-exchange deterioration associated with FOB and to compensate for the increase in work of breathing occurring during FOB, thus avoiding endotracheal intubation and its related complications. The application of NIV to allow FOB has been found of particular interest in the diagnosis of pneumonia in patients spontaneously breathing and in those who started NIV to assist FOB. There is less information for patients who were already receiving NIV for acute respiratory failure and who were scheduled to undergo FOB. In the previous issue of Critical Care, the study by Baumann and colleagues adds new information to this specific issue, addressing the feasibility and safety of FOB during NIV in patients with established hypoxemic respiratory failure.
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Affiliation(s)
- Massimo Antonelli
- Department of Intensive Care and Anesthesiology, Policlinico Universitario A. Gemelli, Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, 00168 Rome, Italy.
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Functional residual capacity-guided alveolar recruitment strategy after endotracheal suctioning in cardiac surgery patients. Crit Care Med 2011; 39:1042-9. [DOI: 10.1097/ccm.0b013e31820eb736] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Nakstad ER, Opdahl H, Skjønsberg OH, Borchsenius F. Intrabronchial Airway Pressures in Intubated Patients during Bronchoscopy under Volume Controlled and Pressure Controlled Ventilation. Anaesth Intensive Care 2011; 39:431-9. [DOI: 10.1177/0310057x1103900314] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bronchoscope insertion through an endotracheal tube increases airflow resistance. Constant tidal volume (TV) ventilation can be maintained by augmenting the inspiratory pressure, but increased outflow resistance cannot be compensated for. Air trapping distal to the tube may lead to higher airway pressures in volume controlled (VC) mode and reduced TV in pressure controlled (PC) mode. Increased end-expiratory airway pressures will not be detected by ventilator pressure sensors. In mechanically ventilated and sedated patients, the effects of bronchoscope insertion on intrabronchial pressures were recorded by a pressure transducer distal to the endoscope. In half of the patients, the ventilator was set in VC mode prior to bronchoscope insertion, keeping the previous TV constant. In the other half, the ventilator was set in PC mode, keeping previous peak inspiratory pressures constant. All patients underwent sequences of VC-PC-VC or PC-VC-PC ventilation with two-minute intervals between mode-changes. In VC mode, bronchoscope insertion increased peak airway pressure from 29 cmH2O (22 to 43) to 41 cmH2O (36 to 49) (P=0.012) and end-expiratory airway pressure from 11 cmH2O (6 to 18) to 22.5 cmH2O (15 to 30) (P=0.012). There were no significant changes in TV, PaCO2 or PaO2 after two minutes. In PC mode, peak airway pressure was unchanged and end-expiratory airway pressure increased from 9.5 cmH2O (7 to 10) to 10.5 cmH2O (9 to 18) (P=0.017). Median TV was reduced from 673 ml (585 to 800) to 450 ml (408 to 560) (P=0.012); median PaCO2 increased from 5.7 kPa to 6.5 kPa (P=0.012). Using distal measurement, positive end-expiratory airway pressure increased markedly in VC mode but only marginally in PC mode after bronchoscope insertion.
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Affiliation(s)
- E. R. Nakstad
- Department of Acute Medicine, The National Center for NBC Medicine and Department of Pulmonary Medicine, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - H. Opdahl
- Department of Acute Medicine, The National Center for NBC Medicine and Department of Pulmonary Medicine, Oslo University Hospital, University of Oslo, Oslo, Norway
- Head of National Center for NBC Medicine, Department of Acute Medicine, Oslo University Hospital
| | - O. H. Skjønsberg
- Department of Acute Medicine, The National Center for NBC Medicine and Department of Pulmonary Medicine, Oslo University Hospital, University of Oslo, Oslo, Norway
- Department of Pulmonary Medicine, Oslo University Hospital
| | - F. Borchsenius
- Department of Acute Medicine, The National Center for NBC Medicine and Department of Pulmonary Medicine, Oslo University Hospital, University of Oslo, Oslo, Norway
- Department of Pulmonary Medicine, Oslo University Hospital
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Heinze H, Eichler W. Measurements of functional residual capacity during intensive care treatment: the technical aspects and its possible clinical applications. Acta Anaesthesiol Scand 2009; 53:1121-30. [PMID: 19681779 DOI: 10.1111/j.1399-6576.2009.02076.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Direct measurement of lung volume, i.e. functional residual capacity (FRC) has been recommended for monitoring during mechanical ventilation. Mostly due to technical reasons, FRC measurements have not become a routine monitoring tool, but promising techniques have been presented. We performed a literature search of studies with the key words 'functional residual capacity' or 'end expiratory lung volume' and summarize the physiology and patho-physiology of FRC measurements in ventilated patients, describe the existing techniques for bedside measurement, and provide an overview of the clinical questions that can be addressed using an FRC assessment. The wash-in or wash-out of a tracer gas in a multiple breath maneuver seems to be best applicable at bedside, and promising techniques for nitrogen or oxygen wash-in/wash-out with reasonable accuracy and repeatability have been presented. Studies in ventilated patients demonstrate that FRC can easily be measured at bedside during various clinical settings, including positive end-expiratory pressure optimization, endotracheal suctioning, prone position, and the weaning from mechanical ventilation. Alveolar derecruitment can easily be monitored and improvements of FRC without changes of the ventilatory setting could indicate alveolar recruitment. FRC seems to be insensitive to over-inflation of already inflated alveoli. Growing evidence suggests that FRC measurements, in combination with other parameters such as arterial oxygenation and respiratory compliance, could provide important information on the pulmonary situation in critically ill patients. Further studies are needed to define the exact role of FRC in monitoring and perhaps guiding mechanical ventilation.
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Affiliation(s)
- H Heinze
- Department of Anesthesiology, University of Lübeck, Lübeck, Germany.
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Bikker IG, Leonhardt S, Bakker J, Gommers D. Lung volume calculated from electrical impedance tomography in ICU patients at different PEEP levels. Intensive Care Med 2009; 35:1362-7. [PMID: 19513694 PMCID: PMC2712617 DOI: 10.1007/s00134-009-1512-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 05/05/2009] [Indexed: 01/08/2023]
Abstract
PURPOSE To study and compare the relationship between end-expiratory lung volume (EELV) and changes in end-expiratory lung impedance (EELI) measured with electrical impedance tomography (EIT) at the basal part of the lung at different PEEP levels in a mixed ICU population. METHODS End-expiratory lung volume, EELI and tidal impedance variation were determined at four PEEP levels (15-10-5-0 cm H2O) in 25 ventilated ICU patients. The tidal impedance variation and tidal volume at 5 cm H2O PEEP were used to calculate change in impedance per ml; this ratio was then used to calculate change in lung volume from change in EELI. To evaluate repeatability, EELV was measured in quadruplicate in five additional patients. RESULTS There was a significant but relatively low correlation (r = 0.79; R2 = 0.62) and moderate agreement (bias 194 ml, SD 323 ml) between DeltaEELV and change in lung volume calculated from the DeltaEELI. The ratio of tidal impedance variation and tidal volume differed between patients and also varied at different PEEP levels. Good agreement was found between repeated EELV measurements and washin/washout of a simulated nitrogen washout technique. CONCLUSION During a PEEP trial, the assumption of a linear relationship between change in global tidal impedance and tidal volume cannot be used to calculate EELV when impedance is measured at only one thoracic level just above the diaphragm.
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Affiliation(s)
- Ido G Bikker
- Department of Intensive Care Medicine, Room H602, Erasmus MC, Postbox 2040, 3000 CA Rotterdam, The Netherlands
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Heinze H, Sedemund-Adib B, Heringlake M, Gosch UW, Eichler W. Functional Residual Capacity Changes After Different Endotracheal Suctioning Methods. Anesth Analg 2008; 107:941-4. [DOI: 10.1213/ane.0b013e3181804a5d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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