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Pozzi T, Coppola S, Chiodaroli E, Cucinotta F, Becci F, Chiumello D. The evaluation of a non-invasive respiratory monitor in ards patients in supine and prone position. J Clin Monit Comput 2024; 38:671-677. [PMID: 38530502 PMCID: PMC11164716 DOI: 10.1007/s10877-024-01147-0] [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: 12/10/2023] [Accepted: 02/27/2024] [Indexed: 03/28/2024]
Abstract
PURPOSE The Prone positioning in addition to non invasive respiratory support is commonly used in patients with acute respiratory failure. The aim of this study was to assess the accuracy of an impedance-based non-invasive respiratory volume monitor (RVM) in supine and in prone position. METHODS In sedated, paralyzed and mechanically ventilated patients in volume-controlled mode with acute respiratory distress syndrome scheduled for prone positioning it was measured and compared non-invasively tidal volume and respiratory rate provided by the RVM in supine and, subsequently, in prone position, by maintaining unchanged the ventilatory setting. RESULTS Forty patients were enrolled. No significant difference was found between measurements in supine and in prone position either for tidal volume (p = 0.795; p = 0.302) nor for respiratory rate (p = 0.181; p = 0.604). Comparing supine vs. prone position, the bias and limits of agreements for respiratory rate were 0.12 bpm (-1.4 to 1.6) and 20 mL (-80 to 120) for tidal volume. CONCLUSIONS The RVM is accurate in assessing tidal volume and respiratory rate in prone compared to supine position. Therefore, the RVM could be applied in non-intubated patients with acute respiratory failure receiving prone positioning to monitor respiratory function.
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Affiliation(s)
- Tommaso Pozzi
- Department of Health Sciences, University of Milan, Milan, Italy
| | - Silvia Coppola
- Department of Anesthesia and Intensive Care, ASST Santi Paolo e Carlo, San Paolo University Hospital, Milan, Italy
| | - Elena Chiodaroli
- Department of Anesthesia and Intensive Care, ASST Santi Paolo e Carlo, San Paolo University Hospital, Milan, Italy
| | | | - Francesca Becci
- Department of Health Sciences, University of Milan, Milan, Italy
| | - Davide Chiumello
- Department of Health Sciences, University of Milan, Milan, Italy.
- Department of Anesthesia and Intensive Care, ASST Santi Paolo e Carlo, San Paolo University Hospital, Milan, Italy.
- Coordinated Research Center on Respiratory Failure, University of Milan, Milan, Italy.
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Yang R, Zhou L, Chen Z, He S, Lian S, Shen Y, Zhang X. Effect and mechanical mechanism of spontaneous breathing on oxygenation and lung injury in mild or moderate animal ARDS. BMC Pulm Med 2023; 23:428. [PMID: 37925442 PMCID: PMC10625710 DOI: 10.1186/s12890-023-02730-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 10/23/2023] [Indexed: 11/06/2023] Open
Abstract
OBJECTIVE The present study aimed to determine the effect and mechanical mechanism of spontaneous breathing during mechanical ventilation on oxygenation and lung injury using Beagles dogs mild or moderate acute respiratory distress syndrome (ARDS) model. METHODS After inducing mild or moderate ARDS by infusion of oleic acid, Eighteen Beagles dogs were randomly split into Spontaneous breathing group (BIPAPSB, n = 6), and Complete muscle paralysis group (BIPAPPC, n = 6),Six Beagles without ventilator support comprised the control group. Both groups were ventilated for 8 h under BIPAP mode. High-pressure was titrated TV to 6 ml/kg. A multi-pair esophageal balloon electrode catheter was used to measure respiratory mechanics and electromyogram. End-expiratory lung volume (EELV), gas exchange and respiratory variables were recorded in the process of mechanical ventilation. The contents of Interleukin (IL)-6 and IL-8 in lung tissue were measure using qRT-PCR. Besides, lung injury score was calculated in the end of mechanical ventilation. RESULTS Based on the comparable setting of ventilator, BIPAPSB group exhibited higher safety peak transpulmonary pressure, abdominal pressure, EELV and P/F(PaO2/FiO2) than BIPAPPC group, whereas mean transpulmonary pressure, the mRNA levels of the IL-6 and IL-8 in the lung tissues and lung injury score in BIPAPSB group were lower than those in BIPAPPC group. CONCLUSION In mild to moderate ARDS animal models, during mechanical ventilation, SB may improve respiratory function and reduce ventilator-induced lung injury. The mechanism may be that spontaneous inspiration up-regulates peak transpulmonary pressure and EELV; Spontaneous expiration decreases mean transpulmonary pressure by up-regulating intra-abdominal pressure, thereby reducing stress and strain.
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Affiliation(s)
- Rui Yang
- First People's Hospital of Guiyang City, Guiyang, Guizhou, China
| | - Leilei Zhou
- Department of Respiratory Medicine, The Affiliated Hospital of Guizhou Medical, 28 Guiyi Street, Guiyang, Guizhou, 550000, China
| | - Zongyu Chen
- Department of Respiratory Medicine, The Affiliated Hospital of Guizhou Medical, 28 Guiyi Street, Guiyang, Guizhou, 550000, China
| | - Shuang He
- Department of Respiratory Medicine, The Affiliated Hospital of Guizhou Medical, 28 Guiyi Street, Guiyang, Guizhou, 550000, China
| | - Siyu Lian
- Department of Respiratory Medicine, The Affiliated Hospital of Guizhou Medical, 28 Guiyi Street, Guiyang, Guizhou, 550000, China
| | - Yi Shen
- Department of Respiratory Medicine, The Affiliated Hospital of Guizhou Medical, 28 Guiyi Street, Guiyang, Guizhou, 550000, China
| | - Xianming Zhang
- Department of Respiratory Medicine, The Affiliated Hospital of Guizhou Medical, 28 Guiyi Street, Guiyang, Guizhou, 550000, China.
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Knopp JL, Chase JG, Kim KT, Shaw GM. Model-based estimation of negative inspiratory driving pressure in patients receiving invasive NAVA mechanical ventilation. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 208:106300. [PMID: 34348200 DOI: 10.1016/j.cmpb.2021.106300] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 07/17/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Optimisation of mechanical ventilation (MV) and weaning requires insight into underlying patient breathing effort. Current identifiable models effectively describe lung mechanics, such as elastance (E) and resistance (R) at the bedside in sedated patients, but are less effective when spontaneous breathing is present. This research derives and regularises a single compartment model to identify patient-specific inspiratory effort. METHODS Constrained second-order b-spline basis functions (knot width 0.05 s) are used to describe negative inspiratory drive (Pp, cmH2O) as a function of time. Breath-breath Pp are identified with single E and R values over inspiration and expiration from n = 20 breaths for N = 22 patients on NAVA ventilation. Pp is compared to measured electrical activity of the diaphragm (Eadi) and published results. RESULTS Average per-patient root-mean-squared model fit error was (median [interquartile range, IQR]) 0.9 [0.6-1.3] cmH2O, and average per-patient median Pp was -3.9 [-4.5- -3.0] cmH2O, with range -7.9 - -1.9 cmH2O. Per-patient E and R were 16.4 [13.6-21.8] cmH2O/L and 9.2 [6.4-13.1] cmH2O.s/L, respectively. Most patients showed an inspiratory volume threshold beyond which Pp started to return to baseline, and Pp at peak Eadi (end-inspiration) was often strongly correlated with peak Eadi (R2=0.25-0.86). Similarly, average transpulmonary pressure was consistent breath-breath in most patients, despite differences in peak Eadi and thus peak airway pressure. CONCLUSIONS The model-based inspiratory effort aligns with electrical muscle activity and published studies showing neuro-muscular decoupling as a function of pressure and/or volume. Consistency in coupling/dynamics were patient-specific. Quantification of patient and ventilator work of breathing contributions may aid optimisation of MV modes and weaning.
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Affiliation(s)
- Jennifer L Knopp
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
| | - J Geoffrey Chase
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Kyeong Tae Kim
- Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand
| | - Geoffrey M Shaw
- Department of Intensive Care, Christchurch Hospital, Private Bag 4710, Christchurch, New Zealand
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Dianti J, Bertoni M, Goligher EC. Monitoring patient-ventilator interaction by an end-expiratory occlusion maneuver. Intensive Care Med 2020; 46:2338-2341. [PMID: 32623476 PMCID: PMC7334114 DOI: 10.1007/s00134-020-06167-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 06/24/2020] [Indexed: 12/23/2022]
Affiliation(s)
- Jose Dianti
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada
- Department of Medicine, Division of Respirology, University Health Network, Toronto, Canada
| | - Michele Bertoni
- Department of Anesthesia, Critical Care and Emergency, Spedali Civili University Hospital, Brescia, Italy
| | - Ewan C Goligher
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada.
- Department of Medicine, Division of Respirology, University Health Network, Toronto, Canada.
- Toronto General Hospital Research Institute, 585 University Ave., 11-PMB Room 192, Toronto, ON, M5G 2N2, Canada.
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Diniz-Silva F, Moriya HT, Alencar AM, Amato MBP, Carvalho CRR, Ferreira JC. Neurally adjusted ventilatory assist vs. pressure support to deliver protective mechanical ventilation in patients with acute respiratory distress syndrome: a randomized crossover trial. Ann Intensive Care 2020; 10:18. [PMID: 32040785 PMCID: PMC7010869 DOI: 10.1186/s13613-020-0638-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 02/02/2020] [Indexed: 01/06/2023] Open
Abstract
Background Protective mechanical ventilation is recommended for patients with acute respiratory distress syndrome (ARDS), but it usually requires controlled ventilation and sedation. Using neurally adjusted ventilatory assist (NAVA) or pressure support ventilation (PSV) could have additional benefits, including the use of lower sedative doses, improved patient–ventilator interaction and shortened duration of mechanical ventilation. We designed a pilot study to assess the feasibility of keeping tidal volume (VT) at protective levels with NAVA and PSV in patients with ARDS. Methods We conducted a prospective randomized crossover trial in five ICUs from a university hospital in Brazil and included patients with ARDS transitioning from controlled ventilation to partial ventilatory support. NAVA and PSV were applied in random order, for 15 min each, followed by 3 h in NAVA. Flow, peak airway pressure (Paw) and electrical activity of the diaphragm (EAdi) were captured from the ventilator, and a software (Matlab, Mathworks, USA), automatically detected inspiratory efforts and calculated respiratory rate (RR) and VT. Asynchrony events detection was based on waveform analysis. Results We randomized 20 patients, but the protocol was interrupted for five (25%) patients for whom we were unable to maintain VT below 6.5 mL/kg in PSV due to strong inspiratory efforts and for one patient for whom we could not detect EAdi signal. For the 14 patients who completed the protocol, VT was 5.8 ± 1.1 mL/kg for NAVA and 5.6 ± 1.0 mL/kg for PSV (p = 0.455) and there were no differences in RR (24 ± 7 for NAVA and 23 ± 7 for PSV, p = 0.661). Paw was greater in NAVA (21 ± 3 cmH2O) than in PSV (19 ± 3 cmH2O, p = 0.001). Most patients were under continuous sedation during the study. NAVA reduced triggering delay compared to PSV (p = 0.020) and the median asynchrony Index was 0.7% (0–2.7) in PSV and 0% (0–2.2) in NAVA (p = 0.6835). Conclusions It was feasible to keep VT in protective levels with NAVA and PSV for 75% of the patients. NAVA resulted in similar VT, RR and Paw compared to PSV. Our findings suggest that partial ventilatory assistance with NAVA and PSV is feasible as a protective ventilation strategy in selected ARDS patients under continuous sedation. Trial registration ClinicalTrials.gov (NCT01519258). Registered 26 January 2012, https://clinicaltrials.gov/ct2/show/NCT01519258
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Affiliation(s)
- Fabia Diniz-Silva
- Divisao de Pneumologia, Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, SP, BR, Av. Dr. Enéas de Carvalho Aguiar, 44, 5 andar, bloco 2, sala 1, São Paulo, SP, CEP 05403900, Brazil
| | - Henrique T Moriya
- Biomedical Engineering Laboratory, Escola Politécnica da USP, Av. Prof. Luciano Gualberto, trav. 3, 158, Cidade Universitária, São Paulo, SP, CEP 05586-0600, Brazil
| | - Adriano M Alencar
- Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, São Paulo, SP, CEP 05314-970, Brazil
| | - Marcelo B P Amato
- Divisao de Pneumologia, Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, SP, BR, Av. Dr. Enéas de Carvalho Aguiar, 44, 5 andar, bloco 2, sala 1, São Paulo, SP, CEP 05403900, Brazil
| | - Carlos R R Carvalho
- Divisao de Pneumologia, Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, SP, BR, Av. Dr. Enéas de Carvalho Aguiar, 44, 5 andar, bloco 2, sala 1, São Paulo, SP, CEP 05403900, Brazil
| | - Juliana C Ferreira
- Divisao de Pneumologia, Instituto do Coracao, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, SP, BR, Av. Dr. Enéas de Carvalho Aguiar, 44, 5 andar, bloco 2, sala 1, São Paulo, SP, CEP 05403900, Brazil.
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Spontaneous Breathing in Early Acute Respiratory Distress Syndrome: Insights From the Large Observational Study to UNderstand the Global Impact of Severe Acute Respiratory FailurE Study. Crit Care Med 2019; 47:229-238. [PMID: 30379668 PMCID: PMC6336491 DOI: 10.1097/ccm.0000000000003519] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Supplemental Digital Content is available in the text. Objectives: To describe the characteristics and outcomes of patients with acute respiratory distress syndrome with or without spontaneous breathing and to investigate whether the effects of spontaneous breathing on outcome depend on acute respiratory distress syndrome severity. Design: Planned secondary analysis of a prospective, observational, multicentre cohort study. Setting: International sample of 459 ICUs from 50 countries. Patients: Patients with acute respiratory distress syndrome and at least 2 days of invasive mechanical ventilation and available data for the mode of mechanical ventilation and respiratory rate for the 2 first days. Interventions: Analysis of patients with and without spontaneous breathing, defined by the mode of mechanical ventilation and by actual respiratory rate compared with set respiratory rate during the first 48 hours of mechanical ventilation. Measurements and Main Results: Spontaneous breathing was present in 67% of patients with mild acute respiratory distress syndrome, 58% of patients with moderate acute respiratory distress syndrome, and 46% of patients with severe acute respiratory distress syndrome. Patients with spontaneous breathing were older and had lower acute respiratory distress syndrome severity, Sequential Organ Failure Assessment scores, ICU and hospital mortality, and were less likely to be diagnosed with acute respiratory distress syndrome by clinicians. In adjusted analysis, spontaneous breathing during the first 2 days was not associated with an effect on ICU or hospital mortality (33% vs 37%; odds ratio, 1.18 [0.92–1.51]; p = 0.19 and 37% vs 41%; odds ratio, 1.18 [0.93–1.50]; p = 0.196, respectively ). Spontaneous breathing was associated with increased ventilator-free days (13 [0–22] vs 8 [0–20]; p = 0.014) and shorter duration of ICU stay (11 [6–20] vs 12 [7–22]; p = 0.04). Conclusions: Spontaneous breathing is common in patients with acute respiratory distress syndrome during the first 48 hours of mechanical ventilation. Spontaneous breathing is not associated with worse outcomes and may hasten liberation from the ventilator and from ICU. Although these results support the use of spontaneous breathing in patients with acute respiratory distress syndrome independent of acute respiratory distress syndrome severity, the use of controlled ventilation indicates a bias toward use in patients with higher disease severity. In addition, because the lack of reliable data on inspiratory effort in our study, prospective studies incorporating the magnitude of inspiratory effort and adjusting for all potential severity confounders are required.
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Standardized Unloading of Respiratory Muscles during Neurally Adjusted Ventilatory Assist: A Randomized Crossover Pilot Study. Anesthesiology 2019; 129:769-777. [PMID: 30045094 DOI: 10.1097/aln.0000000000002335] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
WHAT WE ALREADY KNOW ABOUT THIS TOPIC WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Currently, there is no standardized method to set the support level in neurally adjusted ventilatory assist (NAVA). The primary aim was to explore the feasibility of titrating NAVA to specific diaphragm unloading targets, based on the neuroventilatory efficiency (NVE) index. The secondary outcome was to investigate the effect of reduced diaphragm unloading on distribution of lung ventilation. METHODS This is a randomized crossover study between pressure support and NAVA at different diaphragm unloading at a single neurointensive care unit. Ten adult patients who had started weaning from mechanical ventilation completed the study. Two unloading targets were used: 40 and 60%. The NVE index was used to guide the titration of the assist in NAVA. Electrical impedance tomography data, blood-gas samples, and ventilatory parameters were collected. RESULTS The median unloading was 43% (interquartile range 32, 60) for 40% unloading target and 60% (interquartile range 47, 69) for 60% unloading target. NAVA with 40% unloading led to more dorsal ventilation (center of ventilation at 55% [51, 56]) compared with pressure support (52% [49, 56]; P = 0.019). No differences were found in oxygenation, CO2, and respiratory parameters. The electrical activity of the diaphragm was higher during NAVA with 40% unloading than in pressure support. CONCLUSIONS In this pilot study, NAVA could be titrated to different diaphragm unloading levels based on the NVE index. Less unloading was associated with greater diaphragm activity and improved ventilation of the dependent lung regions.
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Battaglini D, Robba C, Rocco PRM, De Abreu MG, Pelosi P, Ball L. Perioperative anaesthetic management of patients with or at risk of acute distress respiratory syndrome undergoing emergency surgery. BMC Anesthesiol 2019; 19:153. [PMID: 31412784 PMCID: PMC6694484 DOI: 10.1186/s12871-019-0804-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/15/2019] [Indexed: 02/07/2023] Open
Abstract
Patients undergoing emergency surgery may present with the acute respiratory distress syndrome (ARDS) or develop this syndrome postoperatively. The incidence of ARDS in the postoperative period is relatively low, but the impact of ARDS on patient outcomes and healthcare costs is relevant Aakre et.al (Mayo Clin Proc 89:181-9, 2014).The development of ARDS as a postoperative pulmonary complication (PPC) is associated with prolonged hospitalisation, longer duration of mechanical ventilation, increased intensive care unit length of stay and high morbidity and mortality Ball et.al (Curr Opin Crit Care 22:379-85, 2016). In order to mitigate the risk of ARDS after surgery, the anaesthetic management and protective mechanical ventilation strategies play an important role. In particular, a careful integration of general anaesthesia with neuraxial or locoregional techniques might promote faster recovery and reduce opioid consumption. In addition, the use of low tidal volume, minimising plateau pressure and titrating a low-moderate PEEP level based on the patient's need can improve outcome and reduce intraoperative adverse events. Moreover, perioperative management of ARDS patients includes specific anaesthesia and ventilator settings, hemodynamic monitoring, moderately restrictive fluid administration and pain control.The aim of this review is to provide an overview and evidence- and opinion-based recommendations concerning the management of patients at risk of and with ARDS who undergo emergency surgical procedures.
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Affiliation(s)
- Denise Battaglini
- Anaesthesia and Intensive Care, IRCCS for Oncology and Neurosciences, San Martino Policlinico Hospital, Genoa, Italy
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy
| | - Chiara Robba
- Anaesthesia and Intensive Care, IRCCS for Oncology and Neurosciences, San Martino Policlinico Hospital, Genoa, Italy
| | - Patricia Rieken Macêdo Rocco
- Laboratory of Pulmonary Investigation, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcelo Gama De Abreu
- Department of Anaesthesiology and Intensive Care Medicine, Pulmonary Engineering Group, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Paolo Pelosi
- Anaesthesia and Intensive Care, IRCCS for Oncology and Neurosciences, San Martino Policlinico Hospital, Genoa, Italy.
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy.
| | - Lorenzo Ball
- Anaesthesia and Intensive Care, IRCCS for Oncology and Neurosciences, San Martino Policlinico Hospital, Genoa, Italy
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy
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Abstract
Even after many years of intensive research acute respiratory distress syndrome (ARDS) is still associated with a high mortality. Epidemiologically, ARDS represents a central challenge for modern intensive care treatment. The multifactorial etiology of ARDS complicates the clear identification and evaluation of new therapeutic interventions. Lung protective mechanical ventilation and adjuvant therapies, such as the prone position and targeted extracorporeal lung support are of particular importance in the treatment of ARDS, depending on the severity of the disease. In order to guarantee an individualized and needs-adapted treatment, ARDS patients benefit from treatment in specialized centers.
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Gattinoni L, Marini JJ, Collino F, Maiolo G, Rapetti F, Tonetti T, Vasques F, Quintel M. The future of mechanical ventilation: lessons from the present and the past. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2017; 21:183. [PMID: 28701178 PMCID: PMC5508674 DOI: 10.1186/s13054-017-1750-x] [Citation(s) in RCA: 158] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/31/2017] [Indexed: 02/07/2023]
Abstract
The adverse effects of mechanical ventilation in acute respiratory distress syndrome (ARDS) arise from two main causes: unphysiological increases of transpulmonary pressure and unphysiological increases/decreases of pleural pressure during positive or negative pressure ventilation. The transpulmonary pressure-related side effects primarily account for ventilator-induced lung injury (VILI) while the pleural pressure-related side effects primarily account for hemodynamic alterations. The changes of transpulmonary pressure and pleural pressure resulting from a given applied driving pressure depend on the relative elastances of the lung and chest wall. The term ‘volutrauma’ should refer to excessive strain, while ‘barotrauma’ should refer to excessive stress. Strains exceeding 1.5, corresponding to a stress above ~20 cmH2O in humans, are severely damaging in experimental animals. Apart from high tidal volumes and high transpulmonary pressures, the respiratory rate and inspiratory flow may also play roles in the genesis of VILI. We do not know which fraction of mortality is attributable to VILI with ventilation comparable to that reported in recent clinical practice surveys (tidal volume ~7.5 ml/kg, positive end-expiratory pressure (PEEP) ~8 cmH2O, rate ~20 bpm, associated mortality ~35%). Therefore, a more complete and individually personalized understanding of ARDS lung mechanics and its interaction with the ventilator is needed to improve future care. Knowledge of functional lung size would allow the quantitative estimation of strain. The determination of lung inhomogeneity/stress raisers would help assess local stresses; the measurement of lung recruitability would guide PEEP selection to optimize lung size and homogeneity. Finding a safety threshold for mechanical power, normalized to functional lung volume and tissue heterogeneity, may help precisely define the safety limits of ventilating the individual in question. When a mechanical ventilation set cannot be found to avoid an excessive risk of VILI, alternative methods (such as the artificial lung) should be considered.
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Affiliation(s)
- Luciano Gattinoni
- Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany.
| | - John J Marini
- University of Minnesota, Minneapolis/Saint Paul, MN, USA
| | - Francesca Collino
- Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
| | - Giorgia Maiolo
- Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
| | - Francesca Rapetti
- Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
| | - Tommaso Tonetti
- Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
| | - Francesco Vasques
- Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
| | - Michael Quintel
- Department of Anesthesiology, Emergency and Intensive Care Medicine, University of Göttingen, Robert-Koch-Straße 40, 37075, Göttingen, Germany
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Fan E, Del Sorbo L, Goligher EC, Hodgson CL, Munshi L, Walkey AJ, Adhikari NKJ, Amato MBP, Branson R, Brower RG, Ferguson ND, Gajic O, Gattinoni L, Hess D, Mancebo J, Meade MO, McAuley DF, Pesenti A, Ranieri VM, Rubenfeld GD, Rubin E, Seckel M, Slutsky AS, Talmor D, Thompson BT, Wunsch H, Uleryk E, Brozek J, Brochard LJ. An Official American Thoracic Society/European Society of Intensive Care Medicine/Society of Critical Care Medicine Clinical Practice Guideline: Mechanical Ventilation in Adult Patients with Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med 2017; 195:1253-1263. [DOI: 10.1164/rccm.201703-0548st] [Citation(s) in RCA: 976] [Impact Index Per Article: 122.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Abdominal Muscle Activity during Mechanical Ventilation Increases Lung Injury in Severe Acute Respiratory Distress Syndrome. PLoS One 2016; 11:e0145694. [PMID: 26745868 PMCID: PMC4712828 DOI: 10.1371/journal.pone.0145694] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 12/06/2015] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE It has proved that muscle paralysis was more protective for injured lung in severe acute respiratory distress syndrome (ARDS), but the precise mechanism is not clear. The purpose of this study was to test the hypothesis that abdominal muscle activity during mechanically ventilation increases lung injury in severe ARDS. METHODS Eighteen male Beagles were studied under mechanical ventilation with anesthesia. Severe ARDS was induced by repetitive oleic acid infusion. After lung injury, Beagles were randomly assigned into spontaneous breathing group (BIPAPSB) and abdominal muscle paralysis group (BIPAPAP). All groups were ventilated with BIPAP model for 8h, and the high pressure titrated to reached a tidal volume of 6ml/kg, the low pressure was set at 10 cmH2O, with I:E ratio 1:1, and respiratory rate adjusted to a PaCO2 of 35-60 mmHg. Six Beagles without ventilator support comprised the control group. Respiratory variables, end-expiratory volume (EELV) and gas exchange were assessed during mechanical ventilation. The levels of Interleukin (IL)-6, IL-8 in lung tissue and plasma were measured by qRT-PCR and ELISA respectively. Lung injury scores were determined at end of the experiment. RESULTS For the comparable ventilator setting, as compared with BIPAPSB group, the BIPAPAP group presented higher EELV (427±47 vs. 366±38 ml) and oxygenation index (293±36 vs. 226±31 mmHg), lower levels of IL-6(216.6±48.0 vs. 297.5±71.2 pg/ml) and IL-8(246.8±78.2 vs. 357.5±69.3 pg/ml) in plasma, and lower express levels of IL-6 mRNA (15.0±3.8 vs. 21.2±3.7) and IL-8 mRNA (18.9±6.8 vs. 29.5±7.9) in lung tissues. In addition, less lung histopathology injury were revealed in the BIPAPAP group (22.5±2.0 vs. 25.2±2.1). CONCLUSION Abdominal muscle activity during mechanically ventilation is one of the injurious factors in severe ARDS, so abdominal muscle paralysis might be an effective strategy to minimize ventilator-induce lung injury.
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Abstract
Abstract
Background:
In patients with acute respiratory distress syndrome (ARDS), the use of assisted mechanical ventilation is a subject of debate. Assisted ventilation has benefits over controlled ventilation, such as preserved diaphragm function and improved oxygenation. Therefore, higher level of “patient control” of ventilator assist may be preferable in ARDS. However, assisted modes may also increase the risk of high tidal volumes and lung-distending pressures. The current study aims to quantify how differences in freedom to control the ventilator affect lung-protective ventilation, breathing pattern variability, and patient–ventilator interaction.
Methods:
Twelve patients with ARDS were ventilated in a randomized order with assist pressure control ventilation (PCV), pressure support ventilation (PSV), and neurally adjusted ventilatory assist (NAVA). Transpulmonary pressure, tidal volume, diaphragm electrical activity, and patient–ventilator interaction were measured. Respiratory variability was assessed using the coefficient of variation of tidal volume.
Results:
During inspiration, transpulmonary pressure was slightly lower with NAVA (10.3 ± 0.7, 11.2 ± 0.7, and 9.4 ± 0.7 cm H2O for PCV, PSV, and NAVA, respectively; P < 0.01). Tidal volume was similar between modes (6.6 [5.7 to 7.0], 6.4 [5.8 to 7.0], and 6.0 [5.6 to 7.3] ml/kg for PCV, PSV, and NAVA, respectively), but respiratory variability was higher with NAVA (8.0 [6.4 to 10.0], 7.1 [5.9 to 9.0], and 17.0 [12.0 to 36.1] % for PCV, PSV, and NAVA, respectively; P < 0.001). Patient–ventilator interaction improved with NAVA (6 [5 to 8] % error) compared with PCV (29 [14 to 52] % error) and PSV (12 [9 to 27] % error); P < 0.0001.
Conclusion:
In patients with mild-to-moderate ARDS, increasing freedom to control the ventilator maintains lung-protective ventilation in terms of tidal volume and lung-distending pressure, but it improves patient–ventilator interaction and preserves respiratory variability.
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Serpa Neto A, Filho RR, Rocha LL, Schultz MJ. Recent advances in mechanical ventilation in patients without acute respiratory distress syndrome. F1000PRIME REPORTS 2014; 6:115. [PMID: 25580269 PMCID: PMC4251417 DOI: 10.12703/p6-115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
While being an essential part of general anesthesia for surgery and at times even a life-saving intervention in critically ill patients, mechanical ventilation has a strong potential to cause harm. Certain ventilation strategies could prevent, at least to some extent, the injury caused by this intervention. One essential element of so-called ‘lung-protective’ ventilation is the use of lower tidal volumes. It is uncertain whether higher levels of positive end-expiratory pressures have lung-protective properties as well. There are indications that too high oxygen fractions of inspired air, or too high blood oxygen targets, are harmful. Circumstantial evidence further suggests that spontaneous modes of ventilation are to be preferred over controlled ventilation to prevent harm to respiratory muscle. Finally, the use of restrictive sedation strategies in critically ill patients indirectly prevents ventilation-induced injury, as daily spontaneous awakening and breathing trials and bolus instead of continuous sedation are associated with shorter duration of ventilation and shorten the exposure to the injurious effects of ventilation.
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Affiliation(s)
- Ary Serpa Neto
- Hospital Israelita Albert Einstein, Department of Critical Care MedicineAv. Albert Einstein 627, 05652-900 São Paulo, SPBrazil
- Academic Medical Center at the University of Amsterdam, Department of Intensive CareMeibergdreef 9, 1105 AZ, AmsterdamThe Netherlands
| | - Roberto R. Filho
- Hospital Israelita Albert Einstein, Department of Critical Care MedicineAv. Albert Einstein 627, 05652-900 São Paulo, SPBrazil
| | - Leonardo L. Rocha
- Hospital Israelita Albert Einstein, Department of Critical Care MedicineAv. Albert Einstein 627, 05652-900 São Paulo, SPBrazil
| | - Marcus J. Schultz
- Academic Medical Center at the University of Amsterdam, Department of Intensive CareMeibergdreef 9, 1105 AZ, AmsterdamThe Netherlands
- Academic Medical Center at the University of Amsterdam, Laboratory of Experimental Intensive Care and Anesthesiology (L·E·I·C·A)Meibergdreef 9; 1105 AZ, AmsterdamThe Netherlands
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Beatmungskonzepte beim herzchirurgischen Patienten. ZEITSCHRIFT FUR HERZ THORAX UND GEFASSCHIRURGIE 2014. [DOI: 10.1007/s00398-014-1122-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Guo R, Fan E. Beyond low tidal volumes: ventilating the patient with acute respiratory distress syndrome. Clin Chest Med 2014; 35:729-41. [PMID: 25453421 DOI: 10.1016/j.ccm.2014.08.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cornerstone of lung protective ventilation in patients with acute respiratory distress syndrome (ARDS) is a pressure- and volume-limited strategy. Other interventions have also been investigated. Although no method for positive end-expiratory pressure (PEEP) titration has proven most advantageous, experimental and clinical data support the use of higher PEEP in patients with moderate/severe ARDS. There is no benefit to the early use of high-frequency oscillatory ventilation (HFOV) in patients with moderate/severe ARDS, although it may be considered as rescue therapy. Further investigations of novel methods of bedside monitoring of mechanical ventilation may help identify the optimal ventilatory strategy.
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Affiliation(s)
- Ray Guo
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Eddy Fan
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada.
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Ziebart A, Hartmann EK, Thomas R, Liu T, Duenges B, Schad A, Bodenstein M, Thal SC, David M. Low tidal volume pressure support versus controlled ventilation in early experimental sepsis in pigs. Respir Res 2014; 15:101. [PMID: 25189285 PMCID: PMC4172867 DOI: 10.1186/s12931-014-0101-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 08/18/2014] [Indexed: 11/30/2022] Open
Abstract
Background In moderate acute respiratory distress syndrome (ARDS) several studies support the usage of assisted spontaneous breathing modes. Only limited data, however, focus on the application in systemic sepsis and developing lung injury. The present study examines the effects of immediate initiation of pressure support ventilation (PSV) in a model of sepsis-induced ARDS. Methods 18 anesthetized pigs received a two-staged continuous lipopolysaccharide infusion to induce lung injury. The animals were randomly assigned to PSV or volume controlled (VCV) lung protective ventilation (tidal volume each 6 ml kg-1, n = 2x9) over six hours. Gas exchange parameters, hemodynamics, systemic inflammation, and ventilation distribution by multiple inert gas elimination and electrical impedance tomography were assessed. The post mortem analysis included histopathological scoring, wet to dry ratio, and alveolar protein content. Results Within six hours both groups developed a mild to moderate ARDS with comparable systemic inflammatory response and without signs of improving gas exchange parameters during PSV. The PSV group showed signs of more homogenous ventilation distribution by electrical impedance tomography, but only slightly less hyperinflated lung compartments by multiple inert gas elimination. Post mortem and histopathological assessment yielded no significant intergroup differences. Conclusions In a porcine model of sepsis-induced mild ARDS immediate PSV was not superior to VCV. This contrasts with several experimental studies from non-septic mild to moderate ARDS. The present study therefore assumes that not only severity, but also etiology of lung injury considerably influences the response to early initiation of PSV.
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Spontaneous breathing with biphasic positive airway pressure attenuates lung injury in hydrochloric acid-induced acute respiratory distress syndrome. Anesthesiology 2014; 120:1441-9. [PMID: 24722174 DOI: 10.1097/aln.0000000000000259] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND It has been proved that spontaneous breathing (SB) with biphasic positive airway pressure (BIPAP) can improve lung aeration in acute respiratory distress syndrome compared with controlled mechanical ventilation. The authors hypothesized that SB with BIPAP would attenuate lung injury in acute respiratory distress syndrome compared with pressure-controlled ventilation. METHODS Twenty male New Zealand white rabbits with hydrochloric acid aspiration-induced acute respiratory distress syndrome were randomly ventilated using the BIPAP either with SB (BIPAP plus SB group) or without SB (BIPAP minus SB group) for 5 h. Inspiration pressure was adjusted to maintain the tidal volume at 6 ml/kg. Both groups received the same positive end-expiratory pressure level at 5 cm H2O for hemodynamic goals. Eight healthy animals without ventilatory support served as the control group. RESULTS The BIPAP plus SB group presented a lower ratio of dead space ventilation to tidal volume, a lower respiratory rate, and lower minute ventilation. No significant difference in the protein levels of interleukin-6 and interleukin-8 in plasma, bronchoalveolar lavage fluid, and lung tissue were measured between the two experimental groups. However, SB resulted in lower messenger ribonucleic acid levels of interleukin-6 (mean ± SD; 1.8 ± 0.7 vs. 2.6 ± 0.5; P = 0.008) and interleukin-8 (2.2 ± 0.5 vs. 2.9 ± 0.6; P = 0.014) in lung tissues. In addition, lung histopathology revealed less injury in the BIPAP plus SB group (lung injury score, 13.8 ± 4.6 vs. 21.8 ± 5.7; P < 0.05). CONCLUSION In hydrochloric acid-induced acute respiratory distress syndrome, SB with BIPAP attenuated lung injury and improved respiratory function compared with controlled ventilation with low tidal volume.
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Higher levels of spontaneous breathing induce lung recruitment and reduce global stress/strain in experimental lung injury. Anesthesiology 2014; 120:673-82. [PMID: 24406799 DOI: 10.1097/aln.0000000000000124] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Spontaneous breathing (SB) in the early phase of the acute respiratory distress syndrome is controversial. Biphasic positive airway pressure/airway pressure release ventilation (BIPAP/APRV) is commonly used, but the level of SB necessary to maximize potential beneficial effects is unknown. METHODS Experimental acute respiratory distress syndrome was induced by saline lung lavage in anesthetized and mechanically ventilated pigs (n = 12). By using a Latin square and crossover design, animals were ventilated with BIPAP/APRV at four different levels of SB in total minute ventilation (60 min each): (1) 0% (BIPAP/APRV0%); (2) greater than 0 to 30% (BIPAP/APRV>0-30%); (3) greater than 30 to 60% (BIPAP/APRV>30-60%); and (4) greater than 60% (BIPAP/APRV>60%). Gas exchange, hemodynamics, and respiratory variables were measured. Lung aeration was assessed by high-resolution computed tomography. The distribution of perfusion was marked with Ga-labeled microspheres and evaluated by positron emission tomography. RESULTS The authors found that higher levels of SB during BIPAP/APRV (1) improved oxygenation; (2) decreased mean transpulmonary pressure (stress) despite increased inspiratory effort; (3) reduced nonaerated lung tissue, with minimal changes in the distribution of perfusion, resulting in decreased low aeration/perfusion zones; and (4) decreased global strain (mean ± SD) (BIPAP/APRV0%: 1.39 ± 0.08; BIPAP/APRV0-30%: 1.33 ± 0.03; BIPAP/APRV30-60%: 1.27 ± 0.06; BIPAP/APRV>60%: 1.25 ± 0.04, P < 0.05 all vs. BIPAP/APRV0%, and BIPAP/APRV>60% vs. BIPAP/APRV0-30%). CONCLUSIONS In a saline lung lavage model of experimental acute respiratory distress syndrome in pigs, levels of SB during BIPAP/APRV higher than currently recommended for clinical practice, that is, 10 to 30%, improve oxygenation by increasing aeration in dependent lung zones without relevant redistribution of perfusion. In presence of lung recruitment, higher levels of SB reduce global stress and strain despite an increase in inspiratory effort.
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Spontaneous Breathing, Extrapulmonary CO2 Removal, and Ventilator-Induced Lung Injury Risk. Crit Care Med 2014; 42:758-60. [DOI: 10.1097/ccm.0000000000000206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Saddy F, Moraes L, Santos CL, Oliveira GP, Cruz FF, Morales MM, Capelozzi VL, de Abreu MG, Garcia CSNB, Pelosi P, Rocco PRM. Biphasic positive airway pressure minimizes biological impact on lung tissue in mild acute lung injury independent of etiology. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2013; 17:R228. [PMID: 24103805 PMCID: PMC4057608 DOI: 10.1186/cc13051] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 08/28/2013] [Indexed: 01/01/2023]
Abstract
Introduction Biphasic positive airway pressure (BIVENT) is a partial support mode that employs pressure-controlled, time-cycled ventilation set at two levels of continuous positive airway pressure with unrestricted spontaneous breathing. BIVENT can modulate inspiratory effort by modifying the frequency of controlled breaths. Nevertheless, the optimal amount of inspiratory effort to improve respiratory function while minimizing ventilator-associated lung injury during partial ventilatory assistance has not been determined. Furthermore, it is unclear whether the effects of partial ventilatory support depend on acute lung injury (ALI) etiology. This study aimed to investigate the impact of spontaneous and time-cycled control breaths during BIVENT on the lung and diaphragm in experimental pulmonary (p) and extrapulmonary (exp) ALI. Methods This was a prospective, randomized, controlled experimental study of 60 adult male Wistar rats. Mild ALI was induced by Escherichia coli lipopolysaccharide either intratracheally (ALIp) or intraperitoneally (ALIexp). After 24 hours, animals were anesthetized and further randomized as follows: (1) pressure-controlled ventilation (PCV) with tidal volume (Vt) = 6 ml/kg, respiratory rate = 100 breaths/min, PEEP = 5 cmH2O, and inspiratory-to-expiratory ratio (I:E) = 1:2; or (2) BIVENT with three spontaneous and time-cycled control breath modes (100, 75, and 50 breaths/min). BIVENT was set with two levels of CPAP (Phigh = 10 cmH2O and Plow = 5 cmH2O). Inspiratory time was kept constant (Thigh = 0.3 s). Results BIVENT was associated with reduced markers of inflammation, apoptosis, fibrogenesis, and epithelial and endothelial cell damage in lung tissue in both ALI models when compared to PCV. The inspiratory effort during spontaneous breaths increased during BIVENT-50 in both ALI models. In ALIp, alveolar collapse was higher in BIVENT-100 than PCV, but decreased during BIVENT-50, and diaphragmatic injury was lower during BIVENT-50 compared to PCV and BIVENT-100. In ALIexp, alveolar collapse during BIVENT-100 and BIVENT-75 was comparable to PCV, while decreasing with BIVENT-50, and diaphragmatic injury increased during BIVENT-50. Conclusions In mild ALI, BIVENT had a lower biological impact on lung tissue compared to PCV. In contrast, the response of atelectasis and diaphragmatic injury to BIVENT differed according to the rate of spontaneous/controlled breaths and ALI etiology.
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Abstract
Sedation is used almost universally in the care of critically ill patients, especially in those who require mechanical ventilatory support or other life-saving invasive procedures. This review will focus on the sedation strategies for critically ill patients and the pharmacology of commonly used sedative agents. The role of neuromuscular blocking agents in the ICU will be examined and the pharmacology of commonly used agents is reviewed. Finally a strategy for rational use of these sedative and neuromuscular blocking agents in critically ill patients will be proposed.
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Affiliation(s)
- Annop Piriyapatsom
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts 02115, USA
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The comparison of spontaneous breathing and muscle paralysis in two different severities of experimental lung injury. Crit Care Med 2013; 41:536-45. [PMID: 23263584 DOI: 10.1097/ccm.0b013e3182711972] [Citation(s) in RCA: 177] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The benefits of spontaneous breathing over muscle paralysis have been proven mainly in mild lung injury; no one has yet evaluated the effects of spontaneous breathing in severe lung injury. We investigated the effects of spontaneous breathing in two different severities of lung injury compared with muscle paralysis. DESIGN Prospective, randomized, animal study. SETTING University animal research laboratory. SUBJECTS Twenty-eight New Zealand white rabbits. INTERVENTIONS Rabbits were randomly divided into the mild lung injury (surfactant depletion) group or severe lung injury (surfactant depletion followed by injurious mechanical ventilation) group and ventilated with 4-hr low tidal volume ventilation with spontaneous breathing or without spontaneous breathing (prevented by a neuromuscular blocking agent). Inspiratory pressure was adjusted to control tidal volume to 5-7 mL/kg, maintaining a plateau pressure less than 30 cm H2O. Dynamic CT was used to evaluate changes in lung aeration and the regional distribution of tidal volume. MEASUREMENTS AND RESULTS In mild lung injury, spontaneous breathing improved oxygenation and lung aeration by redistribution of tidal volume to dependent lung regions. However, in severe lung injury, spontaneous breathing caused a significant increase in atelectasis with cyclic collapse. Because of the severity of lung injury, this group had higher plateau pressure and more excessive spontaneous breathing effort, resulting in the highest transpulmonary pressure and the highest driving pressure. Although no improvements in lung aeration were observed, muscle paralysis with severe lung injury resulted in better oxygenation, more even tidal ventilation, and less histological lung injury. CONCLUSIONS In animals with mild lung injury, spontaneous breathing was beneficial to lung recruitment; however, in animals with severe lung injury, spontaneous breathing could worsen lung injury, and muscle paralysis might be more protective for injured lungs by preventing injuriously high transpulmonary pressure and high driving pressure.
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Abstract
The ability to compensate for life-threatening failure of respiratory function is perhaps the signature technology of intensive care medicine. Unchanging needs for providing effective life-support with minimized risk and optimized comfort have been, are now, and will be the principal objectives of providing mechanical ventilation. Important lessons acquired over nearly half-a-century of ICU care have brought us closer to meeting them, as technological advances in instrumentation now effectively put this hard-won knowledge into action. Rising demand in the face of economic constraints is likely to drive future innovations focused on reducing the need for user input, automating multi-element protocols, and carefully monitoring the patient for progress and complications.
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Affiliation(s)
- John J Marini
- University of Minnesota, Regions Hospital MS11203B, 640 Jackson Street, St Paul, MN 55101, USA.
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Ho G, Wills A, Cranshaw J. Evaluation of a novel formula for prediction of arterial oxygen partial pressure after changes in F I O2. Br J Anaesth 2013; 110:312-3. [DOI: 10.1093/bja/aes483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Lellouche F, Lipes J. Prophylactic protective ventilation: lower tidal volumes for all critically ill patients? Intensive Care Med 2013; 39:6-15. [PMID: 23108608 DOI: 10.1007/s00134-012-2728-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 09/28/2012] [Indexed: 12/17/2022]
Abstract
High tidal volumes have historically been recommended for mechanically ventilated patients during general anesthesia. High tidal volumes have been shown to increase morbidity and mortality in patients suffering from acute respiratory distress syndrome (ARDS). Barriers exist in implementing a tidal volume reduction strategy related to the inherent difficulty in changing one's practice patterns, to the current need to individualize low tidal volume settings only for a specific subgroup of mechanically ventilated patients (i.e., ARDS patients), the difficulty in determining the predicated body weight (requiring the patient's height and a complex formula). Consequently, a protective ventilation strategy is often under-utilized as a therapeutic option, even in ARDS. Recent data supports the generalization of this strategy prophylactically to almost all mechanically ventilated patients beginning immediately following intubation. Using tools to rapidly and reliably determine the predicted body weight (PBW), as well as the use of automated modes of ventilation are some of the potential solutions to facilitate the practice of protective ventilation and to finally ventilate our patients' lungs in a more gentle fashion to help prevent ARDS.
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Affiliation(s)
- Francois Lellouche
- Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Quebec, Université Laval, 2725 Chemin Sainte Foy, G1V4G5, Quebec, QC, Canada.
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[Ventilation in acute respiratory distress. Lung-protective strategies]. Med Klin Intensivmed Notfmed 2012; 107:596-602. [PMID: 23093038 DOI: 10.1007/s00063-012-0130-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 09/18/2012] [Indexed: 01/11/2023]
Abstract
Ventilation of patients suffering from acute respiratory distress syndrome (ARDS) with protective ventilator settings is the standard in patient care. Besides the reduction of tidal volumes, the adjustment of a case-related positive end-expiratory pressure and preservation of spontaneous breathing activity at least 48 h after onset is part of this strategy. Bedside techniques have been developed to adapt ventilatory settings to the individual patient and the different stages of ARDS. This article reviews the pathophysiology of ARDS and ventilator-induced lung injury and presents current evidence-based strategies for ventilator settings in ARDS.
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