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Avilés-Rojas N, Hurtado DE. Whole-lung finite-element models for mechanical ventilation and respiratory research applications. Front Physiol 2022; 13:984286. [PMID: 36267590 PMCID: PMC9577367 DOI: 10.3389/fphys.2022.984286] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022] Open
Abstract
Mechanical ventilation has been a vital treatment for Covid-19 patients with respiratory failure. Lungs assisted with mechanical ventilators present a wide variability in their response that strongly depends on air-tissue interactions, which motivates the creation of simulation tools to enhance the design of ventilatory protocols. In this work, we aim to create anatomical computational models of the lungs that predict clinically-relevant respiratory variables. To this end, we formulate a continuum poromechanical framework that seamlessly accounts for the air-tissue interaction in the lung parenchyma. Based on this formulation, we construct anatomical finite-element models of the human lungs from computed-tomography images. We simulate the 3D response of lungs connected to mechanical ventilation, from which we recover physiological parameters of high clinical relevance. In particular, we provide a framework to estimate respiratory-system compliance and resistance from continuum lung dynamic simulations. We further study our computational framework in the simulation of the supersyringe method to construct pressure-volume curves. In addition, we run these simulations using several state-of-the-art lung tissue models to understand how the choice of constitutive models impacts the whole-organ mechanical response. We show that the proposed lung model predicts physiological variables, such as airway pressure, flow and volume, that capture many distinctive features observed in mechanical ventilation and the supersyringe method. We further conclude that some constitutive lung tissue models may not adequately capture the physiological behavior of lungs, as measured in terms of lung respiratory-system compliance. Our findings constitute a proof of concept that finite-element poromechanical models of the lungs can be predictive of clinically-relevant variables in respiratory medicine.
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Affiliation(s)
- Nibaldo Avilés-Rojas
- Department of Structural and Geotechnical Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Daniel E. Hurtado
- Department of Structural and Geotechnical Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- *Correspondence: Daniel E. Hurtado,
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2
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Pournajafian A, Sakhaeyan E, Rokhtabnak F, Alimian M, Ghodrati A, Jolousi M, Ghodraty MR. Comparison of Pressure and Volume-Controlled Mechanical Ventilation in Laparoscopic Bariatric Surgery: A Randomized Crossover Trial. Anesth Pain Med 2022; 12:e123270. [PMID: 35991780 PMCID: PMC9375959 DOI: 10.5812/aapm-123270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 11/29/2022] Open
Abstract
Background The number of patients with obesity undergoing various surgeries is increasing annually, and ventilation problems are highly prevalent in these patients. Objectives We aimed to evaluate ventilation effectiveness with pressure-controlled (PC) and volume-controlled (VC) ventilation modes during laparoscopic bariatric surgery. Methods In this open-label randomized crossover clinical trial, 40 adult patients with morbid obesity candidates for laparoscopic bariatric surgery were assigned to VC-PC or PC-VC groups. Each patient received both ventilation modes sequentially for 15 min during laparoscopic surgery in a random sequence. Every 5 min, exhaled tidal volume, peak and mean airway pressure, oxygen saturation, heart rate, mean arterial pressure, and end-tidal CO2 were recorded. Blood gas analysis was done at the end of 15 min. Dynamic compliance, PaO2/FiO2 ratio, P (A-a) O2 gradient, respiratory dead space, and PaCO2-ETCO2 gradient were calculated according to the obtained results. Results The study included 40 patients with a mean age of 35.13 ± 9.06 years. There were no significant differences in peak and mean airway pressure, dynamic compliance, and hemodynamic parameters (P > 0.05). There was no significant difference between the two ventilation modes in pH, PaCO2, PaO2, PaO2/FIO2, dead space volume, and D (A-a) O2 at different time intervals (P > 0.05). Conclusions If low tidal volumes are used during adult laparoscopic bariatric surgery, mechanical ventilation with PC mode is not superior to VC mode.
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Affiliation(s)
- Alireza Pournajafian
- Anesthesiology & Pain Department, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Elmira Sakhaeyan
- Anesthesiology & Pain Department, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Faranak Rokhtabnak
- Anesthesiology & Pain Department, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mahzad Alimian
- Anesthesiology & Pain Department, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | | | - Minoo Jolousi
- Anesthesiology & Pain Department, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Ghodraty
- Anesthesiology & Pain Department, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
- Corresponding Author: Anesthesiology & Pain Department, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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Silva PL, Ball L, Rocco PRM, Pelosi P. Physiological and Pathophysiological Consequences of Mechanical Ventilation. Semin Respir Crit Care Med 2022; 43:321-334. [PMID: 35439832 DOI: 10.1055/s-0042-1744447] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mechanical ventilation is a life-support system used to ensure blood gas exchange and to assist the respiratory muscles in ventilating the lung during the acute phase of lung disease or following surgery. Positive-pressure mechanical ventilation differs considerably from normal physiologic breathing. This may lead to several negative physiological consequences, both on the lungs and on peripheral organs. First, hemodynamic changes can affect cardiovascular performance, cerebral perfusion pressure (CPP), and drainage of renal veins. Second, the negative effect of mechanical ventilation (compression stress) on the alveolar-capillary membrane and extracellular matrix may cause local and systemic inflammation, promoting lung and peripheral-organ injury. Third, intra-abdominal hypertension may further impair lung and peripheral-organ function during controlled and assisted ventilation. Mechanical ventilation should be optimized and personalized in each patient according to individual clinical needs. Multiple parameters must be adjusted appropriately to minimize ventilator-induced lung injury (VILI), including: inspiratory stress (the respiratory system inspiratory plateau pressure); dynamic strain (the ratio between tidal volume and the end-expiratory lung volume, or inspiratory capacity); static strain (the end-expiratory lung volume determined by positive end-expiratory pressure [PEEP]); driving pressure (the difference between the respiratory system inspiratory plateau pressure and PEEP); and mechanical power (the amount of mechanical energy imparted as a function of respiratory rate). More recently, patient self-inflicted lung injury (P-SILI) has been proposed as a potential mechanism promoting VILI. In the present chapter, we will discuss the physiological and pathophysiological consequences of mechanical ventilation and how to personalize mechanical ventilation parameters.
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Affiliation(s)
- Pedro Leme Silva
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lorenzo Ball
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy.,Department of Anesthesia and Critical Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neuroscience, Genoa, Italy
| | - Patricia R M Rocco
- Laboratory of Pulmonary Investigation, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Paolo Pelosi
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy.,Department of Anesthesia and Critical Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neuroscience, Genoa, Italy
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Almeida MR, Horta JGÁ, de Matos NA, de Souza ABF, Castro TDF, Cândido LDS, Andrade MC, Cangussú SD, Costa GDP, Talvani A, Bezerra FS. The effects of different ventilatory modes in female adult rats submitted to mechanical ventilation. Respir Physiol Neurobiol 2020; 284:103583. [PMID: 33202295 DOI: 10.1016/j.resp.2020.103583] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 10/30/2020] [Accepted: 11/11/2020] [Indexed: 12/15/2022]
Abstract
This study aimed to analyze the effects of volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) modes in female Wistar rats. 18 Wistar female adult rats were divided into three groups: control (CG), pressure-controlled ventilation (PCVG), and volume-controlled ventilation (VCVG). PCVG and VCVG were submitted to MV for one hour with a tidal volume (TV) of 8 mL/Kg, respiratory rate of 80 breaths/min, and positive end-expiratory pressure of 0 cmH2O. At the end of the experiment, all animals were euthanized. The neutrophils and lymphocytes influx to lung were higher in VCVG and PCVG compared to CG. The activities of superoxide dismutase, catalase and myeloperoxidase were higher in PCVG compared to CG. There was an increase in lipid peroxidation and protein oxidation in PCVG compared to CG. The levels of CCL3 and CCL5 were higher in PCVG compared to CG. In conclusions, the PCV mode promoted structural changes in the lung parenchyma, redox imbalance and inflammation in healthy adult female rats submitted to MV.
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Affiliation(s)
- Matheus Rocha Almeida
- Laboratory of Experimental Pathophysiology (LAFEx), Department of Biological Sciences (DECBI), Institute of Exact and Biological Sciences (ICEB), Federal University of Ouro Preto (UFOP), Brazil
| | - Jacques Gabriel Álvares Horta
- Laboratory of Experimental Pathophysiology (LAFEx), Department of Biological Sciences (DECBI), Institute of Exact and Biological Sciences (ICEB), Federal University of Ouro Preto (UFOP), Brazil; Department of Clinical Medicine/Pediatrics, School of Medicine, Federal University of Ouro Preto (UFOP), Ouro Preto, MG, Brazil
| | - Natália Alves de Matos
- Laboratory of Experimental Pathophysiology (LAFEx), Department of Biological Sciences (DECBI), Institute of Exact and Biological Sciences (ICEB), Federal University of Ouro Preto (UFOP), Brazil
| | - Ana Beatriz Farias de Souza
- Laboratory of Experimental Pathophysiology (LAFEx), Department of Biological Sciences (DECBI), Institute of Exact and Biological Sciences (ICEB), Federal University of Ouro Preto (UFOP), Brazil
| | - Thalles de Freitas Castro
- Laboratory of Experimental Pathophysiology (LAFEx), Department of Biological Sciences (DECBI), Institute of Exact and Biological Sciences (ICEB), Federal University of Ouro Preto (UFOP), Brazil
| | - Leandro da Silva Cândido
- Laboratory of Experimental Pathophysiology (LAFEx), Department of Biological Sciences (DECBI), Institute of Exact and Biological Sciences (ICEB), Federal University of Ouro Preto (UFOP), Brazil
| | - Mônica Campos Andrade
- Laboratory of Experimental Pathophysiology (LAFEx), Department of Biological Sciences (DECBI), Institute of Exact and Biological Sciences (ICEB), Federal University of Ouro Preto (UFOP), Brazil
| | - Sílvia Dantas Cangussú
- Laboratory of Experimental Pathophysiology (LAFEx), Department of Biological Sciences (DECBI), Institute of Exact and Biological Sciences (ICEB), Federal University of Ouro Preto (UFOP), Brazil
| | - Guilherme de Paula Costa
- Laboratory of Immunobiology of Inflammation (LABIIN), Department of Biological Sciences (DECBI), Institute of Exact and Biological Sciences (ICEB), Federal University of Ouro Preto (UFOP), Brazil
| | - André Talvani
- Laboratory of Immunobiology of Inflammation (LABIIN), Department of Biological Sciences (DECBI), Institute of Exact and Biological Sciences (ICEB), Federal University of Ouro Preto (UFOP), Brazil
| | - Frank Silva Bezerra
- Laboratory of Experimental Pathophysiology (LAFEx), Department of Biological Sciences (DECBI), Institute of Exact and Biological Sciences (ICEB), Federal University of Ouro Preto (UFOP), Brazil.
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Souza Leite W, Novaes A, Bandeira M, Olympia Ribeiro E, dos Santos AM, de Moura PH, Morais CC, Rattes C, Richtrmoc MK, Souza J, Correia de Lima GH, Pinheiro Modolo NS, Gonçalves ACE, Ramirez Gonzalez CA, do Amparo Andrade M, Dornelas De Andrade A, Cunha Brandão D, Lima Campos S. Patient-ventilator asynchrony in conventional ventilation modes during short-term mechanical ventilation after cardiac surgery: randomized clinical trial. Multidiscip Respir Med 2020; 15:650. [PMID: 32373344 PMCID: PMC7196928 DOI: 10.4081/mrm.2020.650] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 03/27/2020] [Indexed: 11/24/2022] Open
Abstract
INTRODUCTION AND AIM Studies regarding asynchrony in patients in the cardiac postoperative period are still only a few. The main objective of our study was to compare asynchronies incidence and its index (AI) in 3 different modes of ventilation (volume-controlled ventilation [VCV], pressure-controlled ventilation [PCV] and pressure-support ventilation [PSV]) after ICU admission for postoperative care. METHODS A prospective parallel randomised trialin the setting of a non-profitable hospital in Brazil. The participants were patients scheduled for cardiac surgery. Patients were randomly allocated to VCV or PCV modes of ventilation and later both groups were transitioned to PSV mode. RESULTS All data were recorded for 5 minutes in each of the three different phases: T1) in assisted breath, T2) initial spontaneous breath and T3) final spontaneous breath, a marking point prior to extubation. Asynchronies were detected and counted by visual inspection method by two independent investigators. Reliability, inter-rater agreement of asynchronies, asynchronies incidence, total and specific asynchrony indexes (AIt and AIspecific) and odds of AI ≥10% weighted by total asynchrony were analysed. A total of 17 patients randomly allocated to the VCV (n=9) or PCV (n=8) group completed the study. High inter-rated agreement for AIt (ICC 0.978; IC95%, 0,963-0.987) and good reliability (r=0.945; p<0.001) were found. Eighty-two % of patients presented asynchronies, although only 7% of their total breathing cycles were asynchronous. Early cycling and double triggering had the highest rates of asynchrony with no difference between groups. The highest odds of AI ≥10% were observed in VCV regardless the phase: OR 2.79 (1.36-5.73) in T1 vs T2, p=0.005; OR 2.61 (1.27-5.37) in T1 vs T3, p=0.009 and OR 4.99 (2.37-10.37) in T2 vs T3, p<0.001. CONCLUSIONS There was a high incidence of breathing asynchrony in postoperative cardiac patients, especially when initially ventilated in VCV. VCV group had a higher chance of AI ≥10% and this chance remained high in the following PSV phases.
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Affiliation(s)
- Wagner Souza Leite
- Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Alita Novaes
- Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Monique Bandeira
- Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | | | | | - Pedro Henrique de Moura
- Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Caio César Morais
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Catarina Rattes
- Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | | | - Juliana Souza
- Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | | | - Norma Sueli Pinheiro Modolo
- Department of Anaesthesiology, Institute of Bioscience, School of Medicine, UNESP-Universidade Estadual Paulista, Botucatu, São Paulo, Brazil
| | | | | | - Maria do Amparo Andrade
- Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | | | - Daniella Cunha Brandão
- Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
| | - Shirley Lima Campos
- Department of Physical Therapy, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil
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Rittayamai N, Katsios CM, Beloncle F, Friedrich JO, Mancebo J, Brochard L. Pressure-Controlled vs Volume-Controlled Ventilation in Acute Respiratory Failure: A Physiology-Based Narrative and Systematic Review. Chest 2015; 148:340-355. [PMID: 25927671 DOI: 10.1378/chest.14-3169] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Mechanical ventilation is a cornerstone in the management of acute respiratory failure. Both volume-targeted and pressure-targeted ventilations are used, the latter modes being increasingly used. We provide a narrative review of the physiologic principles of these two types of breath delivery, performed a literature search, and analyzed published comparisons between modes. METHODS We performed a systematic review and meta-analysis to determine whether pressure control-continuous mandatory ventilation (PC-CMV) or pressure control-inverse ratio ventilation (PC-IRV) has demonstrated advantages over volume control-continuous mandatory ventilation (VC-CMV). The Cochrane tool for risk of bias was used for methodologic quality. We also introduced physiologic criteria as quality indicators for selecting the studies. Outcomes included compliance, gas exchange, hemodynamics, work of breathing, and clinical outcomes. Analyses were completed with RevMan5 using random effects models. RESULTS Thirty-four studies met inclusion criteria, many being at high risk of bias. Comparisons of PC-CMV/PC-IRV and VC-CMV did not show any difference for compliance or gas exchange, even when looking at PC-IRV. Calculating the oxygenation index suggested a poorer effect for PC-IRV. There was no difference between modes in terms of hemodynamics, work of breathing, or clinical outcomes. CONCLUSIONS The two modes have different working principles but clinical available data do not suggest any difference in the outcomes. We included all identified trials, enhancing generalizability, and attempted to include only sufficient quality physiologic studies. However, included trials were small and varied considerably in quality. These data should help to open the choice of ventilation of patients with acute respiratory failure.
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Affiliation(s)
- Nuttapol Rittayamai
- Li Ka Shing Knowledge Institute and Critical Care Department, St. Michael's Hospital, Toronto, ON, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Division of Respiratory Diseases and Tuberculosis, Department of Medicine, Faculty of Medicine Siriraj Hospital, Bangkok, Thailand
| | - Christina M Katsios
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
| | - François Beloncle
- Li Ka Shing Knowledge Institute and Critical Care Department, St. Michael's Hospital, Toronto, ON, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Medical Intensive Care Unit, Hospital of Angers, Université d'Angers, Angers, France
| | - Jan O Friedrich
- Li Ka Shing Knowledge Institute and Critical Care Department, St. Michael's Hospital, Toronto, ON, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada
| | - Jordi Mancebo
- Servei de Medicina Intensiva, Hospital Sant Pau, Barcelona, Spain
| | - Laurent Brochard
- Li Ka Shing Knowledge Institute and Critical Care Department, St. Michael's Hospital, Toronto, ON, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; Keenan Research Centre, St. Michael's Hospital, Toronto, ON, Canada.
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Abstract
Ventilator waveforms are graphic representations of changes in pressure, flow, and volume within a ventilator circuit. The changes in these parameters over time may be displayed individually (scalars) or plotted one against another (pressure-volume and flow-volume loops). There are 6 basic shapes of scalar waveforms, but only 3 are functionally distinct (square, ramp, and sine). The pressure scalar is a particularly valuable tool when constant flow (e.g., volume control) modes are employed and an inspiratory pause is added. In this setting, inspection of the pressure waveform can allow determination of static, quasistatic, and dynamic compliance, as well as relative changes in airway resistance. Inspection of the pressure waveform can also help to identify many important aspects of patient drug responses, dyssynchrony, and air trapping (auto positive end-expiratory pressure [auto-PEEP]). Depending on the ventilation mode employed, the shape of the flow waveform may be set by the ventilator operator or may be dependent on patient effort and lung mechanics. Decelerating flow patterns have several important advantages when this option is available. Inspection of flow waveforms is crucial in the recognition of dyssynchrony, setting optimal inspiratory times, evaluating responses to bronchodilators, and the recognition of auto-PEEP. The volume waveform often contains somewhat less useful information than the other 2 scalars, but plays a crucial role in the identification of leaks in the circuit. Pressure-volume loops are particularly useful in setting PEEP and peak inspiratory pressure ranges. Inspection of these loops also often helps in the evaluation of lung mechanics, in the identification of circuit leaks, and in the assessment of patient triggering effort. Flow-volume loops are extremely useful in the identification of leaks and excessive airway secretions as well as alterations in airway resistance. Lastly, serial waveform inspection is crucial to the identification and resolution of patient-ventilator dyssynchrony in many cases.
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Affiliation(s)
- Matthew S Mellema
- Small Animal Emergency and Critical Care Service, Department of Veterinary Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
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Chacko B, Peter JV, Tharyan P, John G, Jeyaseelan L. Pressure-controlled versus volume-controlled ventilation for acute respiratory failure due to acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Cochrane Database Syst Rev 2015; 1:CD008807. [PMID: 25586462 PMCID: PMC6457606 DOI: 10.1002/14651858.cd008807.pub2] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) account for one-quarter of cases of acute respiratory failure in intensive care units (ICUs). A third to half of patients will die in the ICU, in hospital or during follow-up. Mechanical ventilation of people with ALI/ARDS allows time for the lungs to heal, but ventilation is invasive and can result in lung injury. It is uncertain whether ventilator-related injury would be reduced if pressure delivered by the ventilator with each breath is controlled, or whether the volume of air delivered by each breath is limited. OBJECTIVES To compare pressure-controlled ventilation (PCV) versus volume-controlled ventilation (VCV) in adults with ALI/ARDS to determine whether PCV reduces in-hospital mortality and morbidity in intubated and ventilated adults. SEARCH METHODS In October 2014, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Isssue 9), MEDLINE (1950 to 1 October 2014), EMBASE (1980 to 1 October 2014), the Latin American Caribbean Health Sciences Literature (LILACS) (1994 to 1 October 2014) and Science Citation Index-Expanded (SCI-EXPANDED) at the Institute for Scientific Information (ISI) Web of Science (1990 to 1 October 2014), as well as regional databases, clinical trials registries, conference proceedings and reference lists. SELECTION CRITERIA Randomized controlled trials (RCTs) and quasi-RCTs (irrespective of language or publication status) of adults with a diagnosis of acute respiratory failure or acute on chronic respiratory failure and fulfilling the criteria for ALI/ARDS as defined by the American-European Consensus Conference who were admitted to an ICU for invasive mechanical ventilation, comparing pressure-controlled or pressure-controlled inverse-ratio ventilation, or an equivalent pressure-controlled mode (PCV), versus volume-controlled ventilation, or an equivalent volume-controlled mode (VCV). DATA COLLECTION AND ANALYSIS Two review authors independently screened and selected trials, assessed risk of bias and extracted data. We sought clarification from trial authors when needed. We pooled risk ratios (RRs) for dichotomous data and mean differences (MDs) for continuous data with their 95% confidence intervals (CIs) using a random-effects model. We assessed overall evidence quality using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach. MAIN RESULTS We included three RCTs that randomly assigned a total of 1089 participants recruited from 43 ICUs in Australia, Canada, Saudi Arabia, Spain and the USA. Risk of bias of the included studies was low. Only data for mortality and barotrauma could be combined in the meta-analysis. We downgraded the quality of evidence for the three mortality outcomes on the basis of serious imprecision around the effect estimates. For mortality in hospital, the RR with PCV compared with VCV was 0.83 (95% CI 0.67 to 1.02; three trials, 1089 participants; moderate-quality evidence), and for mortality in the ICU, the RR with PCV compared with VCV was 0.84 (95% CI 0.71 to 0.99; two trials, 1062 participants; moderate-quality evidence). One study provided no evidence of clear benefit with the ventilatory mode for mortality at 28 days (RR 0.88, 95% CI 0.73 to 1.06; 983 participants; moderate-quality evidence). The difference in effect on barotrauma between PCV and VCV was uncertain as the result of imprecision and different co-interventions used in the studies (RR 1.24, 95% CI 0.87 to 1.77; two trials, 1062 participants; low-quality evidence). Data from one trial with 983 participants for the mean duration of ventilation, and from another trial with 78 participants for the mean number of extrapulmonary organ failures that developed with PCV or VCV, were skewed. None of the trials reported on infection during ventilation or quality of life after discharge. AUTHORS' CONCLUSIONS Currently available data from RCTs are insufficient to confirm or refute whether pressure-controlled or volume-controlled ventilation offers any advantage for people with acute respiratory failure due to acute lung injury or acute respiratory distress syndrome. More studies including a larger number of people given PCV and VCV may provide reliable evidence on which more firm conclusions can be based.
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Affiliation(s)
- Binila Chacko
- Christian Medical College & HospitalMedical Intensive Care UnitVelloreIndia
| | - John V Peter
- Christian Medical College & HospitalMedical Intensive Care UnitVelloreIndia
| | - Prathap Tharyan
- Christian Medical CollegeCochrane South Asia, Prof. BV Moses Centre for Evidence‐Informed Healthcare and Health PolicyCarman Block II FloorCMC Campus, BagayamVelloreTamil NaduIndia632002
| | - George John
- Christian Medical College & HospitalMedical Intensive Care UnitVelloreIndia
| | - Lakshmanan Jeyaseelan
- Christian Medical CollegeDepartment of BiostatisticsBagayamVelloreTamil NaduIndia632002
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Elbouhy MS, AbdelHalim HA, Hashem AM. Effect of respiratory muscles training in weaning of mechanically ventilated COPD patients. EGYPTIAN JOURNAL OF CHEST DISEASES AND TUBERCULOSIS 2014. [DOI: 10.1016/j.ejcdt.2014.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Abstract
Respiratory failure (RF) can be attributed to a plethora of neuromuscular diseases (NMDs) and manifests clinically in a multitude of overt or more subtle ways. The basic principles of pathophysiology, diagnosis and treatment of neurologic diseases and of RF apply concomitantly to this subset of patients. Various entities should be approached according to the latest evidence-based recommendations. Treatment follows the natural disease progression, from minimal respiratory assistance to mechanical ventilation (MV). A comprehensive treatment plan has to be formulated that takes into consideration the patient's wishes.
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Gupta SD, Kundu SB, Ghose T, Maji S, Mitra K, Mukherjee M, Mandal S, Sarbapalli D, Bhattacharya S, Bhattacharya S. A comparison between volume-controlled ventilation and pressure-controlled ventilation in providing better oxygenation in obese patients undergoing laparoscopic cholecystectomy. Indian J Anaesth 2012; 56:276-82. [PMID: 22923828 PMCID: PMC3425289 DOI: 10.4103/0019-5049.98777] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Background: The maintenance of oxygenation is a commonly encountered problem in obese patients undergoing laparoscopic cholecystectomy. There is no specific guideline on the ventilation modes for this group of patients. Although several studies have been performed to determine the optimal ventilatory settings in these patients, the answer is yet to be found. The aim of this study was to evaluate the efficacy of pressure-controlled ventilation (PCV) in comparison with volume-controlled ventilation (VCV) for maintaining oxygenation during laparoscopic cholecystectomy in obese patients. Methods: One hundred and two adult patients of ASA physical status I and II, Body Mass Index of 30–40 kg/m2, scheduled for laparoscopic cholecystectomy were included in this prospective randomized open-label parallel group study. To start with, all patients received VCV. Fifteen minutes after creation of pneumoperitoneum, they were randomized to receive either VCV (Group V) or PCV (Group P). The ventilatory parameters were adjusted accordingly to maintain the end-tidal CO2 between 35 and 40 mmHg. Respiratory rate, tidal volume, minute ventilation and peak airway pressure were noted. Arterial blood gas analyses were done 15 min after creation of pneumoperitoneum and at 20-min intervals thereafter till the end of the surgery. All data were analysed statistically. Results: Patients in Group P showed a statistically significant (P < 0.05) higher level of PaO2 and lower value of PAO2–PaO2 than those in Group V. Conclusion: PCV is a more effective mode of ventilation in comparison with VCV regarding oxygenation in obese patients undergoing laparoscopic cholecystectomy.
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Affiliation(s)
- Sampa Dutta Gupta
- Department of Anaesthesiology, Institute of Post Graduate Medical Education and Research, Kolkata, India
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Munroe B, Curtis K. Assessment, monitoring and emergency nursing care in blunt chest injury: A case study. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.aenj.2011.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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