Mechanical insufflation-exsufflation (MI-E) is traditionally used in the neuromuscular population. There is growing interest of MI-E use in invasively ventilated critically ill adults. We aimed to map current evidence on MI-E use in invasively ventilated critically ill adults. Two authors independently searched electronic databases MEDLINE, Embase, and CINAHL via the Ovid platform; PROSPERO; Cochrane Library; ISI Web of Science; and International Clinical Trials Registry Platform between January 1990–April 2021. Inclusion criteria were (1) adult critically ill invasively ventilated subjects, (2) use of MI-E, (3) study design with original data, and (4) published from 1990 onward. Data were extracted by 2 authors independently using a bespoke extraction form. We used Mixed Methods Appraisal Tool to appraise risk of bias. Theoretical Domains Framework was used to interpret qualitative data. Of 3,090 citations identified, 28 citations were taken forward for data extraction. Main indications for MI-E use during invasive ventilation were presence of secretions and mucus plugging (13/28, 46%). Perceived contraindications related to use of high levels of positive pressure (18/28, 68%). Protocolized MI-E settings with a pressure of ±40 cm H2O were most commonly used, with detail on timing, flow, and frequency of prescription infrequently reported. Various outcomes were re-intubation rate, wet sputum weight, and pulmonary mechanics. Only 3 studies reported the occurrence of adverse events. From qualitative data, the main barrier to MI-E use in this subject group was lack of knowledge and skills. We concluded that there is little consistency in how MI-E is used and reported, and therefore, recommendations about best practices are not possible.
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BACKGROUND: Critically ill patients receiving invasive ventilation are at risk of sputum retention. Mechanical insufflation-exsufflation (MI-E) is a technique used to mobilise sputum and optimise airway clearance. Recently, interest has increased in the use of mechanical insufflation-exsufflation for invasively ventilated critically ill adults, but evidence for the feasibility, safety and efficacy of this treatment is sparse. The aim of this scoping review is to map current and emerging evidence on the feasibility, safety and efficacy of MI-E for invasively ventilated adult patients with the aim of highlighting knowledge gaps and identifying areas for future research. Specific research questions aim to identify information informing indications and contraindications to the use of MI-E in the invasively ventilated adult, MI-E settings used, outcome measures reported within studies, adverse effects reported and perceived barriers and facilitators to using MI-E reported.METHODS: We will search electronic databases MEDLINE, EMBASE, CINAHL using the OVID platform, PROSPERO, The Cochrane Library, ISI Web of Science and the International Clinical Trials Registry Platform. Two authors will independently screen citations, extract data and evaluate risk of bias using the Mixed Methods Appraisal Tool. Studies included will present original data and describe MI-E in invasively ventilated adult patients from 1990 onwards. Our exclusion criteria are studies in a paediatric population, editorial pieces or letters and animal or bench studies. Search results will be presented in a PRISMA study flow diagram. Descriptive statistics will be used to summarise quantitative data. For qualitative data relating to barriers and facilitators, we will use content analysis and the Theoretical Domains Framework (TDF) as a conceptual framework. Additional tables and relevant figures will present data addressing our research questions.DISCUSSION: Our findings will enable us to map current and emerging evidence on the feasibility, safety and efficacy of MI-E for invasively ventilated critically ill adult patients. These data will provide description of how the technique is currently used, support healthcare professionals in their clinical decision making and highlight areas for future research in this important clinical area.
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The primary aims of this study were (1) to evaluate whole-body mechanical efficiency (ME) in a large group of chronic obstructive pulmonary disease (COPD) patients with a wide range of degrees of illness and (2) to examine how ME in COPD is related to absolute work rate and indices of disease severity during exercise testing. A total of 569 patients (301 male patients; GOLD stage I: 28, GOLD stage II: 166, GOLD stage III: 265, and GOLD stage IV: 110) with chronic obstructive pulmonary disease (COPD) were included in the data analysis. Individual maximal workload (watt), peak minute ventilation ((Equation is included in full-text article.)E, L/min body temperature and pressure, saturated), and peak oxygen uptake ((Equation is included in full-text article.)O2, mL/min standard temperature and pressure, dry) were determined from a maximal incremental cycle ergometer test. Ventilatory and metabolic response parameters were collected during a constant work rate test at 75% of the individual maximal workload. From the exercise responses of the constant work rate test, the gross ME was calculated. The mean whole-body gross ME was 11.0 ± 3.5% at 75% peak power. The ME declined significantly (P < .001) with increasing severity of the disease when measured at the same relative power. Log-transformed absolute work rate (r = .87, P < .001) was the strongest independent predictor of gross ME. Body mass was the single other variable that contributed significantly to the linear regression model. Gross ME in COPD was largely predicted by the absolute work rate (r = .87; P < .001) while indices of the severity of the disease did not predict ME in COPD.
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