Mechanical insufflation-exsufflation for people with neuromuscular disorders

Abstract

Background: People with neuromuscular disorders (NMDs) may have weak respiratory (breathing) muscles which makes it difficult for them to effectively cough and clear mucus from the lungs. This places them at risk of recurrent chest infections and chronic lung disease. Mechanical insufflation-exsufflation (MI-E) is one of a number of techniques available to improve cough efficacy and mucus clearance. Objectives: To determine the efficacy and safety of MI-E in people with NMDs. Search methods: On 7 October 2013, we searched the following databases from inception: the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL (The Cochrane Library), MEDLINE, and EMBASE. We also searched ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform for ongoing trials. We conducted handsearches of reference lists and conference proceedings. Selection criteria: We considered randomised or quasi-randomised clinical trials, and randomised cross-over trials of MI-E used to assist airway clearance in people with a NMD and respiratory insufficiency. We considered comparisons of MI-E with no treatment, or alternative cough augmentation techniques. Data collection and analysis: Two authors independently assessed trial eligibility, extracted data, and assessed risk of bias in included studies according to standard Cochrane methodology. The primary outcome was mortality throughout follow-up or at six months follow-up. Main results: Five studies with a total of 105 participants were found to be eligible for inclusion in this review. All included trials were short-term studies (two days or less), measuring immediate effects of the interventions. There was insufficient detail in the reports to assess methods of randomisation and allocation concealment. All five studies were at a high risk of bias from lack of blinding. The studies did not report on mortality, morbidity, quality of life, serious adverse events or any of the other prespecified outcomes. One study was a randomised cross-over trial conducted over two days, in which investigators applied two interventions twice daily in randomly assigned order, with a reverse cross-over the following day. Four studies applied multiple interventions for cough augmentation to each participant, in random order. One study reported fatigue as an adverse effect of MI-E, using a visual analogue scale. Peak cough expiratory flow (PCEF) was the most common outcome measure and was reported in four studies. Based on three studies, MI-E may improve PCEF compared to an unassisted cough. All interventions increased PCEF to the critical level necessary for mucus clearance. The included studies did not clearly show that MI-E improves cough expiratory flow more than other cough augmentation techniques. Based on one study, which was at risk of assessor bias, the addition of MI-E may reduce treatment time when added to a standard airway clearance regimen with manually assisted cough. MI-E appeared to be as well tolerated as other cough augmentation techniques, based on three studies which reported comfort visual analogue scores. Authors' conclusions: The results of this review do not provide sufficient evidence on which to base clinical practice as we were unable to address important short- and long-term outcomes, including adverse effects of MI-E. There is currently insufficient evidence for or against the use of MI-E in people with NMDs. Further randomised controlled clinical trials are needed to test the safety and efficacy of MI-E.