Efficacy of Interventions to Improve Respiratory Function After Stroke

Abstract

Background: The aim of this study was to systematically review all current interventions that have been utilized to improve respiratory function and activity after stroke.

Methods: Specific searches were conducted. The experimental intervention had to be planned, structured, repetitive, purposive, and delivered with the aim of improving respiratory function. Outcomes included respiratory strength (maximum inspiratory pressure [P_Imax], maximum expiratory pressure [P_Emax]) and endurance, lung function (FVC, FEV₁, and peak expiratory flow [PEF]), dyspnea, and activity. The quality of the randomized trials was assessed by the PEDro scale using scores from the Physiotherapy Evidence Database (www.pedro.org.au), and risk of bias was assessed in accordance with the Cochrane Handbook for Systematic Reviews of Interventions.

Results: The 17 included trials had a mean PEDro score of 5.7 (range 4-8) and involved 616 participants. Meta-analyses showed that respiratory muscle training significantly improved all outcomes of interest: P_Imax (weighted mean difference 11 cm H₂O, 95% CI 7-15, I² = 0%), P_Emax (8 cm H₂O, 95% CI 2-15, I² = 65%), FVC (0.25 L, 95% CI 0.12-0.37, I² = 29%), FEV₁ (0.24 L, 95% CI 0.17-0.30, I² = 0%), PEF (0.51 L/s, 95% CI 0.10-0.92, I² = 0%), dyspnea (standardized mean difference -1.6 points, 95% CI -2.2 to -0.9; I² = 0%), and activity (standardized mean difference 0.78, 95% CI 0.22-1.35, I² = 0%). Meta-analyses found no significant results for the effects of breathing exercises on lung function. For the remaining interventions (ie, aerobic and postural exercises) and the addition of electrical stimulation, meta-analyses could not be performed.

Conclusions: This systematic review reports 5 possible interventions used to improve respiratory function after stroke. Respiratory muscle training proved to be effective for improving inspiratory and expiratory strength, lung function, and dyspnea, and benefits were carried over to activity. However, there is still no evidence to accept or refute the efficacy of aerobic, breathing, and postural exercises, or the addition of electrical stimulation in respiratory function.

Keywords: comparative effectiveness research; dyspnea; maximal respiratory pressures; motor activity; spirometry; stroke.