Inspiratory and expiratory muscle training in subacute stroke

Objective: To assess the effectiveness, feasibility, and safety of short-term inspiratory and expiratory muscle training (IEMT) in subacute stroke patients.

Methods: Within 2 weeks of stroke onset, 109 patients with a first ischemic stroke event were randomly assigned to the IEMT (n = 56) or sham IEMT (n = 53) study group. The IEMT consisted of 5 sets of 10 repetitions, twice a day, 5 days per week for 3 weeks, at a training workload equivalent to 30% of maximal respiratory pressures. Patients and researchers assessing outcome variables were blinded to the assigned study group. The main outcome was respiratory muscle strength assessed by maximal inspiratory and expiratory pressures (PImax, PEmax). Respiratory complications at 6 months were also recorded.

Results: Both groups improved respiratory muscle strength during the study. IEMT was associated with significantly improved %PImax and %PEmax: effect size d = 0.74 (95% confidence interval [CI] 0.28–1.20) and d = 0.56 (95% CI 0.11–1.02), respectively. No significant training effect was observed for peripheral muscle strength. Respiratory complications at 6 months occurred more frequently in the sham group (8 vs 2, p = 0.042), with an absolute risk reduction of 14%. The number needed to treat to prevent one lung infection event over a follow-up of 6 months was 7. No major adverse events or side effects were observed.

Conclusion: IEMT induces significant improvement in inspiratory and expiratory muscle strength and could potentially offer an additional therapeutic tool aimed to reduce respiratory complications at 6 months in stroke patients.

Classification of evidence: This study provides Class II evidence that short-term training may have the potential to improve respiratory muscle strength in patients with subacute stroke.