Effects of neuromuscular electrical stimulation on functional capacity and quality of life among patients after cardiac surgery: A systematic review and meta-analysis

Background: Neuromuscular electrical stimulation (NMES) is a possible adjunctive therapy applied to cardiac surgery patients to improve physical function, but the results are still controversial. A systematic review and meta-analysis was conducted to investigate the effects of NMES on functional capacity and quality of life (QoL) in cardiac surgery patients. Methods: The following databases PubMed, Embase, Medicine, CINAHL, and the Cochrane Central Register of Controlled Trials were searched for the English language from inception up to March 2021. A systematic targeted literature search evaluating the effects of NMES on physical function and QoL in cardiac surgery patients. The effect size of NMES was presented as the mean difference (MD)/standardized mean difference (SMD) and its 95% confidence interval using fixed/random effect models according to heterogeneity. Two reviewers independently screened and appraised each study by using the Cochrane Risk of Bias Tool. Results: Six studies were included involving 400 cardiac surgery patients. The meta-analysis showed that NMES had effect on knee extensor strength (SMD = 1.68; p = 0.05), but had no effects on 6-minute walking distance (MD = 44.08; p = 0.22), walking speed (MD = 0.05; p = 0.24), grip strength (MD = 3.01; p = 0.39), or QoL (SMD = 0.53; p = 0.19). Conclusions: NMES use in cardiac surgery patients is limited by low to moderate quality. Existing evidence shows that NMES is safe and effective for improving knee extensor strength. (c) 2021 The Authors. Published by Elsevier Ltd on behalf of Japanese College of Cardiology. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )