The Effect of Neuromuscular Electrical Stimulation on Muscle Proteolysis, Muscle Mass and Strength, Cardiorespiratory Fitness, Functional Activity, and Quality of Life in Post-Cardiac Surgery Patients: A Narrative Review.

Advances in medical and surgical practices, along with enhanced cardiac ICU services, have led to a substantial increase in cardiac surgeries (CS). Consequently, CS is now more frequently performed on older patients undergoing complex procedures, which results in higher rates of postoperative complications (POC) such as muscle proteolysis, prolonged hospital stays and worsened clinical and functional outcomes. These complications can delay early mobilization (EM) programs and exercise as core components of post-CS rehabilitation even though sometimes they fail to prevent functional decline. Neuromuscular electrical stimulation (NMES) has emerged as a physical modality to prevent muscle atrophy, improve muscle strength (MS), and enhance overall functional ability in post-CS patients with physical limitations. Therefore, NMES has been chosen for post-operative patients with physical limitations. This review aimed to describe the effects of NMES on muscle proteolysis, muscle mass (MM) and strength (MS), cardiorespiratory fitness (CRF), functional activity, and quality of life (QoL) in post-CS patients. Data were synthesized from PubMed, Google Scholar, and CINAHL using relevant keywords, and the review included six original articles and one systematic review. Findings indicate that perioperative NMES does not significantly affect proteolysis; however, postoperative NMES appears to increase metabolism and reduce protein degradation, thereby preventing muscle weakness. Although NMES has been shown to enhance MS, its impact on increasing MM remains insignificant. Similarly, improvements in the 6-minute walk distance (6MWD), a measure of CRF, were not statistically significant, even if they were clinically meaningful. Secondary outcomes related to functional activity and QoL also did not show significant improvements. In conclusion, post-operative NMES stimulates protein anabolism and insignificantly improves MS and MM without significantly enhancing CRF as measured by 6MWD. This may explain the lack of significant improvements in functional activity and QoL in post-CS patients.