Effects of Neuromuscular Electrical Stimulation on Muscle Layer Thickness of Knee Extensor Muscles in Intensive Care Unit Patients: a Pilot Study

Objective: It is known that patients in the intensive care unit show an enormous loss of muscle mass. Neuromuscular electrical stimulation is effective in enhancing strength and endurance in immobilized patients. The aim of this study was to evaluate the effects of neuromuscular electrical stimulation on muscle layer thickness of knee extensor muscles in intensive care unit patients.

Design: Randomized, controlled, double-blind, pilot trial.

Patients: Thirty-three patients, male to female ratio 26:7, mean age 55 years (standard deviation 15).

Methods: After enrolment in the study, intensive care unit patients (main diagnoses: polytrauma, cardiovascular diseases, transplantation, pneumonia, cancer) were stratified (based on the length of their stay in hospital) into 2 groups: 17 acute patients (< 7 days) and 16 long-term patients (> 14 days). Both groups were randomized to a stimulation group or a sham-stimulation group. Neuromuscular electrical stimulation was applied to knee extensor muscles for a period of 4 weeks (session time 30-60 minutes, 5 days/week). Ultrasound measurements were performed before and after the stimulation period to quantify muscle layer thickness of knee extensor muscles.

Results: Only stimulated long-term patients (+4.9%) showed a significant (p = 0.013) increase in muscle layer thickness compared with sham-stimulated patients (-3.2%).

Conclusion: Neuromuscular electrical stimulation appears to be a useful adjunct to revert muscle wasting in intensive care unit long-term patients; however, larger studies with a larger sample size are needed to confirm these promising, but preliminary, results.