Effect of Electrical Muscle Stimulation on Upper and Lower Limb Muscles in Critically Ill Patients: A Two-Center Randomized Controlled Trial

OBJECTIVES: Electrical muscle stimulation is widely used to enhance lower limb mobilization. Although upper limb muscle atrophy is common in critically ill patients, electrical muscle stimulation application for the upper limbs has been rarely reported. The purpose of this study was to investigate whether electrical muscle stimulation prevents upper and lower limb muscle atrophy and improves physical function. DESIGN: Randomized controlled trial. SETTING: Two-center, mixed medical/surgical ICU. PATIENTS: Adult patients who were expected to be mechanically ventilated for greater than 48 hours and stay in the ICU for greater than 5 days. INTERVENTIONS: Forty-two patients were randomly assigned to the electrical muscle stimulation (n = 17) or control group (n = 19). MEASUREMENTS AND MAIN RESULTS: Primary outcomes were change in muscle thickness and cross-sectional area of the biceps brachii and rectus femoris from day 1 to 5. Secondary outcomes included occurrence of ICU-acquired weakness, ICU mobility scale, length of hospitalization, and amino acid levels. The change in biceps brachii muscle thickness was -1.9% versus -11.2% in the electrical muscle stimulation and control (p = 0.007) groups, and the change in cross-sectional area was -2.7% versus -10.0% (p = 0.03). The change in rectus femoris muscle thickness was -0.9% versus -14.7% (p = 0.003) and cross-sectional area was -1.7% versus -10.4% (p = 0.04). No significant difference was found in ICU-acquired weakness (13% vs 40%; p = 0.20) and ICU mobility scale (3 vs 2; p = 0.42) between the groups. The length of hospitalization was shorter in the electrical muscle stimulation group (23 d 19-34 d vs 40 d 26-64 d) (p = 0.04). On day 3, the change in the branched-chain amino acid level was lower in the electrical muscle stimulation group (40.5% vs 71.5%; p = 0.04). CONCLUSIONS: In critically ill patients, electrical muscle stimulation prevented upper and lower limb muscle atrophy and attenuated proteolysis and decreased the length of hospitalization.