Effects of Neuromuscular Electrical Stimulation on Muscle Mass and Strength in Critically Ill Patients After Cardiothoracic Surgery

Neuromuscular Electrical Stimulation, Intensive Care Unit Acquired Weakness, Muscle Wasting, Muscle Loss

The purposes of this study are 1) to determine whether neuromuscular electrical stimulation (NMES) is effective in preventing loss of muscle mass and strength and 2) to observe the time variation of MLT and strength from preoperative day to hospital discharge.

In the amendment of June 2011, a twofold study setting was defined in order to recruit patients not only before, but also after cardiothoracic surgery. In sample A, patients were recruited before surgery. In sample B, patients were recruited after surgery. On postoperative day 1, randomization was performed for sample A and B separately. To ensure balance of the NMES and control groups with respect to disease severity, randomization was stratified by the SAPS II score on the first postoperative day. In the intervention group, the anterior muscles of both thighs were electrically stimulated from the first postoperative day until ICU discharge for a maximum of 14 days. In the control group, the electrodes were applied, but no electricity was delivered.The primary outcomes muscle layer thickness (MLT) and muscle strength were assessed from the first postoperative day to ICU discharge and at hospital discharge. All patients in sample A had an additional assessment of MLT and strength before surgery. All data are analyzed according to the intention-to-treat principle with no imputation for any missing data. Linear mixed models are used to account for the repeated measurements per patient and to determine any fixed effects on MLT and MRC score.