Nonexcitable muscle membrane predicts intensive care unit-acquired paresis in mechanically ventilated, sedated patients

OBJECTIVES: To investigate the predictive value of electrophysiological measurements including validation of muscle membrane excitability on the development of intensive care unit (ICU)-aquired paresis. DESIGN: Prospective observational study. SETTING: University ICU. PATIENTS: Surgical ICU patients selected upon a simplified acute physiology score > or =20 on three successive days within 1 wk after ICU admission. INTERVENTIONS: We performed serial electrophysiological measurements with onset of critical illness including conventional electrophysiological parameters and compound muscle action potentials after direct muscle stimulation (dmCMAP). Patients' awareness and muscle strength were measured sequentially by Ramsay sedation scale and an additional questionnaire and by Medical Research Council score, respectively. MEASUREMENTS AND MAIN RESULTS: Among 56 sedated patients 34 patients revealed reduced dmCMAP values