Early type II fiber atrophy in intensive care unit patients with nonexcitable muscle membrane


  • J. Bierbrauer
  • S. Koch
  • C. Olbricht
  • J. Hamati
  • D. Lodka
  • J. Schneider
  • A. Luther-Schroeder
  • C. Kleber
  • K. Faust
  • S. Wiesener
  • C.D. Spies
  • J. Spranger
  • S. Spuler
  • J. Fielitz
  • S. Weber-Carstens


  • Critical Care Medicine


  • Crit Care Med 40 (2): 647-650


  • OBJECTIVE: Intensive care unit-acquired weakness indicates increased morbidity and mortality. Nonexcitable muscle membrane after direct muscle stimulation develops early and predicts intensive care unit-acquired weakness in sedated, mechanically ventilated patients. A comparison of muscle histology at an early stage in intensive care unit-acquired weakness has not been done. We investigated whether nonexcitable muscle membrane indicates fast-twitch myofiber atrophy during the early course of critical illness. DESIGN, SETTING, AND PATIENTS: We studied patients at increased risk for development of intensive care unit-acquired weakness with Sepsis-related Organ Failure Assessment scores ≥8 on 3 of 5 consecutive days within the first week in the intensive care unit. Electrophysiological compound muscle action potentials after direct muscle stimulation and muscle biopsies were obtained at median days 7 and 5, respectively. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients with nonexcitable muscle membranes (n = 15) showed smaller median type II cross-sectional areas (p < .05), whereas type I muscle fibers did not compared with patients with preserved muscle membrane excitability (compound muscle action potentials after direct muscle stimulation ≥3.0 mV; n = 9). We also observed decreased mRNA transcription levels of myosin heavy chain isoform IIa and a lower densitometric ratio of fast-to-slow myosin heavy chain protein content. CONCLUSION:: We suggest that electrophysiological nonexcitable muscle membrane predicts preferential type II fiber atrophy in intensive care unit patients during early critical illness.