UMEM Educational Pearls

Neuromuscular Blocking Agents in the Critically Ill

  • NMBAs are used in critically ill patients for RSI, patient-ventilator asynchrony, reducing intra-abdominal pressure, reducing intracranial pressure, and preventing shivering during therapeutic hypothermia.
  • There are a number of alterations in critical illness that affect the action of NMBAs
    • Electrolyte abnormalities
      • Hypercalcemia: decreases duration of blockade
      • Hypermagnesemia: prolongs duration of blockade
    • Acidosis: can enhance effect of nondepolarizing agents
    • Hepatic dysfunction: prolongs effects of vecuronium and rocuronium
  • In addition, there are a number of medications that may interact with NMBAs
    • Increased resistance: phenytoin and carbamazepine
    • Prolongs effect: clindamycin and vancomycin
  • Key complications of NMBAs in the critically ill include:
    • ICU-aquired weakness (controversial)
    • DVT: NMBAs are one of the strongest predictors for ICU-related DVT
    • Corneal abrasions: prevalence up to 60%


Greenberg SB, et al. The use of neuromuscular blocking agents in the ICU: Where are we know? Crit Care Med 2013; 41:1332-1344.