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%

References

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