The use of neuromuscular blocking drugs in intensive care practice

Critically ill patients represent a very different population from that of the operating theatre, but much of our knowledge of many of the neuromuscular blocking drugs is derived from intraoperative use. The diversity of clinical-practice and case-mix differences in intensive care are probably responsible for the absence of a formal consensus about the use of neuromuscular blocking drugs in the intensive care unit (ICU). Various surveys suggest that these drugs are used comparatively infrequently, but we do not know whether current usage is either safe or appropriate. In addition to the adverse effects which inevitably accompany prolonged paralysis and immobility, the steroidal relaxants, pancuronium and vecuronium, have also been associated with myopathy. This seems to be aggravated by concurrent use of pharmacologic doses of corticosteroids or the aminoglycoside antibiotics. Neither the mechanism nor the validity of the association with steroidal relaxants is known at present. Muscle dysfunction is a common feature of critical illness, and it is possible that neuromuscular blocking drugs interfere with muscle repair and regrowth. Patients with multiple organ failure present a particular challenge both because of the extent of tissue injury and because drug clearance via the liver or kidneys is generally impaired.