Neuromuscular-blocking drugs. Use and misuse in the intensive care unit.

The use of NMB agents for more than 24 to 48 hours in critically ill patients is associated with many potential complications. Neuromuscular-blocking drugs should be used only when their use is essential for optimal patient care. The indications for neuromuscular blockade must be defined clearly, and patients should be evaluated during treatment for the need for continued muscle relaxation. The smallest doses of NMB agents that will accomplish clinical goals should be used. This dosage can be determined through clinical evaluations and peripheral nerve monitoring. It is essential that all patients treated with NMB drugs receive appropriate sedation and analgesia. Myopathies, neuropathies, and alterations of the neuromuscular junction can occur in the ICU setting, and nondepolarizing muscle relaxants seem to be involved in the development of these disorders. Clinicians should be aware of risk factors that may predispose certain patients to neuromuscular complications, including sepsis and the use of high-dose steroids. Neuromuscular-blocking agents should be avoided in these patients if possible. Although not proved, early recognition and treatment of iatrogenic neuromuscular complications may improve patient outcome.