Neuromuscular blocking agents in the neurosurgical intensive care unit

The long-term administration of neuromuscular blocking (NMB) agents in the ICU has increased in frequency the last several years. NMB agents in the ICU patient facilitate intubation and ventilatory support, decrease oxygen demand and consumption, facilitate bedside procedures and diagnostics, and potentially decrease intracranial pressure. However, NMB agents have extensive adverse effect profiles and require close monitoring. Two major classes of NMB agents exist: depolarizing and nondepolarizing. Depolarizing NMB agents work by mimicking the effect of acetylcholine at the nicotinic cholinergic receptor. Continuous depolarization inhibits repolarization, resulting in paralysis. Nondepolarizing NMB agents induce muscle paralysis by their competitive antagonism at the nicotinic cholinergic receptor. The neurosurgeon must be aware that NMB agents are paralytics only and should only be used in patients who are sedated and receiving adequate analgesia. Appropriate drug selection demands a thorough knowledge and understanding of each patient's neurologic, metabolic, and cardiovascular status and the hemodynamic, autonomic, pharmacokinetic, pharmacodynamic, and cost profiles of the NMB agents.