Use of Muscle Relaxants in the Intensive Care Unit

Muscle relaxants are now routinely used in intensive care units despite the relative paucity of literature regarding their use, safety, and efficacy in this setting. Although the theory of the pharmacology of muscle relaxants is simple, many clinicians involved in critical care receive little or no formal education about their use either in medical school or during postgraduate training. Proper dosing, careful monitoring, awareness of possible side effects, and adequate sedation facilitate safe use of muscle relaxants in the intensive care unit. Muscle relaxants are not, however, a substitute for sedatives, hypnotics, amnesties, or analgesics and should rarely, if ever, be used without appropriate sedation and analgesia. A wide variety of agents now available with substantial differences in dosing, pharmacology, and side-effect profiles makes clearly delineated indications for use and end points for discontinuation necessary. Using muscle relaxants without monitoring is like using antiarrhythmics without an electrocardiograph.