In the mid-1980s, the two intermediate-duration neuromuscular blocking (NMB) agents atracurium and vecuronium were introduced into practice; within a few years, these accounted for the majority of NMB agent use in critically ill patients. In association with the introduction of these new agents, there was an expansion of the indications for muscle paralysis in this country, which was at least partially related to new ventilatory modes and technologic advances that necessitated cooperative, sedate, or immobile patients. These new indications for an immobile patient, coupled with an expanded knowledge of available NMB agents, led to a dramatic increase in the use of muscle paralysis in the intensive care unit (ICU). In association with that increased use came a growing awareness of the potential for severe complications and side effects.