Residual Paralysis after Emergence from Anesthesia

Abstract

SEVERAL studies have documented that neuromuscular block often persists in the postanesthesia care unit (PACU), even with the administration of acetylcholinesterase inhibitors. The frequency of this phenomenon, which has been called “residual curarization,” “residual neuromuscular block,” “postoperative residual curarization,” or “residual paralysis,” ranges between 4 and 50% depending on the diagnostic criteria, the type of nondepolarizing neuromuscular blocking drug (NMBD), the administration of a reversal agent, and, to a lesser extent, the use of neuromuscular monitoring. The problem is obviously clinically relevant, because residual paralysis after emergence from anesthesia (henceforth referred to as residual paralysis) is associated with muscle weakness, oxygen desaturation, pulmonary collapse, and acute respiratory failure that could lead to severe permanent brain damage or death. Despite extensive documentation of such residual paralysis in the literature, awareness of its clinical consequences remains surprisingly limited, and the use of NMBDs, neuromuscular monitoring, and reversal agents are dictated more by tradition and local practices than by evidence-based medicine. Residual paralysis is associated with postoperative complications such as hypoxia, weakness, and respiratory failure. However, these complications may have many other causes so that the role of neuromuscular block is often unrecognized. Thus, it is important to manage neuromuscular block rationally and have a sound strategy to prevent, diagnose, and treat residual paralysis. This can be accomplished by adhering to simple and consistent guidelines not only before tracheal extubation but also throughout the surgical procedure. The data in the current literature on residual paralysis were obtained with acetylcholinesterase inhibitors as the only agents available to accelerate neuromuscular recovery. Reassessment of practice in this regard is relevant now that sugammadex, a selective binding agent, has become available in certain parts of the world.