Purpose Over the past three decades, many studies have shown a high proportion of patients in the recovery room with residual neuromuscular blockade after anesthesia. The purpose of this Continuing Professional Development module is to present the physiological consequences of residual paralysis, estimate the extent of the problem, and suggest solutions to prevent its occurrence. Principal findings Residual paralysis is defined as a train-of-four ratio (TOFR) \ 0.9 at the adductor pollicis. While tidal volume and, to a lesser extent, vital capacity are well preserved as the intensity of blockade increases, the probability of airway obstruction, impaired swallowing, and pulmonary aspiration increases markedly as TOFR decreases. In recent studies, incidences of residual paralysis from 4-57% have been reported, but surveys indicate that anesthesiologists estimate the incidence of the problem at 1% or less. The decision to administer neostigmine or sugammadex should be based on the degree of spontaneous recovery at the adductor pollicis muscle (thumb), not on recovery at the corrugator supercilii (eyebrow). The most important drawback of neostigmine is its inability to reverse profound blockade, which is a consequence of its ceiling effect. When spontaneous recovery reaches the point where TOFR [ 0.4 or four equal twitch responses are seen, reduced doses of neostigmine may be given. The dose of sugammadex required in a given situation depends on the intensity of blockade. Conclusion Careful monitoring and delaying the administration of neostigmine until four twitches are observed at the adductor pollicis can decrease the incidence of residual paralysis. The clinical and pharmacoeconomic effects of unrestricted sugammadex use are unknown at this time.
ObjectivesAfter reading this module, the reader should be able to:1. Describe the physiological effects of residual neuromuscular blockade 2. Define and justify the current threshold used for residual paralysis 3. Interpret the information provided by qualitative and quantitative monitors 4. Decide the dose and timing of administration of neostigmine 5. Manage neuromuscular blockade and reversal during and after anesthesia.In 1979, Viby-Mogensen et al. 1 reported that 42% of patients receiving non-depolarizing neuromuscular blocking agents during anesthesia followed by neostigmine at the end of the procedure had neuromuscular weakness in the recovery room, as documented by a train-of-four ratio
123Can J Anesth/J Can Anesth (2013) 60:714-729 DOI 10.1007 (TOFR) \ 0.7. This first description of what was later termed residual paralysis, residual curarization, or postoperative residual curarization was followed by many other observations in many countries around the world and in different settings. The introduction of shorter-acting agents, such as vecuronium and atracurium and later rocuronium and cisatracurium, to replace the longer-acting agents available in 1979 led to a decrease in the incidence of residual paralysis. 2 Nevertheless, many lines of evidence now...