Comparison of neostigmine-induced recovery with spontaneous recovery from mivacurium-induced neuromuscular block

2023 American Society of Anesthesiologists Practice Guidelines for Monitoring and Antagonism of Neuromuscular Blockade: A Report by the American Society of Anesthesiologists Task Force on Neuromuscular Blockade

These practice guidelines provide evidence-based recommendations on the management of neuromuscular monitoring and antagonism of neuromuscular blocking agents during and after general anesthesia. The guidance focuses primarily on the type and site of monitoring and the process of antagonizing neuromuscular blockade to reduce residual neuromuscular blockade.

The nature of spontaneous recovery from mivacurium-induced neuromuscular block

The hypothesis of this study was that, in a given patient, recovery from a tracheal intubating dose of mivacurium would indicate the time course of spontaneous recovery after discontinuation of an infusion of mivacurium. Thirty-eight male patients consented to participate in the study. After induction of anesthesia and endotracheal intubation, the ulnar nerve was stimulated with train-of-four (TOF) stimuli at 12-s intervals. Patients received 0.3 mg/kg mivacurium in two evenly divided doses of 0.15 mg/kg each, separated by 30 s. Complete ablation of TOF responses occurred in most patients. Once the first twitch in the TOF (T ) had recovered to 25% of its baseline height, a mivacurium infusion was begun to maintain 95% suppression of T1. As surgery was nearing completion, the infusion was discontinued, and neuromuscular function was allowed to recover spontaneously. Data were analyzed for recovery intervals after the administration of the initial doses of mivacurium and after discontinuation of the infusion. Analysis of variance was used to determine the strength of correlation between the time from administration of the initial 0.3 mg/kg dose to 5% recovery of T1 and the times to recovery of TOF ratios of 70% and 90%. The 25%-75% recovery interval after discontinuation of the infusion ranged from 2.8 to 11.3 min. The time interval after administration of mivacurium 0.3 mg/kg to 5% recovery of T1 correlated with both the time to recovery of a TOF ratio of 70% and 90%. Recovery to a TOF of 90% after discontinuation of the infusion required approximately the same amount of time as recovery to 5% T1 after the administration of 0.3 mg/kg mivacurium. Each patient's recovery of neuromuscular function after discontinuation of a mivacurium infusion was related to his recovery after the administration of 0.3 mg/kg mivacurium. Therefore, the need for pharmacologic antagonism of block can be anticipated well before the end of an anesthetic.

IMPLICATIONS

Mivacurium (0.3 mg/kg) was administered to 38 patients. As they began to recover muscle strength, a mivacurium infusion was begun and later discontinued as surgery was nearing completion. Each patient's early recovery (administration to 5% recovery of T1) after the initial dose of mivacurium correlated well with more complete recovery of muscle strength after discontinuation of an infusion. This relationship enables early prediction of recovery speed after a mivacurium infusion.

Antagonism of mivacurium neuromuscular block: neostigmine versus edrophonium

This study was designed to compare the effectiveness of antagonism of mivacurium blockade with either neostigmine, edrophonium, or spontaneous recovery. Thirty ASA physical status I or II patients provided informed consent and were randomized to one of the following groups: Group 1, placebo saline; Group 2, edrophonium (1 mg/kg); and Group 3, neostigmine (70 micrograms/kg) (n = 10/group). All studied patients had anesthesia induced with propofol and maintained with propofol/N2O/fentanyl. Mivacurium bolus of 0.2 mg/kg was used for endotracheal intubation and an infusion titrated to maintain deep levels of block (T1% = 1%-5%) (T1% = first response/control response x 100). The antagonist was injected at a deep level of the block (T1% = 1%-8%) and neuromuscular (NM) recovery was evaluated by train-of-four twitches (TOF). T1% was used during maintenance, whereas both T1% and TOF% (fourth response/first response x 100) were used during recovery. Investigators were blinded to the antagonist used. Plasma cholinesterase activity was measured prior to antagonist administration (0 min), as well as 15, 30, and 60 min after. Plasma cholinesterase activity was decreased to 29% of control at 15 min and remained at approximately 60% of the control after neostigmine administration. Edrophonium did not affect plasma cholinesterase activity. Clinically adequate spontaneous recovery (TOF% > or = 70%) of the mivacurium block with placebo required 15-18 min. On average, clinically adequate antagonism of mivacurium by edrophonium was 50% faster than placebo and 30%-40% faster than with neostigmine. In summary, the speed of antagonism with edrophonium is faster than with neostigmine when antagonizing deep mivacurium NM block.(ABSTRACT TRUNCATED AT 250 WORDS)