Neuromuscular blocking agents are used as adjuvants in day case anaesthesia to facilitate tracheal intubation and/or surgery. Although the majority of day case procedures are performed without the use of neuromuscular blocking agents, there are procedures, such as laparoscopic surgery, microsurgery, open eye surgery, some ear, nose and throat procedures and some paediatric procedures, which may require neuromuscular blockade. The characteristics of an ideal neuromuscular blocking agent for day case surgery are a short onset, a short clinical duration and a short recovery time, with or without reversal. It should also lack histamine release, provide haemodynamic stability, and be competitively priced. This paper reviews the neuromuscular blocking agents currently available and used, such as succinylcholine and mivacurium, low doses of an intermediate-acting neuromuscular block, such as rocuronium and the recently introduced rapacuronium. Their advantages and disadvantages are described and discussed, with special reference to the needs of day case surgery. Rapacuronium offers certain benefits compared with the currently available neuromuscular blocking agents for day care anaesthesia.

It has been estimated that more than 60% of all paediatric surgery is performed on a day case basis. The benefits of this type of surgery in children include reduced costs, avoidance of the stress of hospitalization and less disruption to family life. The growth of day surgery in children has been facilitated by the development of non-depolarizing neuromuscular blocking agents characterized by short and intermediate duration of action and fewer side-effects. The more rapid onset and shorter duration of action of non-depolarizing neuromuscular blocking agents in children should facilitate the use of these agents in place of succinylcholine for day case procedures.

Anaesthetic agents for day-case surgery ideally should have a short duration of action. This study was designed to compare the efficacy and safety of mivacurium and vecuronium for healthy adults undergoing dental day-case surgery. Thirty fit healthy adult patients (ASA I or II) randomly received either mivacurium 0.15 mg kg−1 (n = 15) or vecuronium 0.1 mg kg−1 (n = 15). Anaesthesia included propofol, fentanyl, nitrous oxide and isoflurane. Maximum depression of T1 was greater in the vecuronium group (99.8%) than in the mivacurium group (98.3%). There was no difference between grade of intubation at 2 min between the two groups, although patients receiving vecuronium had a more profound block at the time of intubation than those who received mivacurium (89.2% vs. 78.9%). Recovery to 10% T1 was faster in the mivacurium group (11.2 min vs. 33.1 min). All patients in the vecuronium group received neostigmine at the termination of surgery. The neostigmine evoked recovery index in the vecuronium group (4.39 min) was less than the spontaneous recovery index in the mivacurium group (6.78 min). One patient in the mivacurium group had a low plasma cholinesterase concentration (0.43 ku L−1); recovery times however, fell within the 95% confidence intervals (CI) for the group. There was no correlation between cholinesterase levels and recovery time. Mivacurium may be the more appropriate agent for dental day-case surgery because it has a shorter duration of action and does not generally require antagonism with an anticholinesterase.

A 21-year-old female weighing 55 kg was anaesthetized for facial reconstruction. After an initial bolus of pancuronium 5 mg and top-up doses of 2 mg at 135 min and 1 mg at 290 min and 335 min, no further relaxant was given for 130 min at which time neuromuscular transmission appeared fully recovered with a full train-of-four twitches and a sustained response to 50 Hz stimulation of the posterior tibial nerve. Subsequently, a single dose of mivacurium 8 mg(2 X ED95) produced extended paralysis with no response to train-of-four stimulation for 85 min. The prolonged effect of mivacurium may have been because of inhibition of plasma cholinesterase by pancuronium. The serum cholinesterase activity 12 h after surgery was 0.38 units mL−1 (normal range 0.65–1.0 units mL−1). There was no evidence of atypical choylinesterase.