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Background: Residual neuromuscular block at the end of surgery may compromise the patient's safety. The risk of airway complications can be minimized through monitoring of neuromuscular function and reversal of neuromuscular block if needed. Effective reversal can be achieved with selective relaxant binding agents, however, sugammadex is the only clinically approved drug in this group. We investigated the concentration–response properties of a novel selective relaxant binding agent, carboxymethyl-γ-cyclodextrin for the reversal of neuromuscular block. We evaluated the hypothesis that it is equally potent for reversing neuromuscular block as sugammadex. Methods: Phrenic nerve – hemidiaphragm tissue preparations were isolated from male Wistar rats and suspended in a tissue holder allowing electrical stimulation of the nerve and monitoring of muscle contraction force. Concentration–response relationships were constructed for the neuromuscular blocking agents rocuronium, pipecuronium, and vecuronium. The half-effective concentrations of sugammadex and carboxymethyl-γ-cyclodextrin for reversal of neuromuscular block were determined. Results: The half effective concentrations (95% confidence interval, CI) were 7.50 (6.93–8.12) μM for rocuronium, 1.38 (1.33–1.42) μM for pipecuronium, and 3.69 (3.59–3.80) μM for vecuronium. The half effective concentrations (95% CI) of carboxymethyl-γ-cyclodextrin and sugammadex were 35.89 (32.67–39.41) μM and 3.67 (3.43–3.92) μM, respectively, for the reversal of rocuronium-induced block; 10.14 (9.61–10.70) μM and 0.67 (0.62–0.74) μM, respectively, for the reversal of pipecuronium-induced block; and 376.1 (341.9–413.8) μM and 1.45 (1.35–1.56) μM, respectively, for the reversal of vecuronium-induced block. Conclusions: Carboxymethyl-γ-cyclodextrin is an effective, but less potent agent for reversal of neuromuscular block than sugammadex. [ABSTRACT FROM AUTHOR]

A general relation between the rate of onset and rate of recovery from non-depolarizing blockade has been demonstrated, with recovery consistently about ten times slower than onset. This observation has led to the suggestion that non-depolarizing agents share a common mechanism of action. Rocuronium, a recently introduced steroidal non-depolarizing agent, is claimed to have a very rapid onset but an intermediate duration and appears to test this hypothesis. To investigate this paradox we have calculated the rates of onset and recovery of rocuronium using the isolated human forearm and compared them with those of pipecuronium. The mean ratio of recovery time/onset time for rocuronium was 31.3, which is significantly greater than that for pipecuronium, 11.6 (P < 0.01). Whilst pipecuronium conforms to the same general relation between onset and offset described previously for other non-depolarizing agents, rocuronium appears to have a disproportionately rapid rate of onset for its rate of recovery. This suggests that onset, recovery, or both onset and recovery, from rocuronium blockade occur in a different manner to that of other non-depolarizing agents. [ABSTRACT FROM PUBLISHER]

We evaluated the neuromuscular effects of pipecuronium during anesthesia with equipotent concentrations of either sevoflurane, isoflurane or enflurane. Twenty-seven patients scheduled for minor elective otolaryngeal or plastic surgery were studied and randomly assigned to 3 groups, one group per anesthetic agent. Anesthesia was induced with thiamylal 5 mg·kg and the trachea was intubated with succinylcholine 1 mg·kg, then anesthesia was maintained with 60% nitrous oxide in oxygen and sevolfurane, isoflurane or enflurane, depending on the group. Neuromuscular blocking effects were monitored by recording the electromyographic activity of the adductor pollicis muscle from supramaximal stimulation of the ulnar nerve at 10-s intervals. Pipecuronium 40 μg·kg was administered when electromyographic activity had reached a stable state, 30 min after succinylcholine administration. The maximum effect (% block of control) and clinical duration (time to 25% recovery) of pipecuronium were 99.1±1.4% and 63.7±14.7 min (mean \+-S.D.) for sevoflurane, 99.0\+-2.0% and 60.9\+-20.5 min for isoflurane, and 98.0\+-2.5% and 62.8\+-28.7 min for enflurane, respectively. There were no significant differences in these values between the anesthetics. Cardiovascular stimulant effects were not observed in any of the groups. We conclude that the effect of pipecuronium under seveflurane anesthesia is similar to that under isoflurane and enflurane anesthesia. [ABSTRACT FROM AUTHOR]

The dose-response relation of pipecuronium, the time course of its neuromuscular blocking effects, and the reversibility of the residual block by neostigmine have been investigated in patients under sevofluraney NO Anesthesia using a neuromuscular transmission analyzer (Accelograph, Biometer, Denmark). After an initial dose of pipecuronium (0.04 mg·kg, i.v., the maximum block rate, onset time, the time from administration until 25% recovery and 50% recovery of control twitch height of the first response to train-of-four nerve stimulation and the interval time of administration of maintenance dose (0.005 mg·kg, i.v.) were 93.7±7.68%, 5.0±1.84, 55.4 ±23.92,73.0±29.44 and 38.7±15.50 minutes, respectively. The average intubation score (excellent; 0, good; 1 fair; 2, poor; 3) was 0.63±0.56 at the level of 95.88±5.06% block. Neostigmine (1.5 mg) promptly reversed the residual neuromuscular blockade induced by pipecuronium (reversal time: 10.1±2.98 minutes). No side effects attributable to pipecuronium was seen in this study. In conclusion, pipecuronium is a very useful nondepolarizing neuromuscular blocking agent especially for moderately long surgical procedure over 4-5 hours. [ABSTRACT FROM AUTHOR]