Potency and time course of mivacurium block during sevoflurane, isoflurane and intravenous anesthesia

Abstract

Under usual conditions of clinical anesthesia the potency of mivacurium was slightly enhanced during sevoflurane compared with intravenous anesthesia but the duration of action was only minimally prolonged during sevoflurane and isoflurane anesthesia.

Sevoflurane and isoflurane, but not propofol, decrease mivacurium requirements over time

“…7 The same applies to mivacurium, and in this case, only late indices of recovery, such as time taken for the return to a train-of-four ratio of 80% were prolonged by sevoflurane. 8 The duration of action to 25% recovery of T1 was not affected. 8 This is a finding analogous to ours, where duration of the intubating dose was not modified by the presence of the volatile anesthetic.…”

“…8 The duration of action to 25% recovery of T1 was not affected. 8 This is a finding analogous to ours, where duration of the intubating dose was not modified by the presence of the volatile anesthetic. Bevan et al 11 compared mivacurium infusion requirements between patients given propofol or sevoflurane in adults and children, in a design very similar to ours.…”

“…5 However, prolongation of the duration of action of neuromuscular blocking agents is not always found, 6,7 and in certain settings the degree of potentiation is very modest. 8 In one study, isoflurane did not alter mivacurium infusion rates compared with propofol. 9 One possible explanation is that potentiation with volatile agents takes time to develop, because of the time taken for equilibrium of the agent with muscle tissue.…”

“…For example, only a slight decrease was found for the ED 50 of mivacurium, and no change in its duration of action. 8 As is the case for isoflurane, the degree of potentiation provided by sevoflurane might be time-dependent. 12 The purpose of this study was to determine the time course of potentiation of neuromuscular blockade by isoflurane and sevoflurane in the clinical situation, when a bolus dose of neuromuscular blocking agent is administered at induction, followed by a maintenance dose when recovery started.…”

Xenon does not modify mivacurium induced neuromuscular block

“…1 On the other hand, it is well known that most inhaled anesthetics variably prolong and enhance the effects of nondepolarizing neuromuscular blocking drugs, compared to total iv anesthesia. [2][3][4] Xenon, a rediscovered inhaled anesthetic with an extremely low blood-gas solubility of 0.115 to 0.14 5 and a minimum alveolar concentration (MAC) of 63 to 71%, 6,7 has proven its clinical safety and efficacy in the past. 8 With its ecological and pharmacological qualities, xenon is an interesting alternative to other inhaled anesthetics.…”