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Mivacurium after atracurium in children
N G Goudsouzian1, W Denman, E Matta
1Department of Anaesthesia, Harvard Medical School, Massachusetts General Hospital, Boston 02114, USA.
Insights
Mivacurium administered after atracurium in children prolonged mivacurium
Area of Science:
- Anesthesiology
- Pharmacology
- Neuromuscular Blockade
Background:
- Atracurium and mivacurium are neuromuscular blocking agents used in pediatric anesthesia.
- Understanding their combined effects is crucial for safe anesthetic practice.
Purpose of the Study:
- To evaluate the effect of mivacurium when administered after atracurium in pediatric patients.
- To assess the impact of prior atracurium administration on mivacurium's duration and recovery profile.
Main Methods:
- 36 children anesthetized with halothane-nitrous oxide-oxygen were studied.
- Two groups received either sequential bolus doses or a mivacurium infusion after atracurium.
- Neuromuscular blockade was monitored using train-of-four stimulation of the adductor pollicis.
Main Results:
- Mivacurium's effect was prolonged following atracurium in Group 1, with longer recovery indices compared to mivacurium alone.
- In Group 2, initial mivacurium infusion requirements were lower but increased over time.
- Recovery indices in Group 2 were similar to those with mivacurium as a sole agent.
Conclusions:
- Prior administration of atracurium can prolong the neuromuscular effects of subsequent mivacurium.
- Residual neuromuscular effects of atracurium may be detectable beyond typical recovery periods.
- Careful monitoring is advised when using mivacurium after atracurium in pediatric anesthesia.
Abstract:
The effect of mivacurium after atracurium was evaluated in 36 children anesthetized with halothane-nitrous oxide-oxygen by measuring the force of contraction of the adductor pollicis during train-of-four stimulation at 0.1 Hz. The children were evaluated in two main groups. In Group 1 the effect of bolus doses of mivacurium after equipotent repeat doses of atracurium were evaluated. When the first twitch of the train-of-four response (T1) had recovered to 25% of control after a tracheally intubating dose of atracurium, a repeat dose of atracurium was given, on subsequent recovery to 25%, an equipotent dose of mivacurium was administered. In Group 2 when T1 had recovered to > 10% from 0.5 mg/kg atracurium, a mivacurium infusion was started; the initial infusion rate was 4 micrograms.kg-1.min-1 with adjustments made to maintain 90%-99% depression of T1. Patients were allowed to recover spontaneously from the effect of the relaxants. In Group 1 prolongation of the effect of mivacurium was noted after atracurium; the recovery indices (25%-75% and 5%-95%) of mivacurium were longer than those seen when mivacurium is the sole relaxant but shorter than atracurium. In Group 2, 15 min after the start of the mivacurium infusion, the dose requirement was 3.7 +/- 0.3 micrograms.kg-1.min-1 (approximately about one-third that required after a tracheally intubating dose of mivacurium). The infusion requirement increased gradually (P < 0.0001) until, at 90 min of infusion, it was 7.4 +/- 0.8 micrograms.kg-1.min-1. In Group 2 the recovery indices were similar to those seen when mivacurium is the sole relaxant given. When mivacurium is given after atracurium, evidence of the residual neuromuscular effects of the atracurium are detected beyond the usual recovery range.