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Neuromuscular and cardiovascular effects of doxacurium in children anaesthetized with halothane
N G Goudsouzian1, J K Alifimoff, L M Liu
1Department of Anesthesia, Harvard Medical School, Massachusetts General Hospital, Boston 02114.
Insights
Doxacurium chloride demonstrated safe neuromuscular blockade in children, with median effective doses (ED50) of 19 mcg/kg and ED95 of 32 mcg/kg. Cardiovascular effects were minimal, and recovery times were rapid, suggesting suitability for pediatric anesthesia.
Area of Science:
- Anesthesiology
- Pharmacology
- Pediatric Medicine
Background:
- Neuromuscular blocking agents are essential in pediatric anesthesia.
- Doxacurium chloride (BW A938U) is a non-depolarizing neuromuscular blocker.
- Limited data exists on doxacurium's effects in pediatric populations.
Purpose of the Study:
- To evaluate the neuromuscular and cardiovascular effects of doxacurium chloride in children.
- To determine the dose-response relationship and recovery characteristics of doxacurium in pediatric patients.
- To compare the effects of doxacurium in children versus adults.
Main Methods:
- 27 children (2-12 years) undergoing anesthesia with halothane and nitrous oxide were studied.
- Incremental doses were used in 9 children to establish a dose-response curve via train-of-four stimulation.
- The remaining children received a single bolus of 30 or 50 mcg/kg of doxacurium.
Main Results:
- Median effective dose 50% (ED50) was 19 mcg/kg; median effective dose 95% (ED95) was 32 mcg/kg.
- No clinically significant changes in heart rate or arterial pressure were observed.
- Recovery to 25% of baseline neuromuscular function occurred at 25 min (30 mcg/kg) and 44 min (50 mcg/kg); recovery index was 27 min.
Conclusions:
- Doxacurium chloride provides effective neuromuscular blockade in children with minimal cardiovascular impact.
- Pediatric patients may require higher doses of doxacurium per kilogram compared to adults but exhibit faster recovery.
- The duration of action is comparable to tubocurarine and dimethyl-tubocurarine in children.
Abstract:
The neuromuscular and cardiovascular effects of doxacurium chloride (BW A938U) were evaluated in 27 children (2-12 yr) anaesthetized with 1% halothane and nitrous oxide in oxygen. In nine children the incremental technique was used to establish a cumulative dose-response curve by train-of-four stimulation. The remaining children received either 30 or 50 micrograms kg-1 of the drug as a single bolus. The median ED50 and ED95 of doxacurium in children were 19 and 32 micrograms kg-1, respectively. No clinically significant change in heart rate or arterial pressure occurred. Following doxacurium 30 micrograms kg-1 and 50 micrograms kg-1, recovery to 25% of control occurred in 25 (SEM 6) and 44 (3) min, respectively. The recovery index (25-75% of control) was 27 (2) min. The duration of action of doxacurium is similar to that of tubocurarine and dimethyl-tubocurarine in children. Compared with adults, children seem to require more doxacurium (microgram kg-1) to achieve a comparable degree of neuromuscular depression, and they recover more rapidly.