Mivacurium or vecuronium for paediatric ENT surgery. Clinical experience and cost analysis

The present study compared the quality of neuromuscular block and costs after equipotent doses of mivacurium and vecuronium in the context of paediatric ENT surgery.

A total of 30 children undergoing elective tonsillectomy were included and randomised in two groups (n = 15 for each) according to the neuromuscular blocking agent (NMBA) used. Anaesthesia was induced with alfentanil (15 micrograms/kg), propofol (3 mg/kg) and either 0.2 mg/kg mivacurium or 0.14 mg/kg vecuronium. For maintenance of anaesthesia propofol (8-12 mg/kg/h) was given. Neuromuscular block was assessed by electromyography using train-of four stimulation and the following parameters were quantified: Twitch height (T1) 2 min after the initial bolus of the myorelaxant; duration until recovery to 10% T1, number and duration of bolus injections of the myorelaxant needed to maintain neuromuscular block to a T1 < 10%. In addition, the intubating conditions, number of patients needing pharmacological reversal at the end of surgery, adverse reactions and the costs for neuromuscular block and pharmacological antagonization were assessed.

Intubation conditions were comparable between both study groups: mivacurium--excellent: 7, good: 5, not acceptable: 1; vecuronium--excellent: 11, good: 4 (n.s.). T1 at 2 min was 16 (15)% for mivacurium and 6 (9)% for vecuronium (P < 0.05). Time to 10% T1 recovery was 6.1 (1.7) min for mivacurium and 21.8 (3.7) min for vecuronium (P < 0.01). In the mivacurium group 7 repetitive doses (range: 4-18) were needed to maintain T1 < 10% during surgery, whereas children treated with vecuronium needed only 1 maintenance dose (range: 0-2) (P < 0.01). Two children in the mivacurium group and 11 in the vecuronium group required pharmacological reversal of the NMB at the end of surgery (P < 0.01). The overall costs of NMB were significantly higher in the mivacurium group as compared to vecuronium 12.88 (4.5) Euro vs 9.96 (2.4) Euro; P < 0.05.

In conclusion, mivacurium-induced NMB is of very short duration in paediatric patients, and therefore repetitive doses are required to maintain a deep neuromuscular block. Nevertheless, residual paralysis is less frequent after mivacurium. The neuromuscular block after mivacurium was more expensive and residual paralysis less frequent compared to vecuronium.