Mivacurium infusion requirement and spontaneous recovery of neuromuscular transmission in children anaesthetized with nitrous oxide and fentanyl, halothane, isoflurane or sevoflurane.
BACKGROUND
Forty children, aged 3-11 years, ASA I or II, were allocated at random to receive N2O/O2-fentanyl or 1 MAC halothane, isoflurane or sevoflurane-N2O/O2 anaesthesia. Mivacurium was used for muscle relaxation.


METHODS
Electromyographic response of the adductor pollicis to train-of-four (TOF) stimulation, 2 Hz for 2 s, applied to the ulnar nerve at 10-s intervals was recorded using the Relaxograph (Datex, Helsinki, Finland). An intubating dose of mivacurium, 0.2 mg.kg-1 was given, and when T1 returned to 5%, muscle relaxation was maintained by continuous infusion of mivacurium, adjusted manually to maintain a stable 90-99% block.


RESULTS
Halothane, isoflurane and sevoflurane groups had lower infusion requirements for mivacurium than the N2O-fentanyl group (P=0.000083). Mivacurium requirement was 18.8 +/- 6.8, 10.8 +/- 4.2, 6.9 +/- 3.9 and 9.6 +/- 5.6 microg.kg-1.min-1 for children receiving N2O/O2-fentanyl, halothane, isoflurane and sevoflurane anaesthesia, respectively.


CONCLUSIONS
Spontaneous recovery from T1=10% to TOF ratio=0.7 was insignificantly prolonged from 6.3 to 12.5 min in the fentanyl group to 7-16.5 min in children anaesthetized with inhalational anaesthetics.
Woloszczuk-Gebicka
B
B
Department of Anaesthesiology and Intensive Therapy, Memorial Children's Health Institute, Warsaw, Poland. gebicka@czd.waw.pl
D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005283:Fentanyl; D006221:Halothane; D006801:Humans; D007262:Infusions, Intravenous; D007530:Isoflurane; D007546:Isoquinolines / Q000008:administration & dosage; D008738:Methyl Ethers; D000077590:Mivacurium; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage; D009609:Nitrous Oxide; D000077149:Sevoflurane; D009435:Synaptic Transmission / Q000187:drug effects
D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D007546:Isoquinolines; D008738:Methyl Ethers; D003473:Neuromuscular Nondepolarizing Agents; D000077149:Sevoflurane; D000077590:Mivacurium; D007530:Isoflurane; D009609:Nitrous Oxide; D005283:Fentanyl; D006221:Halothane