Assessment of immediate post-anaesthetic recovery in young children following intravenous morphine infusions, halothane, and isoflurane.

Within 15 minutes of terminating general anaesthesia, progressive recovery of consciousness, spontaneous ventilation and cough, and limb movements were assessed in 60 young children (age range 0-5 years, mean +/- SEM; 2.83 +/- 0.34; weight 13.86 +/- 0.41 kg). All patients were ASA physical status class I-III, received a standard intravenous induction (atropine 0.02 mg X kg-1, thiopental sodium 5 mg X kg-1, diazepam 0.2 mg X kg-1), were intubated with an orotracheal tube following the administration of metocurine, 0.4 mg X kg-1, and were maintained under general anaesthesia with nitrous oxide and oxygen in a 70:30 mixture administered by a T-piece circuit. They were ventilated mechanically to maintain normal blood-oxygen tension and normocarbia. The patients were assessed in three equal groups according to the anaesthetic supplement they received. Group I received intravenous infusions of morphine sulfate (loading dose 60 micrograms X kg-1 administered over 5 minutes followed by a continuous intravenous infusion of 2 micrograms X kg-1 X min-1. Patients in Groups II and III had 0.5 per cent halothane and 1.0 per cent isoflurane respectively added to the nitrous oxide/oxygen fresh gas mixture rather than morphine sulphate infusions. By the end of the study period, there was no significant difference in the degree of recovery between the morphine and the isoflurane groups but the patients in the halothane group had recovered to a lesser degree. Generally, the patients in the morphine group were awake but not crying, while those in the other two groups were less sedated.