Effect of humidification on inhalation induction with isoflurane in children.

A well practised technique is important in achieving quiet induction of anaesthesia in children, but the volatile agent used also influences the process. Isoflurane results in more airway problems than halothane but recent studies have described several ways of improving the acceptability of isoflurane for inhalation induction of anaesthesia. We have studied the effect of humidification of inspired gases on respiratory complications and hypoxic episodes during induction. Forty-one children undergoing inhalation induction of anaesthesia with isoflurane and nitrous oxide in oxygen were allocated randomly to receive either humidified or non-humidified gas. Humidification did not result in a lesser incidence of problems. These findings are contrary to the results in a similar study in a predominantly adult sample which demonstrated a significantly lower incidence of complications using humidified gases.