Halothane anesthesia in infancy: identification and correlation of preoperative risk factors with intraoperative arterial hypotension and postoperative recovery.

Infants are well known to be sensitive to the myocardial depressant effects of halothane. In this study of more than 300 infants, 0 to 24 weeks of age, who received halothane anesthesia, preoperative risk factors were correlated with intraoperative outcome and postoperative recovery. Possible risk factors considered were age, history of respiratory distress syndrome (RDS), preoperative fasting time, and anemia. Intraoperative morbidity was evaluated by occurrence of significant hypotension, slow heart rates, or serious bradycardias. Parameters of postoperative recovery included postanesthetic recovery room admission score, duration of recovery room stay, and time to first feeding. Arterial hypotension occurred with an unexpectedly high frequency of 49.2%. Infants younger than 8 weeks of age (particularly newborns), infants 9-16 weeks of age (fasting eight or more hours), and RDS survivors 0-16 weeks of age were found to be most susceptible to hypotension. Only age and history of RDS, however, proved to be statistically significant risk factors in predicting the probability of intraoperative circulatory depression. Though circulatory depression during halothane inhalation was common, it was not associated with significant intraoperative or postoperative morbidity in terms of cardiorespiratory arrests, serious dysrhythmias, prolonged postanesthetic recovery, or delayed feeding times.