Canadian Journal of Anesthesia, Vol 17, 256-260, Copyright © 1970 by Canadian Anesthesiologists' Society

The Use of Epinephrine in the Presence of Halothane in Children

A series of 230 cases of children who received epinephrine by subcutaneous injection during halothane anaesthesia is presented. Almost half of these cases were bilateral otoplasties. Plastic surgery procedures constituted three quarters of all cases. Epinephrine in local anaesthetic solution was in a concentration of either 1:100, 000 (10 /µg/ml) or 1:200, 000 (5 µg/ml). Doses prorated from the allowable dose based on adult studies (100 µ/150 pounds body weight) were likely to be exceeded in pharyngoplasties, cleft palates, and mastoidectomies. The anaesthesia maintenance technique most commonly used was Ayre's T-piece with a flow of 5 L of nitrous oxide to 3 L of oxygen and 0.5 per cent halothane, in an attempt to avoid hypercapnia during spontaneous ventilation. The technique of marking and tattooing by the surgeon, in otoplasties, not uncommonly resulted in either mild tachycardia or hypertension, or both. These appeared to subside during the injection of the epinephrine which followed. It is suggested that perhaps children may be more tolerant of exogenous epinephrine injected subcutaneously than are adults.

However, the explanation might be quite simple. As an example, the latest study of Walts and Dillon⁶ suggests that if dose per unit body weight, rather than the newer concept of dose per unit body area, is used in translating adult doses down to children, then the children will receive less of the drug than they actually require or can tolerate. This present study was based on dose for weight.