Epinephrine-Halothane Interactions in Children

Abstract

A prospective survey of heart rate and rhythm was undertaken in halothane-anesthetized children who received s.c. epinephrine for hemostasis. Mass spectrometry was used to quantify end-tidal halothane and to avoid hypercarbia. In 83 children anesthetized with halothane ECG, heart rate (HR), end-tidal halothane (ETHalo), and CO2 (ETCO2) were continuously recorded. The surgeons injected 0.4-15.7 .mu.g/kg of epinephrine (in saline or 1% lidocaine) to provide hemostasis at various sites. No child developed a ventricular dysrhythmia. One child had self-limited premature atrial contractions (PAC). Sixty-three children had some increase in HR after epinephrine injection, while in 7 HR increased 15% or more above pre-injection levels. No relation between any increase in HR and epinephrine dosage, ETHalo, ETCO2, physical status or age was found by multiple linear regression. HR was increased significantly in patients receiving epinephrine in head and neck sites other than palate. Evidently children tolerate higher doses of s.c. epinephrine than adults during halothane anesthesia. The arrhythmogenic dose of epinephrine in children receiving halothane has yet to be determined, but at least 10 .mu.g/kg of epinephrine infiltration may be used safely in normocarbic and hypocarbic pediatric patients without congenital heart disease. The presence of PAC and tachycardia emphasize the need for continuous ECG monitoring and caution during halothane anesthesia with epinephrine injection.