Effects of atropine and scopolamine on bradycardia and emetic symptoms in otoplasty.

Abstract

To assess the effects of unilateral or bilateral otoplasty on bradycardia and postoperative nausea and vomiting (PONV) and the efficiency of transdermal scopolamine in the prophylaxis of PONV. Post hoc assessment of the data from a double-blind, randomized study. Fifty otoplasty patients were studied; half of them received randomly and in double-blind fashion a transdermal therapeutic system (patch) of scopolamine (TTS-scopolamine) as prophylaxis against PONV before general anesthesia. The placebo group received atropine 10 microg x kg(-1) intravenously during induction. The scopolamine-treated patients suffered more from moderate peroperative bradycardia (8/25; P < .05) than the atropine-treated patients (1/25). Two patients wearing a half of the TTS-scopolamine patch needed intravenous atropine. After unilateral otoplasty, none of the TTS-scopolamine-treated patients and 50% of the atropine-treated patients suffered from PONV. After bilateral operation, the respective incidences were 39% and 81% (P < .01). After unilateral otoplasty no patient needed droperidol, but after bilateral otoplasty, 12 of 19 of the atropine-treated and 4 of 18 (P < .05) of the scopolamine-treated patients needed droperidol. The mean numbers of doses of droperidol were 0.8+/-0.9 and 0.3+/-0.6 (P < .05), respectively. Two additional patients, wearing half of the TTS-scopolamine patch, suffered from mild central anticholinergic syndrome. TTS-scopolamine offers effective prophylaxis against PONV (auriculoemetic reflex), but does not protect from bradycardia (auriculocardiac reflex) in otoplasty. Cutting of the TTS-scopolamine patch may lead to undesirable side effects.