Prevention of halothane-induced bradycardia: is intranasal premedication indicated?

Eighty ambulatory surgical patients with ASA physical status 1 and 2, aged 1-10 years, were studied. One group received intranasal (IN) midazolam 0.25 mg.kg-1; a second group received IN 0.25 mg.kg-1 of midazolam plus 0.02 mg.kg-1 of atropine; the third group received 0.25 mg.kg-1 of midazolam plus 0.02 mg.kg-1 of atropine administered intramuscularly, and the fourth group received IN saline drops. All patients were anaesthetized with nitrous oxide, oxygen and halothane administered via mask. Heart rate (HR) was recorded every minute up to start of surgery. Children receiving midazolam had better preoperative sedation and anaesthesia induction scores. The IN administration of neither midazolam alone nor midazolam-atropine altered the incidence or degree of halothane-induced bradycardia.