The effect of prophylactic clonidine on postoperative shivering. A large prospective double-blind study

The primary goal of this study was to assess the influence of clonidine administered after induction on postoperative shivering after elective peripheral surgery. The effect of clonidine on intra-operative haemodynamics (blood pressure and heart rate) during the first 30 min after induction and on the postoperative sedation of the patient was also investigated. Two hundred and eighty male ASA 1 and 2 patients, undergoing elective peripheral surgery were randomly administered either placebo or clonidine 2 micrograms.kg-1 intravenously over 10 min after induction of anaesthesia. Clonidine was found to reduce the total incidence (p = 0.024), the severity (p = 0.005) and the duration (p = 0.01) of postoperative shivering. Clonidine did not increase postoperative sedation or diminish overall consciousness. We conclude that administration of clonidine 2 micrograms.kg-1 intravenously after induction of anaesthesia is safe and reduces postoperative shivering in this group of patients.