A survey on the effect of clonidine in prevention of shivering following general anesthesia

Shivering is an unpleasant complication of General Anesthesia which is seen in 40% of cases. Shivering is a serious complication that increases oxygen consumption to several times and results in increased ventilation, cardiac output, myocardial ischemia, intraocular & intracerebral pressure and intensity of postoperative pain. Preventing this unwanted complication is necessary to reach perfect anesthesia and to decrease its hazards. This study was performed as a double-blinded randomized clinical trial on 100 patients demanding eye surgery, aged over 18 years old, having ASA class I and II in Alzahra hospital of Zahedan. The patients were randomly divided into two groups using blocking Group A received Clonidine and Group B received placebo. Before anaesthesia, each of the cases and controls received 0.2 mg of clonidine and placebo with 30 ml of plain water, respectively. General anesthesia techniques were the same for both groups. In the recovery room, all the subjects were assessed for shivering and special questionnaires were filled out. The obtained data was analyzed through statistical analysis by SPSS version 13 software, using chi-square test, at the significant level of P<0.05. It was found that only 2% of the cases but 20% of the controls developed shivering; the difference was statistically significant (P=0.004). This study revealed that clonidine is effective in preventing post-anesthetic shivering and could be used as a routine preoperative medication.