Minimum effective dose of Tramadol in the treatment of postanesthetic shivering

Background: to determine the minimum effective dose of intravenous administration of tramadol on controllingpostanesthetic shivering (pas) and frequency of effects.methods: seventy five patients who had shivering grade iii or iv after general anesthesia with isotlurane in the recoveryroom were included in the study. the patients were divided randomly among five groups to receive the same doseof tramadol: 0.2 mg/kg, 0.4 mg/kg, 0.6 mg/kg, 0.8 mg/kg and 1 mg/kg. the shivering grades, tympanic temperatureimmediately prior to administering the treatment, time spent to control shivering, shivering relapse, time interval betweenthe two shivering periods and side effects were registered. data were analyzed with spss software, version 14.chi-square test, t-student test and analysis of variance were used where they were appropriate. p value<0.05 was consideredsignificant.results: there were no statistically significant differences among treatment groups with respect to demographic data,duration of anesthesia, room temperature of postanesthesia care unit, shivering grade before treatment and central temperatureat the time of treatment. there was no significant difference among the number of patients who stopped shiveringwith 0.2 mg/kg compared with 1 mg/kg of tramadoi. there was no significant difference among the five doses forshivering relapse. frequency distributions of side effects were not different among the five groups.conclusions: all patients completely stopped shivering with tramadol 0.4 mg/kg or more in 5 minutes after treatment.with 0.2 mg/kg only 80% of patients stopped shivering. although the difference between 0.2 mg/kg and i mg/kg wasnot statistically significant, because of the limited number of cases we were not able to reject type two errors. accordingto this study, we suggest 0.4 mg/kgoftramadol for shivering control.