BACKGROUND: Shivering associated with spinal anesthesia is uncomfortable to the patient and may interfere the monitoring of patient. Hence, we have investigated whether intrathecal meperidine could decrease the incidence and intensity of shivering during spinal anesthesia for unilateral herniorrhaphy.

METHODS: Forty ASA class 1 or 2 patients undergoing unilateral herniorrhaphy were randomly allocated into two groups (group C and M). The patients of group C (n = 20) received hyperbaric bupivacaine (0.5%; 13 mg) and normal saline (0.004 ml/kg), and the patients of group M (n = 20) received hyperbaric bupivacaine (0.5%; 13 mg) and meperidine (0.2 mg/kg). After spinal block, the incidence and intensity of shivering were determined objectively by observing involuntary muscle activity. The measurement of the mean arterial pressures and heart rates of the patients, for every two minutes for ten minutes, and subsequently for every five minutes for thirty minutes were carried out. We have also checked the highest sensory block level, and other side effects.

RESULTS: There were no significant differences in age, height, weight and duration of surgery between the two groups. Also, the mean arterial pressures, heart rates, and the highest sensory block levels exhibited no differences between the two groups. But, the incidence and intensity of shivering in group M were significantly less than in group C (P<0.05).

CONCLUSIONS: Intrathecal meperidine (0.2 mg/kg) was effective in reducing the incidence and intensity of shivering associated with spinal anesthesia for herniorrhaphy.