Effect of active warming on shivering during spinal anesthesia.

Background: Hypothermia is considered one of the reasons for intraoperative shivering. The purpose of this study is to assess whether active warming can prevent hypothermia and shivering in young adults under spinal anesthesia.

Methods: Fifty male patients scheduled for an elective operation on lower extremity under spinal anesthesia were randomly assigned into the warming group (n = 25) and the control group (n = 25). The active warming was performed using a forced air-warming device, a warmed blanket and warmed fluid. Axillary and tympanic temperatures, shivering degree, thermal discomfort, and anesthetic level were checked every 10 minutes after intrathecal injection of local anesthetics.

Results: Patients' characteristics and anesthetic levels were comparable between the groups. Axillary and tympanic temperatures were maintained higher in the warming group than the control group 10 minutes and 20 minutes after intrathecal injection respectively. The lowest temperature in operating room was higher in the warming group (36.3 +/- 0.5degrees C) compared with the control group (35.7 +/- 0.5degrees C) (P < 0.05). Incidences of intraoperative shivering and thermal discomfort were lower in the warming group.

Conclusions: We conclude that intraoperative active warming can prevent hypothermia and shivering during spinal anesthesia.