Contribution of extradural temperature to shivering during extradural anaesthesia.

Thirty patients having postpartum tubal ligation under extradural anaesthesia were studied. All received bupivacaine at 4 degrees C initially and the incidence of shivering (47%), and the extradural temperatures measured with a small thermistor threaded into the extradural catheter, were recorded. To eight patients in whom the resultant shivering was marked, further bupivacaine warmed to 41 degrees C was injected. In four of these patients, shivering was stopped. The results suggest that thermosensitive tissue within the spinal canal contributes to the shivering observed in association with extradural anaesthesia.