Evaluation of the success of sciatic nerve blockade by skin temperature measurement through infrared thermography

We hypothesized that blocking the sciatic nerve with ropivacaine (local anesthetic) will lead to a (measurable) temperature increase in innervated skin, and that this will correlate with existing sensory block tests.Therefore, 18 individuals undergoing foot surgery were studied.Skin temperature was measured just before nerve blockade and every 10 minutes thereafter.Baseline skin temperatures showed a significant proximal to distal gradient.Thereafter, temperatures on increased significantly in the toes and foot.Pinprick correlates well to skin temperature, with an AUC in a Receiver Operating Curve of 85.9% (p