The role of temperature in the action of local anesthetics: a double study in vitro and in vivo.

The purpose of this study was the examination of the role of temperature in the action of lidocaine via electrophysiological recordings on the sciatic nerve of the rat in vitro and in vivo. 20 Male Wistar rats were used in each type of experiment. In vitro, lidocaine shows no statistically significant difference regarding the onset of anesthesia but at the temperature of 25 degrees C it is significantly more potent on the establishment of anesthesia compared to the temperature of 36.5 degrees C. In vivo, lidocaine at the temperature of 4 degrees C is statistically significantly more effective in the establishment and the duration of anesthesia related to the temperature of 20 degrees C.