Background: The current investigation was aimed on the effect of topical lidocaine application on the wound after back surgery and the emergence from general anesthesia in the rat.
Methods: Each group (n = 14) consisted of male SD rats weighting 290 to 320 g. After oro-tracheal intubation and epidural catheter placement under sevoflurane anesthesia (2.8%), the animals were treated as follows; the first group: none, the second group: subcutaneous infiltration of 2% lidocaine 3 ml to the wound, and the third group: intraperitoneal injection of 2% lidocaine 3 ml. Then, the time was measured from the discontinuation of anesthetics to the appearance of eyelid reflex or body movement.
Results: The time to eyelid reflex was 133.8 +/- 59.2, 160.2 +/- 52.0 and 152.8 +/- 68.5 sec (mean +/- SD), respectively. The time to body movement was 197.2 +/- 28.7, 247.1 +/- 46.7 and 220.2 +/- 39.1 sec, and a significant difference was found between first and the second group.
Conclusions: Topical application of local anesthetics prolonged the time to extubation without the delay for an appearance of eyelid reflex. The developed method using rats could be useful for future investigations of the nature of emergence from general anesthesia.