[Peridural anesthesia with 0.5% bupivacaine-fentanyl. Evaluation of the pre-heating effect].

The effect of preheated (37 degrees C) mixture of 0.5% bupivacaine and fentanyl on peridural anaesthesia have been studied in a double blind randomized clinical trial. Fifty patients of both sexes, ASA I-II, undergoing elective surgery for inguinal hernia repair or radical saphenectomy have been randomly assigned either to the control group (n = 25) receiving 0.5% bupivacaine-fentanyl at room temperature (20 degrees C), or to the group receiving the same anaesthetic mixture preheated for 12 hours up to 37 degrees C (n = 25). The latency period, extension, duration and quality of anaesthetic block were evaluated. A significative difference in the extension of anaesthetic block was detected at 6' (p less than 0.05 for extension up to T10 and T11, p less than 0.025 up to T12), and at 8' (less than 0.05 for extension up to T10). However no difference was observed between the two groups at 10' and later. The use of 0.5% bupivacaine-fentanyl mixture resulted in a short latency period, as previously observed, and its preheating does not seem to affect substantially the parameters evaluated in this study.