手術中使用Propofol合併笑氣麻醉對體温調節閾值之研究

The Thermoregulatory Threshold during Surgery with Propofol-Nitrous Oxide Anaesthesia

林嘉祥(Chia-Shiang Lin) ； 林億守(I-Shou Lin) ； 劉正鴻(Cheng-Hung Liu) ； 王祈斐(Chir-Feei Wang) ； 吳弘山(Hung-Shan Wu) ； 劉朝貴(Chaur-Guey Liu) ； 陳龍華(Lung-Wha Chen)

《Acta Anaesthesiologica Sinica》 33卷1期 (1995/03) Pp. 15-20

摘要

背景：全身麻醉會明顯抑制體溫調節反應。Halothane、isoflurane及fentanyl／N_2O經實驗證明使用於人體手術中均會降低體溫調節性血管收縮的閾值。Propofol是新近研發的全身性靜脈麻醉劑，但它在手術麻醉中對體溫調節閾值的影響，文獻尚未深入探討。方法：本研究選擇14位ASA class I、無術前給藥並接受free flap手術的病人，給予N_2O（67%）及propofol 2 mg／kg靜脈推注，其後6mg／kg／h持續靜脈灌注之麻醉。14位病患隨機分為保溫組（warming，n＝5）及常規處置組（no warming，n＝9）。明顯的體溫調節性血管收縮定義為前臂為指尖的表面溫度差距大於4°C，而此時的食道溫度（中心體溫）定義為體溫調節閾值。結果：結果5位保溫組病人，均沒有產生體溫調節性血管收縮。平均最低中心體溫為36.3±0.4°C。而常規處置組的9位無保溫病人臨床上皆顯現低體溫，最後均產生明顯的血管收縮，其中心體溫平均為33.6±0.7°C（p＜0.05）。結論：於人體手術中以笑氣合併propofol之全身麻醉會明顯抑制體溫調節性血管收縮，而降低體溫調節閾值。此現象若於長時間使用propofol（如使用於ICU sedation）時，亦值得注意。

關鍵字

麻醉：全身 ； 麻醉藥劑：propofol ； 體温調節性血管收縮：體温調節閾值

並列摘要

Background: Thermoregulatory responses are thought to be drastically suppressed by general anesthesia. In previous studies, it was shown that halothane, isoflurane and fentanyl-N_2O combination decrease the threshold of vasoconstriction in general anesthesia. Propofol is a recently introduced intravenous anesthetic. The thermoregulatory threshold of its administration during surgery has not been quantified. Materials: Fourteen unpremedicated ASA class I patients were anesthetized with N_2O (67%) and propofol (2 mg/kg in bolus followed by 6 mg/kg/h infusion) during elective surgery of free flap. Patients were randomly assigned either to receive additional warming (n=5) or standard (n=9) management. Significant vasoconstriction was prospectively defined as the temperature gradient between forearm surface, and finger-tip surface is ≥ 4°C, and the thermoregulatory threshold was defined as the esophageal temperature (core temperature) at a point where the skin temperature gradient between two tested zones exceeds 4°C. Results: Vasoconstriction did not occur in patients who received additional warming and they remained in nearly normothermia. The average minimum core temperature was 36.3±0.4°C. In patients who underwent standard management the core temperature ranged from 32.8 to 34.6°C (33.6±0.7°C), signifying significant vasconstriction. Conclusions: General anesthesia with propofol/ N_2O during surgery drastically inhibits thermoregulatory vasoconstriction. This effect should also be noted during long-term use of propofol (e.g. ICU-sedation).