交感神經阻斷劑對全身麻醉患者凝血功能的影響

中文摘要 深部靜脈血栓是手術後重大合併症之一。深部靜脈血栓的發生與凝血能力增加(hypercoagulibility) 以及不正常之纖維素溶解(fibrinolysis)的過程有關。而手術和麻醉的過程常造成病患的緊張、焦慮和疼痛，這些現象皆會引起交感神經興奮， 釋出catecholamine 等神經傳導物質，進而造成凝血能力過高 ，並影響纖維素溶解。 過去，已有一些研究報告指出：區域麻醉(相較於全身麻醉)可以減低手術後深部靜脈血栓的風險。 這種效果可能是因為區域麻醉可以把身體對於手術刺激而產生cortisol 的反應加以抑制。 而本研究則設計來探討全身麻醉的病人， 於麻醉誘導及麻醉維持時給予交感神經阻斷劑「labetalol」，所造成的凝血能力的變化及對手術後靜脈血栓的影響。 材料與方法： 共納入非急診婦科手術病人 24名， 隨機編入A、B二組，每組12人。 A組接受常規之麻醉誘導及麻醉維持； B組則於麻醉誘導和維持期間加入labetalol， 其餘處置同A組。麻醉當中兩組皆給予標準之常規監測。兩組病人皆於麻醉前、麻醉後恢復室停留一小時後、 以及手術後24小時抽取靜脈血，測量血液之前凝血酵素時間（PT）、活化部份血栓生成質時間（APTT）、纖維蛋白原（fibrinogen）、 第三型抗凝血酵素( antithrombin III)、C 蛋白質（ Protein C） 等項目加以比較。兩組測量結果的平均值以「t-檢驗」來檢查是否有顯著差異 (當P值 ＜ 0.05 為顯著)。 結果：兩組病人在手術後一小時與二十四小時，血液的PT 、APTT、 fibrinogen、antithrombin III 和protein C 等五項數據都沒有顯著差別。 討論：檢討兩組測量結果沒有顯著差別原因可能真實情況就是沒有差別，或是檢力不足。血栓形成的風險增高也可能是其他的凝血參數變化導致的。 另外，全身麻醉的用藥、手術中的輸液與術後止痛的情形，也可能對結果造成影響。 結論：全身麻醉全程併用labetalol ，對於婦科病人手術後一小時及二十四小時的PT、 APTT、fibrinogen、antithrombin III、 protein C 等五項實驗室檢查的結果雖有差異但並未達到統計學上顯著的差別；這種現象可能是樣本大小不足所造成。 將來的研究方向是增加每組的人數，應可以得到統計上有意義的差別。然而靜脈血栓形成的機制十分複雜，若要探討手術後靜脈血栓的預防效果，也需要對整體的「纖維蛋白溶解系統」檢驗項目作測量和分析，並追蹤術後病人是否發生靜脈血栓，才能找出交感神經阻斷劑與發生手術後靜脈血栓風險的關聯性。

Abstract Introduction: Venous thromboembolism is a relatively common clinical problem. Post surgery patients are at the risk of developing thromboembolic complications. Anesthetic procedures and agents possibly changes the blood coagulation profile and subsequently results in postoperative deep venous thromboembolic events. It has been suggested that the incidence of postoperative deep venous thrombosis may be decreased by regional anesthesia. Stress produced by anesthesia and surgery has been associated with release of catecholamines which may trigger blood coagulation cascade. Regional anesthesia has been thought to decrease stress hormone release and thus decrease the incidence of postoperative thromboembolic complications. The objective of this study was to evaluate the effect of labetalol, an α and β blocker, on blood coagulability in patients who are scheduled to receive general anesthesia. Material & Methods : Twenty four patients who are presented to have elective gynecologic operations are randomly assigned into two groups. The patients of group A had undergone routine induction and maintenance of general anesthesia, while labetalol was used for group B in addition to routine anesthesia procedures. Venous blood was drawn before induction, at the 1st and 24th hours after the operation. Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen level, antithrombin III and protein C activity were measured. The means of these parameters were compared. The significance of differences was tested with t-test at significance level of 0.05. Ninety-five % confidence intervals of the differences were presented. Results : There was no significant difference in the means of PT, APTT, fibrinogen level, antithrombin III and protein C activity before induction, at the 1st hour and 24th hours after the operation between the two groups. Conclusions : Use of labetalol during general anesthesia does not affect PT, APTT, fibrinogen level, antithrombin III and protein C activity at the 1st and 24th hours after surgery in elective gynecological surgery patients. Since the hypercoagulability status in general anesthesia might be due to some other coagulation profile, the risk of thromboembolism might be further studied with completely examining all the risk factors with larger sample size. .