口服Clonidine 可以降低冠狀動脈心臟病患在接受非心臟手術心肌缺血之風險

Oral Clonidine Reduces Myocardial Ischemia in Patients with Coronary Artery Disease Undergoing Noncardiac Surgery

背景：本研究旨在針對具有心肌缺血病史之高危險病患，於手術前給予口服clonidine，以連續心電圖監測二十四小時為指標，評估其對於心肌缺血之療效。方法：研究採六十位具有心肌缺血病史的高危險（美國麻醉醫學會體位分級第III級）病患為對象，並且排除了具有低血壓、第一度心房室束傳導阻滯以上、左束枝傳導阻滯、或是慢性服用clonidine之患者。以前瞻性、雙盲、隨機的方式將病患分為兩組，於接受全身麻醉前九十分鐘，分別給予口服clonidine （3微克／公斤）或是安慰劑（對照組）；同時於手術前一天晚上十點將三導程(V2, V5, Lead II)心電圖機器安裝妥當，並開始連續紀錄二十四小時。我們比較手術期間的心電圖，若其ST段下降達1毫米以上，同時在J點60毫秒後持續三分鐘以上即定義為心肌缺血。結果：在對照組，三十位手術病患中，術前有九位(30％)，術中有七位(23.3％)，術後有十二位(40％)病患在心電圖監測到有心肌缺血的現象，其中以術後發生的機率最高(P< 0.05)。而在實驗組，則是術前有十位(33.3％)，術中有三位(10％)，術後有五位(16.7％)病患在心電圖監測到心肌缺血的現象。比較兩組結果，我們發現clonidine組病患術中及術後心肌缺血之發生率明顯較對照組為低(P< 0.05)，我們也同時發現到實驗組病患的平均血壓和demerol的消耗量都要比對照組為低(P< 0.05)，不過病患術後昏睡的比例較高，但均可被輕易叫醒。結論：本研究結果顯示，手術前給予口服clonidine，可以降低患有冠狀動脈心臟病病史之高危險病患在接受非心臟手術時心肌缺血之發生率，同時其昏睡副作用不大。

Background: To access the clinical effect of clonidine on reduction of myocardial ischemia events in patients with history of coronary artery disease undergoing noncardiac surgeries. Methods: Sixty ASA class III patients with coronary artery disease were allotted at random to two groups in a prospective, double-blind study to receive either clonidine (3 μg/kg) or placebo (control group) 90 minutes before arrival at the operating room. Continuous EKG monitoring (Holter monitor) was performed to analyze the ST segment in lead II, V2 and V5 during the preoperative (since late hours the night before operation), intraoperative and early postoperative periods (total monitoring time = 24 hours). The episode of myocardial ischemia defined as the magnitude of ST segment depression of at least 1 mm, occurring 60 ms after the J point and persisting for three minutes or more was recorded. Perioperative hemodynamic data were analyzed with two-way ANOVA with repeated measures. Student's t-test for unpaired data was used for analysis of demographics. Chi-square test was used for ST segment changes. Results are expressed as mean ± SD and P< 0.05 was considered to be statistically significant. Results: In the control group, 9 patients (30%) were noted to have episodes of ischemia preoperatively, 7 patients (23.3%) intraoperatively, and 12 patients (40%) postoperatively. The occurrence of myocardial ischemia peaked in the early postoperative period (P< 0.05). On the contrary, in the clonidine group, 10 patients (33.3%) saw ischemic episodes preoperatively, 3 patients (10%) intraoperatively and 5 patients (16.7%) postoperatively. The incidence of myocardial ischemia in clonidine group was significantly lower than that in placebo group in intraoperative and postoperative periods. The mean arterial pressure was significantly lower in some clonidine-treated patients during perioperative periods (P< 0.05). A number of patients in clonidine group suffered from drowsiness (66.7%) after operation (P< 0.05), but they could be easily aroused. In regard to dryness of mouth, nausea and vomiting clonidine and control groups did not differ much (P> 0.05). Demerol consumption was significantly lower in clonidine group (43.7 ± 4.6 mg) than in control group (76.3 ± 3.7 mg, P<0.05). Conclusions: We conclude that premedication with oral clonidine can significantly reduce the incidence of perioperative myocardial ischemia in patients with CAD undergoing noncardiac surgeries. The incidence of myocardial ischemia in these patients is rather high during perioperative period, which deserves our exceptional caution.