围术期美托洛尔对老年非心脏手术病人血流动力学及心肌缺血的影响

目的：比较围术期关托洛尔（metoprolol）对老年非心脏手术病人血流动力学和心肌缺血的影响。方法：30例60～75岁拟行择期非心脏手术病人被随机分为metoprolol组和对照组，每组15例。Metoprolol组病人于麻醉诱导前和气管插管后分别静脉注射0．5mg和1．5mgmetoprolol。围术期监测：①血流动力学指标为有创血压、HR和心率-收缩压乘积（rate—pressure product，RPP）；②心肌缺血发作指标为ECGⅡ，V5导联ST段偏移幅度及持续时间。心肌缺血被规定为ST段上抬≥0．2mv或下移≥0．1mv，至少持续1min；③心肌损伤指标为心肌钙蛋白Ⅰ（cardiac troponinⅠ，cTnⅠ）的释放；④反映metoprolol心血管和呼吸副作用的指标为HR〈50次／分发生率、阿托品用量和气道峰压。结果：两组病人在麻醉诱导后气管插管前，HR和RPP明显低于麻醉前基础值，但组问差异无统计学意义（P〉0．05）；气管插管期对照组HR和RPP明显高于基础值（P〈0．05）和metoprolol组同时点值（P〈0．05）；心肌缺血发生率对照组为30％，metoprolol组为13％（P〈0．05）；麻醉前没有检测到1例病人的血清cTnⅠ，手术开始2h后，可检测到对照组5例（30％），metoprolol组2例（13％）病人的血清cTnⅠ（P〈0．01）。HR〈50次／分发生率和阿托品平均用量组间差异无统计学意义（P〉0．05），但腹腔手术病人被牵拉内脏时．心动过缓发生率在metoprolol组有增高倾向。Metoprolol没有引起明显的气道压升高。结论：麻醉诱导前和气管插管后小量分次静脉注射总量2mg metoprolol可以使老年非心脏手术病人心肌耗氧降低，血流动力学稳定，心肌缺血和心肌损伤发生率降低。当metoprolol用于腹腔手术病人时，应注意牵拉内脏可能引起较高的心动过缓发生率和需要用较高荆量的阿托品治疗。

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OBJECTIVE: To observe the influences of metoprolol on hemodynamics and myocardial ischaemia in elderly patients undergoing noncardiac surgery. METHODS: Thrity patients (60 approximately 75 years) undergoing elective noncardiac surgery were randomly divided into a metoprolol group (n = 15) and a control group (n = 15). In the metoprolol group, metoprolol (0. 5 mg and 1.5 mg) was slowly injected into the vein of patients before the induction of intravenous anesthesia and after the tracheal intubation. The hemodynamic indice (invasive BP, HR and rate pressure product-RPP), the myocardial ischaemia indice (reversible ST segment depression of ECG II, V5 leads more than 0.1 mv or reversible ST segment elevation more than 0.2 mv from the baseline, ST segment depression or elevation over 1 min), the myocardial damage indice (serum cardiac troponin I, cTn I), and the indice of metoprolol cardiac and the respiratory adverse effects (incidence of HR below 50 beats/min, average doses of atropine, airway peak pressure) were observed intraoperatively. RESULTS: The HR and RPP were lower before the tracheal induction than the baseline (before anesthesia) in all patients, but there is no significant difference between the two groups (P > 0.05). During the tracheal intubation, the HR and RPP of the control group significantly increased, compared with the baseline (P < 0.05) and those of metoprolol group (P < 0.05). The incidence of perioperative hypertension was higher in the control group than that in the metoprolol group. The incidence of myocardical ischaemia episode was 30% in the control group, and 13% in the metoprolol group (P < 0.01). The release of cTn I was detected in 5 patients in the control group, and 2 patients in the metoprolol group (P < 0.05). The incidence of HR < 50 beats/min, and the average doses of atropine had no statistic difference between the two groups, but a tendency of high incidence of bradycardia in the metoprolol group occurred when abdominal viscera was tracted by surgical manupilation. There was no significant difference in airway peak pressure, SpO2 and PET CO2 between the two groups (P > 0.05). CONCLUSION: Intravenous administration of 0.5 mg and 1. 5 mg metoprolol before the induction of anesthesia and after the tracheal intubation has several advantages, including the decrease of myocardial oxygen consumption, the improvement of hemodynamic stability, and the lowering perioperative incidence of myocardial ischeamia and damage, but the tendency of high bradycardia incidence caused by peritoneal traction should be noticed.