甲氧明对心肺转流冠状动脉搭桥后老年低血压患者冠脉血流的影响

Effects of methoxamine on coronary artery blood flow in elderly patients with post volume treatment hypotension after cardiopulmonary bypass undergoing coronary artery bypass grafting

目的探讨静脉泵注甲氧明和去氧肾上腺素对老年冠状动脉搭桥术患者心肺转流停机经容量治疗后仍低血压的疗效及对冠脉血流的影响。方法择期行冠状动脉搭桥心肺转流停机经容量治疗后低血压(MAP低于基础血压的70%)的老年患者40例,男27例,女13例,年龄>65岁,ASAⅡ或Ⅲ级,随机分为甲氧明组(M组)和去氧肾上腺素组(P组),每组20例。患者出现低血压后开始静脉泵药,M组起始速度为3μg·kg^(-1)·min^(-1),P组起始速度为0.24μg·kg^(-1)·min^(-1),根据患者血压调整泵药速度,单次递增、递减速度均为起始的1/3,使MAP波动幅度不超过基础值的20%。分别在泵药前、泵药后3、5、10、15、30 min经食管超声心动图(TEE)测量冠脉窦收缩期血流速度时间积分(SVTI)和舒张期血流速度时间积分(DVTI),并计算冠脉窦血流量(CSBF)。结果 P组1例患者因未能获得理想TEE切面而退出研究。与泵药前比较,泵药后不同时点M组和P组SVTI、DVTI、CSBF明显升高(P<0.01)。与P组比较,泵药后5、10、15、30min M组DVTI和CSBF明显升高(P<0.05或P<0.01)。M组术后发生心房颤动2例,频发室性早搏1例;P组术后发生心动过缓1例,频发室性早搏1例。结论静脉泵注甲氧明和去氧肾上腺素均可纠正老年冠状动脉搭桥患者心肺转流后低血压状态,但甲氧明增加冠脉血流量更明显,可能对冠心病患者更有利。

Ojective To investigate the effects of intravenous infusion of methoxamine and phenylephrine on blood pressure and coronary artery blood flow in elderly patients with post volume treatment hypotension after cardiopulmonary bypass （CPB） undergoing coronary artery bypass grafting （CABG）. Methods Forty patients, physical status ASA Ⅱ or Ⅲ, 〉65 years old, undergoing CABG, following CPB, with a mean arterial pressure （MAP） 〈70% of baseline, despite adequate volume replacement （based on achieving a normal CVP）, were randomly assigned to methoxamine group （group M, n=20） or phenylephrine group （group P, n=20）. The initial infusion rate was 3 μg·kg-1·min-1 in group M and 0.24 μg·kg-1·min-1in group P, respectively. The rate was increased or decreased by one third of initial dose in order to maintain the MAP at the target level （±20% of baseline MAP）. Coronary sinus （CS）, systolic blood flow velocity time integral （SVTI）, diastolic velocity time integral （DVTI）, CS blood flow （CSBF） were recorded before administration, at 3, 5, 10, 15, 30 min after administration. Results Compared with pre-administration, SVTI, DVTI, CSBF were increased at each point in the two groups （P〈0.05 or P〈0.01）. SVI was increased at 15 min and 30 min in group M （P〈0.05）. Compared with group P, DVTI and CSBF at 10, 15 min and 30 min was higher in group M （P〈0.05 or P〈0.01）. There were 2 cases of atrial fibrillation and 1 case of frequent ventricular premature beat after operation in group M; 1 case of bradycardia and 1 case of frequent ventricular premature beats after operation in group P. Conclusion Intravenous infusion of methoxamine and phenylephrine both can correct post volume treatment hypotension after CPB in elderly patients undergoing CABG, but methoxamine increases coronary blood flow more significantly and may be more beneficial to patients with coronary heart disease.