不同剂量右美托咪定对成人心脏瓣膜术后心肌细胞氧化应激程度和血流动力学的影响

Effects of Different Doses of Dexmedetomidine on Myocardial Oxidative Stress and Hemodynamics in Patients Undergoing Heart Valve Surgery

关键词:  心脏瓣膜术  心脏术后  右美托咪定  抗氧化  剂量

Key words:  heart valve surgery  postcardiac surgery  dexmedetomidine  antioxidation  dose

摘要:

目的 探讨不同剂量右美托咪定（dexmedetomidine，Dex）对成人心脏瓣膜术后心肌细胞氧化应激程度和血流动力学的影响。方法 选择143例因心脏瓣膜病接受心脏手术的成人患者为研究对象并随机分为对照组（n=45）、低剂量Dex组（低剂量组，n=50）和高剂量Dex组（高剂量组，n=48）。所有患者均采用静脉麻醉并在气管插管后均给予常规麻醉药物维持，在此基础上低剂量组患者以0.3 μg·kg^-1·h^-1的速度持续泵入Dex，高剂量组以0.6 μg·kg^-1·h^-1的速度持续泵入Dex，对照组患者持续泵入等量生理盐水。分别在体外循环开始前即刻（T₀）、手术结束时（T₁）、术后6 h（T₆）、术后12 h（T₁₂）和术后24 h（T₂₄）采集外周血测定超氧化物歧化酶（superoxide dismutase，SOD）、丙二醛（malondialdehyde，MDA）和肌钙蛋白-I（malondialdehyde，cTnI）水平，并记录各时点的心率（heart rate，HR）、平均动脉压（mean arterial pressure，MAP）和心指数（cardiac index，CI）。比较3组间各时点的指标差异并分析其临床意义。结果 术后各组cTnI水平均明显升高，高剂量组升高幅度最小，其次为低剂量组和对照组，3组间术后各时点cTnI水平均有明显差异（均P<0.05）。术后各组SOD水平均逐渐降低，高剂量组降低幅度最小，其次为低剂量组和对照组，3组间术后各时点SOD水平均有明显差异（均P<0.05）。而MDA的变化呈现出与SOD相反的趋势，高剂量组升高幅度最小，其次为低剂量组和对照组，3组间术后各时点MDA水平均有明显差异（均P<0.05）。术后HR和MAP均有所降低，CI逐渐升高，但3组间未显示出统计学差异。结论 Dex能够明显减轻心脏术后心肌细胞的氧化应激程度并发挥心肌保护作用，呈现出明显的量效关系，对血流动力学无明显不良影响，值得在临床中推广应用。

Abstract:

OBJECTIVE To discuss the effects of different doses of dexmedetomidine (Dex) on myocardial oxidative stress and hemodynamics in patients undergoing heart valve surgery. METHODS A total of 143 adult cases undergoing cardiac surgery because of heart valve disease were selected as research object and divided into control group (n=45), low-dose Dex group (low-dose group, n=50) and high-dose Dex group (high-dose group, n=48) randomly. All patients were given intravenous anesthesia and conventional anesthetic after intubation. And on this basis the patients of low-dose group and high-dose group were given Dex at 0.3 μg·kg^-1·h^-1 and 0.6 μg·kg^-1·h^-1 by pumping persistently while the patients of control group were given same dosege normal saline. To test the levels of superoxide dismutase (SOD), malondialdehyde (MDA) and malondialdehyde (cTnI) in peripheral blood at timing of before cardiopulmonary bypass (T₀), the end of surgery (T₁), 6 h after surgery (T₆), 12 h after surgery (T₁₂) and 24 h after surgery (T₂₄) and record the heart rate (HR), mean arterial pressure (MAP) and cardiac index (CI). The differences in the three groups were compared and their clinical significance was analyzed. RESULTS The levels of cTnI significantly increased in all groups after operation, the increase of the high-dose group was the lowest in three groups, followed by the low-dose group and the control group. There were statistical significance about cTnI at different timing in three groups (all P<0.05). The levels of SOD decreased gradually after operation and the decrease of the high-dose group was the lowest in three groups, followed by the low-dose group and the control group. There were statistical significance about SOD at different timing in three groups (all P<0.05). The changes of MDA took on opposite trend compared with SOD, the increase of the high-dose group was the lowest in three groups, followed by the low-dose group and the control group. There were statistical significance about SOD at different timing in three groups (all P<0.05). The HR and MAP decreased gradually after operation and the CI increased, while there were no statistical significance among three groups. CONCLUSION The dexmedetomidine can significantly reduce the oxidative stress of myocardial cells after cardiac surgery and play a protective role in protecting myocardium. It presents a significant quantitative relationship and there is no obvious adverse effect on hemodynamics, it is worth popularizing and applying in clinic.