尼卡地平与低剂量艾司洛尔联合控制性降压对血液儿茶酚胺、β_2-微球蛋白和血乳酸的影响

Influence of the controlled hypotension induced by nicardipine combined with low dose esmolol on blood catecholamine, beta2-microglobulin and lactate

目的 研究尼卡地平与低剂量艾司洛尔联合控制性降压方法的可行性及对血液儿茶酚胺、β2-微球蛋白（β2-mG）和组织氧代谢的影响。方法 选择30例择期手术的骨肿瘤病人,随机分为三组:对照组（C组,n=10）,不实施控制性降压,仅泵入生理盐水;尼卡地平组（N组,n=10）,尼卡地平、艾司洛尔联合1:5组（N+E组,n=10）朴组和N+E组尼卡地平起始药物速率为2.5μg·kg-1·min-1,艾司洛尔速率12.5μg·kg-1·min-1（N:E=1:5）。降至目标血压后（MAP60～70mmHg）,调整药物剂量使MAP维持在此范围。分别于降压前、降至目标血压时、降至目标血压后30min、降压停止时以及术毕,采集动脉血分别测定血液儿茶酚胺水平、血清β2-mG含量、血乳酸含量和血红蛋白,同时记录各时间点的HR、MAP、CVP和降压期间的尿量。结果C组与N组降压期间血去甲肾上腺素（NE）水平明显增加且呈递增趋势（P<0.05）,N+E组病人 NE水平虽有升高但保持在低水平（P>0.05）;而其它两组病人则无明显改变。三组病人降压期间β2-mG含量均无明显升高,但降压期间的血乳酸含量升高显著（P<0.05）。结论 尼卡地平控制性降压不会造成组织无氧代谢发生及潜在肾损害,其与低剂量艾司洛尔联合（1:5）可作为一种控制性降压方法,且具有部分抗应激作用。

Objective To investigate the feasibility of inducing controlled hypotension (CH) with nicardipine and low dose esmolol and its influence on blood catecholamine, blood beta 2-microlobulin (β2-mG) and tissue aerobic metabolism. Methods Thirty patients undergoing elective surgery for bone tumor were randomly divided into 3 groups: control group (C, n = 10); nicardipine group (N, n = 10) and nicardipine + esmolol group (N + E, n= 10). Controlled hypotension (CH) was started 15 min after incision. In group N nicardipine was infused at 2.5μg·kg-1·min-1 initially and in group N + E nicardipine (2.5μg·kg-1·min-1 ) and esmolol (12. 5μg·kg-1·min-1) were infused initially. When MAP was reduced to 60-70mm Hg nicardipine infusion rate was adjusted to maintain MAP at this level in both groups. In control group no CH was induced. The patients were premedicated with pethidine 25-50mg and scopolamine 0.3μg im. Anesthesia was induced with fentanyl 3μg·kg-1, propofol 1.2-2.5mg·kg-1 and vecuronium 0. 12mg·kg-1 iv and maintained with isoflurane inhalation (end-tidal concentration 1.0%-2.0%) and intermittent iv boluses of vecuronium . Radial artery was cannulated for continuous BP monitoring and internal jugular vein was cannulated for CVP monitoring. ECG , SpO2 and end-tidal CO2 concentration were continuously monitored . Blood samples were taken before CH (T0) , when MAP was reduced to 60-70mm Hg (T1), 30 min after CH had been maintained for 30min(T2 ), at the end of CH (T3) and at the end of operation (T4 ) for determination of concentrations of catecholamine ,β2-mG , lactate and Hb. Results The demographic data including age, body weight and height were comparable among the three groups. There was no significant difference in preoperative Hb and ALT, AST, Cr andBUN levels. There was also no significant difference in the duration of CH between group N and group N + E . In group C and N norepinephrine (NE) level gradually increased during CH whereas in group N + E NE level increased only slightly during CH as compared with the baseline value (T0) , and was maintained at this low level.β2-mG level was not significantly elevated during CH but lactate level increased significantly during CH in all three groups . There was no significant difference in urine output during CH among the three groups. Conclusion Hypotension with nicardipine does not result in tissue anaerobic metabolism and renal damage. Its combination with low dose esmolol has stress-inhibiting effect.