艾司洛尔对心脏手术中β-肾上腺素能受体失敏的影响

Effect of esmolol on beta-adrenoceptor desensitization during cardiac surgery

目的 以外周血淋巴细胞为模型探讨心脏手术中应用艾司洛尔对心肌β肾上腺素能受体失敏的预防作用。方法24例行心脏瓣膜置换术患者随机分为艾司洛尔组（Esm组）和对照组（Contr组）,各12例,Esm组于肝素化时经静脉注射艾司洛尔500μg·kg-1·min-14 min,继而以 200μg·kg-1·min-1持续输注,直至开放主动脉后10min。Contr组于同一时期内用相同容积的复方氯化钠液。观察停用药后,平均动脉压（MAP）、心率（HR）、中心静脉压（CVP）的变化,多巴胺和硝普钠的用量之比（DA/SNP）、肝素化前和停体外循环后30min两组中心静脉血氧饱和度（ScvO2）。于肝素化时（T1）,主动脉开放10min时（T2）,主动脉开放60min时（T3）抽取动脉血6ml,用改良Boyum法分离淋巴细胞,用放免法测定异丙肾上腺素刺激淋巴细胞的环磷酸腺苷（cAMP）的产量。结果 停用药后两组间MAP、HR、CVP无明显差异;Esm组ScvO2高于Contr组（P<0.05）,Esm组多巴胺/硝普钠的用量之比低于Contr组（P<0.01）;两组T2时cAMP产量较T1时明显下降,T3时继续下降,但Esm组T2和T3时的cAMP产量明显高于Contr组（P<0.05）。结论 心脏瓣膜置换术中应用艾司洛尔能减轻β肾上腺素能受体-cAMP系统失敏,有利于患者心功能的恢复。

ve To investigate the effect of esmolol preventing myocardial bata-adrenocepter from desensitization using a lymphocyte model during cardiac valve replacement. Methods Twenty-four cardiac function class II -III patients of either sex(13 male, 11 famale), aged 25-50 yr, undergoing cardiac valve replacement were randomly divided into two groups of 12 patients each: esmolol group (E) and control group (C) . The patients had not received long-term treatmrnt with glucocorticoids, calcium channel blocker, β-adrenocepter agonist or antagonist, or angiotensin converting enzyme (ACE) inhibitior. Patients with bradycardia, atrioventricular (AC) block > II degree, severe liver/kidney function abnormality, diabetes, hypertension, thyroid disease or blood diseases were also excluded. Anesthesia was induced with midazolam 0. 1mg·kg-1, fentanyl 10μg·kg-1 and vecuronium 0.15 mg·kg-1 and maintained with midazolam and fentanyl. In group E esmolol was infused first at rate of 500μg·kg-1 · min-1 for 4 min, then the infusion was continued at a slower rate of 200μg·kg-1· min-1 until 10 min after aortic declamping. In group C Ringer's solution was infused instead of esmolol. Radial artery and right internal jugular vein were cannulated and BP, HR, CVP were monitored during operation. Arterial and right atrial blood was obtained for blood gas analysis and central venous oxygen saturation ( ScvO2) was recorded before heparinization and 30 min after CPB was terminated. Dopamine/sodium nitroprusside (DA/SNP) ratio was calculated after CPB when blood pressure was stable. In addition, arterial blood samples were taken at the time of heparinizaion (T1), 10 min (T2 ) and 60 min (T3 ) after aortic declamping for determination of cAMP content in isoproterenol-stimulated lymphocytes. Results The DA/SNP ratio was significantly higher in group C than in group E (P<0.01). The ScvO2 at 30 min after CPB was significantly lower in group C than in group E (P<0.05) . The cAMP content in isoproterenol-stimulated lymphocytes decreasedat T2 and T3 in both groups but when the two groups were compared the amount of cAMP produced at T2 and T3 in group E was significantly higher ( P < 0.05 ) . Conclusions Esmolol can partly prevent bata-adrenoceptor from being desensitized and improve cardiac function after CPB.