胸段硬膜外阻滞对心脏辦膜置换术后病人血浆皮质醇、IFN-γ、IL-4的影响

Effects of thoracic epidural block on plasma levels of cortisol, IFN-γ and IL-4 in patients undergoing cardiac valve replacement

目的 探讨胸段硬膜外阻滞对心脏辦膜置换术后病人血浆皮质醇（Cor）、干扰素-γ（IFN-γ）、白细胞介素-4（IL-4）的影响。方法 心脏辦膜置换术病人20例，心功能Ⅱ级或Ⅲ级，射血分数〉0．4，随机分为2组（n=10）：单纯全麻组（GA组）和全麻复合硬膜外阻滞组（GEA组）。采用视觉模拟评分法（VAS）评价术后的疼痛程度。于麻醉诱导前、术后4h和1、3、7d取外周血，测定血浆Cor、IFN-γ、IL-4的浓度。结果 血浆Cor浓度的比较：与麻醉诱导前比较，GA组术后4 h、1 d升高，GEA组术后4 h升高（P〈0．05）;与GA组比较，GEA组术后4 h、1 d降低（P〈0．05）。血浆IFN-γ浓度的比较：与麻醉诱导前比较，2组术后4 h和1、3 d均升高（P〈0．05）;与GA组比较，GEA组术后1 d升高（P 〈0．05）。血浆IL-4浓度的比较：与麻醉诱导前比较，GA组术后4 h降低（P〈0．05）。IFN-γ／IL-4比值的比较：与麻醉诱导前比较，2组术后4h、1d升高（P〈0．05）;与GA组比较，GEA组术后1d升高（P〈 0．05）。结论 胸段硬膜外阻滞可降低心脏辦膜置换术后病人血浆Cor水平，提高IFN-γ／IL-4比值。

Objective To investigate the effects of thoracic epidural block on stress and immune responses of the patients undergoing cardiac valve replacement. Methods Twenty NYHA class Ⅱ or Ⅲ patients with ejection fraction 〉 0.4 undergoing cardiac valve replacement were randomly assigned to one of 2 groups （ n = 10 each） ： group Ⅰ general anesthesia （GA） and group Ⅱ general anesthesia ＋ epidural block （GEA）. The patients were premedicated with intramuscular phenobarbital 0.1 g and scopolamine 0.3 mg. Radial artery and right internal jugular vein were cannulated for BP and CVP monitoring. Epidural catheter was placed at T3-4 interspace and advanced cephalad for 3-4 cm at 12-24 h before heparinization in GEA group. A loading dose of 1.0% lidocaine 12-15 ml with fentanyl 5 μg/ml was injected via epidural catheter before induction of anesthesia. Lidocaine 1% 6- 8 ml was given every hour through epidural catheter during maintenance of anesthesia. Anesthesia was induced with midazolam, fentanyl and vecuronium and maintained with propofol infusion and isoflurane inhalation and intermittent IV boluses of fentanyl and vecuronium in both groups. The patients received PCEA with 0.125% bupivacaine and fentanyl in group GEA or PCIA with fentanyl in group GA after operation. Venous blood samples were taken before induction of anesthesia （ T0, baseline ） at 4 h （ T1 ） and day 1, 3 and 7 after operation for determination of plasma cortisol, IFN-γ and IL-4 concentrations. Results The two groups were comparable with respect to age, M/F sex ratio, body weight, ejection fraction and type of operation performed. The plasma cortisol level was significantly increased after operation at T1 in both groups as compared to baseline at To and was significantly lower in group GEA than in group GA. The plasma IFN-γ level was significantly increased after operation at T1-3 as compared with the baseline at To in both groups and was significantly higher at T2 in GEA group than in GA group. The IL-4 level was significantly decreased at T1 in GA group. The IFN-γ/IL-4 ratio was significantly increased after operation at T1 and T2 in both groups and was significantly higher at T2 in GEA group than in GA group. Conclusion Thoracic epidural block can attenuate the stress response and increase IFN-γ/IL-4 ratio in patients undergoing cardiac valve replacement.