体外循环中梯度控制氧分压对紫绀型先天性心脏病心肌保护的影响

目的探讨体外循环（CPB）中梯度控制动脉氧分压（PaO2）对紫绀型先天性心脏病心肌保护的影响。方法3岁以下经皮血氧饱和度〈85％、行根治术的法洛四联症患儿90例，随机分为三组：实验1组（G1组，n=30）以接近患儿术前水平的低氧分压启动CPB并控制CPB中血流复温前的PaO2≤130mmHg，CPB血流复温后使PaO2逐渐升至250～300mmHg；实验2组（G2组，n=30）CPB中PaO2在250～300mmHg启动CPB，血流复温后使PaO2逐渐升至450～500mmHg；对照组（G3组，n=30）CPB中PO2始终控制在450—500mmHg。观察心肌生化改变：于CPB前、CPB10min、升主动脉开放（CCR）10min、术后6h、24h抽外周血检测心肌酶CKMB、LDH活性及cTnⅠ浓度。结果①CKMB：CPB前及CPB10min三组间无差异；CCR10min、术后6h及24h G1组显著低于G3组（P〈0．01）；CCR10min G2组显著低于G3组（P〈0．05）。②LDH：CPB前及CPB10min三组间无差异；CCR10min、术后6h和24hG1组显著低于G3组（P〈0．01或P〈0．05）。③cTnⅠ：CPB前及CPB10min三组间无差异；CCR10min、术后6h、术后24h G1组显著低于G3组（P〈0．01）；术后6hG2组cTnⅠ也显著低于G3组（P〈0．05）。结论对于紫绀型先天性心脏病，CPB中PaO2控制在G1组的低水平能减少CKMB、LDH活性及cTnⅠ的释放，改善心肌保护效果。

Effects of Arterial Oxygen Partial Pressure during Cardiopulmonary Bypass on Myocardial Enzymes and cTnI of Cyanotic Congenital Heart Disease

OBJECTIVE To evaluate the effects of arterial oxygen partial pressure （ PaO2 ） at the beginning and during cardiopulmonary bypass （CPB） on myocardial injury of cyanotic congenital heart diseas. METHODS 90 Children diagnosed Tetrallogy of Fallot （TOF） under 3 years of age with SpO2 〈 85% underwent one stage repairing operations were divided into 3 groups： G1 （n = 30） , experimental group 1, PaO2 at the beginning and during CPB was maintained below 130 mmHg before CPB rewarming phase; G2（ n = 30）, experimental group 2, PaO2 at the beginning and during CPB was controlled between 250 - 300 mmHg before CPB rewarming phase ; G3 （ n = 30）, control group, PaO2 during CPB was maintained between 450 -500 mmHg. Myocardial enzymes and cTnⅠ were measured before CPB, 10 min after CPB, 10 min after cross clamp releasing （CCR） , 6 hrs and 24 hrs post operation with peripheral blood samples. RESULTS CK- MB ,LDH and cTnⅠ had no significantly different between 3 groups preoperatively and 10 min after CPB among 3 group. At 10 min after CCR, 6 hrs and 24 hrs post operation, KMB, LDH and cTnⅠ in G1 were significantly lower than that in G3 （ P 〈0.01 orP 〈0.05）. At 24 hrs post operation, also cTnⅠ in G1 was significantly lower than that in G2（ P 〈0.05）. At 10min after CCR, CKMB in G2 was significantly lower than that in G3 （ P 〈0.05）. At 6hrs post operation, cTnⅠ in G2 was signifieantly lower than that in G3 （ P 〈 0.05 ）. CONCLUSION During CPB controlling PaO2 to a preoperative low level would reduce releasing enzymes of myocardial and eTnI in cyanotic congenital heart disease.