静脉滴注不同剂量硝酸甘油对心力衰竭婴幼儿血流动力学的影响

Effect of different dosages of nitroglycerin on hemodynamics in infants with congestive heart failure secondary to congenital heart disease

目的 了解不同剂量硝酸甘油 (NTG)对左向右分流型先天性心脏病合并心力衰竭患儿血流动力学的影响。方法 连续监测 2 6例患儿的心率、血压、总外周阻力 (TPR) ,分别于用药前及用药 0 .5、1.0、1.5、2 .5、5 .0 μg (kg·min)剂量NTG时 ,利用超声心动图测定左心室射血分数 (EF)、左心室舒张末期容量指数 (EDVI)、肺毛细血管楔压 (PCWP)、肺动脉平均压 (PAMP)、左心室壁应力 (LVWS)等。结果 患儿的心率、血压、EF、每搏指数、心脏搏出指数等在用药前后及不同剂量NTG间差异没有显著性 ;PCWP由用药前 (15 .5± 2 .3)mmHg(1mmHg =0 .133kPa)降至用药后 (14.3± 2 .2 )mmHg,最低降至 (12 .3± 2 .4)mmHg(P <0 .0 5 ) ;左心室壁舒张期应力 (LVWSI)由 (4 0 7± 6 5 )N cm2 × 10 - 2 降至(35 7± 75 )N cm2 × 10 - 2 ,最低降至 (32 1± 5 0 )N cm2 × 10 - 2 (P <0 .0 5 ) ;左心室壁收缩期应力 (LVWSII)由 (16 6± 48)N cm2 × 10 - 2 降至 (136± 48)N cm2 × 10 - 2 ,最低降至 (114± 42 )N cm2 × 10 - 2 (P <0 .0 5 ) ;左心室壁舒张期和收缩期平均应力 (LVWSIII)由 (2 5 5± 5 2 )N cm2 × 10 - 2 降至 (2 18± 5 2 )N cm2 × 10 - 2 ,最低降至 (187± 42 )N cm2 × 10 - 2 (P <0 .0 5 ) ;

Objective Intravenous nitroglycerin (NTG) has been widely used in the treatment of the congestive heart failure because of its effect of vasodilatation. However, less well known is hemodynamic effect of NTG in children, especially infants with heart failure. The purpose of the study was to investigate the effect of intravenous NTG on hemodynamics in infants with congestive heart failure secondary to congenital heart defects of left to right shunts. Methods Twenty six infants with the mean age of 10 months were investigated clinically. Continuous monitoring of the heart rate, blood pressure and total peripheral resistance was done. The echocardiography was used to measure the left ventricular ejection fraction, left ventricular end diastolic volume index, pulmonary capillary wedge pressure, mean pulmonary artery pressure and left ventricular wall stress(LVWS) before the administration of NTG and at the administration with dosages of 0.5, 1.0, 1.5, 2.5 and 5.0 μg/(kg·min), respectively. Results Intravenous NTG had no significant effect on the hemodynamic indexes including the heart rate, blood pressure, ejection fraction, stroke volume index, cardiac output index and left ventricular end diastolic volume index in infants with congestive heart failure. At the dosage of 0.5 μg/(kg·min), the pulmonary capillary wedge pressure decreased from (15.5±2.3) mm Hg before the use of NTG to (14.3±2.2) mm Hg after the use of NTG, and reached a minimum pressure of (12.3±2.4) mm Hg. After the administration of NTG, the LVWS I, II and III decreased from (407±65 ) N/cm 2×10 -2 , (166±48) N/cm 2×10 -2 , (255±52) N/cm 2×10 -2 to (357±75) N/cm 2×10 -2 ,(136±48) N/cm 2×10 -2 and (218±52) N/cm 2×10 -2 ( P <0.05), respectively, and reached the minimum level of (321±50) N/cm 2×10 -2 , (114±42) N/cm 2×10 -2 ,(187±42) N/cm 2×10 -2 , respectively. With a higher dosage of 2.5 μg/(kg·min), decreases in peripheral vascular resistance and mean pulmonary arterial pressure ?were ?evident ?( P <0.05), ?while the above indexes did not show any statistical difference among the different dosages. Conclusion The congestive heart failure secondary to congenital cardiac defects of left to right shunts in infants was proved to be the indication of using intravenous NTG to improve hemodynamics. There was a different dosage selectivity between artery and venous vasodilatation, but the hemodynamic changes were independent of dosages. The dosages of 0.5 and 1.0 μg/(kg·min) NTG were recommended on the purpose of decreasing the cardiac preload in the treatment of the heart failure.