Kuipers J R, Sidi D, Heymann M A, Rudolph A M
Pediatr Res. 1984 Jul;18(7):618-26. doi: 10.1203/00006450-198407000-00010.
Resting cardiac output is high relative to body weight during the neonatal period and there is a limited reserve for further increasing cardiac output. We assessed the effect on the circulation of reducing peripheral vascular resistance by infusing high doses of sodium nitroprusside in 1- and 3-week-old lambs. In a dose of 5 micrograms X kg-1 X min-1 over 1 h, nitroprusside caused a decrease in aortic and left atrial pressure, an increase in heart rate, and no significant changes in cardiac output or oxygen consumption. Infusing 10 micrograms X kg-1 X min-1 for 2 h resulted in an initial marked decrease in aortic pressure, cardiac output, and also heart rate. Within 50 min aortic pressure gradually increased, but was still well below control levels, while cardiac output returned to control level and heart rate slowly increased. Distribution of cardiac output and organ blood flows was measured by the radionuclide microsphere method. Blood flows to the kidneys and to the skin fell markedly, but flows to other organs did not change significantly.
在新生儿期，静息心输出量相对于体重而言较高，进一步增加心输出量的储备有限。我们评估了在1周龄和3周龄羔羊中输注高剂量硝普钠降低外周血管阻力对循环系统的影响。以5微克·千克⁻¹·分钟⁻¹的剂量持续输注1小时，硝普钠导致主动脉压和左心房压降低、心率增加，而心输出量或氧耗无显著变化。以10微克·千克⁻¹·分钟⁻¹的剂量输注2小时，起初主动脉压、心输出量和心率均显著降低。50分钟内主动脉压逐渐升高，但仍远低于对照水平，而心输出量恢复到对照水平，心率缓慢增加。采用放射性核素微球法测量心输出量分布和器官血流。肾血流和皮肤血流显著下降，但其他器官的血流无显著变化。
