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为探讨急性低氧时主动脉输入阻抗对心泵功能的影响,本文用电子计算机对10条麻醉开胸狗升主动脉压力波和血流波进行富里叶(Fourier)分析。给狗吸入不同氧分压的氧氮混合气体造成急性低氧,以动脉血氧分压123毫米汞柱为对照状态,对中度低氧状态(68毫米汞柱)和严重低氧状态(15毫米汞柱)及心泵衰竭(F)进行观察比较。随着低氧程度加重,令频率血管阻抗摸数下降。其余数量级谐波阻抗模数先降低后增高;特征性阻抗在动物处于心泵衰竭时增加。心泵的压力功率和总功率下降后回升,在心泵衰竭时降低;动能功率及反冲功率分别为增加和下降。结果表明急性低氧引起心泵外功功率的变化与由谐波分析所描述的后负荷变化并不一致,这提示在急性低氧引起的心泵功率的变化上,后负荷不起重要的制约作用,变化的主要关键还可能在心泵本身。
In order to investigate the effect of aortic input impedance on cardiac pump function during acute hypoxia, we analyzed the pressure wave and the wave of ascending aorta in 10 anesthetized open-chest dogs by Fourier computer. Acute hypoxia was induced in dogs by inhaling oxygen-nitrogen mixed gas with different partial pressure of oxygen. The control group was given 123 mmHg of arterial partial pressure of oxygen and had moderate hypoxia (68 mmHg) and severe hypoxia MmHg) and heart failure (F) were observed and compared. As the degree of hypoxia aggravates, the frequency of vascular impedance decreases. The other orders of magnitude harmonic impedance first decreased and then increased; the characteristic impedance increased when the animal was in heart failure. Cardiac pump pressure power and total power decreased after the rise in cardiac pump failure decreased; kinetic energy and recoil power were increased and decreased. The results showed that the changes of cardiac pump external power caused by acute hypoxia were inconsistent with the post-load changes described by harmonic analysis, which suggested that post-load could not play an important role in the change of heart pump power caused by acute hypoxia. The key change may also be in the heart pump itself.