急性低氧时狗心泵代偿-失代偿转变的力学特征

为了分析急性低氧时心泵代偿-失代偿转变过程的力学特征,在22条麻醉开胸狗上,于吸入气氧分压递降条件下,作了心泵舒缩功能测定。结果表明,虽然严重低氧时心泵外功功率尚可保持在增大状态,但其压力作功成分减小,容积作功成分增大。动脉导纳的增加是容积作功增大的主要原因。这时,主动脉内有效血液推动力进一步增大,而泵缩力量却开始减弱。肌力效应在泵失代偿发生前,对舒缩功能的增强起着重要作用。在泵代偿-失代偿转变阶段,斯塔林效应的作用显著。“舒-缩谐调”的变化,早在泵失代偿前就已出现,并渐明显,值得注意。

MECHANICAL CHARACTERISTICS OF THE CARDIAC PUMP FROM COMPENSATION TO DECOMPENSATION UNDER ACUTE HYPOXIA

To analyse the mechanic characteristics of compensation-decompensation of the cardiac pump,the cardiac pump function was measured under acute hypoxia by inhaling hypoxic oxygen-nitrogen gas mixtures in 22 anesthetized open-chest dogs. The results revealed that under severe hypoxia though the total cardiac power and the power doing volume work increased, the power of doing pressure work decreased. The increase of artery admittance was the main factor responsible for the increase of total cardiac power and the power of doing volume work. During that time, the intra-aortic effective driving force increased and the cardiac force began to decrease. Inotropic effect played an important role in the increase of the cardiac pump before decompensation occur red Starling effect took part in the regulation of the cardiac pump function during the course from compensation to decompensation. The alteration of "Relaxation-contraction harmoniousness" occured in the early compensation stage and became increasing. This phenomenon deserves attention.