狗在急性低氧后复氧过程中的心脏功能损伤

六条在心脏上装有高精度压力传感器及微型超声测距探头的慢性实验狗,经两个星期的手术恢复期后,于Halothane麻醉下,给予低氧气体吸入,使动脉血氧饱和度从对照时的99.8±0.1％降到60.7-4.4％。低氧时,左心室功能随着动脉血氧饱和度的下降,表现为中度低氧时增强、严重低氧时减弱的变化。复氧时,出现与低氧时不相同的左心室功能异常,如心动过速、严重心律紊乱、后负荷增高、舒张期末室壁厚度显著增加,室壁舒-缩厚度差减小、室壁舒缩的不匀质性以及极低的心肌顺应性等。这些结果表明,在急性低氧后的复氧过程中,左心室功能存在着一种“复氧损伤”。

FUNCTIONAL INJURY OF CARDIAC REOXIDATION AFTER ACUTE HYPOXIA IN DOGS

Six Mongrel dogs were instrumented with a konigsberg(P 7 )high fidelity micromonometer to measure left ventricular pressure and four pairs of sonomicrometers to measure ventricular wall thickness. Two weeks after the surgery operation, under Halothane anesthesia, the dogs were ventilated with hypoxic gas mixture to reduce the arterial bloo doxygen saturation(SaO2) to 60.7-4.4% ( control value = 99.8 + 0.1% ) .During hypoxia, the left ventricular function (LVF) depended on the change .in SaO2 and showed an increase in the moderate hypoxia and a decrease in the severe hypoxia . During re-oxygenation, the abnormal parameters of LVF were different from that during hypoxia, e.g., techycardia, severe arrhythmia, high afterload, increase in the end diastolic wall thickness,decrease in the wall thicking, inho-mogenity of wall contraction, low myocardial compliance and etc.. The results indicate that there exists a "reoxidation injury" of the LVF during re-oxygenation after acute hypoxia.