Study of ventricular assisted circulation aiming at new physiological control

我们主要通过动物实验研究了脉动式或连续式左心辅助装置对长期左心辅助的生理反应。本研究观察了在脉冲式和连续式左心辅助装置长期左心辅助循环下，脑循环代谢和中枢神经系统及其动脉的病理变化。脑循环代谢未受影响，中枢神经系统及其动脉未观察到明显的病理变化。在自主神经系统方面，我们通过动物实验研究了长时间搏动性和连续性左心转流对心率变异性（HRV）的影响，发现长时间左心转流对HRV的影响在搏动性和连续性左心转流中是不同的。低频带（0.04-0.15 Hz; LF）和高频带（ ...更多信息 0.15-0.40 Hz; HF）在连续流左心转流期间呈增加趋势，表明心脏迷走神经活动增加。在连续流左心转流期间，在其他条件稳定的动物中经常观察到心动过缓现象，认为这是由心脏迷走神经活动增加引起的。我们还评估并发现，在慢性搏动性和连续性左心转流条件下，血浆儿茶酚胺水平无显著差异。关于全身血管阻力，我们使用血管a-1受体激动剂苯肾上腺素或去甲肾上腺素检查血管系统的收缩功能。长时间搏动性左心转流时，体循环血管阻力及其反应无明显变化，但体循环血管对苯肾上腺素和去甲肾上腺素的反应明显降低，提示血管收缩功能下降。另外，全身血管阻力反应硝酸甘油注射显示没有显着的变化，在脉动流和连续流左心转流。对压力感受器敏感性进行了评估，结果显示其无显著变化。我们评价了长时间搏动和连续流左心转流期间昼夜节律的变化，重点是激素因素、体温和主动脉压。褪黑激素和体温的昼夜节律不受影响，但它在血流动力学反应性肾素和主动脉压的变化中被修改。少

We have conducted studies concerning physiological reactions to a long-term left heart assist with pulsatile or continuous left ventricular assist device, mainly by the use of animal experiments. We evaluated the cerebral circulatory metabolism and pathological changes of the central nervous system and its arteries under the circulation of a long-term left heart assist with pulsatile or continuous left ventricular assist device. The cerebral circulatory metabolism was not affected, and there were not observed remarkable pathological changes in the central nervous system and its arteries. As for autonomic nervous system, we investigated changes of heart rate variability (HRV) during long-term pulsatile and continuous flow left heart bypass in an animal study and found that a long-term left heart bypass exerts a different influence on HRV between pulsatile and continuous flow left heart bypass. The powers of the low frequency band (0.04-0.15 Hz; LF) and those of the high frequency band ( … More 0.15-0.40 Hz; HF) showed an increasing tendency during continuous flow left heart bypass, indicating an increase of cardiac vagal activity. During continuous flow left heart bypass, bradycardia phenomena, supposed to be caused by an increase of cardiac vagal activity, were often observed in animals with otherwise stable conditions. We also evaluated and found that there was no significant difference in plasma catecholamine level between the conditions under chronic pulsatile and continuous flow left heart bypass. Concerning systemic vascular resistance, we examined the constrictive function of the vascular system using vascular a-1 receptor agonist phenylephrine or norepinephrine administration. Prolonged continuous flow left heart bypass caused a significant decrease in systemic vascular resistance response to phenylephrine and norepinephrine, indicating a decrease of vasoconstrictive function although no remarkable change was not observed in systemic vascular resistance and its response during under prolonged pulsatile left heart bypass. Alternatively, systemic vascular resistance response to nitroglycerin injection showed no significant changes during pulsatile and continuous flow left heart bypass. Baroreceptor sensitivity was evaluated and it did not change significantly. We evaluated changes in circadian rhythm during prolonged pulsatile and continuous flow left heart bypass focusing on hormonal factors, body temperature, and aortic pressure. The circadian rhythm of melatonin and body temperature was not affected, while it was modified in the variations of hemodynamics-responsive renin and aortic pressure. Less