血液为何从压力低的主动脉流向压力高的外周动脉?

Why does the blood flow from the aorta with lower pressure to the peripheral arteries with higher pressure?

传统生理学认为,血液从主动脉流向外周时,由于能量消耗血压会逐渐降低。然而大量研究发现,生理状态下随着逐渐远离心脏,动脉血压逐渐升高。尚未明确在病理条件下,外周动脉的血压是否依然高于中心动脉。本研究的目的是为了明确心血管疾病状态下(冠心病),人体主动脉和外周桡动脉内的血压变化情况。我们用导管测压法先后测量了43例冠心病患者在平卧位的平静状态下主动脉和桡动脉内的血压并求平均值。桡动脉处的收缩压显著高于同一个体主动脉内的压力,差异有统计学意义(P<0.000 1)。舒张压、平均动脉压在同一个体无显著变化(P>0.05)。在排除心衰和外周血管疾病的冠心病患者中,外周桡动脉的收缩压及脉压显著高于主动脉,这一发现与生理条件下相同。利用伯努利方程很容易理解其中的原理。

Multi-edition traditional physiology books indicate that because of the energy loss during the blood flowing from the aorta to the peripheral arteries, the blood pressure gets lower. However, lots of studies reveal that in normal physiological state, the farther the artery from the heart, the higher the arterial blood pressure is. It is unclear whether the peripheral blood pressure is still higher than that of the central artery under pathological conditions. The purpose of this study was to find out the change of the blood pressure of the aorta and peripheral radial arteries in patients with cardiovascular disease. The blood pressure of the aorta and peripheral radial arteries in 43 patients with coronary heart disease were measured by heart puncture and the mean value was calculated. The systolic pressure of radial artery was significantly higher than that of the aorta in the same individual, and the difference was statistically significant （P〈0.000 1）, while the diastolic pressure and mean arterial pressure did not change obviously （P〉0.05） in the same individual. Under physiological and pathological conditions, the systolic pressure and pulse pressure of the peripheral radial artery were significantly higher than those of the aorta in coronary heart disease patients without heart failure and peripheral vascular diseases. The Bernoulli equation may be the mechanism of this phenomenon.