Williams B O, Caird F I, Lennox I M
Age Ageing. 1985 Jul;14(4):193-201. doi: 10.1093/ageing/14.4.193.
The haemodynamic response to postural stress (60 degrees foot-down tilt) was measured by impedance cardiography in six elderly cardiovascular-normal patients and 39 with symptomatic postural hypotension (systolic blood pressure drop greater than or equal to 20 mmHg or more). In the normal elderly the mean increase in heart rate, fall in blood pressure and cardiac output, and rise in peripheral resistance was less than that described in younger subjects. The changes were at their maximum in 1 min, and there was little further change over the next 5 min. In those with postural hypotension, orthostatic reduction (or failure to rise) of the peripheral resistance was the mechanism in 83% of cases, whatever the cause, and the time course of the haemodynamic changes was the same in the majority as in the normals. Serial tests in patients whose postural hypotension was controlled (by cessation of causal drugs, often multiple, by fludrocortisone, or by dihydroergotamine) showed return to normal.
通过阻抗心动描记法测量了6名心血管功能正常的老年患者和39名有症状性体位性低血压（收缩压下降大于或等于20mmHg或更多）患者对体位应激（60度足下垂倾斜）的血流动力学反应。在正常老年人中，心率的平均增加、血压和心输出量的下降以及外周阻力的增加均小于年轻受试者。这些变化在1分钟时达到最大值，在接下来的5分钟内几乎没有进一步变化。在体位性低血压患者中，无论病因如何，83%的病例中，外周阻力的直立性降低（或未升高）是其机制，并且血流动力学变化的时间过程在大多数情况下与正常人相同。对体位性低血压得到控制（通过停用通常为多种的致病药物、通过氟氢可的松或通过双氢麦角胺）的患者进行的系列测试显示恢复正常。
