Kuwajima I, Suzuki Y, Hoshino S, Shimozawa T, Kanemaru A, Sakai M, Kuramoto K
Department of Cardiology, Tokyo Metropolitan Geriatric Hospital, Japan.
Jpn Heart J. 1991 Mar;32(2):157-66. doi: 10.1536/ihj.32.157.
In order to evaluate the effects of aging on cardiopulmonary receptor function in hypertensive patients, hemodynamic responses after unloading were studied in middle aged and older hypertensive patients. Twenty-one hypertensive patients were divided into 2 groups according to age. The younger group consisted of 9 patients less than 65 years old (mean age: 57.2 years) and the older group contained 12 patients more than 65 years old (77.2 years). Following 10 min rest, deactivation of cardiopulmonary receptors was obtained by reducing central venous pressure through the application of graded negative pressures of -10, -20, and -40 mmHg to the lower body. Blood pressure, pulse rate, and forearm blood flow were measured at baseline and at each level of negative pressure. Furthermore, plasma norepinephrine and plasma renin activity levels were measured at baseline and at -40 mmHg. Forearm blood flow was measured by venous occlusive plethysmography using a Silastic strain gauge applied around the forearm. Forearm peripheral vascular resistance was calculated by dividing the mean arterial pressure by the forearm blood flow. Baseline mean blood pressure, pulse rate, and peripheral vascular resistance were similar in both age groups. Following lower body negative pressure (LBNP), mean blood pressure and pulse rate did not change, suggesting the selective deactivation of cardiopulmonary receptors. The increase in peripheral vascular resistance at LBNP of -40 mmHg in the older group (20.0 +/- 6.2) was significantly lower than that in the younger group (15.5 +/- 8.9, p less than 0.05). Furthermore, the increase in peripheral vascular resistance after LBNP was inversely related to age (Y = -0.32X + 38.8, r = -0.43, p less than 0.05). Increases in plasma norepinephrine and plasma renin activity in the older group were not different from those in the younger group. It is concluded that the sensitivity of cardiopulmonary baroreceptor function in hypertensive patients deteriorates with increasing age.
为了评估衰老对高血压患者心肺感受器功能的影响，我们研究了中年和老年高血压患者在负荷减轻后的血流动力学反应。21名高血压患者根据年龄分为2组。较年轻组包括9名年龄小于65岁的患者（平均年龄：57.2岁），较年长组包含12名年龄大于65岁的患者（77.2岁）。休息10分钟后，通过对下半身施加-10、-20和-40 mmHg的分级负压来降低中心静脉压，从而使心肺感受器失活。在基线以及每个负压水平下测量血压、脉搏率和前臂血流量。此外，在基线和-40 mmHg时测量血浆去甲肾上腺素和血浆肾素活性水平。使用围绕前臂的硅橡胶应变片通过静脉闭塞体积描记法测量前臂血流量。通过将平均动脉压除以前臂血流量来计算前臂外周血管阻力。两个年龄组的基线平均血压、脉搏率和外周血管阻力相似。在下半身负压（LBNP）后，平均血压和脉搏率没有变化，提示心肺感受器选择性失活。较年长组在-40 mmHg的LBNP时外周血管阻力的增加（20.0±6.2）显著低于较年轻组（15.5±8.9，p<0.05）。此外，LBNP后外周血管阻力的增加与年龄呈负相关（Y = -0.32X + 38.8，r = -0.43，p<0.05）。较年长组血浆去甲肾上腺素和血浆肾素活性的增加与较年轻组无差异。结论是高血压患者心肺压力感受器功能的敏感性随年龄增长而恶化。
