Department of Anesthesiology, Tri-Service General Hospital/National Defense Medical Center, and Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Clin Auton Res. 2012 Apr;22(2):63-9. doi: 10.1007/s10286-011-0142-6. Epub 2011 Nov 6.
Water ingestion induces a pressor effect in patients with efferent baroreflex impairment and a mild pressor effect in elderly healthy subjects. However, water raised the total peripheral vascular resistance (TPR) without a prominent change in blood pressure in young healthy subjects. We try to investigate whether water elicits a cardiovascular response via regulating regional skin blood flow (SkBF) in young healthy subjects.
In a randomized, controlled, crossover fashion, 15 healthy male subjects (19-27 years old) ingested either 500 (water session) or 50 ml of water (control). The heart rate, blood pressure, cardiac index, and TPR were measured using a Task Force Monitor. A laser Doppler velocimeter was used to determine the change in the SkBF at the left thenar eminence. Plasma catecholamines and their metabolites were also measured.
At 25 min after ingestion of 500 ml water, the cardiac index and SkBF significantly decreased compared to control. In contrast, the TPR significantly increased after ingestion of 500 ml water. Plasma dihydroxyphenylalanine significantly increased at 25 min after water.
Water ingestion decreases the cardiac index to compensate for the increase in the TPR, leading to no net change in blood pressure in young healthy subjects. This study suggests that water decreases the SkBF, a mechanism that might account partly for the nature of osmopressor response to water in young healthy subjects.
水摄入会在传出性压力感受反射受损的患者中引起升压效应，在老年健康受试者中引起轻度升压效应。然而，水会升高总外周血管阻力（TPR），而不会使年轻健康受试者的血压明显升高。我们试图研究水是否通过调节年轻健康受试者的局部皮肤血流量（SkBF）引起心血管反应。
采用随机、对照、交叉设计，15 名健康男性受试者（19-27 岁）分别饮用 500ml（水组）或 50ml 水（对照组）。使用任务力监测仪测量心率、血压、心指数和 TPR。使用激光多普勒流速计测量左手大鱼际的 SkBF 变化。还测量了血浆儿茶酚胺及其代谢物。
在饮用 500ml 水 25 分钟后，与对照组相比，心指数和 SkBF 显著降低。相反，在饮用 500ml 水后 TPR 显著增加。在饮用 500ml 水 25 分钟后，血浆二羟苯丙氨酸显著增加。
水摄入会降低心指数以补偿 TPR 的增加，导致年轻健康受试者的血压没有净变化。本研究表明，水会降低 SkBF，这可能是年轻健康受试者对水的渗透升压反应的部分机制。
