[Salt and water loads and water-sodium metabolism in patients with hypertension].

Thirty-seven subjects including 29 patients with essential hypertension (8 with labile and 21 with stable disease patterns) and 8 controls received salt and water loads. Sodium chloride was administered per os at a rate of 0.12-0.22 g bw, water at a rate of 20 ml bw. Before loads the measurements were taken of the total water content in the body and of the total metabolic sodium. Radiocardiography was employed to study the central hemodynamics. After sodium chloride load BP measurements were taken over 2 h, within the first 45 min every other 5 to 10 min. Sodium excretion with urine was measured hourly, whereas the changes in the central hemodynamics were evaluated every other 5 to 10 min. After water load BP measurements were taken for 1.5 h. Urine excretions were evaluated too. It was demonstrated that patients with labile and stable hypertension responded differently to salt and water loads. In the first case the increment of BP was similar to that seen in the controls, being measured by increases in the cardiac and stroke indices. In the second case BP rises were more prolonged and more significant than in the controls and occurred primarily at the expense of the high total peripheral resistance of the blood flow. There were two types of the response to salt load: the first one involved a rapid BP elevation (after 1 to 5 min) accompanied by the violent vegetative symptomatology and BP returning to normal after 20 to 30 min.(ABSTRACT TRUNCATED AT 250 WORDS)