[Measurement of plasma renin activity, blood volume and exchangeable sodium: an aid in the orientation of treatment of essential arterial hypertension].

95 patients with essential uncomplicated hypertension were mostly submitted to measurement of plasma renin activity, plasma volume and exchangeable sodium. According to the results of the plasma renin activity, we noted variations in blood volume and exchangeable sodium in order to determine the best possible treatment based on these data. Single treatment, based either on diuretics or beta-blockaders was rarely sufficient to bring the blood pressure down to normal. Association of these two types of drug was often very useful. Finally, a critical study of these 3 parameters was made in an economic view of investigations of the blood pressure. The plasma volume seemed to us the most useful investigation, after which came the measurement of plasma renin activity. for the exchangeable sodium seemed of little interest.