Regulation of Arterial Pressure in the Anephric State

Abstract

Three anephric patients were studied during sequential periods of normal hydration and overhydration. The increase in arterial pressure caused by the overhydration (+7% of body weight) was associated with an increase in peripheral resistance (+21.1%, P < 0.01). The elevation of peripheral resistance was preceded by an increased cardiac output (+22.3%, P < 0.02) which then fell part way to control levels (+13.2%, P < 0.05). Return to normal hydration resulted in return of all variables to control levels. The fall in peripheral resistance was preceded by a transient fall in cardiac output to below control levels (—5.6%, not significant). With both normal and elevated pressures, plasma renin activity levels were low, and sensitivity to angiotensin infusion was greater than normal. Long-term autoregulation of blood flow is suggested as an important factor in the observed sequence of events.