RENAL ULTRASONOGRAPHY AS A TOOL FOR DETECTING DYNAMIC CHANGES IN BLOOD-PRESSURE

Renal ultrasonography has been used to assess renal blood flow under p athological conditions. We attempted to determine if sonographically d erived renal resistive index measurements would be affected by subtle changes in flow as a consequence of transiently induced mild increases in blood pressure in persons with normal renal functioning. Nine subj ects free of structural renal disease were studied with duplex Doppler ultrasonography. Main renal artery resistive indices were determined under resting baseline conditions and in response to graded infusions of phenylephrine sufficient to increase blood pressure by approximatel y 13/5 mm Hg. Change in blood pressure correlated with the change in m ain renal artery resistive index (r = 0.254, P < 0.05). Thus, the resi stive index varies in association with transient increases in blood pr essure and may reflect concurrent alterations in distal resistance und er physiologic conditions.