THE EFFECTS OF THE RENAL PELVIC PRESSURE ELEVATION UPON LOCAL RENAL BLOOD FLOW DISTRIBUTION

Abstract

The effects of fast elevation of intra-pelvic pressure on total renal blood flow (RBF) and local renal blood flow were studied in 34 mongrel dogs anesthetized with pentobarbital, including 4 dogs given mannitol beforehand. The RBF was measured by an electromagnetic flow meter, and local blood flow by two methods based on differing principles: the hydrogen-gas clearance method and the heat electrical method.
1) In the dogs without mannital administration, during the elevation of pevic pressure an increase in RBF was observed in the increase of RBF in the groups with low grade (25mmHg) and high grade (75mmHg) pelvic ressure elevation.
Cortical and medullary blood flow decreased as measured by the hydrogen-gas clearance method, and cortical blood flow increased as measured by the heat electrical method, in high grade pelvic pressure elevation. This seemed to be caused by the flow directly returning to the renal vein, resulting in a retardation of the Vasa Recta's flow.
2) After the mannitol infusion, an increase in RBF and cortical and medullary flow was observed by both methods. Following the administration of mannitol, unilateral ureteral ligation brougth about a decrease of ipsilateral RBF and cortical and medullary flow.
3) In the group without mannitol administration, the blood flow returned to the pre-elevated pelvic pressure level after release of the ureteral occlusion. In the group given mannitol, recovery of blood flow did not occur.
4) Through the results measured by the two different methods, the non-nutrient blood flow seemed to be the important part of the hemodynamic response of the obstructed kidney.