The effects of total renal ischemia (TRI) of 15-87 min duration due to suprarenal clamping of the aorta were studied in 15 mannitol-treated patients undergoing abdominal aortic surgery. 15 patients undergoing similar surgery but requiring only infrarenal clamping served as controls. 1-2 h following TRI, GFR was reduced to only 39% of that in controls, 23 +/- 5 vs. 59 +/- 7 ml/min (P less than 0.001). This could not be ascribed to impaired renal plasma flow (RPF), which was mildly reduced to 331 +/- 71 and was not different from the value in controls, 407 +/- 66 ml/min. However, impaired PAH extraction (43 +/- 7%) and isosthenuria, not present in controls, suggest a primary role for tubular injury in lowering GFR at this time. 24 h following TRI, the GFR remained depressed below controls, 45 +/- 8 vs. 84 +/- 8 ml/min (P less than 0.005), while the transglomerular sieving of neutral dextrans was significantly enhanced (radius interval, 24-40 A). A theoretical analysis of transcapillary solute exchange revealed that these findings could be largely explained by a selective reduction of either RPF (-61%) or of transmembrane hydraulic pressure difference (-18%) below control values. Alternately, a combination of these two factors with changes of smaller magnitude could explain the findings. In contrast, a selective increase in oncotic pressure or decrease of the glomerular ultrafiltration coefficient could be excluded as a cause of hypofiltration 24 h after TRI. These observations lead us to suggest that the transient azotemia observed following TRI is due to a self-limited injury to the nephron that is identical to that seen in overt and sustained forms of acute renal failure.
View details for Web of Science ID A1984SD74800006
View details for PubMedID 6421876