Renal function during intravenous infusion of urological irrigating fluids in the sheep

Background: Oliguria or anuria is an important sign of the transurethral resection syndrome, but the mechanism is not clear. Methods: We gave an intravenous infusion of 40 ml/kg of glycine 1.5%, sorbitol 2%-mannitol 1%, and isotonic saline (control) in 6 conscious ewes and studied if irrigating fluids cause acute disturbances of kidney function. Results: Both the electrolyte-free solutions induced an increase in urine flow and persistent hypo-osmolality. The renal clearances of p-aminohippuric acid and inulin as well as the unilateral renal blood flow, which was measured via ultrasonic flow probes, increased in response to infusion of glycine but not to sorbitol-mannitol. After the infusions, the renal clearances decreased transiently to below baseline levels. Hypertonic saline was given after half of the infusions of electrolyte-free irrigating fluid. This treatment redistributed water from the cells to the extracellular fluid, but had no effect on renal function. Conclusions: We conclude that 2500 mi of electrolyte-free irrigating fluid had no detrimental effects on kidney function in sheep. The changes we observed were essentially the same as after infusion of isotonic saline.