Water and solute dynamics after intravenous infusion of new irrigating fluids in the rabbit

We used 25 rabbits to study blood chemistry, urinary flow and solute excretion for 2 h during and after intravenous infusion of 50, 75 and 100 ml/kg of 4 solutions that have recently been introduced in Sweden for irrigation during transurethral operations. Infusion of mannitol 3% + ethanol 1% and sorbitol 2% + mannitol 1% were followed by a higher urinary flow and excretion of sodium and other solutes than after glycine 1.5% + ethanol 1%, glycine 1.0% + ethanol 1%, and normal saline (control). The volume of urine and the total solute excretion, but not the sodium and potassium excretion, increased with the infused volume. The urea and creatinine clearances increased in proportion to the urinary flow. Using a mathematical model, we found a volume-dependent increase in the ratio of extracellular to intracellular accumulation of water, although the average ratio was the highest for glycine 1.5% + ethanol 1% (mean 0.78) and the lowest for mannitol 3% + ethanol 1% (mean 0.60). We conclude that there are marked differences between recently introduced irrigating fluids with respect to diuretic effects and the distribution in the body.