Experience with hypotonic 2.5% sorbitol solution as an irrigating fluid in transurethral resection of the prostate.

19 patients were studied in connection with transurethral resection of the prostate using the intermittent technique and hypotonic 2.5% sorbitol solution as an irrigating fluid. No diuretics were given postoperatively. In 2 patients there was a slight elevation of the serum creatinine level preoperatively but in 17 patients serum creatinine was within the reference limits. The plasma sorbitol concentration was determined at 20-min intervals for two hours. The mean plasma concentration of sorbitol immediately postoperatively was 379 mg/l (2.1 mmol/l) and the highest level observed was 1,900 mg/l (10.6 mmol/l). The half-life for sorbitol in plasma was 21 min (mean calculated in 11 cases). The range was 11-33 min. With increasing immediate postoperative plasma sorbitol levels there was also an increase in the half-life, corresponding to saturation of the sorbitol metabolizing enzyme system. The absorbed fluid volumes were calculated from the immediate postoperative plasma concentration of sorbitol, which gave a mean of 0.23 1 and a maximum of 1.01. Haemodilution effects with decrease in the serum sodium and serum albumin concentrations were noted, but they were much less marked than when 5% sorbitol solution was used as an irrigating fluid. There were only insignificant increases in the plasma haemoglobin concentrations postoperatively, which were probably due to heat decomposition of red blood cells in the bladder during the operation. About 7% of the absorbed amount of sorbitol was eliminated in the urine (mean). The highest value observed was 18% in the case showing the highest plasma sorbitol concentration immediately postoperatively (1,900 mg/l). Sorbitol was eliminated in the urine over a period of 6 hours postoperatively.