Isotonic solutions of mannitol, sorbitol and glycine and distilled water as irrigating fluids during transurethral resection of the prostate and calculation of irrigating fluid influx.
The aim of the study was to evaluate the clinical properties of some irrigating fluids used in transurethral resection of the prostate, to study humoral changes and disposition of the various fluids and solutes on intravenous absorption and, finally, to draw conclusions concerning a suitable composition of irrigation fluid. 60 patients undergoing transurethral resection of the prostate were included in the study. Plasma concentrations of mannitol, sorbitol and glycine were determined (during and after operation) as indicators of intravenous irrigation fluid influx. The serum concentration of prostatic acid phosphatase and, in patients irrigated with distilled water, the postoperative increase in plasma haemoglobin and the serum lactate dehydrogenase increase were used as semiquantitative estimates of fluid influx. A wide-ranging series of biochemical analyses was performed on blood in all cases before, during and after the resection (inter alia, sodium, albumin, haptoglobin in serum). The half-lives in plasma were estimated for mannitol, sorbitol and glycine. Fluid absorption was calculated in several ways. Haemodilution occurred with all iso-osmolar solutions on absorption but not with distilled water. The dilution effect of glycine solution was the most pronounced. Calculation of absorbed fluid volumes gave values up to 3.0 litres. Plasma osmolality was unchanged with all irrigating fluids used. The half-life in plasma for sorbitol was about 30 min, for glycine about 90 min and for mannitol about 120 min. Glycine entered muscle cells and changed the amino acid pattern. There was an increase in the serine and ammonia concentrations in plasma postoperatively. On absorption of distilled water there was an increase in the concentration of plasma haemoglobin and in erythrocyte-derived enzymes. The immediate postoperative concentration of glycine, mannitol and sorbitol in plasma was used to calculate fluid absorption. These concentrations showed good correlation with the immediate postoperative decrease in serum sodium concentration. The serum sodium decrease can be used for calculations of the absorbed fluid volume. On absorption of large volumes of water with haemolysis products, kidney damage is possible. The osmotic diuretic effect of mannitol gives a tendency to low postoperative blood pressure if combined with an intravenous diuretic. Water as an irrigating fluid can be recommended for diagnostic purposes and for general bladder surgery.