Changes in serum sodium concentration after transurethral procedures.

The aim of this study is to evaluate the changes in serum sodium concentration and the degree of correlation with factors such as the amount of intravenous fluid intake, the kind and the amount of irrigating fluids and the duration of the procedure. In this framework, 98 male patients who underwent transurethral procedure were studied and the correlation between the magnitude of hyponatraemia and the above-mentioned parameters was evaluated. All procedures were performed under spinal anesthesia and a solution of either manitol-sorbitol or sterilized water was used as irrigation fluid. Serum sodium concentration was measured before and after the procedure, while the kind and amount of the irrigating fluids, the amount of fluid intake and the duration of the procedure were also recorded. The patients were divided into three groups according to the duration of the procedure (i) <30 min, (ii) 30-60 min, and (iii) >60 min. Significant reduction in serum sodium concentration was found postoperatively (P < 0.001) and this was more profound in procedures longer than 1 h. This reduction was strongly correlated only with the duration of the transurethral procedure (P < 0.01). In conclusion, in transurethral procedures the reduction in serum sodium is postoperatively related to the duration of the procedure, while the intravenous and irrigating fluids to play no role on it.