Changes in the serum concentrations of sodium, potassium, and free haemoglobin during transurethral resection of the prostate--parts of the TUR-syndrome?

In 133 patients undergoing transurethral resection of the prostate under standardized conditions the concentration of serum sodium decreased, and the concentration of free plasma haemoglobin increased significantly after the operation. Such changes were not found in a control group of 31 patients undergoing cystoscopy or bladder biopsy. The changes in the operated group are believed to be caused by the absorption of water used as irrigating fluid during the resection.