Electrolyte and acid base imbalance in patients with rectosigmoid bladder

The aim of the present investigation was to study systemic metabolic consequences following rectosigmoid bladder (RSB) operation. RSB after cystectomy has recently been employed with increasing frequency in the Urologic Clinic of the University of Rome inasmuch as, compared with ureterosigmoidostomy (USS), it shows a lower incidence of complications. Acid base balance, serum electrolytes and renal function were studied in 22 patients submitted to RSB and in 25 submitted to USS. Urine from patients with RSB and urine-feces mixture from patients with USS was also analyzed. Metabolic acidosis occurred in 86 per cent of patients with RSB and in 80 per cent of patients with USS but was significantly less severe (p less than 0.01) in patients with RSB (pH 7.34 +/- SD 0.04) than in those with USS (pH 7.29 +/- 0.07). This finding corresponded to a significantly lower intestinal loss of HCO3- in the RSB than in the USS group. The frequency of hyperchloremia was very low in both groups of patients whereas the incidence of an increased anion gap was surprisingly high. Data obtained demonstrate that metabolic acidosis develops even after RSB surgery thus indicating that the reduction in the area of the colonic mucosa in contact with the urine is not in itself sufficient to prevent the metabolic changes. Nevertheless patients with RSB were usually asymptomatic, insofar as metabolic alterations were not severe in any of the cases. In conclusion, RSB ensures good functional results and may be considered a satisfactory solution in those patients in whom radical cystectomy is mandatory. Nonetheless, even in these patients, constant clinical surveillance and monitoring of the metabolic situation is necessary.