Acid-base changes following urinary tract reconstruction for continent diversion and orthotopic bladder replacement

A prospective determination of serum electrolytes, arterial blood gases, urinalysis and urine cultures was done in 31 patients who underwent a successful continent urinary reservoir or orthotopic bladder replacement. The patients who underwent reconstruction with a long detubularized intestinal segment (group 1-50 cm. long) demonstrated the greatest tendency for metabolic hyperchloremic acidosis (35.2%). In group 2 (patients with an orthotopic bladder replacement) only 1 individual (16.7%) had hyperchloremia, which proved to be the sole metabolic derangement encountered. In group 3 (individuals with a continent gastroileac reservoir) 2 patients (25%) had a slight tendency for compensated and asymptomatic alkalosis. Urinalyses and urine cultures in groups 1 and 2 demonstrated a trend toward urine alkalinity (52.1%) and asymptomatic bacteriuria (74%), respectively. On the contrary, among the patients undergoing a gastroileac reservoir (group 3), mild urinary acidity (pH between 5 and 6) was demonstrated in 4 (50%), while asymptomatic bacteriuria was present in 3 (37.5%). In this group symptomatic urinary acidity and/or ulceration of the ileal component has not occurred to date. Metabolic hyperchloremic acidosis predominates when longer colonic segments are used for reservoir construction. This abnormality is magnified in patients in whom an accessory small bowel was resected. The majority of the gastroileac reservoir patients showed electrolytic neutrality. With our surgical technique, the gastric secretory properties predominate over those of the ileum. The differences in homeostatic findings with the use of these varieties of bowel segments suggest that we could modify the final electrolytic environment by using different combinations of bowel and bowel length.