Association between Development of Metabolic Acidosis and Improvement of Urinary Continence after Ileal Neobladder Creation.

PURPOSE: Ileal neobladder construction is a common choice for orthotopic urinary diversion following radical cystectomy. We investigated risk factors for metabolic acidosis during the early recovery period.

MATERIALS AND METHODS: This study relied on retrospectively collected data on 345 patients who underwent inpatient rehabilitation after radical cystectomy and ileal neobladder construction for bladder cancer between January 2014 and March 2017. Acid-base status, use of sodium bicarbonate to correct metabolic acidosis and continence status were evaluated at the beginning and end of 3 weeks of inpatient rehabilitation. Multivariate logistic regression analysis was performed to identify risk factors associated with the development of metabolic acidosis.

RESULTS: At the start of rehabilitation a median of 29 days after surgery (IQR 23-37) 200 patients (58.0%) had metabolic acidosis. During the inpatient rehabilitation period the need for oral sodium bicarbonate replacement due to acidosis increased significantly from 45.2% to 86.7% of patients (p <0.001) while urine loss measured by a 24-hour pad test decreased significantly from a median of 387 (IQR 98-918) to 88 gm (IQR 5-388, p <0.001). The median base excess was within the normal range (-1.2 mmol/l, IQR -2.4 - 0.0) at the end of inpatient rehabilitation. Decreased urinary leakage was identified as an independent risk factor for metabolic acidosis . Conclusions:The risk of metabolic acidosis after neobladder construction correlated with continuously improved continence in the early recovery period. Therefore, during this period the acid-base status should be assessed more frequently to identify metabolic acidosis.