Comparison of 2 techniques to predict voiding efficiency after inpatient urogynecologic surgery.
We compared 2 techniques used to assess adequate postoperative bladder emptying. We performed a prospective, randomized, crossover study of 2 voiding trial techniques. 1) For back fill the bladder is filled with 300 cc saline before the Foley catheter is removed. 2) For auto fill the catheter is removed and the bladder is allowed to fill spontaneously. Patients were randomized into 2 groups for voiding trials, including group 1-auto fill followed by back fill or group 2-back fill followed by auto fill. Within 15 minutes of each void we measured post-void residual urine by straight catheterization. A void of two-thirds or greater of total bladder volume (voided volume plus post-void residual urine) at void 2 of the 2 voids was considered successful voiding. Patients who voided successfully were discharged home without a urethral catheter. We used the chi-square test with κ to determine successful bladder emptying. We recruited 79 patients, of whom 65 with a mean age of 59.7 years (range 33 to 81) had complete data sets available for analysis. Of the patients 38 (58%) underwent prolapse repair only, 1 (2%) underwent a continence procedure only and 26 (40%) underwent each procedure. The back fill void trial correlated better with a successful voiding trial than the auto fill trial (κ = 0.91, 95% CI 0.81-1.00 vs κ = 0.56, 95% CI 0.39-0.74). Overall 40.5% of patients had an unsuccessful void trial on day 1 postoperatively and were discharged home with a catheter. None subsequently experienced urinary retention. The back fill technique appears to be a better predictor of adequate postoperative bladder emptying than the auto fill technique for inpatient void trials.