CHARLESTON, S.C. – Most women who undergo an isolated midurethral sling procedure pass active bladder testing on the first attempt, but the likelihood of being discharged with an indwelling catheter increases as bladder capacity increases, maximum flow rate decreases, or detrusor overactivity occurs, findings from a retrospective cross-sectional study have shown.
Of 112 patients who underwent an isolated midurethral sling procedure at a single site, 90 (80.4%) passed active bladder testing (ABT) on the first attempt prior to discharge home, and 22 (19.6%) failed, Dr. Meadow M. Good reported at the annual meeting of the Society of Gynecologic Surgeons.
Bladder testing involved filling the bladder with sterile fluid to 300 mL or to patient discomfort, whichever came first. Passing the test required that two-thirds of the instilled volume was voided.
Average bladder capacity among those who failed ABT was 415 cc, compared with 381 cc in those who passed; average maximum flow rate in those who failed ABT was 15.6 cc/second, compared with 21.6 cc/second in those who passed; and detrusor overactivity was observed in 41% of those who failed ABT, compared with 20% of those who passed, said Dr. Good of the University of Texas Southwestern Medical Center, Dallas.
Furthermore, the capacity-to-infused volume ratio was 1:5 for those who failed ABT and 1:3 for those who passed. Most (81.8%) of those who failed had bladder capacity greater than the infused amount, but no significant difference in the capacity-to-infused volume ratios was seen in the group who passed ABT.
On multivariate analysis, every 50-cc increase in bladder capacity significantly increased the odds of failing ABT (odds ratio, 1.25); every unit increase in the maximum flow rate significantly decreased the odds of ABT failure (OR, 0.91); and the presence of detrusor overactivity was associated with a fivefold increase in the odds of failure (OR, 5.0).
Age, race, body mass index, maximum urethral closure pressure, and maximum detrusor pressure during pressure-flow studies were not found to be associated with ABT outcomes.
Patients included in this study were all those who underwent an isolated midurethral sling procedure at the medical center between January 2011 and August 2012, excluding those who had intraoperative complications requiring discharge with a Foley catheter.
The findings are important because the rates of postoperative urinary retention following midurethral sling procedures are highly variable, and the identification of factors associated with ABT failure could help improve outcomes.
"Patients with postoperative retention are generally discharged home with an indwelling catheter or intermittent self-catheterization; catheter-associated bacteria lead to increased urinary tract infections and health care costs, and to decreased quality of life," Dr. Good said, adding that reducing the rates of postoperative catheter use should be a priority.
"While further research is needed, filling patients to cystometric capacity may improve the success of postoperative bladder testing," she said.
Dr. Good reported having no relevant financial disclosures.