Objectives: To prospectively examine the effect of a 6F urethral catheter on the urinary flow rate in healthy women without lower urinary tract symptoms undergoing pressure-flow studies.
Methods: Women between the ages of 30 and 70 years, without lower urinary tract complaints and without a history of surgery for incontinence, were recruited. All women completed the Urogenital Distress Inventory-6 questionnaire, and only women with mild or no symptoms were enrolled. After a free flow rate was determined, cystometry and pressure-flow studies were performed once and then repeated using a 6F urethral catheter. The peak flow rates during the first and second studies were compared with one another and with the nonintubated values.
Results: Of the 59 women that applied, 20 volunteers (mean age 41.7 years) met the entry criteria and were evaluated. The mean nonintubated flow rate was 22.65 mL/s. With a 6F urethral catheter in place, our cohort had a mean peak flow rate of 16.25 mL/s on the first study and 15.25 mL/s on the second. A significant difference was demonstrated between the free and intubated peak flow rates for both the first (P = 0.0006) and the second (P = 0.0001) study. No significant difference was detected between the two intubated peak flow rates (P = 0.262).
Conclusions: Our data suggest that the presence of a 6F urethral catheter significantly reduces the maximal flow rate compared with free flow studies. Whether these findings represent a truly obstructive effect of the catheter, detrusor fatigue, or other possible effect of the catheter remains to be elucidated.