Impact of urethral catheterization on uroflow during pressure-flow study

OBJECTIVE: To investigate the impact of urethral catheterization on uroflow by comparing urodynamic parameters of free uroflowmetry versus pressure-flow study in adult patients with benign prostatic hyperplasia, female stress incontinence, lumbosacral spinal injury or spina bifida. METHODS: Each patient was required to perform pressure-flow study immediately following free uroflowmetry. Maximum flow rate (Q(max)), average flow rate (Q(ave)), voided volume (VV), T(max) (time to Q(max)) and post-voiding residual urine (PVR) were compared between the two tests. RESULTS: Out of 120 patients, transurethral catheterization significantly impacted uroflow. In male patients with benign prostatic hyperplasia (n = 50), Q(max), Q(ave) and T(max) were significantly different between free uroflow and pressure-flow study. In patients with female stress incontinence (n = 30), there were no statistically significant between-test differences in VV and T(max), but Q(max), Q(ave) and PVR were significantly different. In patients with spinal injury or spina bifida (n = 40), Q(max), Q(ave) and VV were significantly different between free uroflow and pressure-flow study. CONCLUSION: Urethral catheterization adversely impacts uroflow in patients with benign prostatic hyperplasia, female stress incontinence, spinal injury or spina bifida. Free uroflowmetry should be performed before pressure-flow study.