Position-related changes in uroflowmetric parameters in healthy young men

Uroflowmetric measurements are a common procedure in urological examination of patients presenting with lower urinary tract symptoms and it can be influenced by various factors. In this study, we investigated position-related changes in uroflowmetric parameters and postvoiding residual urine (PVR) volume in healthy young men.

Thirty normal healthy male volunteers, whose mean age was 28.6 +/- 0.7 years old were studied and evaluated with uroflowmetry in the standing, sitting, and squatting down voiding positions. Three measurements were obtained for each voiding position and for each man (total 270 urinary flows). PVR were measured by transabdominal ultrasound. The maximum flow rate (Q(max)), average flow rate (Q(ave)), corrected maximum flow rate (cQ(max)), voiding volume (VV), voiding time (VT), and PVR values were compared between the three different voiding positions.

The mean Q(max) values for the standing, sitting, and squatting down voiding positions of the patient group were 26.8 +/- 1.3, 31.3 +/- 1.2, 31.0 +/- 1.0 ml/sec, respectively and the mean Q(ave) values were 16.8 +/- 0.6, 18.5 +/- 0.6, 18.6 +/- 0.6 ml/sec, respectively. There were significant differences between voiding positions regarding the Q(max) (P < 0.0001) and Q(ave) (P = 0.0002) values in the patient groups. However, the difference between VT, VV, and PVR in the standing, sitting, and squatting down voiding position of the patient group was not statistically significant.

Our results suggest that the urinary flow rates are affected by the voiding position. Therefore, it is important to perform uroflowmetric measurements in the same position.