Does position affect uroflowmetry parameters in women?

Purpose: To investigate the effect of position on voiding using uroflowmetric variables and postvoid residual urine volume assessment in healthy normal women.
Materials and Methods: 67 healthy females volunteered to participate in this study. Their mean age was 32 years. Each female attended the urodynamic suite on 2 separate days. They performed 2 voids, 1 in a sitting and another in a squatting posture each day. Maximum flow rate (Q(max)), average flow rate (Q(ave)), voided volume and corresponding postvoid residual urine (PVR) were compared for each position using paired Student's t test.
Results: The mean Q(max) values obtained for sitting and squatting postures were 18.4 +/- 3.2 and 24.8 +/- 4.9 ml/s, respectively, and corresponding Q(ave) values were 9.2 +/- 1.9 and 12.3 +/- 3.3 ml/s, respectively. Mean PVR values for sitting and squatting were 51.8 +/- 22.2 and 21.6 +/- 12.7 ml, respectively.
Conclusion: The posture adopted for micturition affects uroflowmetric variables. The squatting posture is associated with a significantly higher maximum flow rate and a lower postvoid residue. Therefore, when low urine flow rates or high residual urine volumes are encountered during urodynamic study, the patients should be asked whether they normally micturate in a sitting or squatting position. If the former position is used, repeat studies with the patients squatting should be considered before accepting an abnormal test result as indicative of lower-urinary-tract dysfunction.
((c) 2008 S. Karger AG, Basel.)