Comparison of position-related changes on uroflowmetric parameters in healthy young men.

OBJECTIVE: To determine the mean difference in maximum urine flow rate and post-void residual urine volume in sitting as well as standing voiding position in healthy males.

METHODS: This descriptive, cross-sectional study was conducted at the Department of Urology, Indus Hospital, Karachi, from October 2013 to March 2014, and comprised healthy volunteers enrolled using non-probability, consecutive sampling technique. Each volunteer was asked to perform uroflowmetry in sitting and standing positions on two separate days, and a post-void residual volume was assessed after each test. The values of maximum flow rate, average flow rate, voiding volume, and post-void residue were compared between the different voiding positions.

RESULTS: A total of 50 volunteers were inducted. In standing position the maximum flow rate was 32.4±9.6 ml/sec, average flow rate 8.8±16.9 ml/sec, and post-void residue was 8.8±16.9ml. Similarly, in sitting position, the maximum flow rate was 14.8±5.4 ml/sec, average flow rate 14.8±5.4 ml/sec, and post-void residue was 6.6±9.4ml. A significant difference in both voiding positions was observed regarding the maximum flow rate, and average flow rate (p=0.001; p=0.003). However, the difference was not significant for voided volume (p=0.676), or post-void residual volume (p=0.771) in either position. Age-wise stratification of data showed significant difference in both younger and older age groups in terms of maximum flow rate (p=00.19). However, the average flow rate was only significantly different in younger age group (p=0.00). There was no difference in voided volume or post-void residue in either age group (p>0.05).

CONCLUSIONS: The standing voiding position in healthy people influenced uroflowmetry findings, and was associated with higher flow rates.