Age, gender, and voided volume dependency of peak urinary flow rate and uroflowmetry nomogram in a tertiary care centre

Abstract

Uroflowmetry is a simple, diagnostic screening procedure used to calculate the flow rate of urine over time. The measurement
of urine flow by uroflowmetry is non-invasive and is the easiest urodynamic test useful as preliminary or follow-up investigation
of the lower urinary tract symptoms. Introduction: Uroflowmetry is a non-invasive test used to assess bladder and sphincter
function. Even though uroflowmetry is not specific in identifying outlet obstruction, the flow rate remains an extremely sensitive
indicator of lower urinary tract symptoms..Here the amount of urine, rate of flow in seconds, and length of time is calculated
until completion of the void and this information is converted into a graph and interpreted by a urologist. The information helps
to evaluate function of the lower urinary tract or help determine obstruction of normal urine outflow. Materials and Methods:
The present study was conducted on 5 groups of people attending the emergency surgical ward and OPD at a tertiary care centre
from Jan 2011 to Oct 2012 who were analyzed separately and intergroup differences were statistically studied.l Nomograms were
presented in centile form and prepared for each group. The difference was assessed for significance using a student’s t- test.
Nomograms were constructed depicting the normal Gaussian distribution of maximum and average urinary flow rate at volumes
ranging from 50 to 1000 cc.. Evaluated parameters were voided volume, maximum flow rate, average flow rate, flow time, and time
to Qmax Results: Maximum flow rate (Qmax) is more significantly correlated with age and voided volume than average flow rate
(Qavg); hence, Qmax is the single most useful parameter of uroflowmetry.Qmax increases with age in the paediatric population
and decreases with age in the adult and elderly population.Qmax in girls was significantly higher than in boys.Nomogramsin
centile form can be constructed to provide normal reference ranges for urinary flow rates covering a wide range of voided volumes.