Urine flow rate measurement based on volumetric pressure measurement principle

Abstract

Measurement of Urine Flow Rate is one of the important parts of Urodynamics. The study and analysis of Urodynamics is helpful in diagnosing lower urinary tract diseases. Uroflowmetry, part of Urodynamics, is a non-invasive test very easy to implement. It involves measurement of urine flow rate and other associated parameters. This paper presents Urine Flow Rate measurement based on Volumetric Pressure measurement technique. For implementation of this technique special purpose probe is designed. Pressure sensor used in this paper is from MPX series. The output of the sensor is connected to Analog to Digital Converter and microcontroller after signal conditioning and amplification. The main principle of measurement technique uses the air pressure in a closed tube above a column of water (urine). As flow rate changes, the level in container changes accordingly and the air pressure in the closed tube above the column will change proportionally. By measuring the air pressure and associated time the flow rate is calculated. Once flow rate is calculated the other parameters as decided by the International Continence Society like Maximum flow rate, Average flow rate, voided volume and total time for voiding, time for maximum flow rate are calculated and displayed on PC. The graph of Flow rate (milliliters) versus time (sec) is plotted. This graph has typical nature in normal functioning of lower urinary tract if this nature gets changed then there might be some problem associated with this tract or patient may need further investigations. By observing this nature of graph Doctor used to do the diagnosis.