Skip to main content Accessibility help
×
Hostname: page-component-6b989bf9dc-pmhlf Total loading time: 0 Render date: 2024-04-14T23:15:53.613Z Has data issue: false hasContentIssue false

3 - Flow rate testing

Published online by Cambridge University Press:  05 February 2014

Marcus Drake
Affiliation:
Bristol Urological Institute
Ahmed Shaban
Affiliation:
Bristol Urological Institute
Ranee Thakar
Affiliation:
St George’s University of London
Philip Toosz-Hobson
Affiliation:
Birmingham Women’s Hospital
Lucia Dolan
Affiliation:
Belfast City Hospital
Get access

Summary

Flow rate testing is a simple, non-invasive test, which can provide useful clinical information, although with important limitations. It is an assessment of the volume passed in unit time and is often undertaken in conjunction with other measurements, most notably post-void residual urine volume (PVR) measurement.

Methods of flow rate assessment

The two most common flow rate measurement systems are:

  1. Gravimetric: the weight of urine voided is measured over time; the flow rate is calculated from the rate of change in weight of urine.

  2. Rotating disc: as the urinary stream falls on to a spinning disc, it increases the weight of the disc, so the motor has to increase power to keep the disc spinning. The flow rate is proportionate to the power needed to keep the disc spinning at the same rate.

Both approaches are widely employed in current commercial systems. They are prone to variations in reliability and need to be calibrated before use. Regular checks are needed at intervals specified by the manufacturer and should also be done if the equipment is moved or disturbed.

Preparation for the test

Patients should have completed a pre-test frequency volume chart, which will show the typical and maximum voided volume. The set-up for uroflowmetry has been described in chapter 2. The flow rate machine should be in a private area. The patient should be well hydrated and prepared to wait for as long as needed to obtain an adequate result.

Type
Chapter
Information
Publisher: Cambridge University Press
Print publication year: 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Save book to Kindle

To save this book to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×