The obstructive effect of a urethral catheter
Related Experiment Video
Updated: Nov 6, 2026

In Vivo Luminal Measurement of Distension-Evoked Urothelial ATP Release in Rodents
Published on: September 7, 2022
1Bristol Urological Institute, Southmead Hospital, United Kingdom.
Purpose:
The effect of a urethral catheter on pressure-flow relationships of the urethra has important implications for the practice to this question in the past in men with benign prostatic hyperplasia. We assessed the obstructive effect of an 8 Ch. urethral catheter in men who presented with lower urinary tract symptoms due to benign prostatic hyperplasia.
Materials And Methods:
During combined pressure-flow studies 59 men completed 2 voids of similar volume with and without a urethral catheter in situ. Maximum flow rate, detrusor pressure at maximum flow and the group of specific urethral resistance factor were measured and compared between these 2 voids.
Results:
There was no significant difference in maximum flow rate between voids (with catheter 9.1 ml. per second versus without catheter 8.6 ml. per second). Although detrusor pressure was significantly greater with the urethral catheter in situ (80 versus 67 cm. water), voids (with catheter 42.1 cm, water versus without catheter 36.6 cm water).
Conclusions:
A 8 Ch. catheter does not appear to have a significant obstructive effect in the urethra. This finding has important implications for the practice and interpretation of pressure-flow studies.
Related Concept Videos
Urodynamic Studies: Uroflowmetry
Cardiac Catheterization IV: Nursing Management
Urologic Endoscopic Procedure: Cystoscopic Examination
Urethra
The anatomy of the urethra differs between males and females. In females, the urethra is short, measuring about 3–4 cm in length, and opens anterior to the vaginal opening. In males, the urethra is longer and passes through the penis, serving dual purposes: expelling urine and ejaculating semen. The male urethra is...
Disorders of the Urinary System
Urinary tract infections (UTIs) are one of the most common urinary system disorders. They are caused by bacteria that enter the urethra and can spread to the bladder resulting in cystitis. Pyelonephritis is the result of a UTI that has ascended to the level of the...
Urinary Tract Calculi II: Pathophysiology and Clinical Manifestations

