Post-void Residual Urine Test - Indication and Complications
Published on Mar 01, 2023 - 4 min read
Abstract
Post-void residual urine test is a diagnostic test to detect the cause of urine retention in the urinary bladder. The article explains the procedure further.
Introduction
The urinary bladder is a sac-like structure that stores urine. When one goes to the restroom, the bladder should empty completely. However, at times some amount of urine remains in the bladder even after passing out the urine. Some volume of residual urine is usually present, but the problem arises when the residual amount is significant. Even after urinating, this amount of urine left in the bladder is known as pot-void residual (PVR) urine. A post-void residual test measures the amount of leftover urine in the bladder. This test may help the doctor to decide on a better treatment plan.
What Does Post-void Residual Urine Test Evaluate?
Post-void residual urine test evaluates:
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Urine incontinence in men and women.
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Problems with the passing of urine.
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An enlarged prostate gland.
When Is the Post-void Residual Urine Test Indicated?
The physician can order a post-void residual urine test if one has urinary incontinence or retention symptoms. Urine incontinence could be due to:
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A blockage in the urinary tract.
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Side effects of certain medications.
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Narrowing of the urethra- the tube through which urine passes out.
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Neurogenic bladder-The nerves that carry the messages between the bladder and brain do not function properly.
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Urinary tract infections (UTIs).
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Damage to the kidneys.
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Kidney or bladder stones.
How Does One Prepare for the Test?
Before proceeding with the procedure, the individual is asked to empty the bladder as completely as possible. The process begins immediately after passing urine.
What Is a Post-void Urine Test?
The post-void residual test is done by measuring the remaining amount of urine in the bladder immediately after passing urine. This test can be performed via ultrasound, bladder scan, or directly measuring the volume of urine drained by the catheter. The most crucial step before proceeding is immediately carrying out the procedure after urination. A delay of even five or ten minutes from bladder emptying to the post-void residual urine test likely causes a false reading of overestimating the post-void residual volume. The various tests and their procedure are:
1. Ultrasound - Standard ultrasound, also known as sonography, is a diagnostic imaging technique that uses sound waves to produce images of the internal organs or structures within the body. For example, it is used to picture the urinary bladder directly, either through the abdomen (transabdominal), belly, or vagina (transvaginal). It estimates the bladder’s volume using the ultrasound equipment’s internal volume calculations or mathematical equations. The transvaginal technique usually gives the correct estimation of the bladder volume.
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Transabdominal Ultrasound - The individual is made to lie on their belly. Some gel is applied on the skin of the suprapubic area (the region below the belly button), and a transducer or a probe is moved around the place to get a clear picture of the bladder. Then sound waves are sent via the device through the abdomen. The waves are recorded and transformed into images on the computer screen. The pictures of the urinary bladder are recorded in both vertical and horizontal planes. Finally, the gel is wiped off the area. This procedure takes around thirty minutes to an hour.
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Transvaginal Ultrasound - The transvaginal ultrasound is done to view the uterus, ovaries, fallopian tubes, cervix, and pelvis. The individual is made to lie on her back with her legs folded and knees bent. A clean probe is inserted into the vagina. The probe is usually covered with a condom and smeared with a get at the end. The procedure might be a little uncomfortable but not painful. The probe sends sound waves, which are recorded when they bounce back. The ultrasound equipment creates images of the bladder. Then the probe is gently rotated to view the other pelvic structures. The bladder images are recorded in a vertical plane.
Many ultrasound machines can automatically calculate the post-void residual urine volume from the measurements with calipers- a device that measures the dimensions of objects. In case of the unavailability of ultrasound calipers, the volume can be calculated with the help of a formula. The formula is post-void volume = length x width x height x 0.52.
Measurement calculated using this method is standard because it is fast and easy.
Limitations: The precise information of transabdominal ultrasound for determining the post-void urine volume is mixed, though many studies show high certainty with the use of transabdominal ultrasound. In comparison, some recent studies question their accuracy.
2. Portable Bladder Ultrasound Device (Bladder Scanner) - A portable bladder ultrasound device is a device that uses technology to digitally report the urine in the bladder and give 3D images of the urinary bladder. This is a non-invasive procedure. The individual is made to lie on their back. An ultrasound gel is applied to the suprapubic area (the area just below the navel). A transducer or probe is placed over the gel and moved around until the bladder is visible. Once the bladder is recognized, the volume of urine present in the bladder is recorded.
Limitations: Portable bladder ultrasound is not acceptable for use on individuals with severe abdominal scars, uterus prolapse, or pregnancy. In addition, a fluid-filled abdomen (ascites) due to conditions such as liver diseases, etc. might give a false result. However, some studies have found that portable bladder ultrasounds are much more precise than 2D ultrasound imaging techniques.
3. Urethral Catheterization - This technique directly measures the post-void residual urine volume and is considered the standard benchmark. Different techniques are required to insert a urethral catheter in males and females. However, the overall procedure remains the same. First, the individual is made to lie in a frog-leg position. Sterilized drapes cover the genitals exposing the urethral opening. For men, the penis is held straight up towards the ceiling, and in females, the skin folds around the vaginal orifice should be held and separated to expose the urethral opening. A lubricated catheter is inserted into the urethral orifice and observed for a return of urine to confirm its position within the bladder. Once the positioning is established, the catheter balloon is inflated with the help of saline. Then the bladder is entirely drained into a graduated or marked container, and the volume is measured. Once the bladder is fully emptied, the catheter is removed.
Limitations: Urethral catheterization can cause urethral trauma, the creation of faulty passage within the urethra, and unintended balloon inflation within the urethra. It can also lead to bacteria-led urinary tract infection if the procedure is not carried out with proper sanitization.
What Are the Complications of the Post-void Residual Urine Test?
The ultrasound techniques for determining the post-void residual volume do not pose grave risks. However, urethral or bladder catheterization has complications such as discomfort, developing urinary tract infection, injury, painful urination, or blood in the urine. Antibiotics can be prescribed in such cases.
Conclusion
Post-void residual urine test is a diagnostic procedure determining the cause of bladder urine retention. There are a few techniques to carry out the test. However, the procedures have limitations and complications that can be managed with medicines and hygiene.
Frequently Asked Questions
1.
What Is Normal Post-void Residual Urine?
The volume of urine that remains in the bladder after urinating is referred to as normal post-void residual urine. When the residual volume is typically less than 50 milliliters, it is regarded as normal. This suggests that the bladder was effectively empty during urination. It is critical to monitor and maintain a normal post-void residual volume for the health of the bladder and for good urine performance.
2.
What Factors Contribute to the Occurrence of Post-void Residual Urine?
One usual cause is insufficient bladder emptying induced by weak bladder muscles or a urinary tract obstruction. Post-void residue can also result from neurological diseases such as spinal cord injuries or nerve damage. Urinary tract infections, prostate enlargement in men, and specific drugs all contribute to inadequate bladder emptying.
3.
What Are the Consequences of Having a High Post-void Residual Volume?
When the post-void residual (PVR) is high, it means that the bladder still contains a substantial volume of urine after passing. This may result in a number of issues. High PVR increases the risk of urinary tract infections, as the stagnant urine provides a favorable environment for bacterial growth. Additionally, it may result in urine incontinence, bladder dysfunction, and urinary retention over time. It may also induce bladder distention.
4.
What Does the Presence of Residual Urine Indicate?
Residual urine indicates the presence of urine that remains in the bladder after urination. It denotes inadequate bladder emptying and may be a sign of bladder blockage or malfunction. The presence of residual urine may indicate weak bladder muscles, a urinary tract infection, enlarged prostate in men, neurological disorders, or other abnormalities of the urinary system.
5.
Should Post-void Residual Urine Be Considered a Serious Condition?
The precise circumstances and the quantity of remaining urine determine how dangerous post-void residual (PVR) is. A small level of PVR is typically seen to be normal and may not raise any issues. But if the PVR is always high or linked to symptoms like urinary tract infections, urine retention, or bladder dysfunction, it can point to a medical issue that has to be treated.
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Can Post-void Residual Urine Lead To Urinary Tract Infections?
Yes, post-void residual urine can potentially lead to urinary tract infections (UTIs). When urine remains in the bladder after voiding, it provides a breeding ground for bacteria to multiply, increasing the risk of infection. The stagnant urine can promote bacterial growth and make it easier for bacteria to reach the urinary tract
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What Are Some Natural Methods to Reduce Post-void Residual Urine?
It involves drinking enough fluids to encourage regular urination, exercising the pelvic floor to strengthen the muscles that control the bladder, thoroughly emptying the bladder when using the restroom, and establishing a healthy lifestyle that includes regular exercise and a well-balanced diet.
8.
Does Regular Exercise Have an Impact on Decreasing Post-void Residual Volume?
Regular exercise can potentially help decrease post-void residual (PVR) urine. Physical activity, particularly exercises that engage the pelvic floor muscles, can strengthen the muscles involved in bladder control. This enhanced muscle tone may aid in more efficient bladder emptying and reduce the amount of residual urine.
9.
What Is Post-void Urine Leakage?
It can happen due to residual urine remaining in the urethra or bladder, which may be expelled during activities such as walking, standing, or changing positions. This leakage is often a result of weak pelvic floor muscles or impaired bladder control. Managing post-void urine leakage may involve pelvic floor exercises, lifestyle modifications, and, in some cases, medical interventions, depending on the underlying cause and severity of symptoms
10.
Is There a Relationship Between Post-void Residual Volume and Blood Pressure?
Blood pressure and post-void residual (PVR) volume often have no direct correlation. PVR is the volume of urine retained in the bladder following voiding, whereas blood pressure is the force of flowing blood acting against blood vessel walls. Although underlying medical illnesses like certain neurological abnormalities, urinary tract obstructions, or renal issues might have an impact on both PVR and blood pressure, they are separate physiological parameters and are not always connected.
11.
What Is the Procedure for Conducting a Post-void Residual Test?
A post-void residual (PVR) test is typically conducted by using a non-invasive ultrasound or a catheter. In order to see the bladder and gauge how much urine is still in it, a portable device is put on the lower abdomen for an ultrasound test. As an alternative, any leftover urine can be drained from the bladder through the urethra and measured using a catheter. The process, which is usually short and painless, gives important information regarding how much pee is still in the bladder after voiding.
12.
What Treatment Options Are Available for Managing Post-void Residual Urine?
Exercises for the pelvic floor muscles, scheduled voiding, and fluid control are a few non-invasive treatment options. Interventions, including medication, catheterization, or surgery, may be required in situations where PVR is brought on by a blockage or other particular medical issues.
13.
Is Post-void Residual Volume a Treatable Condition?
In most cases, post-void residual (PVR) volume is a condition that can be treated. The underlying reason for the high PVR will determine the best course of treatment. Treatment options may include modifying one's lifestyle, performing pelvic floor exercises, taking drugs to enhance bladder function, or undergoing surgery to remove obstructions or correct anatomical anomalies.
14.
What Symptoms Are Commonly Associated With Post-void Residual Urine?
Common symptoms associated with post-void residual (PVR) urine include a frequent need to urinate, urgency, weak urine flow, a feeling of incomplete bladder emptying, urinary dribbling or leakage after urination, recurrent urinary tract infections, and an increased risk of bladder-related complications. These symptoms may vary depending on the individual and the underlying cause of PVR.
- Post-Void Residual Urine Test
https://www.peacehealth.org/medical-topics/id/ug1859 - Bladder Post Void Residual Volume
https://www.ncbi.nlm.nih.gov/books/NBK539839/ - Post-void residual
https://radiopaedia.org/articles/post-void-residual
Last reviewed at:
01 Mar 2023 - 4 min read
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