What are some urodynamic tests?
Urodynamic tests include:
- Cystometry, leak point pressure measurement and pressure flow study.
- Pressure flow study.
- Postvoid residual measurement.
- Video urodynamic tests.
How do you prepare for urodynamic testing?
Most of these tests don’t require any special planning. For some, though, you might be asked to drink fluids before the test so that your bladder is full.
A cystometric test, or a cystometrogram, is a test that uses catheters to measure pressure inside your bladder. The test can tell how much the bladder can hold, how elastic your bladder is and when you feel the need to urinate. The test can measures abnormal contractions or spasms of your detrusor muscle (smooth muscle in the wall of the bladder) while the bladder is filling. While you might feel the catheter being inserted into the urethra, the test does not hurt. A catheter is a small and flexible tube.
During a cystometric test, a manometer can measure the pressure at the point of leakage if the bladder contracts when the bladder is being filled for the cystometrogram. You might be asked to cough or strain while the bladder is being filled so that the point of pressure (leak point pressure) can be measured.
At the end of a cystometrogram, you will be asked to empty your bladder. The manometer will measure the pressure of your bladder and your flow rate (pressure flow measurement). In men, the results of this test might indicate an enlarged prostate, which can make it difficult to urinate.
Some people may find it difficult to empty their bladders with a tube inserted or with another person in the room. Don’t be embarrassed or worry if this happens.
If your healthcare provider thinks the urinary problem is related to nerve or muscle damage, they will order an electromyogram. Electromyography uses sensors to measure the electrical activity of the muscles and nerves in and around the bladder and the sphincters. The test uses electrode patches placed near the urethra and rectum to record electrical currents when muscles in the pelvic floor contract.
Another test that measures how much and how quickly you urinate is uroflometry. For this test, your provider will ask you to have a full bladder when you come to the office. You’ll be asked to urinate into special equipment that will allow measurements to happen. A computer is used to automatically measure the amount and flow rate, creating a graph that shows any changes. Test results will let the provider know if you have weak bladder muscles or some kind of blockage.
Postvoid residual measurement
The postvoid residual measurement test measures the amount of urine left in your bladder after you empty it. The urine that is left is called the postvoid residual. This can be measured with ultrasound equipment that uses sound waves to create a picture of the bladder (called a bladder scanner). Postvoid residual can also be tested by using a catheter that is placed into the urethra and then into the bladder to remove the excess urine. A postvoid residual is five to six ounces or more is a sign that the bladder is not emptying completely, but this can vary. Your provider will review this with you.
Video urodynamic tests
Video urodynamic tests combine cystometry, uroflowmetry, and X-ray cystography into a single test. The digital equipment used in this test can measure urine flow and pressure in the bladder and rectum by using X-rays. The equipment takes images of your bladder during filling and emptying. These tests provide useful information about bladder and urethral function and show the size and shape of your bladder. If X-rays are done, your bladder will be filled with a fluid that contains contrast medium which makes the images show up more clearly.
What happens after an urodynamic test?
You might have mild discomfort or soreness when you urinate. This should only last a few hours. You might even see a small amount of blood due to the catheter. These symptoms might ease up if you drink eight to 16 ounces of water every hour for two hours.
Your healthcare provider might also suggest taking a warm bath or holding a warm, damp washcloth over the urethral opening. You might also be told to take over-the-counter pain medication if you need it. ‘
In some cases, your provider might give you a prescription for an antibiotic to prevent infection, but this is not always necessary. However, if you have any symptoms of infection, such as a fever, chills or a lot of pain, you should call your healthcare provider immediately.