Urodynamics
Information provided by Dr. Consuelo Sierralta, Pediatric Unit, Hospital Roberto del Río.
Why was I asked to take this test?
Urodynamics is a test performed to evaluate bladder function in children or adolescents (NNA). The study seeks to measure the following variables:
- The process that occurs as the bladder fills.
- The degree of stretching of the bladder during filling.
- The amount of urine the bladder can hold.
- The sensations experienced in the bladder.
- Changes in internal bladder pressure.
- Contraction and emptying of the bladder, when the patient has the capacity to do so.
What does Urodynamics consist of?
Urodynamics examination aims to monitor the bladder. For this, it is necessary to use two catheters. The first one is installed through the urethra and through it the bladder is filled with serum. This catheter makes it possible to monitor the pressure inside the bladder.
Once the first probe has been established, a second, smaller probe is placed in the patient's rectum, with which the rectal pressure is measured during the study. The rectum, being in direct contact with the bladder, exerts pressure, which can affect the measurement of bladder pressures. Finally, it is necessary to stick stickers near the anus, called electrodes. These are used to monitor the activity of the pelvic floor muscles while the bladder is being filled. At the end of the procedure, the patient is asked to try to urinate, during which time the bladder emptying is evaluated.
To reduce the risk of urinary tract infection in the patient, it is necessary to administer antibiotics. The physician is the one who prescribes the antibiotic and the corresponding dose, which must be taken the day before the examination, the day of the Urodynamics and the day after it.
One week before the Urodynamics, urine tests should be performed. Urodynamics may be discontinued if the results of these tests are abnormal or if the patient has symptoms of urinary tract infection, such as difficulty urinating, cloudy or foul-smelling urine, fever or blood in the urine.
It is essential that the patient has no bowel movements for the study to be performed correctly, therefore, it is necessary to perform intestinal lavage with Fleet enema the night before the exam. Fleet enema can be purchased at the pharmacy and it is suggested to use 1 adult Fleet enema when the child weighs more than 30 kg and 1⁄2 Fleet enema or 1 pediatric Fleet enema in children under 30 kg.
Is the exam painful?
The installation of these probes may be uncomfortable, but it is not painful. The examination will be easier and less uncomfortable for the patient if he/she is relaxed. It is recommended to explain beforehand what the examination consists of and, to make it more comfortable, it is suggested that he/she bring his/her favorite toy, a video, books or a bottle.
During the study, the patient may have a sensation similar to the desire to urinate when the bladder is full. He/she may also have the urge to urinate or defecate, but these sensations are less if he/she is relaxed.
What happens if I decide not to take the exam?
The treating physician may not be able to get the answers needed to make a diagnosis. If the physician is unable to understand how the bladder works, he or she should look for alternative ways to try to understand how the bladder works.
What should I do on the day of the exam?
- Eat a light breakfast.
- Bring the results of complete urine and urine culture tests performed one week prior to the examination.
- It is necessary to take the prescribed antibiotics to reduce the risk of urinary tract infection.
- If the patient is taking Oxybutynin, it is important to inform the physician who will perform the Urodynamics.
- If the patient needs catheterization, he/she should arrive already catheterized before the examination.
- If the child is taking Oxybutynin, it is important to inform the physician who will perform the Urodynamics.
- Bring socks and a bottle of water to drink during the procedure.
