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Urodynamics.... Why Me? Urodynamics refers to a series of diagnostic tests that evaluate the function of the bladder and urethra. These tests may be recommended if you have urinary incontinence (leakage of urine), recurrent bladder infections, slow or weak urinary stream, incomplete bladder emptying, or frequent urination. These tests help the clinician understand the 2 S’s and 3 C’s of Urodynamics: Sensitivity, Stability, Compliance, Capacity, and Competence.
Sensitivity
“Often I feel like I have to go again, right after I just went!”
During the procedure your bladder will be filled with sterile water. You will be asked about various urinary sensations and desires you might be feeling during this stage. The results will help better diagnose the overall sensitivity or your bladder such as, does your bladder feel full when it actually is full, does your bladder feel empty after voiding, and other various bladder sensations.
Stability
“Doctor I have to go several times during the night, and when I go it’s not very much.”
Your bladder can perform interesting acts, and one is most often referred to as an overactive bladder. This is similar to a muscle spasm equivalent to an eye twitch. During the filling stage the clinician will monitor the muscle in your bladder for over-activity. The muscle called the detrusor is the muscle that can perform this “twitching” activity, resulting in several unnecessary trips to the restroom or even leaking called urge incontinence.
Compliance
“It seems like I go to bathroom 7-8 times a day regardless of what I drink. I must have a very small bladder.”
Your bladder is constructed of striated elastic muscles. When your bladder is filling, it expands to accommodate the urine and later contracts when empting. The catheter placed in your bladder will constantly measure your pressure to ensure these they stay within optimum levels.
Capacity
“I drink half a glass of milk and I have to go to the bathroom, and I go all the time.”
Bladder capacity is an important part of determining the results of Urodynamic testing. The amount of fluid needed to fill your bladder can help determine the elasticity and overall bladder health. Should you be asked to complete a voiding diary, it is important to accurately record voiding times and amounts.
Competence
“When I cough with a bad cold, run up stairs, or even lift a heavy bag of groceries, I leak. Sometimes I have to push on my belly to completely empty.”
Your bladder has the ability to expand when filling, properly store urine, and contract to empty. Incomplete voiding can be caused by several issues, and most importantly can be easily assessed by Urodynamics. You might even be instructed to cough heavily in efforts to reproduce urinary leakage identifying leak point pressures for additional diagnosis and/or treatment
Problems in the urinary system can be caused by aging, illness, or injury. The muscles in and around your bladder and urethra tend to become weaker with age. Weak bladder muscles may result in your not being able to empty your bladder completely, leaving you at a higher risk for urinary tract infections. Weak muscles of the sphincters and pelvis can lead to urinary incontinence because the sphincter muscles cannot remain tight enough to hold urine in the bladder, or the bladder does not have enough support from the pelvic muscles to stay in its proper position.
incontinence
frequent urination
sudden, strong urges to urinate
problems starting a urine stream
painful urination
problems emptying your bladder completely
recurrent urinary tract infections
These tests may be as simple as urinating behind a curtain while a doctor or nurse listens or more complicated, involving imaging equipment that films urination and pressure monitors that record the pressures of the bladder and urethra.
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Seeing Your Doctor or Nurse
The first step in solving a urinary problem is to talk with your doctor or nurse. He or she should ask you about your general medical history, including any major illnesses or surgeries. You should talk about
the medicines you take, both prescription and nonprescription, because they might be part of the problem. You should talk about how much fluid you drink a day and whether you use alcohol or caffeine. Give
as many details as you can about the problem and when it started. The doctor or nurse may ask you to keep a voiding diary, which is a record of fluid intake and trips to the bathroom, plus any episodes of leakage.
If leakage is the problem, the doctor or nurse may ask you to do a pad test. This test is a simple way to measure how much urine leaks out. You will be given a number of absorbent pads and plastic bags of a
standard weight. You will be told to wear the pad for 1 or 2 hours while in the clinic or to wear a series of pads at home during a specific period of time. The pads are collected and sealed in a plastic bag. Your
health care team will then weigh the bags to see how much urine has been caught in the pad. A simpler but less precise method is to change pads as often as you need to and keep track of how many pads you use in a day.
A physical exam will also be performed to rule out other causes of urinary problems. This exam usually includes an assessment of the nerves in the lower part of your body. It will also include a pelvic exam in women to assess the pelvic muscles and the other pelvic organs. In men, a rectal exam is given to assess the prostate. Your doctor will also want to check your urine for evidence of infection or blood.
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Preparing for the Test
If the doctor or nurse recommends bladder testing, usually no special preparations are needed, but make sure you understand any instructions you do receive. Depending on the test, you may be asked to come
with a full bladder or an empty one. Also, ask whether you should change your diet or skip your regular medicines and for how long.
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Taking the Test
Any procedure designed to provide information about a bladder problem can be called a urodynamic test. The type of test you take depends on your problem.
Most urodynamic testing focuses on the bladder’s ability to empty steadily and completely. It can also show whether the bladder is having abnormal contractions that cause leakage. Your doctor will want
to know whether you have difficulty starting a urine stream, how hard you have to strain to maintain it, whether the stream is interrupted, and whether any urine is left in your bladder when you are done. The
remaining urine is called the postvoid residual. Urodynamic tests can range from simple observation to precise measurement using sophisticated instruments.
At the beginning of the test you will be asked to urinate, so please arrive for the study with a relatively full bladder. The Uroflow test measures the speed and amount of urine you void. You will be asked to urinate into a commode with a funnel attached to a computer that measures your urine flow. Next, catheters used to measure bladder and abdominal pressure are placed and EMG electrodes may be placed near the rectum to record muscle activity. This test measures how well you can control your sphincter (outlet) muscles and determines if they are working in coordination with your bladder. The CMG/Pressure-Flow study evaluates how your bladder holds urine, measures your bladder capacity, and also determines how well you can control your bladder. Through a catheter your bladder is filled with fluid. In order to reproduce your bladder symptoms, you should report any sensations you feel during the study. In addition, you may be asked to cough, bear down, stand, or walk in place during the test. At the end of the study, you will be asked to urinate.
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After the Test
You may have mild discomfort for a few hours after these tests when you urinate. Drinking an 8-ounce glass of water each half-hour for 2 hours should help. Ask your doctor whether you can take a warm
bath. If not, you may be able to hold a warm, damp washcloth over the urethral opening to relieve the discomfort.
Your doctor may give you an antibiotic to take for 1 or 2 days to prevent an infection. If you have signs of infection—including pain, chills, or fever—call your doctor at once.
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Getting the Results
Results for simple tests can be discussed with your doctor or nurse immediately after the test. Results of other tests may take a few days. You will have the chance to ask questions about the results and possible treatments for your problem.
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Urodynamic Testing
Uroflowmetry (Measurement of Urine Speed and Volume)
This study measures your urinary flow rate. You
should come to the test feeling as though you
need to urinate. Try not to empty your bladder
one hour before your test is scheduled.
You will be asked to urinate into a special commode
that allows a computer to measure your
urine flow rate and voided volume.
Your doctor or nurse can also get some idea of your bladder function by using a stopwatch to time you as you urinate into a graduated container. The volume of urine is divided by the time to see what your average flow rate is. For example, 330 milliliters (mL) of urine in 30 seconds means that your average flow rate is 11 mL per second.
Measurement of Postvoid Residual
After you have finished, you may still have some urine, usually only an ounce or two, remaining in your bladder. To measure this postvoid residual, the doctor or nurse may use a catheter, a thin tube that can be gently glided into the urethra. He or she can also measure the postvoid residual with ultrasound equipment that uses harmless sound waves to create a picture of the bladder. A postvoid residual of more than 200
mL, about half a pint, is a clear sign of a problem. Even 100 mL, about half a cup, requires further evaluation. However, the amount of postvoid residual can be different each time you urinate.
Cystometrogram (CMG)
This study measures your bladder capacity, evaluates how your bladder holds urine, and determines how well you can control your bladder muscle. One very small catheter will be placed in your bladder, and another catheter will be placed in your rectum. These catheters will measure both the pressure inside your bladder, and the pressure your body exerts on your bladder. You will be asked to report the sensations you feel as your bladder is filled (such as when you first feel the need to urinate and when that feeling intensifies). You may be asked to cough, bear down, or stand during the test so as to check for leakage of urine. At the end of the study, you will be asked to urinate.
Measurement of Leak Point Pressure
While your bladder is being filled for the CMG, it may suddenly contract and squeeze some water out without warning. The manometer will record the pressure at the point when the leakage occurred. This
reading may provide information about the kind of bladder problem you have. You may also be asked to apply abdominal pressure to the bladder by coughing, shifting position, or trying to exhale while holding
your nose and mouth. These actions help the doctor or nurse evaluate your sphincter muscles.
Pressure Flow Study
After the CMG, you will be asked to empty your bladder. The catheter can measure the bladder pressures required to urinate and the flow rate a given pressure generates. This pressure flow study helps to
identify bladder outlet obstruction that men may experience with prostate enlargement. Bladder outlet obstruction is less common in women but can occur with a fallen bladder or rarely after a surgical procedure for urinary incontinence. Most catheters can be used for both CMG and pressure flow studies.
Electromyography (Measurement of Nerve Impulses)
If your doctor or nurse thinks that your urinary problem is related to nerve or muscle damage, you may be given an electromyography. This test measures the muscle activity in and around the urethral
sphincter by using special sensors. The sensors are placed on the skin near the urethra and rectum or they are located on the urethral or rectal catheter. Muscle activity is recorded on a machine. The patterns
of the impulses will show whether the messages sent to the bladder and urethra are coordinated correctly.
Video Urodynamics
This study allows the physician to see the shape
and position of your bladder as it fills and empties.
This is done at the same time as the tests
described below. A special fluid will be used to fill
your bladder and x-ray images will be taken.
EMG
This study measures how well you can control your sphincter (outlet) muscles and helps determine if they are working in coordination with your bladder. “Sticky patches” (electrodes) will be placed near the rectum to record sphincter muscle activity.
Biofeedback & Pelvic Floor Therapy
This non-surgical form of therapy is used to retrain the pelvic floor and/or bladder muscles. Typically, pelvic floor therapy consists of weekly sessions for six weeks. The first session will last about one hour, but the remaining sessions will be shorter. Using biofeedback and electrical stimulation techniques, a nurse will evaluate your muscle strength and instruct you on how to properly isolate and exercise these pelvic floor muscles. A computer will be used to guide you and monitor
your progress. The nurse will educate you in these techniques so that you can continue the exercises at home.
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