Investigations: Urodynamics

Urodynamics is the term given to tests used to investigate how the bladder and urethra (the tube through which you pass urine) work. Many women are anxious or embarrassed before the test. The clinic staff do understand this and do everything to try and make you feel relaxed. The test may be performed by a nurse or doctor who will explain what the test involves. The test is performed in a private room. Most patients leave the clinic feeling the test was not as bad as they thought it would be.

In the vast majority of cases, the test is divided into two parts: uroflowmetry and cystometry.

Uroflowmetry - this is the first part of the test. You are advised to attend the clinic with a comfortably full bladder because the first thing you will be asked to do is to pass urine into a special toilet so that we can measure the speed with which the urine flows out, i.e. the flow rate.

Cystometry - after you have passed urine, you will be given a hospital gown to wear and you will be asked to lie on an examination couch. Two fine, flexible tubes, one the thickness of a noodle and the other the thickness of spaghetti are inserted by a few inches through your urethra so that they sit in the bladder. The first tube fills your bladder with water and the second measures the pressure in your bladder as it fills. This pressure is then recorded on a computer. A third tube is inserted into your rectum (back passage) and records the pressure inside your abdomen, but outside the bladder. You may feel a little discomfort as the three tubes are inserted, but this settles quite quickly.

Your bladder can be filled with you lying on the couch, sitting or standing up. The idea behind the test is to try and reproduce the symptoms, such as urgency to pass urine and/or leakage, that you experience from day to day. As your bladder fills you will get a feeling of wanting to pass urine. From time to time we will ask you to cough. During the test you may leak some water but try not to feel embarrassed. This is an important part of the test. When your bladder is full we will ask you to pass water again. Finally the tubes are removed and the test is over.

The doctor or nurse will explain the results to you immediately after the test and discuss any treatment that may be required.

Are there any risks with the test?
Most women have no problems at all after the test. When passing urine for the first time, a few may experience a slight discomfort. You may want to pass urine a little more often, but all this settles down quite quickly. It is advisable to maintain a good fluid intake for the first couple of days to 'flush things through'. If things do not settle within a couple of days it is possible that you may develop a urine infection which is uncommon, in which case you should visit your family doctor just in case you need some antibiotics.