Pressure flow urodynamic studies
When is this exam indicated?
Complete urodynamic examination is not a first level examination. It is indicated in cases of complex urinary dysfunction not responsive to a first line of treatment or when it may be useful in changing therapeutic approach to the patient. It is sometimes useful in predicting the outcome of certain types of lower urinary tract surgery and in selecting patients who are most likely to benefit from a particular surgical approach. In addition, it is very important that it is performed in a whole series of neurological diseases with bladder involvement.
How is it performed?
A standard urodynamic exam includes: free uroflowmetry, cystomanometry, and pressure/flow study. The evaluation takes 50 to 60 minutes. Flowmetry consists of the graphic recording of urinary flow during urination. Cystomanometry is the continuous recording of bladder pressure changes during bladder filling. The Flow Pressure Study is performed, instead, for the study of the bladder emptying phase as it allows to evaluate the exact intravesical pressure together with the flow, during the emptying phase. From a practical point of view, in order to carry out the examination, it is necessary to place two catheters, one in the bladder and one in the rectum (or vagina), which allow to fill the bladder, using a saline solution or contrast medium (where an X-ray evaluation is foreseen), with known volumes of liquid, simultaneously measuring the pressures in the bladder and abdomen. At the end of filling, when the patient feels the need to urinate, a urinary assessment is performed by measuring both urinary flow and corresponding pressures.
There are no absolute contraindications to this type of examination After a urodynamic examination, it is quite common for the patient to experience discomfort upon urination. Typically, this sensation lasts a maximum of 24 hours. More rarely, the patient may also suffer from hematuria (or blood in the urine); as in the previous case, this disorder does not continue for more than one day after the conclusion of the diagnostic test. The examination should not be performed in the presence of the following diseases: macroscopic hematuria, urinary tract infections, bladder stones, bladder tumors.