During urodynamic uroflowmetry, the patient empties his or her bladder into a funnel. A connected device determines the amount of urine passed per unit of time, allowing conclusions to be drawn about any micturition disorders that may be present. The procedure takes place on an outpatient basis and is not associated with any risks or side effects.
What is uroflowmetry?
During urodynamic uroflowmetry, the patient empties his or her bladder into a funnel. A connected device determines the amount of urine passed per unit of time, allowing conclusions to be drawn about any micturition disorders that may be present. Bladder emptying disorders are micturition disorders and, as a group of diseases, include many different conditions with leading symptoms after, before or during urination. Urology is concerned with micturition disorders and includes a variety of specific diagnostic procedures to investigate the causes of disturbed bladder emptying. A subgroup of urological examination procedures is represented by the group of urodynamic examination procedures. Uroflowmetry belongs to this group of methods. In this procedure, the amount of urine passed per unit of time is determined. Micturition disorders are often manifested by decreased values in this examination. More rarely, increased values above a certain level indicate a micturition disorder. To perform uroflowmetry, a patient urinates into a funnel. A sensor unit on the funnel records the amount of urine passed per unit time. Ideally, the urine flow rate should be around 20 milliliters per second. Decreased values are present when there is obstruction to the flow of urine from the bladder or are associated with weakness of the bladder muscle.
Function, effects, and goals
To perform uroflowmetry, the patient’s bladder is ideally well-filled. Urinary urgency must be present to a sufficient degree at the time of the examination. The patient withdraws and directs his or her urine stream into a funnel provided by the urologist. The funnel is connected to an examination device that carries a unit of sensitive sensors. For this reason, when the patient directs the urine stream into the funnel, the device can determine the amount of urine per unit time. Overall, this determination serves the device to calculate different values. Among the most important of these values, in addition to the urinary flow rate Q, are the urinary flow time t, the maximum urinary flow Qmax and the mean urinary flow Qave. The micturition volume V and the micturition duration or bladder emptying time are also recorded by the device. In a majority of cases, a sonographic examination takes place following uroflowmetry. This imaging by ultrasound device detects the residual urine left in the bladder. For the evaluation of the urine flowmetry, the urologist follows the standard values and their reference ranges. The reference range for the value of maximum urine flow in an adult patient is between 15 and 50 milliliters per second. If the maximum urine flow has values below ten milliliters per second, an obstruction in the urethra is usually underlying the micturition disorder. On the other hand, if the values are between ten and 15 milliliters per second, this is a gray area. In this case, the urologist must consult further investigative procedures for diagnosis. Various phenomena and symptoms are indications for uroflowmetry. For example, uroflowmetry can be used to clarify symptoms such as a subjectively perceived weakening of micturition. If the patient complains of prolonged micturition in the medical history, the procedure is also indicated. The same applies to symptoms such as intermittent micturition that stops unexpectedly from time to time. A disturbed onset of urination, an imperative urge to urinate, or a recurrent urinary tract infection may also indicate testing. If patients experience bladder voiding with markedly increased frequency with small amounts of urine, or if they stop to urinate abnormally frequently during the night, uroflowmetry may also be used to clarify these symptoms.
Risks, side effects, and hazards
Uroflowmetry is an extremely gentle examination procedure that is not perceived as unpleasant by the patient. Risks and side effects do not occur. The short time required for the procedure also suits the patient.Inpatient admission to a hospital is not required to perform uroflowmetry. Normally, the examination is performed on an outpatient basis by a urologist in private practice. The patient receives the results on the same day. Since the examination does not place any further strain on the patient and his organism, uroflowmetry should be given preference over imaging diagnostics, for example, for the diagnosis of a micturition disorder. Imaging diagnostics are usually associated with radiation exposure and the associated risks and side effects. In most cases, contrast medium is also used, which can cause the patient to experience headaches or similar discomforts and puts a strain on his or her organism. The patient is spared such risks and side effects with uroflowmetry. In this context, the diagnostic procedure is ideally suited for diagnostic prefeeling. Only under certain circumstances and after certain findings of uroflowmetry does the diagnostic method need to be combined with additional procedures. The more detailed determination of an existing micturition disorder can usually not be determined to a sufficient degree by the procedure. For this reason, additional procedures for diagnostic clarification usually take place after an abnormal uroflowmetry. If uroflowmetry is unremarkable, the urologist will order additional diagnostic steps only in rare cases. Uroflowmetry may not provide meaningful results under certain circumstances. One prerequisite for meaningful results is an existing urge to urinate. In addition, the bladder must be well filled. Only when the amount of urine passed exceeds 150 milliliters can there be talk of a meaningful result.
