Kystometria

Kystometria, known in English as cystometry, is a urodynamic test used to evaluate how the bladder stores and releases urine. The procedure measures bladder pressure, volume, and compliance during filling, and, in some protocols, during voiding, to assess detrusor function and urethral outlet resistance.

During the test, a sterile catheter is inserted into the bladder to fill it with saline while intravesical pressure is recorded. A second sensor placed in the abdomen or rectum may be used to estimate abdominal pressure, allowing calculation of detrusor pressure by subtraction. In some protocols a urethral catheter monitors flow during voiding. The filling rate is controlled and standardized, typically ranging from about 10 to 60 milliliters per minute, depending on local practice and patient factors. The patient reports sensations of filling, and the bladder is observed for involuntary contractions or leakage. The filling phase ends at a predefined point such as maximum cystometric capacity or leakage.

A complete study may include a voiding phase, sometimes with a pressure-flow assessment, to evaluate the relationship between detrusor pressure and urinary flow. This helps determine whether there is bladder outlet obstruction, detrusor underactivity, or other dysfunctions.

Indications for kystometria include storage symptoms such as urinary urgency and incontinence, suspected detrusor overactivity, impaired bladder compliance, neurogenic bladder, and evaluation prior to treatment or surgery. It can aid in guiding pharmacologic therapy, neuromodulation, or other interventions.

Interpretation focuses on detrusor pressure, bladder capacity and compliance, and the presence of involuntary contractions, underactivity, or dyssynergia. Risks are generally minor but can include urinary tract infection, bleeding, or discomfort, and results may be influenced by technique and patient factors.