Norm of Cystometry
Normal filling pattern. Absence of residual urine; sensation of fullness at 300–500 mL; urge to void at 150–450 mL; filling bladder pressure constant until capacity reached with contraction at capacity. Normal thermal sensation when hot and cold sterile fluids are introduced into the bladder.
Usage of Cystometry
Evaluation of detrusor muscle function and tonicity, determination of the cause of bladder dysfunction (urinary incontinence and retention), and differentiation of the type of neurogenic bladder dysfunction.
Description of Cystometry
Cystometry involves assessment of bladder neuromuscular function after instillation of measured quantities of fluid or air and evaluation of the client's neurologic sensations and muscular responses. It also includes assessment of the voiding flow pattern for abnormalities. Neuromuscular dysfunction of the bladder can occur when brain or spinal cord lesions (spinal cord or brain surgery or injury; stroke) interfere with the neural pathways that transmit bladder reflexes to and from the brain or with progressive diseases (such as multiple sclerosis), congenital malformations, strokes, or postoperatively. Cystometry is most often performed in a physician's office or clinic.
Professional Considerations of Cystometry
Consent form IS required.
Clients with spinal cord lesions (usually with cervical lesions or a history of higher cord lesions) may exhibit autonomic dysreflexia (bradycardia, hypertension, flushing, diaphoresis, and headache) during instillation of fluid or carbon dioxide. Intravenous or oral nifedipine or propantheline bromide may help to counteract this response.
This procedure is contraindicated in the acute phase of urinary tract infection and in urethral obstruction.
- Obtain a gas cystometer, a cystometric set, a 6- or 8-French special multiple-port transducer catheter, and an irrigation solution of sterile 0.9% saline or sterile, distilled water.
- The client should disrobe below the waist or wear a gown.
- Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.
- The client urinates into a funnel attached to a machine that plots the amount, flow, and time of voiding on a graph.
- Residual urine volume, if any, is then measured by means of an inserted indwelling catheter.
- As the client lies in a supine position, thermal sensation is evaluated by the client's reported sensations in response to the instillation of 30–60 mL of room temperature 0.9% sterile saline solution, followed by 30–60 mL of 29–32 degrees C, 0.9% sterile saline solution through the catheter into the bladder.
- The fluid is then drained from the bladder.
- The client is then placed on a special commode chair attached to a cystometrogram table or placed in the semi-upright position. The client's sensations to bladder filling are measured next after the catheter is connected to a cystometer and measured amounts of sterile fluid or carbon dioxide are instilled into the bladder. Sometimes another catheter is placed into the rectum for abdominal pressure measurement. This allows true bladder muscle (detrusor) pressure to be electronically determined (bladder pressure - abdominal pressure = detrusor pressure). Needle or surface electrodes may be used to measure pelvic floor muscle activity.
- The cystometer measures and graphically records bladder pressure and volume, along with the client's reported descriptions of sensations (such as when he or she first feels the urge to void or feels unable to go any longer without voiding) and any reported discomfort.
- The instillation is stopped when the client feels uncomfortably full or if it is determined that there is an absence of filling sensation.
- The air or fluid and catheter are removed, or the client may be asked to void the fluid.
- The test may be repeated in standing or sitting positions or after the administration of bladder-tone stimulants such as bethanechol chloride.
- Encourage the oral intake of fluids when not contraindicated; 125 mL/hour for 24 hours is desirable.
- Monitor fluid intake and urine output for 24 hours.
- Observe for urinary retention, symptoms of urinary tract infection (fever; chills; tachycardia; tachypnea; abdominal, suprapubic, or flank pain; hesitancy and frequency; dysuria; and hematuria).
- Hematuria for more than 4–6 hours is abnormal. More postprocedure discomfort may be experienced after carbon dioxide instillation than after irrigant instillation.
- Analgesics may be prescribed for bladder spasms.
Client and Family Teaching
- The client must lie very still during the test.
- The client may experience bladder spasms and see blood in his or her urine after the procedure. Spasms occurring for longer than 24 hours or bloody urine for more than 4–6 hours is abnormal. Call the physician if either of these occurs.
Factors That Affect Results
- Antihistamines may interfere with bladder function by causing relaxation.
- Movement during the test may interfere with bladder reflexes.