Urodynamics

Question 1

What is the initial evaluation for patients who screen positive for UI?

Answer 1

UA
PVR (goal < 150 mL)

Question 2

Do all patients need urodynamics?

Answer 2

No
If PVR < 150, negative UA, and positive stress test on exam, then no need for urodynamics

Question 3

What are the components of urodynamics?

Answer 3

1. Uroflometry
2. Cystometrography
3. Urethral pressure profilometry

Question 4

What is uroflowmetry?

Answer 4

How long it takes a patient to empty bladder.
Should be 15-20 seconds with a flow rate of 20 mL/sec.

Positive test is when flow rate is < 15 mL/sec and/or urine volume retention is > 200 mL

Question 5

What is Cystometrography?

Answer 5

It helps to distinguish between stress UI and OAB.

Question 6

How is cystometrography performed?

Answer 6

Two catheters.
One in bladder, one in vagina.
- Bladder catheter measures bladder pressure.
- Vaginal catheter measures abdominal pressure.
- Detrusor pressure = Bladder pressure - abdominal pressure

Bladder is incrementally filled and patient is asked to cough/Valsalva

Question 7

How is ISD diagnosed?

Answer 7

During cystometrography; if cough leak point is less than 60 cm H20.

(if higher pressures required to leak, more indicative of urethral hypermobility contributing to SUI)

Question 8

How is OAB diagnosed?

Answer 8

When acute increase in detrusor pressure is identified during filling phase of cystometrography.

Question 9

What is urethral pressure prolifometry?

Answer 9

Once bladder is filled, the catheter is slowly pulled back to record the maximal urethral closing pressure.
- If < 20 cm H2O = ISD