Editing Pathophysiology of Urinary Tract Obstruction (section)

==== Whitaker test ====

* Involves placement of a percutaneous needle in the collecting system of the kidney and the infusion of contrast at a rate of 10 mL/min. A urodynamic catheter is also placed in the bladder, and intravesical pressures are monitored and subtracted from measured intrapelvic pressures during the infusion. Intrapelvic pressures are noted at the time that contrast is first seen extending passed the ureteropelvic junction and passed the ureterovesical junction.
* '''Interpretation:'''
** Pressure <15 cm H2O considered normal
** Pressure 15-22cm considered indeterminate
** '''Pressure >22 cm H2O suggestive of obstruction'''