Intravesical pressure changes during bladder drainage in patients with acute urinary retention.

Using a transurethral approach intravesical pressure and blood pressure were recorded in 10 males with acute urinary retention during either continuous or fractionated drainage. Upon evacuation of the initial 100 cm3 urine the intravesical pressure declined to approximately 50% of the initial value in both groups relieving pain in all patients. Blood pressure was significantly lowered following the procedure, but clinical manifestations were absent. One patient demonstrated hematuria, but treatment was not necessary. The study renders no support for previous recommendations of fractionated outlet of urine in this condition.