The effect of bladder outflow obstruction on detrusor blood flow changes during the voiding cycle in conscious pigs

Purpose: We monitored detrusor blood flow in pigs with bladder outflow obst ruction. Materials and Methods: Partial urethral obstruction was created in 9 immatu re, female large white pigs with an implanted ring, and 10 normal animals w ere used for comparison. Urodynamic parameters and detrusor blood flow were measured using chronically implanted access catheters and laser Doppler fi bers. Repeated recordings were made from each animal while it was lightly s edated. Results: The animals with implanted rings developed prolonged, high pressur e voiding contractions in association with poor urinary flow, indicating bl adder outflow obstruction, and had evidence of detrusor instability. In obs tructed and normal animals detrusor blood flow was maintained during bladde r filling. Elevated detrusor pressure during voiding significantly decrease d blood flow to similar levels in each group. The duration of the ischemic period was much greater in obstructed animals. Conclusions: Bladder outflow obstruction is associated with repeated episod es of prolonged detrusor ischemia which may account for the biochemical and neuronal alterations in such bladders.