EFFECTS OF BLADDER CATHETERIZATION AND EMPTYING ON BLOOD FLOW AFTER OUTLET OBSTRUCTION
 

Authors:

A.Schröder1,2, B.A.Kogan2 , J. Lieb2 and R.M.Levin2,3,4
   

Institution:

Department of Urology, Johannes Gutenberg-University, Mainz, Germany1, Albany Medical College, Albany, NY2, Albany College of Pharmacy, Albany, NY3, Stratton VA Medical Center, Albany, NY4, USA
     

Conference:

ICS 2000 Tampere
       

Type:

Informally Discussed Posters
         

Category:

Bladder Outlet Obstruction
                 

Aims of Study:
Previous studies have shown that catheterization and drainage of the urinary bladder results in a significant nitric oxide-induced increase of blood flow to the bladder. It was also shown that long term obstruction causes a significant decrease in blood flow to the bladder. The purpose of this study was to determine the effects of catheterization and drainage on blood flow after 4 weeks of partial outlet obstruction.

Methods:
15 New Zealand White rabbits received a partial outlet obstruction by standard methods. After 4 weeks the rabbits were anaesthetized and blood flow to the bladder muscle and mucosa were determined by a standardized fluorescent microsphere technique. After transurethral catheterization and complete drainage of the bladder the blood flow was determined again. The same procedure was performed in 5 unobstructed control animals. The bladders were assingned to groups based on bladder weight and were named compensated (<5.1g), intermediately compensated (5.1.-15g) and decompensated (>15.1g).

Results:
4 weeks of partial bladder outlet obstruction caused a significant decrease of blood flow to the bladder muscle (without changes in the blood flow to mucosa) and a increases of bladder weight and residual urine. After drainage of the bladder the blood flow increased 6 fold in the obstructed group and 2.5 fold in the control animals (Figure). Within the obstructed animal group the increase was highest in the intermediate group. The severely decompensated bladders (weight > 15g) showed a limited ability to increase blood flow after drainage.

Conclusion:
The overall decreased blood flow to the bladder smooth muscle appears to be an etiological factor in bladder contractile dysfunction secondary to partial outlet obstruction. The ability to increase blood flow after emptying the bladder could be an important determinant of compensation in the early phase of outlet obstruction. Loss of the ability to increase the blood flow after emptying might be the turning point from reversible to irreversible damage of the bladder due to outlet obstruction.