Effects of bladder capacity and height of fluid bag on intravesical pressure during transurethral resection of the prostate.

We studied the intravesical pressure profile and the fluid absorption in 30 men undergoing transurethral resection of the prostate with the irrigating fluid bags placed 55-60, 70-75, 80-85 or 90-100 cm above the operating table. The maximum intravesical pressure, but not the mean pressure or the period of time during which there was excessive pressure (> 2 kPa), increased when the fluid bags were placed higher. The urologist consistently reached about half the possible maximum pressure as indicated by the bag height at the end of each intermittent filling of the bladder. A large bladder capacity promoted lower maximum and mean pressures and shortened the period of excessive intravesical pressure. However, neither bag height nor bladder capacity correlated with the absorption of irrigating fluid.