Experimental study of the pressure-volume and pressure-time relations in the completely obstructed pelvis of the porcine kidney. Part 4: Instability and blow out.

In a series of experiments with pigs the completely obstructed renal pelvis was filled with Ringer's lactate at a constant rate of 2 ml/min until the pressure did not longer increase linearly. By means of continuous X-ray monitoring and histological examination of the infused kidneys it was found that blow out may occur at pressure levels individually varying from 60 to 180 mmHg. The histological features of this phenomenon are presented and the clinical significance is discussed.