Catheter obstruction with omental wrap stimulated by dialysate exposure

A new implantation technique and catheter design (Moncrief-Popovich Catheter) were tested in the continuous ambulatory peritoneal dialysis (CAPD) dog model. With this technique the catheter distal (external) segment was implanted in a subcutaneous tunnel for 4-6 weeks. Therefore, no irrigation of exposure to dialysate was present. Secondary exteriorization and irrigation (CAPD exchanges) demonstrated no episodes of primary catheter obstruction. Fifteen mongrel female dogs had 30 catheters implanted; 2 catheters simultaneously in each dog. One catheter was implanted with the interabdominal segments in the pelvis and the second interabdominal segment directed upward in direct contact with the omentum. Following initial irrigation, all catheters were patent, but within 24-48 hours all upwardly directed catheters were obstructed. Nine of the 15 downwardly directed catheters became obstructed by omentum wrapping around the catheter within 5 days. Preliminary studies have failed to demonstrate the cause of this "omental stimulation," which occurs with peritoneal contact with fresh dialysate. Possible explanations include pH, osmolality, flow direction, volume, vasodilator effect of osmols or lactate, and glucose, among others. This effect needs study, and this model would allow evaluation of improvements in the biocompatibility of dialysis fluids.