Experimental approach to prevention of catheter-related central venous thrombosis

The role of catheter material in the formation of deep venous thrombosis during parenteral nutrition has been widely emphasized. Systematic venograms show central venous thrombosis in 20 to 33% of cases with polyethylene catheters and in 4% of cases with silicone catheters. Heparin infusion through the catheter diminishes but does not totally eliminate the risk of thrombosis. The aim of this study was to define the conditions under which the risk of thrombophlebitis was minimal. Four series of experiments were carried out, each on five rabbits. Catheters were inserted into the vena cava and, after 10 days, venograms were performed. The animals were then sacrificed, and the vena cava was macroscopically and microscopically studied. Plastic catheters were used in the first series, heparin-Benzalkonium-bonded plastic catheters in the second, silicone catheters in the third, and heparin-Benzalkonium-bonded silicone catheters in the fourth. The results revealed thrombosis of the vena cava and a fibrin sleeve around the catheters in series 1; thrombosis of the vena cava in series 2; a fibrin sleeve around the catheters in series 3; and neither thrombosis nor a fibrin sleeve in series 4. In conclusion, heparin-Benzalkonium-bonded silicone catheters appear to provide the best protection against thrombophlebitis by reducing the damage caused to the intima by the catheters and by slowing down platelet-aggregation around them.