Characterisation and evaluation of a new double lumen central venous catheter

The performance of a new double lumen central venous haemodialysis catheter was tested in two laboratory models. In a bench model the patient's venous system was simulated by a reservoir from which water or glycerol was drawn through a fixed tube. A double lumen silastic catheter was then inserted into the tube, as it would in a major vein, with the tip directed away from the direction of flow. The catheter was linked to a dialysis circuit incorporating pressure sensors and dye was infused at constant rate so that recirculation at the tip could be measured and found to be less than 5%. The same catheters were inserted operatively into the superior vena cava via the external jugular vein of three pigs (weight 27-31 kg). The catheters remained patent for four weeks and when connected to an extracorporeal circuit had recirculation and pressure flow characteristics comparable to the bench model in the range 50-400 ml/min. The new double lumen catheter is worthy of clinical evaluation.