Central Venous Catheter Task Trainer Phantom with Purple Vessels

If you are using task trainer procedural phantoms for ultrasound guided vascular access you may notice a problem over time.  The phantom vessels may start to be filled with purple fluid.  If you have blue and red liquid to differentiate the artery versus vein in the phantom there are 2 reasons you could have purple fluid.

  1. Aspiration of fluid from one vessel and re-injection into the other, mixing the red and blue to form purple.
  2. There is a fistulous connection between the artery and the vein.

If the purple fluid is due to aspiration and injection of fluid from one vessel into the other that is easy to fix.  Drain and refill the vessels with red and blue.  Then instruct your users not to re-inject the fluid in to the phantom vessel.  Instead dispense of the aspirate into a container on the side with a separate one for each color.  This will prevent mixing and injection of air in to the vessels leading to artifacts.  This will also prevent the accidental injection of fluid in to the phantom tissue itself which can damage the inserts and reduce the life of the phantom.  You can then inject the fluid through the fill port later.

The other reason is if you have a fistula between the vessels.  The following video shows what an aterio-venous fistula can appear like on the phantom with both an electronic and hand pump model.

One way to fix both problems is to fill the vessels with a single color fluid so if there is mixing or a fistula it won’t matter.