Purge system for rotary blood pumps.

Purge liquid has been supplied successfully to lubricate the bearings and wash the seals of rotary blood pumps to minimize hemolysis and thrombosis, extending their operating endurance. Although encouraging results have been obtained and development is proceeding for pumps with blood lubricated bearings, their validation and clinical use will occur some time in the future. For rotary blood pumps with purged bearings, a miniature purge liquid pump weighing 80 g has been successfully developed to meet the design point of 1 ml/h at 1,000 mm Hg (required by an existing rotary blood pump) with a motor power of 4 mW. The novel device maintains the flow rate for a sufficient time to service or replace the pump without flow interruption. A preliminary design has been made for a wearable purge delivery unit comprising a purge liquid pump, an electronic control, a purge liquid reservoir, and a battery.