Biocompatible polycarbonate aids medical design

A Sabic Innovative Plastics product story

Edited by the Engineeringtalk editorial team Feb 20, 2008

The use of Lexan HPM resins in the Pulsar blood pump helps prevent buildup of thrombus on the pump's walls that could potentially interfere with treatments.

A haemodialysis blood pump from Renal Solutions, featuring Sabic Innovative Plastics' advanced haemocompatibility polycarbonate (PC) resin, is helping meet demands for new and innovative healthcare devices.

The patented Pulsar blood pump made with Lexan HPM resins helps prevent buildup of thrombus on the pump's walls that could potentially interfere with the effectiveness of treatments.

Renal Solutions worked closely with Sabic Innovative Plastics to identify a material that met the mechanical and physical needs for the blood pump's optimum haemodynamic filling design while offering enhanced blood-contact properties.

Lexan HPM resin's improved performance compared with standard PC allows the Pulsar pump to benefit from reduced platelet and fibrinogen binding characteristics, as well as reduced leukocyte and C3a protein activation, resulting in reductions in overall clotting.

In contrast to traditional peristaltic (roller) pumps that use compression to squeeze blood through the dialyzer, the pressure-limited Pulsar pump alternately applies positive and negative pressure to a flexible membrane within each pumping chamber, thereby reducing pressures at the patient's access site during circuit occlusions.

The Pulsar pump's design also makes it easy to convert to single-needle application by simply selecting single-needle mode on the graphical user interface, a process that is cumbersome and difficult in traditional peristaltic (roller) pump designs.

"Sabic Innovative Plastics' commitment to bringing high-performance materials to the healthcare industry is stronger than ever, as shown by our relationship with Renal Solutions", says Clare Frissora, Market Director for Healthcare, Sabic Innovative Plastics.

"Through our legacy of high-performance technology and strong customer co-operation, Sabic Innovative Plastics aims to stay in the forefront of healthcare innovation".

"We originally used conventional polycarbonate for the Pulsar pump, but after dialysis sessions, we would observe fibrin production and clot formations adhering to the pump walls", says John Maholtz, Senior Vice President of Operations and Engineering for Renal Solutions.

"To minimise the potential for formation of clots that could interfere with treatment, we not only modified the design, but also worked with Sabic Innovative Plastics to incorporate Lexan HPM1944 resin for improved haemocompatibility performance".

"By implementing these design and material changes, it appears that we have reduced the likelihood for thrombosis or clotting in the pump".

"In fact, based on initial treatments of up to six hours in duration, the walls of the Pulsar pump remain clean".

The Pulsar blood pump is an integral part of Renal Solutions' Allient Sorbent Haemodialysis System.

The Pulsar pump's gentle blood movement provides expanded safety and versatility advantages through the pump's unique, pressure-limited two-chamber design.

The unique design, coupled with Sabic Innovative Plastics' materials expertise, brings the first significant advancement in haemodialysis blood pump evolution since the 1960s.

Compared with conventional PC, Lexan HPM1944 resin is a biocompatible polycarbonate that provides up to 50% greater retention of platelets in the blood; up to 50% lower leukocyte activation; and up to 60% lower fibrinogen adsorption to the material's surface, all of which may result in fewer interactions and improved preservation of blood composition.