The effects of heparin coated circuits on pulmonary injury. A clinical study

Heparin-coated circuits have dramatic effects on the coagulation cascade, but their role on complement activation has not been clearly defined. In this clinical study the effect of heparin-coated circuits on static lung compliance and pulmonary vascular resistance is described.

Thirty patients were randomly divided into two groups: with either a heparin-coated circuit or an identical but non-coated circuit control group. In the heparin-coated group, all the blood contacting surfaces were treated with immobilized heparin (Duraflo II.)

Early postoperative pulmonary function is determined with measurements of static lung compliance, pulmonary vascular resistance and arterial blood gases. Static lung compliance was significantly better in the heparin coated (HC) group in the early postoperative period (p=0.001). Pulmonary vascular resistance was significantly lower in the heparin-coated (HC) group in the early postoperative period (p=0.001).

We believe that the method of heparin binding may play a role in its diminished effect on complement activation, but the general augmentation of the circuit's biocompatibility may explain its beneficial effect on pulmonary vascular resistance and static lung compliance.