Original Article

An Experimental Evaluation of the Capiox 1.6 and 5.4M² Membrane Oxygenators for Air Removal Efficiency in the Conventional and Inverted Positions

¹ Department of Surgery, School of Medicine, University of Colorado Health Sciences Center, Denver, CO
² PSICOR Inc. San Diego, CA
³ Technical Support, Terumo Corp.

^* Direct Communications to: Richard Berryessa, PSICOR, Inc. 16818 Via del Campo Ct., San Diego, CA 92127.

Abstract

Membrane oxygenators do not create bubbles but most will transmit the bubbles which are common in venous reservoir bags. We previously reported the elimination of arterial micro-air in the 0.8m² Capiox when operated in the inverted position with an open purge line. This same lung failed to eliminate micro-air when operated in the conventional orientation.

The purpose of this study was to test the effectiveness of the Capiox as a bubble trap in lungs with a larger surface area (subgroup a-1.6m²) (subgroup b-5.4m²) and at higher flows.

Two test circuits were constructed for each size lung (Group 1—conventional orientation) (Group 11—inverted). The circuits were primed with dilute, outdated human blood (Hct. 20 ± 2%). Ten injections of air (5ml) were done for each lung in both test positions. A bubble counter on the outlet side of the lung was used to count bubbles passed through the membrane oxygenator following the air challenge.

Thirty second counts were significantly higher (p<.001) in Group I than in Group II for both size lungs. The counts for both groups were:

The inverted orientation of both the Capiox 1.6 and 5.4 m² lungs with an open purge line was superior to the conventional orientation for micro-air removal. As a bubble trap, both lungs compare favorably to an arterial filter in air handling characteristics.

(All data reported as mean ± S.D.).