Air trapping ability of the Spiral Gold™ membrane oxygenator: an ex vivo study

Abstract

Despite an overall improvement in cardiopulmonary bypass (CPB) technology and materials, air emboli still occur. The latest generation membrane oxygenator from Bentley Laboratories, the SpiralGold™, was tested ex vivo for its air handling ability. The study was conducted on four calves. Bolus amounts of air of 10, 15 and 20 cm³ were each injected three times, upstream of the oxygenator and a bubble detector located directly downstream. The amount of bubbles was measured semiquantitatively on a 10 unit scale (U = one semiquantitative unit). The animals were killed 10 days after the CPB.

When 10 cm³ of air was injected, no bubbles were detected. With 15 and 20 cm³, respectively, 1 ± 1.5 and 5 ± 3.3 U of bubbles were detected. Despite a total of 135 cm³ of air injected as large bolus amounts, all the animals survived without any obvious neurological deficit secondary to air bubble manipulation. In conclusion, the Spiral Gold™ oxygenator per se can reliably trap an air bolus of up to 10 cm³. This feature should be taken into account when choosing an oxygenator, as it offers an additional barrier to air bubbles in the CPB circuit.