Arterial line filters ranked for gaseous micro-emboli separation performance: an in vitro study.

UNLABELLED: Arterial line filters (ALFs) are arguably the most important component in the cardiopulmonary bypass circuit to protect the patient from gaseous macro- and micro-emboli (GME) originating in the perfusion circuit. The GME separating ability of 10 ALFs was ranked according to seven performance criteria. Ten ALFs rated between 20 and 43 microm were evaluated for flow resistance, the count, size, and volume of GME passed after a 10-mL room air bolus, and the ability to separate a high-count, 10- to 200-microm flowing distribution of GME. The Luna Innovations EDAC emboli detector was used to size, count, and sort GME. Three test trials were conducted for 3 each of the 10 filters. Performance criteria were correlated by regression analysis, statistically compared using analysis of variance, or ranked using non-parametric tests. Significance was set at 0.05. Weighting all seven test parameters equally, the most effective ALFs were the Cobe 21 and Gish 25-microm filters. The Pall LG-6 ranked more efficient than the Medtronic 20 and Dideco 27-microm filters. The Cobe 43, Terumo 40, Medtronic 38, Terumo 37, and Gish 40-microm filters were less effective as a group compared with the other filters. For the 10 filters, blood flow resistance was not correlated to rated pore size. Generally, the smaller the pore rating, the higher the GME separation ability rank, except for the leuko-reduction filter, which performed more effectively than other large pore filters. KEYWORDS: arterial line filter, gaseous microemboli, in vitro test.