Can the oxygenator screen filter reduce gaseous microemboli?

Area of Science:

• Biomedical Engineering
• Cardiovascular Surgery
• Medical Device Technology

Background:

• Gaseous microemboli (GME), defined as bubbles < 200 micrometers, are linked to increased morbidity following cardiopulmonary bypass (CPB) and cardiac surgery.
• Arterial line filtration is standard practice during CPB to prevent systemic GME intrusion.
• Emerging oxygenator designs integrate arterial filtration within the device housing.

Purpose of the Study:

• To evaluate the GME removal efficiency of an integrated arterial screen filter in a standard microporous oxygenator.
• To compare the performance of an oxygenator with an integrated filter (Terumo Capiox FX25) against one without (Capiox RX25).

Main Methods:

• An experimental CPB circuit using a blood analog prime solution was established.
• Recirculation was performed at 4 and 6 L/min flow rates with controlled air introduction.
• GME activity was measured using an ultrasonic device, calculating removal efficacy based on GME counts and volume.

Main Results:

• Screen filtration reduced GME volume by 99.1% at 4 L/min and 97.9% at 6 L/min, significantly outperforming controls (p < .001).
• Conversely, GME count reduction was less effective with screen filtration (89.6% at 4 L/min, 55.6% at 6 L/min) compared to controls (91.4% at 4 L/min, 76.0% at 6 L/min) (p < .001).
• The integrated filter reduced GME volume effectively while increasing GME counts.

Conclusions:

• The integrated arterial screen filter demonstrates high efficacy in reducing GME volume during CPB.
• Despite volume reduction, the filter's impact on GME counts warrants careful consideration for clinical application.
• Further research is needed to optimize integrated filter designs for comprehensive GME management.