CFR › Title 21 › Part 868 › §868.202521 CFR §868.2025Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗Copy link(a)Identification. An ultrasonic air embolism monitor is a device used to detect air bubbles in a patient's blood stream. It may use Doppler or other ultrasonic principles.(b)Classification. Class II (performance standards).