Perfusion and Protection Practice Test

When air shows up in the CPB circuit, the fastest and safest move is to clamp the lines and de-air the circuit. Air in the bypass circuit can be forced into the patient’s arterial circulation, causing air emboli that can damage the brain, heart, or other organs. By clamping the cannula lines, you stop any further air from entering the patient, and then you remove the trapped air from the circuit through de-airing steps — venting the venous reservoir, aspirating air from the oxygenator and arterial line, and priming the lines with saline until the circuit is bubble-free. Once the circuit is free of air, flow can be resumed safely.

Increasing pump flow or increasing FiO2 does not remove the air embolus risk and can, in some scenarios, worsen embolization or mislead the team about the circuit’s status. Stopping CPB is not the immediate action when air is detected; you first isolate and eliminate the air, and only consider stopping CPB if air cannot be removed promptly.