VAVD vacuum may cause bubble transgression in membrane oxygenators

Area of Science:

• Cardiovascular Surgery
• Biomedical Engineering
• Medical Device Safety

Background:

• Vacuum-assisted venous drainage (VAVD) is crucial for enhancing venous blood return during cardiopulmonary bypass (CPB).
• Accidental vacuum in the oxygenator can lead to bubble transgression (BT), introducing gas bubbles into the arterial blood line.
• Understanding oxygenator tolerance to vacuum is vital for preventing BT and minimizing patient injury.

Purpose of the Study:

• To determine the vacuum threshold at which bubble transgression occurs in membrane oxygenators.
• To assess the impact of VAVD vacuum on different adult oxygenator models.

Main Methods:

• Four adult oxygenators (Quadrox-i, Affinity Fusion, Capiox RX25, Inspire 6M) were tested in an in vitro setup.
• VAVD vacuum was applied to the oxygenator via a non-occlusive roller pump.
• An ultrasonic bubble counter (Gampt BCC 200) measured bubbles in the arterial line post-restart.

Main Results:

• Significant bubble count increases were observed in Affinity Fusion and Inspire 6M oxygenators at -30 mmHg VAVD vacuum.
• Massive air ingress occurred in Capiox RX25 at -30 mmHg and Affinity Fusion at -40 mmHg VAVD vacuum.
• All tested oxygenators demonstrated some level of bubble transgression under VAVD vacuum.

Conclusions:

• VAVD vacuum poses a risk of bubble transgression and massive air ingress in oxygenators.
• Specific oxygenator models exhibited vulnerability at different vacuum levels.
• Implementing negative pressure alarms or pressure relief valves could enhance safety during VAVD use.