Risk Factors of Air Embolism During Cardiovascular Surgeries
- Cardiovascular surgeries with cardiopulmonary bypass have a significant risk of venous air embolism. Air can enter the heart chambers during cannulation, decannulation, or mishaps with air in the perfusion circuit.
- Intracardiac procedures such as valve replacements or atrial septal defect repairs, especially when performed in the presence of a PFO, increase the risk of systemic air embolism due to the possibility of paradoxical embolism.
- Hemodynamic Instability: Using nitrous oxide during cardiovascular procedures can exacerbate venous air embolism by expanding air bubbles in circulation.
Prevention and Management of Air Embolism
- Cardiopulmonary Bypass (CPB) Techniques: Ensure the CPB circuit is primed correctly and air bubbles are removed from the tube.
- Air Detection Devices: CPB machines are equipped with air-detection systems that can immediately alert the surgical team if air is detected in the circuit. These systems should be routinely checked and calibrated before the procedure.
- Avoidance of Nitrous Oxide: Nitrous oxide must be avoided in cardiovascular surgeries because it can cause air bubbles in the heart or pulmonary circulation to expand, worsening the hemodynamic consequences of air embolism. Instead, 100% oxygen should be used throughout the procedure, especially when the risk of air embolism is high.
- Immediate Air Aspiration: If an air embolism occurs during CPB, the immediate focus should be on the air removal from the heart chambers. Cannulas inserted into the right atrium or left ventricle can be used to aspirate air, and the CPB circuit may need to be adjusted to remove any air that has entered the perfusion loop.
- Hyperbaric Oxygen Therapy (HBOT) helps shrink air bubbles and improves oxygen delivery to ischemic brain tissue, enhancing patient recovery in paradoxical embolism cases.
- Hemodynamic Management: Vasopressors like norepinephrine and intravenous fluids should be used to maintain right heart function. Mechanical ventilation with 100% oxygen will help reduce the size of the embolus and optimize oxygenation.
