Retained intracardiac air in cardiovascular surgery: a re-visited problem

Intracardiac air remains an unsolved problem in the realm of cardiac surgery, leading to embolic events encompassing conduction disturbance, heart failure, and stroke. Transesophageal echocardiography allows the visualization of three distinct types of retained intracardiac air: pooled air, coarse bubbles, and microbubbles. The former two predominantly manifest in the right upper pulmonary vein, left atrium, and left ventricle, exhibiting passive movement along the vessel walls by buoyancy. De-airing, involving "eradication" of air from circulation and "expulsion" of air from the heart into the systemic circulation assumes paramount importance in averting embolic events. Optimal de-airing strategies necessitate the thorough elimination of air during the static phase before the resumption of cardiac activity, achieved through aspiration or guided exit leveraging buoyancy. While the dynamic phase, characterized by active cardiac beating, presents challenges for air eradication, the majority of air expulsion occurs towards the aorta during this period. In this latter phase, collaborative efforts among the surgeon, anesthesiologist, and clinical engineer are pivotal to mitigate the risk of bolus air embolism. The efficacy of carbon dioxide insufflation is limited, as it is rapidly aspirated by wall suction or absorbed into the bloodstream. Consequently, the "air" identified by TEE is acknowledged as conventional air. Understanding the distinctive properties of air as well as timely and judicious collaboration for detection and removal, with the ultimate goal of eradication, emerges as an essential prerequisite for successful de-airing in the evolving era of cardiac surgery.