[Retained intracardiac air in coronary artery bypass grafting detected by intraoperative transesophageal echocardiography].

The incidence and location of retained air in 35 patients who underwent coronary artery bypass grafting (CABG) were examined using B mode transesophageal echocardiography. The origin of air detected in the left atrium or left ventricle on weaning from a cardiopulmonary bypass was sought as far as the 4 pulmonary veins. Air appeared as: highly echogenic dots with high mobility, buoyancy and no disappearance in the blood flow. Retained intracardiac air was detected in 10 of the 35 patients: in the right upper pulmonary vein (RUPV) in 9 patients and in the left ventricular (LV) apex in 7. Six of the 7 patients with air retained at the LV apex also had air in the RUPV, suggesting that air from the RUPV collected again at the LV apex. Air from the RUPV was observed flowing into the left atrium on resumption of the pulmonary vein flow. Air at the LV apex appeared as a strong echo area which exhibited a pop-up motion in systole, while air bubbles gradually flowed into the ascending aorta. In one patient, the air at the LV apex was suddenly flushed into the ascending aorta when the heart was manipulated. Air retention is not uncommon in CABG and is mainly located in the RUPV. Retained air at the LV apex may remain indefinitely, and suddenly flow into the aorta with manipulation of the heart or a change of posture.(ABSTRACT TRUNCATED AT 250 WORDS)