UNEXPECTED OXYGEN DESATURATION AFTER CARDIOPULMONARY BYPASS - RAPID CONFIRMATION OF UNROOFING OF THE CORONARY SINUS BY INTRAOPERATIVE EPICARDIAL ECHOCARDIOGRAPHY

Unexpected arterial oxygen desaturation occurred immediately after car diopulmonary bypass in two children. Epicardial echocardiography demon strated unroofing of the coronary sinus after a Fontan procedure in th e first child and rapidly excluded this abnormality in the second, who had undergone closure of a sinus venosus defect and in whom there was also a left superior vena cava draining to the coronary sinus. Epicar dial echocardiography determined management in both patients: Oversewi ng of the ostium of the coronary sinus was undertaken in the first cas e during an additional period of cardiopulmonary bypass. Oxygen satura tion values improved with aggressive endotracheal lavage and aspiratio n of secretions in the second child. Epicardial echocardiography can i dentify unroofing of the coronary sinus (which may be difficult to dia gnose by transesophageal echocardiography) and can identify or exclude this condition when unexpected arterial oxygen desaturation is presen t after cardiac surgery.