[The seated position in patent foramen ovale?]

Anesthetic management of patients presenting for posterior cranial fossa surgery in the seated position includes detection and treatment of venous air embolism. Atrial positioning of a central venous (cv) line may be verified by either X-ray or an atrial ECG tracing. We report a case where a chest X-ray film proved superior. A 26-year-old white female was scheduled for posterior cranial fossa exploration. A cv line was inserted via the left antecubital vein; the chest X-ray film documented correct positioning of the catheter tip within the atrium but an aberrant course of the superior vena cava. Echocardiography was performed in the induction room and indicated a patent foramen ovale. In view of the risk of paradoxical air embolism, surgery was postponed. Subsequent cardiologic and radiologic examinations revealed a patent foramen ovale and a persisting left superior vena cava draining into a dilated coronary sinus. Surgery was rescheduled and carried out uneventfully in the prone position. This case demonstrates: 1) an advantage of a thoracic-X-ray film compared to atrial ECG tracing as not only the catheter tip position, but also the course of the catheter can be identified; and 2) the usefulness of preoperative screening for a patent foramen ovale in patients scheduled for surgery in the seated position.