Fatal cerebral air embolism complicating esophageal dilation.

We present the case of a 72-year-old man with cardiac adenocarcinoma treated with a metal stent and radiation therapy for pulmonarymetastases. After 6 months of this treatment he developed a malignant esophageal stricture. Endoscopy was carried out under moderate sedation and constant monitoring. Dilation with an over-the-scope balloon dilator (CRE single-use, wire-guided esophageal dilation balloon, 240cm, balloon length 5.5cm, outer diameter 10–12mm, Boston Scientific, Natick, Massachusetts, USA) was carried out. The patient’s vital signs and oxygen saturation were normal throughout the procedure. However, when flumazenil was administered the patient did not recover. Neurological examination revealed a GlasgowComa Scale score of 4/15 points, pupils equal and reactive to light, and no focal neurological signs. Cardiac and respiratory functions were stable. Brain computed tomography (CT) revealed bilateral multifocal cerebral air embolismwith air bubbles within the sagittal sinus, straight sinus, great vein of Galen, and the cerebral venous network of the cortex (●" Fig.1), and 24 hours later the patient died. The entry of air into the vascular system during endoscopy is a serious complication and is usually accompanied by interruption of the mucosal barrier [1–3]. Our patient developed pneumocephalus as a result of gas entry either directly into the arterial system or indirectly through the venous system. Paradoxical embolism via an intracardiac shunt [4] or pulmonary shunts due to metastases cannot be excluded, although hemodynamic instability was not observed. The esophagus is directly in contact with the posterior wall of the left atrium between the mid-posterior part of the atrium and the distal border of the inferior pulmonary veins [5]. Arterial gas entry may have occurred under positive air pressure due to proximity of malignant and radiation trauma. Cerebral air embolism during an endoscopic intervention has not been reported previously, but it should be suspected in case neurological deterioration ensues as the prognosis is poor.