A 71-year-old man experienced the sudden onset of right-sided chest discomfort shortly after the takeoff of a commercial flight. He never reported dyspnea. Several minutes later, a headache developed followed by a sudden loss of consciousness. A physician on the airplane found his vital signs to be normal. Because the patient was unresponsive, the flight was diverted for further care of the passenger. The patient had a history of anticardiolipin syndrome and prior deep vein thrombosis, Sneddon syndrome (cerebrovascular disease associated with livedo reticularis), coronary artery disease status post-coronary artery bypass graft surgery, and permanent pacemaker for paroxysmal atrial fibrillation. He was receiving therapy with clopidogrel and warfarin. On arrival at the hospital, he was unresponsive and had a Glasgow coma score of 3. His pulse oximetry showed an arterial oxygen saturation of 96% on a fraction of inspired oxygen of 0.45. Funduscopy did not demonstrate bubbles within the retinal arteries. The patient was then orally intubated for airway protection and placed on mechanical ventilation. A chest radiograph revealed a right pulmonary cyst (Fig 1
). A chest CT angiogram demonstrated no pulmonary embolism and a large right intrapulmonary cyst with an air-fluid level (Fig 2
). An initial head CT scan demonstrated several gas emboli (Fig 3
). His international normalized ratio was 4.0. Troponin I measurements were as high as 17.2 μg/L, suggesting a gas embolism to the heart resulting in myocardial damage. Because the patient’s neurologist was at our institution, the family requested his transfer. Approximately 48 to 72 h after the initial event, the patient arrived at our hospital in a comatose state. The findings of contrast-enhanced echocardiography were compatible with an intrapulmonary shunt and demonstrated pulmonary artery pressures that were within normal limits. A repeat head CT scan demonstrated severe cerebral edema. No more brain gas emboli were seen. On review of his prior imaging studies from our institution, a smaller right intrapulmonary cyst was noted on an abdominal CT scan that had been performed several months prior because of abdominal discomfort. On further questioning of the patient’s wife regarding his history of flying, she reported an episode of syncope during another flight a few years ago. This was attributed to his hypercoagulable state and/or cerebrovascular disease. It was felt to be too late to attempt hyperbaric oxygen (HBO) therapy. Despite some improvement in cerebral edema after therapy with high-dose steroids, his overall clinical picture did not improve, and he died 16 days after initial presentation.