[Pulmonary edema due to venous air embolism during craniotomy: a case report]

We present a 35-year-old healthy male patient who developed pulmonary edema (PE) probably due to venous air embolism during craniotomy in the semi-sitting position for arteriovenous malformation (AVM). Anesthesia was maintained with oxygen, nitrous oxide, propofol and fentanyl. During craniotomy, end-tidal carbon dioxide pressure decreased suddenly from 26 to 9 mmHg. Concurrently, a decrease in oxygen saturation from 99% to 91% occurred. There were no serious changes in blood pressure and heart rate. A "mill-wheel murmur" was confirmed. PE due to venous air embolism was suspected. The operation was discontinued and the patient was transferred to the intensive care unit. In the post-operative period, the patient developed PE and made a full recovery within a week. Four months later, the patient was scheduled again for surgical excision of AVM in the semi-sitting position in the same way as the first time. Anesthesia was maintained with oxygen, air, propofol and fentanyl. Transoesophageal echocardiography and pulmonary artery catheter were used. Saline was filled at the surgical site to prevent aspiration of air bubbles and surgical procedure was performed carefully without large vein injury and uneventfully. During neurosurgical intervention in the sitting position, special attention should be paid to entry of air bubbles into the venous system which may lead to PE.