Air embolism during awake craniotomy.

A case of venous air embolism during awake craniotomy is described. Chest pain and electrocardiographic changes were the major presenting features. Capnography detected a decrease in end-tidal carbon dioxide and demonstrates its use as an aid in the diagnosis of air embolism in the awake patient. Following this episode persistent hypoxaemia developed secondary to acute pulmonary oedema and a pleural effusion.