Central venous catheters are commonly used in the management of critically ill patients. This case report described a rare but potentially fatal complication of central venous catheter use. A 52-year-old man underwent mechanical aortic valve replacement for infective endocarditis. On day 8 postoperatively he accidentally removed his catheter and collapsed with symptoms and signs suggestive of a cerebral air embolism. A transthoracic echocardiogram showed air bubbles in both the right and left ventricles of the heart confirming the presence of a paradoxical air embolism.