Venous air embolism (VAE) during intestinal endoscopy is a rare complication. We report a case of cardiovascular collapse due to VAE confirmed by transesophageal echocardiography (TEE) during intraoperative intestinal endoscopy. TEE detected air bubbles in the left ventricle up to 1 hour after the event. When a patient deteriorates during endoscopic procedures, VAE and possible paradoxical air embolism (PAE) should be suspected. This case demonstrates that TEE can play an important role in diagnosing and managing an air embolism in anesthetized patients. In addition, this case demonstrates that PAEs may occur longer than expected after recovery from VAE-induced cardiovascular collapse.