Possible complications of this procedure include but are not limited to infection, bleeding, tearing or perforation of the intestine. Serious complications are estimated to occur in 2 out of 1000 cases. Should the complications occur they might require surgery and /or transfusion. Also certain complications such as respiratory problems or drug reactions may result from the use of conscious sedation or anesthesia. Other risks that can be serious and possibly fatal include aspiration, difficulty breathing, heart attack and stroke. These are extremely rare but may occur. Although gastrointestinal endoscopy is an extremely safe and effective means of examining the gastrointestinal tract, it is not 100% accurate in diagnosis. In a small percentage of cases a failure of diagnoses or misdiagnosis may result.