In fact, in one study of physicians in outpatient clinics the subjects of the survey recalled only 50% of patient information 5 minutes after the appointment. Sixty percent of the physicians surveyed did not know the names of their patients' drugs, and 20% did not recall the purpose of the patients' medications. It has been estimated that 180,000 patients are dying each year as a result of medical error. Another source suggests that 1.3 million injuries may occur in the U.S. annually during hospitalization. Although many hospital injuries are unpredictable and unavoidable, 20% to 70% may be preventable. These findings illustrate the limitations of the human memory and underscore the urgent need for alternatives.