Dozens of hospitals across the country lost access to crucial electronic medical records for about five hours during a major computer outage last week, raising fresh concerns about whether poorly designed technology can compromise patient care. Cerner Corp., a leading supplier of electronic health records to hospitals and doctors, said "human error" caused the outage July 23 that it said affected an unspecified number of hospitals that rely on the Kansas City, Mo., company to remotely store their medical information. Adventist Health, which runs White Memorial Medical Center in Los Angeles and 18 other hospitals, and St. Jude Children's Research Hospital were among those affected by the outage.