Duke University Health System Releases Few Details In Ongoing Investigation

In January, Raleigh Duke Health and Durham Regional Hospital sent letters to thousands of patients about a "possible problem." The hospitals used hydraulic fluid to clean surgical instruments.

Duke officials blame the mix-up on contractors working on hospital elevators. Several patients are worried about possible health issues and want to know exactly what was in the fluid to look out for any side effects.

Hospital officials said they cannot give the information to anyone while they investigate the mistake. They did say infection rates have not increased as a result.