BOSTON -- A former Children's Hospital anesthesiologist who fell asleep in the operating room must prove he's clean before practicing medicine again.

Thomas Ho admitted to falling asleep during surgery in December 2005 after taking a prescribed medication. Ho admitted that he "was under a great deal of personal stress," the state said in its complaint against him.

He also said he inhaled Isoflurane, an anesthetic, during his lunch break in January 2006 because he was having a panic attack and "felt he was going to die."

Ho, 30, was in a residency program at Brigham and Women's Hospital, but was doing a rotation at Children's Hospital when the two incidents occured.

Ho had been practicing on a limited license that expired June 2006.

The Board of Registration in Medicine revoked his license saying he cannot apply for a new one until he proves he hasn't used drugs or alcohol for 15 continuous months and agrees to chemical dependency monitoring.