TORONTO - Dr. George Doodnaught's boss said he thought he followed protocol when an Oshawa, Ont., woman complained that Doodnaught sexually assaulted her during her surgery in February 2010.

Dr. Stephen Brown, the former chief of anesthesiology at North York General Hospital, testified Friday at Doodnaught's trial.

Doodnaught, 64, has pleaded not guilty to sexually assaulting 21 patients between 2006 and 2010.

Brown met with several hospital department heads, outlining the allegations and two earlier sexual complaints against Doodnaught.

But Brown said he never mentioned a fourth sexual assault complaint in February 2006, although he learned of it before he took charge.

Brown said that in July 2006, he and the retiring head of anesthesiology, Dr. Derek Shilletto, were in the operating room when he revealed the complaint of the 55-year-woman.

"Shilletto told me there was a complaint against George. It has been dealt with. Nothing to worry about. Something about touching the patient's breast," said Brown.

Two other women complained in August 2007 and January 2009 when Brown was in charge.

Brown said he met with the 85-year-old knee-replacement patient and her family, and interviewed staff, including Doodnaught about the allegations, in 2007.

Doodnaught insisted to Brown that it was impossible.

Brown said he concluded the drug ketamine caused the patient to hallucinate and ordered his staff to stop using it.

In the other 2009 case, Brown heard that a 48-year-old woman had gone to police with more allegations of sexual impropriety.

Brown testified that he did not inform police about the two prior allegations against Doodnaught.