Murray, 58, stands accused of involuntary manslaughter and faces a maximum of four years if convicted.

A doctor who worked futilely to save Michael Jackson's life testified at the trial of his personal physician Monday that she had never heard of the surgical anesthetic that killed Jackson being used in a home setting.

Cardiologist Thao Nguyen said the drug,propofol, poses a severe danger to a patient's respiratory system and in her experience is used only in an operating room staffed with nurses, doctors, and heart and lung monitors.

"Propofol does not have an antidote, so we have to prepare for the worst," Nguyen told jurors at the trial of Dr. Conrad Murray.

She was part of a 14-member team that tried to revive Jackson atRonald Reagan UCLA Medical Center on June 25, 2009. Murray, who rode in the ambulance with his famous patient, never told the hospital staff he had given Jackson propofol. He told Nguyen and another doctor who testified Monday that he had administered only small doses of a sedative to treat Jackson's exhaustion and dehydration.

Murray, 58, stands accused of involuntary manslaughter and faces a maximum of four years if convicted. He contends that Jackson self-administered the fatal dose when he stepped out of the room.