Joan Rivers autopsy says comedian died of low blood oxygen

NEW YORK (KABC) -- An autopsy revealed that Joan Rivers was sedated with propofol before she died of low blood oxygen during an upper gastrointestinal endoscopy to treat voice changes and acid reflux.

Rivers died on Sept. 4 at the age of 81. She had been hospitalized since Aug. 28 when she went into cardiac arrest during the routine medical procedure at Yorkville Endoscopy.

Medical examiner spokeswoman Julie Bolcer said Thursday that the cause was brain damage due to lack of oxygen. It is classified as a therapeutic complication, which means the death resulted from a predictable complication of surgery.

"Your brain is starved from oxygen and thus dies, and so your heart can keep going and pumping, but you're not a functional human being," said Dr. Angelique Campen, head of emergency medicine at Providence St. Joseph Medical Center.

According to the report, a doctor who was only supposed to observe allegedly took part in the procedure, and that doctor was not certified by the Yorkville Endoscopy clinic, as required by New York health law.

After the procedure, Rivers was taken to Mount Sinai Hospital and put into a medically-induced coma. She died a few days later.

Rivers had been sedated during the procedure with propofol, the report said. Propofol is often used before and during general anesthesia for surgery or other medical procedures. It was brought to the public eye after it was revealed that Michael Jackson's doctor Conrad Murray administered the drug to the singer at his home.

"Any place that does sedation, as I understand she had sedation with propofol, has to have the backup equipment ready for this type of a complication because this is a rare, yet expected complication," Campen said.

A separate investigation by the New York State Department of Health is ongoing. The clinic has already said there was a lapse in judgment when it allowed an unaffiliated doctor into the room. Yorkville Endoscopy asked the doctor who performed Rivers' procedure to step down.

The report does not explain what caused the sudden lack of oxygen. The New York City medical examiner's office says, due to New York state law, no additional information will be released.

Joan Rivers' daughter and TV partner Melissa Rivers said they had no comment on the medical examiner's report. In a statement, she said, "We continue to be saddened by our tragic loss and grateful for the enormous outpouring of love and support from around the world."

The Associated Press contributed to this report.