LOS ANGELES — Michael Jackson was clinically dead when he arrived at a hospital and two emergency room doctors said they thought it was futile to attempt to revive him. His doctor, however, insisted that they try.

Both doctors, testifying at Dr. Conrad Murray’s involuntary manslaughter trial Monday, said Murray failed to tell them that he had been giving Jackson the anesthetic Propofol or when Jackson had been medicated or stopped breathing.

“He said he did not have any concept of time, that he did not have a watch,” said Dr. Thao Nguyen, a cardiologist at Ronald Reagan UCLA Medical Center, where Jackson was taken on June 25, 2009.

“Dr. Murray asked that we not give up easily and try to save Michael Jackson’s life,” she said. “ … In Dr. Murray’s mind, if we called it quits, we would be giving up easily.”

Nguyen said Murray “sounded desperate and he looked devastated.” But, she said, without knowing how much time had passed since he stopped breathing, resuscitation was a remote hope.

“It was not too little too late,” she said. “It was a case of too late. I feared that time was not on Mr. Jackson’s side.”

Murray, 58, has pleaded not guilty. Authorities say Murray administered the fatal dose and acted recklessly by providing Jackson the drug as a sleep aid at his home when it is supposed to be administered in a hospital. The defense argues that Jackson gave himself an additional dose of the drug when Murray was out of the room.

Nguyen and Dr. Richelle Cooper, who oversaw Jackson’s care in the emergency room, said Murray never mentioned that he had given the singer the Propofol. They said he told them that he had given two doses of Lorazepam, also known as Ativan, trying to get him to sleep.

“Did he ever mention Propofol to you?” Deputy District Attorney David Walgren asked Nguyen.

“Absolutely not,” she said in a firm voice.

Before leaving the stand, Nguyen said, “I’ve never heard of Propofol being used outside of a hospital.”

She said at least three medical personnel, including an anesthesiologist, should be present when the drug is given. Walgren asked her: “Have you ever heard of Propofol being used in someone’s private bedroom?”

Nguyen replied: “That would be a first. I’ve never heard of it.”

In cross-examination, defense attorney Michael Flanagan was able to get Cooper to say that, even if they had known about the Propofol, they could not have saved Jackson’s life.

“Michael Jackson had died long before he became my patient,” she said. “It is unlikely with that information I could have done something that would have changed the outcome.”

She also said that the amount of Propofol which Murray has since claimed he gave Jackson would not have put him to sleep and would have dissipated from his body in five to seven minutes.

Murray claimed he administered 25 milligrams. An autopsy showed that he died of an overdose of the drug.

Cooper said Jackson was “clinically dead” by the time he reached the hospital and she had advocated pronouncing him dead at his home when she received radio calls from paramedics describing his condition.

“Mr. Jackson was my patient and I didn’t really have an explanation of why he was dead. I knew it would be a coroner’s case,” she said and suggested he should have been pronounced dead at 12:57 p.m. when the radio call came in.

But she yielded to Murray and Jackson was brought to the emergency room where more than 14 people worked on the effort to revive him.

“My assessment when he arrived was he was clinically dead and given the time — it was about an hour — I thought the attempt at rescue would be futile,” Cooper said. She has said more than an hour of resuscitation efforts at the hospital did nothing to improve Jackson’s condition.

Cooper also told jurors about trying to speak to Jackson’s children after he was pronounced dead at the hospital at 2:26 p.m.

“They were crying,” Cooper said. “They were fairly hysterical.”

Murray’s phone records are a central part of the prosecution case. Two staffers from cell phone providers identified records of his calls on the day of Jackson’s death.

Prosecutors intend to show records of Murray’s phone calls and emails from the hours before Jackson’s death to show that Murray had other things on his mind — getting his $150,000 a month deal to serve as Jackson’s personal physician approved, running his medical practices and fielding calls from mistresses.

One of Murray’s former patients, Las Vegas salesman Robert Russell, detailed one of those calls for jurors last week and the phone traced a call to his number.

Later in the case, prosecutors will further detail calls and messages Murray fielded that day, including several the physician apparently made to his girlfriend as he rode in the back of the ambulance on the way to the hospital.