A West Virginian miner who survived a coal mine catastrophe and the Israeli prime minister who suffered a bleeding stroke have something in common: Their doctors put them in what they called medically induced comas.

The idea is to try to prevent brain injury from getting worse, explained Dr. Jack Wilberger, chairman of the neurosurgery department at Allegheny General Hospital.

"There is a cascade of biochemical processes that are unleashed after insults like this that just keep the damage going," he said. "So we try to slow or halt the damage by shutting the brain down."

But the precise meaning of the term can vary. Physicians at Allegheny General, for instance, emphasized last week that Randal McCloy Jr., the 26-year-old survivor of the Sago mine explosion, was in a medically-induced coma. Others would describe him as a comatose patient who was also sedated.

		People who want to check on the condition of miner Randal McCloy Jr. or send him a greeting can go to the West Virginia University Hospitals Web site.

Mr. McCloy, who was transported back to West Virginia University's Ruby Memorial Hospital Saturday night after receiving hyperbaric oxygen treatment at Allegheny General, remained in a coma today despite the withdrawal of sedating drugs.

He responds to stimuli and is able to breathe on his own, but as a precaution is still connected to a ventilator. He has a fever, which is not unexpected, his doctors said.

Doctors at Ruby today said there has been no significant change in Mr. McCloy's "critical but stable" condition.

Dr. Larry Roberts said while the mild fever is persisting, there is no sign of infection or cause for alarm.

Dr. Julian E. Bailes, chairman of the department of neurosurgery at WVU Hospitals, expressed optimism after tests have shown Mr. McCloy "has a lot of brainwave activity" that "one might see in someone who is asleep."

Dr. Bailes said most of the gray matter of Mr. McCloy's brain seems to have been spared from damage by the 42 hours of exposure to carbon monoxide in the mine.

It is the white matter, the fiber tracks that enable brain cells to communicate with each other, that has been damaged.

"Without being overly optimistic, I think there is a great hope here," Dr. Bailes said.

"We have no clear clue of the extent of his injury or the time, of course, of his recovery. But I think we understand it better."

Dr. Bailes said there was no way to guess how the brain damage might manifest itself as Mr. McCloy recovers.

To try to rouuse him from the coma, "We've tried shouting and shaking him, which is standard procedure for assessing someone in a coma. We try that several times a day. Shouting and shaking, you know, has its limitations in effectiveness, obviously, but that's just part of the assessment," Dr. Bailes said.

When Mr. McCloy was at Allegheny General, he was sedated with a drug called propofol, in part to keep him calm and still while in the hyperbaric chamber.

But it was also used to "rest the brain," as doctors put it. In the aftermath of oxygen deprivation, the brain's metabolic rate can rise dramatically, Dr. Wilberger said.

In a medically induced coma, "you're shutting down the brain so it doesn't require the normal amount of blood and oxygen and glucose that it would otherwise," he said. "We're essentially using strong drugs to put the patient under a form of anesthesia."

Israeli Prime Minister Ariel Sharon, who had a major stroke and two surgeries because of bleeding in his brain, has been in a medically induced coma since Thursday.

It's possible that his physicians are using high doses of barbiturates to reduce high pressures in his skull, said Dr. Joe Darby, director of trauma intensive care at the University of Pittsburgh Medical Center.

Strictly speaking, "you can't induce coma in a patient who is already comatose," Dr. Darby noted. "Our goal is provide them with a degree of sedation that will allow them to be comfortable and safe."

Even a comatose patient might roll or jerk, which could dislodge tubes or lines or lead to an increase in brain pressure.

"All significantly head-injured patients will get some level of sedation ... for anxiety and any pain they might have to keep them calm and quiet," Dr. Wilberger said.