Eleven years ago, the parents of Karen Ann Quinlan persuaded a judge to order their comatose daughter removed from a respirator. But Joseph Quinlan was astonished when asked if he also wanted her intravenous feeding ended. "Oh, no," he said, "that is her nourishment."

Since then, a growing number of families have tried, with varying results, to have the feeding tubes of wives, husbands and other relatives taken away on the ground that they are in a "vegetative state" and should be allowed to die "with dignity."

This prescription for euthanasia -- although the controversial word itself is avoided -- now has the official support of the American Medical Association. Its seven-member judicial council has unanimously ruled that it is ethical for doctors to withhold "all means of life-prolonging medical treatment," including food and water, if a patient is in a coma that "is beyond doubt irreversible and there are adequate safeguards to confirm the accuracy of the diagnosis." Death, it is carefully noted, need not be imminent for food and water to be stopped.

Dr. Nancy Dickey, chairman of the council, told Lawrence K. Altman of The New York Times that "There is no medical definition of adequate safeguards . . . no check list" that doctors would have to fill out in each case. The decision would be up to each doctor. (In an editorial, The Times has called the AMA's adoption of the euthanasia principle "a welcome contribution.")

Medical ethics and human rights aside, giving physicians such ultimate power is rather disquieting because not all doctors may be competent to make such final decisions on their own. Dr. Arnold Relman, editor of the New England Journal of Medicine, estimates that out of a physician population of 400,000, there may well be "20 or maybe even 30 thousand bad or impaired doctors." And that, he adds, could be a conservative estimate.

It is hardly unknown, says Michigan University law professor Yale Kamisar, for doctors to make "all

TAKE 040554 PAGE 00002 TIME 15:47 DATE 03-30-86 kinds of mistakes in their diagnoses. In some cases, there might be a 10 percent or a 5 percent chance that the patient would come out of the coma."

As for the long-range effects of the AMA's ruling, Dr. Norman Levinsky, chief of medicine at Boston University Medical Center and a prominent medical ethicist, told me, "This gives doctors and other care-givers a message that it's okay to kill the dying and get it over with. It ought to be difficult for doctors to stop doing things for their patients, but this makes it a little easier. Also, it is not a huge step from stopping the feeding to giving a patient a little more morphine to speed his end. I mean, it is not a big step from passive to active euthanasia."

Dr. Levinsky is also concerned about the effect of the AMA position on what he calls the making of medical decisions according to class. "I have no question," he says, "that some physicians and other care-givers consider the life of someone over 80 to be less worthy than that of someone who is 28. This approval by the AMA of withholding food and water could accelerate that kind of medical care."

As originally reported in The New York Times, the AMA announcement appeared to have been made in conjunction with the Hastings Center, which specializes in thorny bioethical problems. The center, whose members are of different minds on the subject, denies this, and points to a 1983 article by its director, Daniel Callahan, in which he wrote: ". . . the feeding of the hungry, whether because they are poor or because they are physically unable to feed themselves, is the most fundamental of all human relationships . . . (I)t is a most dangerous business to tamper with, or adulterate, so enduring and central a moral emotion."

And Kamisar, who for years has been tracking the growing acceptance of euthanasia, which has appeared under such disguises as "the right to die," points out that the courts will give the AMA pronouncement "great weight." But, he emphasizes, "this fundamental moral, legal and philosophical issue is not for only doctors to decide."

Yet many physicians seem to believe it essential that only they determine the ethics of bringing life to an end. This disturbed one of them, the late Dr. Leo Alexander, who was with the Office of the Chief of Counsel for War Crimes at Nuremberg. Last year, philosophy professor Patrick Derr wrote in The Boston Globe that Dr. Alexander had been much distressed at a New England Journal of Medicine article by a group of doctors advocating the starvation of certain kinds of patients.

"It is much like Germany in the '20s and '30s," Dr. Alexander said, "the barriers against killing are coming down."