Orders not to resuscitate very sick patients are failing to achieve their two major goals -- decision-making before a crisis and allowing patients to make life-or-death decisions -- a study suggests.

In the past 10 years, many hospitals have adopted so-called "do-not-resuscitate" (DNR) policies, designed to allow families and terminally ill patients themselves to choose death rather than life-saving efforts in the event of a heart attack or other emergency.

But use of DNR orders is not consistent, Dr. Andrew L. Evans and Baruch A. Brody write in the Journal of the American Medical Association.

Some DNR patients "are still receiving such measures as chemotherapy, surgery, and admission to the intensive care unit," they write. "At the other extreme, there are patients receiving no supportive care."

"House officers and nurses are often confused about what sort of care is to be provided" for DNR patients. And in some cases, they disagreed with decisions to try to keep patients alive.

The study, which looked at 758 patients at the Baylor College of Medicine in Houston, found that in 10 percent of the cases, no decision had been reached on whether to try to keep the patient alive, indicating that "attempts to decide about resuscitation in advance of a crisis are failing in a considerable number."

In most of those no-decision cases, the subject had not even been brought up with the patient or family.