President's Council on Bioethics: advance directives may impede patient care.(Practice Trends)

ARLINGTON, VA. -- Designed to preserve individual autonomy, advance directives may prevent some patients from getting the best possible care, members of the President's Council on Bioethics concluded at a meeting.

An advance directive "shouldn't be used as a substitute for a doctor at the bedside," noted Dr. Leon Kass, chairman of the council. They should be treated as a rough guidance, he said. "It would help if we did not fit people into binding documents."

Advance directives--sometimes called living wills--evolved more than 30 years ago as new technologies to sustain life were being developed and a perception existed that physicians "hadn't developed good judgment on how to use this new power," said Rebecca Dresser, professor of law and ethics in medicine at Washington University, St. Louis.

"It seemed to follow that if illness or injury made a patient unable to decide, the best alternative would be to decide based on instructions issued while he or she could still think about choice," Ms. Dresser said.

Although attractive from the standpoint that it avoids placing the decision making in the hands of the physician or family, studies show that advance directions pose some practical problems that can't be ignored. They tend to be quite general, she said, and they often fail to offer clear guidance in actual treatment settings.

Some provide more specific information about treatment preferences, but "the concern then becomes whether the person completing such a document has adequate understanding of specific decisions they are making," Ms. Dresser said.

In particular, patients may not have envisioned how they could experience their decisions in a future incapacitated state. "Even with competent individuals, treatment preferences change, but often without the person's awareness," she said. As a result, they may not fix the advance directive to reflect the change.