WEDNESDAY, Sept. 17, 2003 (HealthDayNews) -- Age and the extent of organ damage used to be the two most important criteria in determining who in an intensive care unit would be kept on life support and who would not.
But a new Canadian study says decisions to take critically ill patients off life support now have less to do with these conventional measures and more often reflect a doctor's subjective opinion about the patient's chances of surviving.
That, in turn, suggests a doctor's views and personal biases about the quality of life often loom large in the move to end a patient's life in the intensive care unit.
"Our findings reflect a move toward more patient-centered decision-making about life-support withdrawal," says study author Dr. Deborah Cook, a critical care specialist at McMaster University in Hamilton, Ontario.
In the past, such decisions were made much later in the course of a patient's critical illness, says Cook, chairwoman of the Canadian Critical Care Trials Group, which organized the research. The choice was based on several factors, notably the age of the patient and how many of their organs had failed. The calculus provided little room for other considerations.
Now, she says, doctors appear to be far more concerned with the wishes of the patient or the estimations of his or her family members, their odds of surviving, and the quality of life they can expect if they manage to live without support.
The study, reported in the Sept. 18 issue of the New England Journal of Medicine, looked at 851 patients on mechanical ventilation -- the most common form of life support -- at 15 hospitals in North America, Europe and Australia. (The United States typically lags Canada, Europe and Australia when it comes to limiting futile care.) Of those, 539, or about 63 percent, were weaned gradually off the machines and survived. Of the rest, 146 died while on life support and 166, or about 20 percent, died after having life support withdrawn.
An additional form of advanced life support -- the use of drugs to keep the heart pumping and blood flowing -- was associated with the decision to end breathing assistance. But it was only one of four most significant factors.
Doctors were likely to take patients off a breathing machine if they thought their odds of surviving were less than 10 percent and if they thought the patient had a strong chance of suffering brain damage.
Doctors were most likely to cut off life support if they believed the patient would make the same decision -- a perception almost always divined from speaking with family members. "The family members bring to that conversation their long-standing knowledge of the patient and their belief about the patient's preferences," Cook says. Only a few of the patients in the study had advanced directives with instructions on what to do if they required life support.
The typical patient who died in the study survived six days on life support before dying or before it was withdrawn. Cook says that's "several days" shorter than before the new thinking about life support began percolating in medicine.
In six cases, patients who were disconnected from life support ended up surviving and leaving the intensive care unit.
Those miraculous recoveries don't undermine the general policy of taking patients off life support when further treatment is futile, says Dr. Lawrence Schneiderman, an expert in medical ethics at the University of California at San Diego. "We can sometimes be wrong; sometimes the unexpected happens." Trying to avoid the rare error by keeping everyone on ventilators would subject the vast majority to unnecessary, and perhaps cruel, procedures, he says.
However, the intensive care unit is thick with ethical dilemmas. Doctors believe they know what patients want in terms of life support, and that family members can fill in blanks. But Schneiderman says his own research suggests that what physicians think critically ill people want is in fact nearer to what they would choose for themselves. Family members, too, aren't especially reliable translators of their loved one's wishes.
"We're always relying on surrogate decision makers or physicians," Schneiderman says. "But there's plenty of evidence that it doesn't correlate too well" with what patients truly desire.