Hospitals may be writing off heart attack victims too soon when hypothermia is used
Hospitals may be pulling the plug too soon on some patients who have undergone therapeutic hypothermia after a heart attack, researchers said Saturday. Therapeutic hypothermia, which has been part of the American Heart Assn. guidelines for treatment of a heart attack since 2005, involves lowering the patient’s body temperature to between 90 and 93 degrees Fahrenheit for about 24 hours. The idea is to slow the body’s metabolism, reducing the demand for oxygen and giving the brain and other organs time to recover in the aftermath of the heart attack. The body is then slowly warmed back to normal temperature and neurological activity is assessed after three days. But that may be too soon, according to three papers presented at a Chicago meeting of the American Heart Assn.
Dr. Shaker Eid of the Johns Hopkins Bayview Medical Center in Baltimore studied 47 men and women treated for cardiac arrest at the hospital. Fifteen were treated with hypothermia, and seven of those survived to be discharged. Of the 32 patients who did not receive hypothermia, 13 survived to be discharged. At the end of three days, 38.5% of the patients who did not receive hypothermia were alert again, but none of those receiving hypothermia was alert and conscious. But at seven days, 33% of the hypothermia patients who ultimately survived were alert and, at discharge, 83% were alert and had only mild deficits. “Our data are preliminary and provocative, but not robust enough to prompt changes in clinical practice,” Eid said at a news conference.
In a second study, Dr. Keith Lurie of the University of Minnesota and his colleagues found that withdrawing life support 72 hours after rewarming “may prematurely terminate life in at least 10% of all potentially neurologically intact survivors” of heart attacks treated with cooling. They studied 66 patients and found that six showed signs of reawakening well beyond the traditional 72-hour cutoff for withdrawing life support.
In the final study, Dr. Kyle McCarty of the Maricopa Medical Center in Phoenix reported on a survey of 1,292 patients who suffered out-of-hospital cardiac arrests and then were treated at one of 26 state-recognized heart attack centers. All centers had protocols calling for withdrawal of care at least 72 hours after therapeutic hypothermia. Fifty-four percent of the patients were excluded from the study because they died in the emergency room. Of the remainder, only 25.4% were kept on life support for 72 hours, despite the protocols, he found.
Clearly, physicians should not be so quick to pull the plug.
