Not So Fast: Study Suggests Physicians Wait Longer for Signs of Brain Recovery After Hypothermia Use

Heart experts at Johns Hopkins say that physicians might be drawing conclusions too soon about irreversible brain damage in patients surviving cardiac arrest whose bodies were for a day initially chilled into a calming coma.

The chilling, known as therapeutic hypothermia, is one of the few medical practices known to improve brain recovery after sudden heart stoppages, with brain recovery usually assessed three days after the incident. The therapy, recommended in American Heart Association treatment guidelines since 2005, is thought to work by slowing down the body’s metabolism, delaying the brain’s need for oxygen until the heart, lungs and kidneys can recover.

Senior study investigator and cardiologist Nisha Chandra-Strobos, M.D., says large, multicenter studies will be required before experts can definitively suggest changes to current standards of care.

However, early indications are that “we may need to be much more deliberate in allowing the brain to recover before adjudicating on the neurological benefits of therapeutic hypothermia, as there is obviously more variability in patient response to treatment than previously thought.

“It is definitely a clinical situation about which we have much more to learn in order to maximize care for our cardiac arrest patients,” says Chandra-Strobos, a professor at the Johns Hopkins University School of Medicine and its Heart and Vascular Institute, where she also serves as director of cardiology at Johns Hopkins Bayview Medical Center.

Reporting on a study of 47 men and women treated for cardiac arrest at Johns Hopkins Bayview, lead study investigator and internist Shaker Eid, M.D., says their results “show that people who have been immediately treated with hypothermia are more likely to wake up and are taking longer to wake up, as opposed to those who do not receive such treatment.

“Hypothermia patients are showing initial signs of renewed brain activity five and sometimes even seven days after suffering cardiac arrest,” says Eid, who is scheduled to present the team’s findings Nov. 13 at the American Heart Association’s (AHA) annual Scientific Sessions in Chicago.

“Physicians and family members may need to wait longer than the traditional three days before making irrevocable decisions about brain function recovery and possible withdrawal of care,” says Eid, an assistant professor at Johns Hopkins. The Johns Hopkins study is believed to be the first timeline analysis of neurological recovery after hypothermia treatment in victims of cardiac arrest.

“An obvious concern in light of these results is that we may be withdrawing support prematurely in selected patients,” says Chandra-Strobos. “The concern is valid; however, our clinical and study experience are re-assuring since most patients are observed and treated more than seven days.” The average length of stay at Johns Hopkins Bayview for such patients is 13 days, which she says is more than adequate to allow for neurological recovery.