Preventing brain damage in cardiac arrest crises
When the heart fails, the most endangered organ is the brain, according to Joshua Reynolds, Michigan State University assistant professor of emergency medicine.
Reynolds is researching emergency medical care technologies that could reduce instances of brain damage in cardiac arrest victims. He said brain impairment due to cardiac arrest—not the heart stoppage itself—is generally what prevents doctors from restoring their clinically-dead patients to full health.
“We can get the heart to restart about half the time during cardiac arrest,” Reynolds said. “The real issue is the subsequent brain damage occurring when oxygen isn’t reaching the brain.”
Reynolds said one way to increase oxygen flow to the brain after heart failure is ECLS, or extracorporeal life support. ECLS acts as a mechanical heart and lung, pumping blood and providing oxygen while the organs rest.
About 90 percent of cardiac arrest patients in the United States, where medics rely solely on CPR, sustain brain injury after heart failure. In nations like France, Italy and Japan using ECLS in similar emergencies, the number lies between 70 and 80 percent.
“The likelihood CPR alone will work after the first 10 or 15 minutes is very low, but practices haven’t changed,” Reynolds said. “It’s a problem with health care—there’s always a lag between the release of studies showing the benefit of certain treatments and when those treatments actually catch on.”
ECLS equipment is scarce due to cost and technically challenging, and not every cardiac arrest patient is suited for the treatment. Reynolds said restoring a patient’s heart whose brain has already been severely impaired would be a mismanagement of limited resources.
“Our ultimate goal is not to be able to restart hearts with this treatment only to have patients succumb to devastating brain injury,” Reynolds said. “Medics need to be able to discern brain activity to make the right call.”
Reynolds has identified pupillometers as a possible means of identifying brain activity in cardiac arrest patients. Pupilometers are hand-held devices that detect pupil movements too subtle for the human eye to notice.
If pupil movements are undetectable, a patient is most likely not an appropriate candidate for ECLS. Reynolds is working with Kent County and Grand Rapids Fire Department officials to have pupillometers deployed with medics within a month.
“Kent County EMS leaders have been very responsive to my requests for collaboration,” Reynolds said. “The MSU Department of Emergency Medicine is right on the cusp of a lot of growth, and we’ve got a bright future here.”