Cardiac arrest patients once "left for dead" at emergency scenes are surviving through an experimental treatment protocol at the University of Minnesota Medical Center.

The hospital reports 50-50 survival for patients who suffer cardiac arrests in which the heart is still quivering but can't be immediately shocked with external defibrillation back to a functional pulse.

Without this approach, survival is 8 percent at best, said Dr. Demetris Yannopoulos, who directs the U's interventional cardiology research. The standard approach is to continue defibrillation and CPR at the scene until a pulse is restored or the patient dies. But that delays getting patients into hospitals.

"If you identify them correctly," he said, "there is no point in staying in the field anymore. You can shock them on the way to the hospital."

The idea is to get patients into hospitals and immediately address cardiac problems, such as blockages to blood flow, which likely cause the arrests. Around 85 percent of these patients have blockages.

Under the treatment protocol, medics determine whether arrest victims have "shockable rhythms," rather than no pulse, and attempt three rounds of defibrillation to get their hearts beating.

If those efforts fail, the medics place the patients on automated CPR systems in their ambulances and try to get to hospitals in 30 minutes. (The approach is only possible with automated CPR, because manual CPR by medics is considered unsafe in moving ambulances.)

Patients bypass the ER and go straight to coronary cath labs to fix their blockages. If CPR hasn't restored heartbeats, the patients are placed on heart-lung machines that pump blood through their bodies until the end of their procedures.

Studying 18 patients brought to the university by North Memorial, St. Paul Fire or Ridgeview medics, researchers found that nine survived and left the hospital with no worse than mild or moderate neurological deficits.

More proof in the form of a comparative federal study is needed along with training for medics to determine when patients have arrests that can be treated with this approach. The U study involved 27 patients, but nine didn't meet its criteria. Five were incorrectly determined to have arrests with "shockable" heart rhythms.

Yannopoulos said he is confident more research will prove that this approach saves patients. "Until five years ago, no one would take them to the cath lab to open their arteries up. They thought they were dead."

jeremy.olson@startribune.com

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