Study: Theraputic hypothermia improves cardiac arres patient outcomes

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ST. PAUL

A new study shows that a Twin Cities medical program dubbed "Cool It" helped cardiac arrest patients have better outcomes by quickly putting them on ice.

The findings, which were published Monday in Circulation: Journal of the American Heart Association, should provide a model for how other communities can use a treatment known as "therapeutic hypothermia," said Dr. Michael Mooney, a researcher at the Minneapolis Heart Institute Foundation.

"Right now, the way therapeutic hypothermia is delivered across the country is very spotty," Mooney said. "This paper will be challenging for those folks who currently are not offering this therapy."

Cardiac arrest is the abrupt loss of heart function caused by a malfunction of the heart's electrical system. Nearly 300,000 out-of-hospital cardiac arrests occur in the United States each year, and most are fatal, according to the American Heart Association.

While a heart attack may cause cardiac arrest and sudden death, it is a distinct medical problem caused by a blockage that stops blood flow to the heart.

In the new study, researchers tracked 140 patients who suffered out-of-hospital cardiac arrest between February 2006 and August 2009 and were treated by a network of first responders, EMS departments and hospitals within 200 miles of Minneapolis.

Most patients ultimately were treated at Abbott Northwestern Hospital, where doctors have been studying therapeutic hypothermia for years and helped develop the Cool It network.

All patients in the study had their heartbeat and circulation restored within an hour of collapse, but remained unresponsive. Ice packs were placed at the neck, armpits and groin to begin cooling patients during their initial EMS transport to the hospital.

Cooling continued in hospital emergency rooms with the patients' core body temperature being lowered to about 92 degrees Fahrenheit over a three- to four-hour period. Doctors held patients at that low temperature for a day before re-warming them.

The study found that of the 56 percent of patients who survived to hospital discharge, 92 percent had neurological scores that suggested no severe disability. Without the Cool It program, it was about 77 percent, researchers said.

Also, the risk of death rose 20 percent for each hour of delay between the return of spontaneous circulation and cooling.

"We have demonstrated that simple cooling with ice bags initiated soon after (cardiac) arrest can be associated with incrementally improved outcomes," wrote researchers from the Minneapolis Heart Institute Foundation. "(Therapeutic hypothermia) is an achievable standard of care that can be applied in urban and rural settings equally where regional systems of care have been developed."

If cardiac arrest patients survive the initial loss of oxygen, they then face trouble once blood flow is restored. Therapeutic hypothermia can help prevent this latter source of damage, according to the American Heart Association.

Distributed by McClatchy-Tribune Information Services.

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