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Fla. medics to induce hypothermia to treat heart attacks

By Bob LaMendola
Sun-Sentinel
Copyright 2008 Sun-Sentinel Company

BROWARD COUNTY, Fla. — Broward County paramedics will soon become the third department in the nation trying to save heart attack victims by pumping ice-cold saltwater into their blood vessels on the way to the hospital.

The idea is to chill the body to slow the metabolism and minimize damage to the brain and organs caused by the lack of blood flow, much like what happens when a skater is found alive long after falling through the ice.

“Cooling it down reduces the swelling, reduces the damage and saves people from dying or disability,” Dr. Nabil El Sanadi, medical director of Broward Sheriff Fire-Rescue, said Tuesday while training paramedics on new heart techniques now being adopted.

Studies have shown that hospitalized cardiac arrest patients cooled for 24 hours until their body temperatures reach 90 to 92 degrees — compared to the normal 98.6 — are more likely than other patients to survive and regain brain function.

There’s only limited evidence that starting the process a few minutes early in the ambulance makes a difference, but El Sanadi said it’s worth doing as one in a series of steps to raise the odds of saving heart attack patients.

About 1.2 million Americans have heart attacks each year, fatal for 38 percent of them.

One type of incident called sudden cardiac arrest, caused by an electrical disruption of the heartbeat, kills 93 percent of the time.

When the heart stops beating normally, the flow of oxygen-carrying blood stops or decreases, killing brain and organ tissue every minute. If the stoppage lasts 10 minutes, paramedics can do little.

If paramedics can restore the patient’s heartbeat with an electrical shock or chest compressions, they can try the cooling, called induced hypothermia.

They give the comatose patient intravenous bags full of saline chilled to 32-34 degrees. Studies have shown the technique cools the body by up to 2 degrees on the way to the emergency room, where doctors insert tubes that fully chill the patient.

In a 2002 study, 55 percent of patients chilled for 24 hours had good recovery or moderate disability, compared to 39 percent of other heart patients.

In another study, 49 percent of chilled patients survived to be discharged, compared to 26 percent of other patients.

Ambulance personnel in Seattle and Raleigh-Durham, N.C., now use the chilling process, and Broward County’s 16 ambulances should be equipped and paramedics trained to start doing so by March, said Stephen Krivjanik, an assistant fire and rescue chief.

“I think this is the direction that everyone will be heading at some point,” said El Sanadi, who also is director of emergency medicine for the four hospitals of Broward Health, also called the North Broward Hospital District.

The American Heart Association since 2005 has urged hospitals to use the chilling process, but only about 10 percent do.

El Sanadi said the four district hospitals and two others have started, opening the door for county ambulances to start.

He expects some city rescue departments in Broward County to follow suit.

Not every heart patient can be chilled. It can’t be used on patients with drug overdoses, unstable blood pressure or poor breathing.

Aside from the chilling technique, Broward County has equipped about half its ambulances with Auto-Pulse, a portable life-vest-type device that gives cardiopulmonary resuscitation more precisely and regularly than can a paramedic.

By eliminating inadvertent stops when paramedics tire or check for a pulse, and by squeezing the whole chest instead of just the breastbone, the machine keeps blood flowing as much as twice as efficiently as before, officials said.