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Healthy Monday: Inducing hypothermia aids victims of heart attacks
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Caroline Thompson, 70, and her husband, Carel, were watching football Aug. 30 in their Hoschton home when Caroline complained that she felt faint. Carel Thompson performed CPR on his wife until ambulances arrived. - photo by SARA GUEVARA

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Dr. Mohak Davé, emergency physician at Northeast Georgia Medical Center, explains how induced hypothermia can help patients recover from cardiac arrest.

In recent years, there has been a push to have automated external defibrillators made available in public places. These devices can shock a heart back to life when someone goes into cardiac arrest.

What has not been widely publicized is that restarting a heart does not guarantee a good outcome. In some cases, the patient is left with permanent brain damage because their body went without oxygen for too long.

Dr. Mohak Davé, an emergency physician at Northeast Georgia Medical Center, has begun using a technique that helps patients survive cardiac arrest without neurological damage.

It’s called induced hypothermia, or deliberately lowering the patient’s body temperature. It’s easy, cheap, and low-tech, and can be done with ice, cooling blankets, or chilled IV fluids.

Doctors have known for centuries that extreme cold can put the body into almost a state of hibernation. When a person falls into an icy lake, they sometimes survive a lot longer than expected because their body functions automatically slow down.

Induced hypothermia is now used for some patients undergoing cardiac bypass surgery. But Northeast Georgia Medical Center only began using the treatment in the ER in July, and Davé believes it is the only hospital in Georgia that is doing it so far.

"My hope is to have more and more hospitals in our region start using this technique," Davé said.

Why haven’t they done it already? "Until recently, there was skepticism among doctors," he said.

Davé explains that while there were plenty of anecdotal reports about the benefits of hypothermia, until a few years ago there weren’t enough controlled scientific studies that showed a clear advantage. Now, the evidence is more compelling.

"The literature says the sooner you can initiate cooling after restoring a pulse, the better chance the patient has of a neurologic recovery," Davé said.

He said the technique works because the brain and nervous system are particularly vulnerable to oxygen deprivation. "By cooling the body, you decrease metabolic demand to vital organs, so the brain has less work to do."

The patient’s body temperature is lowered to about 90 degrees and kept there for 24 to 48 hours, allowing time for healing. Without this intervention, there can be severe and permanent consequences. Some patients are left in a persistent vegetative state, or they are dependent on a ventilator for breathing.

Davé said hypothermia is not needed for every patient who has suffered a cardiac arrest. "If they’re brought in (to the ER) alert and talking, they’re probably OK neurologically," he said. "We initiate hypothermia when the patient is unresponsive."

That’s why hypothermia was used to treat Caroline Thompson, 70, of Hoschton. On Aug. 30, she was sitting at home watching a football game on TV with her husband, Carel, and suddenly she had a strange feeling.

"My husband says I turned to him and said, ‘I think I’m going to pass out,’ and I did," she said. "That was a Saturday afternoon, and I don’t remember anything else until Wednesday."

Her husband called 911, but it took 13 minutes for a Hall County EMS team to arrive from a fire station in Flowery Branch. Carel kept his wife alive by performing CPR on her during that time.

"The paramedics had to use the (defibrillator) paddles on me twice," Caroline Thompson said.

Although they got her heart restarted, she still was in grave condition.

"She arrived in the ER comatose, meaning that her body had not received enough oxygen after the cardiac arrest," Davé said.

ER doctors induced hypothermia, and the treatment was continued in the intensive-care unit, for about 36 hours. All told, Thompson was at Northeast Georgia Medical Center for 12 days, including five in the ICU, while doctors ran tests to figure out why her heart had stopped.

To their surprise, a cardiac catheterization showed Thompson’s arteries contained hardly any plaque. Thompson has no family history of heart disease, and unlike many people her age, she was in good shape. She walks daily and regularly uses the treadmill, elliptical machine and weights she keeps in her basement.

Thompson was then examined by a cardiac electrophysiologist, who determined that her heart’s electrical impulses had somehow gone haywire, causing an abnormal heartbeat.

Doctors implanted a combined pacemaker/defibrillator in her chest, which should prevent a recurrence of the problem.

Thompson said she’s eager to get back to her exercise routine. "I’m a little tired, but otherwise I feel fine," she said.

What’s significant is that she has no apparent neurological deficit. Her memory and her ability to perform complex tasks seem to be intact. "I love music, and thank God I will still be able to play my piano and organ," she said.

Davé believes there could be more happy outcomes like Thompson’s if all hospital ERs began implementing hypothermia. But he’s taking it a step further. As medical director for White County EMS, he developed a protocol in which paramedics can administer hypothermia on the way to the hospital.

"White County is the only EMS in Georgia that is cooling patients in the field, in the back of an ambulance," he said.

Starting hypothermia immediately can improve outcomes even more, and it requires no equipment other than an ice chest or small refrigerator to keep the IV fluids cold.

Davé is now in discussions with EMS services in Hall and other counties that transport patients to Northeast Georgia Medical Center, trying to develop hypothermia protocols for them as well.

But he said the technique only makes sense if the patient is being taken to a hospital that performs hypothermia in the ER, because once the process has been initiated, it has to be continued.

"The hospital’s entire spectrum of critical care has to be on board with it — the ER, the ICU, cardiology," he said. "We were only able to start doing hypothermia in the ER because our ICU started doing it last year."