Monday, May 2, 2011
In the wild, freezing temperatures can kill. But under controlled circumstances, extreme cooling of the body can actually save lives. Therapeutic hypothermia is emerging as the treatment of choice for people who've suffered a cardiac arrest.
SAN DIEGO It happened one year ago, during the La Jolla Half Marathon. And it happened at mile 12, right in front of the La Jolla Beach & Tennis Club.
It was early Sunday morning. 62-year-old Al Fields was running in the race. Suddenly, he collapsed.
The next thing Fields knew, he was in a hospital bed. Field’s son, Austin, was by his side. It was four days later.
"My son said, dad, do you know why you’re here?" Fields recalls. "And I said, it can’t be good, what it is? And he told me I had a heart attack, and I thought, they got the wrong guy. It wasn’t me, I couldn’t have had a heart attack. And I looked at my arms, and I saw the tubes all around, and I knew it was true."
Fields remembers something else.
"I do remember it being a little bit cold when I woke up," he said. "And I saw some blankets around my legs and arms, and I just couldn’t figure out what they were for."
Fields’ heart stopped during the race. A nurse on the scene gave him CPR.
By the time paramedics got Fields to Scripps Memorial Hospital in La Jolla, his normal heart rhythm had returned. But he was still in a coma.
That’s when hospital staff placed Fields in a hypothermic state.
Scripps’ critical care nurse Amy Stuck explained the process.
"When the patients come in after cardiac arrest," she said, "we wrap these wraps around their thighs and their torso, and it gets filled with water that’s cooled. And we can actually dial in a temperature that we want to cool ‘em too, which is between 34 and 32 degrees Celsius, and that water circulates around their torso, until they hit that target temperature. And then we keep ‘em there for 24 hours."
Therapeutic hypothermia dates back to ancient Greece, when Hippocrates recommended wounded soldiers be packed in snow.
Today, it’s used to help prevent people who’ve had a cardiac arrest from suffering brain damage.
Here’s the idea: cooling a person’s temperature to about seven degrees below normal slows the metabolism and the functioning of the organs and tissues. That minimizes inflammation.
Dr. Shawn Evans is an emergency room physician at Scripps La Jolla.
"Essentially at that point, we’re minimizing the body’s antagonistic response to the insult of having arrested," he explained. "And by that, we are essentially protecting the brain."
After 24 hours, patients are gradually warmed back to the body’s normal temperature.
It’s important to note most people who have a cardiac arrest in the field don’t survive. Studies show for those that make it to the hospital alive, hypothermia improves the chances they won’t suffer a crippling brain injury.
In 2005, the American Heart Association issued guidelines recommending hypothermia.
Since then, the number of hospitals using it has grown. Even so, only about 10 percent of hospitals nationwide use hypothermia.
Dr. Bruce Haynes directs San Diego County’s Emergency Medical System.
"I think just everybody’s been watching the medical literature for the last few years and kind of waiting to see how things went, get a little bit more experience with it," he said.
He says his department is working with local hospitals to make sure people who need therapeutic hypothermia get it.
Starting in July, paramedics will take candidates for hypothermia to one of the county’s 13 designated cardiac care hospitals. These centers have committed to using the treatment.
"Most of the hospitals do have the ability to do therapeutic hypothermia now, and all of the cardiac hospitals do, so we can move forward," he pointed out.
Al Fields probably wouldn’t be around today without it. Fields says he can’t run like he did before, but…
"Everything seems to be going well," he said. "I have moments, I don’t have the strength or the ability to go long distances like I used to. But I’ll get back to it."
Dr. Haynes estimates once the new system is in place countywide, an additional 25 people will survive a cardiac arrest each year.