Menus Subscribe Search

Cardiac Arrest’s Heartwarming Hope: Hypothermia

• September 08, 2008 • 10:00 PM

Dramatically cooling patients after cardiac arrest improves survival, recovery.

The woman was sitting in a friend’s car laughing at a joke when suddenly she slumped over, unresponsive. The panicked driver had the presence of mind to speed 15 blocks to the nearest hospital, the University of Chicago Medical Center, where doctors determined she had suffered a potentially lethal cardiac arrhythmia and worked to get her heart beating normally.

Then they put her on ice. The sedated woman’s body temperature was rapidly lowered, putting her in a state of mild hypothermia, and kept there.

“She should not have done well,” said Dr. David Beiser, one of the emergency-room physicians who treated the woman, “but we cooled her, and six days later she woke up.” The woman has since returned to work.

Roughly 90 percent of the 300,000 people who suffer cardiac arrest in the U.S. each year die, but a growing body of research shows that cooling a patient’s body to around 32-34 degrees Celsius (89-93 degrees Fahrenheit) after restarting the heart significantly improves survival.

Doctors may use ice packs, cooling blankets, an intravenous drip of chilled saline solution or special catheters with refrigerated tips to lower the patient’s core temperature and keep it there for up to 24 hours.

“Hypothermia represents one of the most important advances in cardiac care since the development of defibrillators 50 years ago,” said Dr. Benjamin Abella, an assistant professor of emergency medicine at the University of Pennsylvania. “If it was being aggressively implemented in hospitals, we would probably have thousands more survivors of cardiac arrest every year.”

Although cardiac arrest is “one of the most lethal conditions in medicine,” Abella said most doctors still are not using it on a routine basis. He co-authored a 2005 study showing that many wrongly believed there was insufficient evidence to adopt the procedure.

Cardiac arrest is not the same thing as a heart attack. In a myocardial infarction, a blocked coronary artery may cause chest pain and shortness of breath, but the condition can often be treated with clot-dissolving drugs, angioplasty or stents.

Cardiac arrest, where the heart loses its rhythm or stops beating altogether, may follow a heart attack or strike without warning. A sudden loss of consciousness results as blood flow to the brain stops, and if the heart is not restarted quickly, death follows.

A 2003 report in the American Heart Association journal Circulation found that prospective randomized trials in Europe and Australia had shown inducing mild hypothermia in comatose survivors of out-of-hospital cardiac arrest led to higher survival rates and fewer neurological complications.

In the European study, patients were kept chilled for 24 hours before being allowed to rewarm naturally. The study of 273 patients found 55 percent of the hypothermia group patients were living independently six months later, compared with 39 percent in a control group of patients who did not receive hypothermia treatment. And at six months, only 41 percent of the hypothermia group had died, while 55 percent of the un-chilled group had.

Doctors in the Australian study, conducted at four hospitals in Melbourne, used cold packs to cool patients. Their lowered temperatures were maintained for 12 hours after admission, and active rewarming started at 18 hours. This study of 67 patients found that 49 percent of its hypothermia group survived, as compared with only 42 percent of the unchilled control group.

The Circulation article’s authors endorsed the October 2002 recommendations of the International Liaison Committee on Resuscitation, which said, “Unconscious adult patients with spontaneous circulation after out-of-hospital cardiac arrest should be cooled to 32 degrees Celsius to 34 degrees Celsius for 12 to 24 hours when the initial rhythm was ventricular fibrillation (VF).”

Beiser, an assistant professor of emergency medicine at Chicago, is conducting animal studies to try to understand how hypothermia protects patients. The research could yield lifesaving — and potentially lucrative — results. “We’re looking at pharmaceuticals that mimic hypothermia,” he said.

Most people understand the danger to the oxygen-starved brain when the heart stops pumping blood, but many other secondary injuries also occur when circulation stops. “We’re beginning to understand how the secondary injury occurs and how to limit it,” Beiser said. “When you restart the heart and blood goes back to previously blood-starved tissue, you create a lot of oxidants, which can damage the tissue or transmit signals (that) can trigger cell death and inflammation.”

Patients revived from cardiac arrest sometimes suffer something called total body inflammation, which may stop capillaries from working and obstruct blood flow to vital organs, he said.

Hypothermia modulates this secondary injury, increasing certain oxidants and decreasing others, Beiser said, but exactly how is not well understood. For a long time, scientists thought it had to do with reduced energy needs. “The initial hypothesis with cooling is that we’re decreasing the metabolic rate of the body,” Beiser said.

“What we’re actually finding is it’s turning up the transcription of certain genes while turning down the transcription of other genes,” he said, referring to the genetic activity involved in the production of new proteins within cells.

One might expect emergency physicians would rush to embrace the use of therapeutic hypothermia, given the robust research in support of its use, but that hasn’t been the case. In the February 2005 issue of the journal Resuscitation, Abella, Chicago’s Terry Vanden Hoek and others reported that a survey of 265 physicians had found 87 percent said they were not using the technique.

“Among reasons cited for non-use, 49 percent felt that there were not enough data, 32 percent mentioned lack of incorporation of hypothermia into advanced cardiovascular life support (ACLS) protocols, and 28 percent felt that cooling methods were technically too difficult or too slow,” the report said.

Another reason may be that many doctors believe that there is little that can be done for cardiac arrests.

“There’s a culture of despair and a feeling of futility in these cases,” said Beiser, who adds that he makes sure to let his ER staff know about successful outcomes from hypothermia treatment to instill a sense of optimism.

“This culture of hope really helps get hypothermia off the ground in an institution.”

Sign up for our free e-newsletter.

Are you on Facebook? Click here to become our fan.

Add our news to your site.

Michael Haederle
Michael Haederle lives in New Mexico. He has written for the Los Angeles Times, People Magazine, Tricycle: The Buddhist Review and many other publications. He has also taught at Syracuse University's S.I. Newhouse School of Public Communications and is a Zen lay monk.

More From Michael Haederle

A weekly roundup of the best of Pacific Standard and PSmag.com, delivered straight to your inbox.

Recent Posts

July 22 • 2:00 PM

The Alabama Judge Who Refuses to Let Desegregation Orders Go Ignored

A federal judge in Alabama says a local school board has failed to meet legal mandate to integrate.


July 22 • 12:00 PM

On the Destinations of Species

It’s almost always easier to cross international borders if you’re something other than human.


July 22 • 10:51 AM

The Link Between Carbs, Gut Microbes, and Colon Cancer

Reduced carb intake among mice protected them from colon cancer.


July 22 • 10:47 AM

Irrational Choice Theory: The LeBron James Migration From Miami to Cleveland

Return migrants to Cleveland have been coming home in large numbers for quite some time. It makes perfect sense.


July 22 • 9:32 AM

This Time, Scalia Was Right

President Obama’s recess appointments were wrong and, worse, dangerous.


July 22 • 8:00 AM

On Vegas Strip, Blackjack Rule Change Is Sleight of Hand

Casino operators are changing blackjack payouts to give the house an even greater advantage. Is this a sign that Vegas is on its way back from the recession, or that the Strip’s biggest players are trying to squeeze some more cash out of visitors before the well runs dry?


July 22 • 6:00 AM

Label Me Confused

How the words on a bag of food create more questions than answers.


July 22 • 5:07 AM

Doubly Victimized: The Shocking Prevalence of Violence Against Homeless Women

An especially vulnerable population is surveyed by researchers.


July 22 • 4:00 AM

New Evidence That Blacks Are Aging Faster Than Whites

A large study finds American blacks are, biologically, three years older than their white chronological counterparts.



July 21 • 4:00 PM

Do You Have to Learn How to Get High?

All drugs are socially constructed.


July 21 • 2:14 PM

The New Weapon Against Disease-Spreading Insects Is Big Data

Computer models that pinpoint the likely locations of mosquitoes and tsetse flies are helping officials target vector control efforts.


July 21 • 2:00 PM

Why Are Obstetricians Among the Top Billers for Group Psychotherapy in Illinois?

Illinois leads the country in group psychotherapy sessions in Medicare, and some top billers aren’t mental health specialists. The state’s Medicaid program has cracked down, but federal officials have not.



July 21 • 12:00 PM

What Makes You So Smart, MacArthur Genius?

Noah Davis talks to Yoky Matsuoka about youth tennis, wanting to be an airhead, and what it’s like to win a Genius Grant.


July 21 • 11:23 AM

People Are Clueless About Placebos

Doctors know that sometimes the best medicine is no medicine at all. But how do patients feel about getting duped into recovery?


July 21 • 10:00 AM

How Small-D Democratic Should Our Political Parties Be?

We need to decide how primaries should work in this country before they get completely out of hand and the voters are left out entirely.


July 21 • 8:00 AM

No, Walking on All 4 Limbs Is Not a Sign of Human ‘Devolution’

New quantitative analysis reveals that people with Uner Tan Syndrome don’t actually walk like primates at all.


July 21 • 6:00 AM

Sequenced in the U.S.A.: A Desperate Town Hands Over Its DNA

The new American economy in three tablespoons of blood, a Walmart gift card, and a former mill town’s DNA.


July 21 • 5:00 AM

Celebrating Independence: Scenes From 59 Days Around the World

While national identities are often used to separate people, a husband-and-wife Facebook photography project aims to build connections.


July 21 • 4:00 AM

Be a Better Person: Take a Walk in the Park

New research from France finds strangers are more helpful if they’ve just strolled through a natural environment.



July 18 • 4:00 PM

The Litany of Problems With the Pentagon’s Effort to Recover MIAs

A draft inspector general report found that the mission lacks basic metrics for how to do the job—and when to end it.


July 18 • 2:00 PM

Sure, the Jobs Are Back, but We Need a Lot More

We’re back to where we were before the 2008 recession, but there are now 12 million more people in the United States.


July 18 • 12:00 PM

What Are the Benefits of Government-Funded Research?

Congress wants to know.


Follow us


Subscribe Now

The Link Between Carbs, Gut Microbes, and Colon Cancer

Reduced carb intake among mice protected them from colon cancer.

The New Weapon Against Disease-Spreading Insects Is Big Data

Computer models that pinpoint the likely locations of mosquitoes and tsetse flies are helping officials target vector control efforts.

People Are Clueless About Placebos

Doctors know that sometimes the best medicine is no medicine at all. But how do patients feel about getting duped into recovery?

No, Walking on All 4 Limbs Is Not a Sign of Human ‘Devolution’

New quantitative analysis reveals that people with Uner Tan Syndrome don't actually walk like primates at all.

Why Didn’t California’s Handheld Phone Ban Reduce Motor Accidents?

Are handheld cell phones as dangerous as they have been made out to be?

The Big One

Today, the United States produces less than two percent of the clothing purchased by Americans. In 1990, it produced nearly 50 percent. July/August 2014

Copyright © 2014 by Pacific Standard and The Miller-McCune Center for Research, Media, and Public Policy. All Rights Reserved.