Freezing the Heart to Save the Life

Cold Relief John B. Carnett

At 3 p.m. last June 22, Pam Barco’s heart stopped. The 46-year-old ER clerk at the Children’s Hospital of Philadelphia was near the end of her shift when she felt dizzy, put her head down on her desk, and suddenly stopped breathing. A nearby co-worker saw Barco slump over and shouted, “Staff emergency!” Minutes later, a dozen doctors and nurses surrounded Barco’s body. They shocked her with a defibrillator. No response. They shocked her twice more. Nothing. Then: Beep. Beep. Beep.

On TV, this is when everyone breathes a sigh of relief. In real life, though, 9 out of 10 cardiac-arrest patients whose hearts are restarted end up dying in the hospital; of the survivors, one out of eight suffers permanent brain damage. Every minute that the heart isn’t pumping starves the brain and other organs of oxygen, depriving their cells of energy.

Although Barco’s heart was beating, her blood pressure was dangerously low, and she wasn’t getting enough oxygen. Doctors inserted a breathing tube. When she was stable enough to be moved, they wheeled her next door to the University of Pennsylvania hospital and up to the cardiac-care unit on the eighth floor.

Nurse Jamie Weller had everything set up. First she gave Barco a sedative to knock her out, and then another drug that paralyzed her so she wouldn’t shiver. She hooked Barco’s IV up to a bag of 35°–40°F saline and wrapped her legs and torso in what looked like bubble wrap with cold water flowing through it. By the morning, Barco’s body temperature was 91°, cold enough that she officially had hypothermia, just as the doctors intended. She stayed like that for 24 hours.

Barco was lucky. She happened to collapse next door to the Penn Center for Resuscitation Science, where doctors Lance Becker and Benjamin Abella are convinced that a procedure that sounds like torture would in fact increase Barco’s chances of surviving, while minimizing brain damage. The treatment is called therapeutic hypothermia, and it’s based on the idea that what damages tissue in the heart and brain isn’t the heart stopping, but rather its sudden restarting and the destructive natural reactions that occur when the oxygen comes back—unless the body is cold enough to slow the process. Two clinical trials in 2002 showed that cooling resuscitated patients within four hours of defibrillation increased their survival rate by 20 percent, even if they had been clinically dead for as long as an hour. A more recent study at the University of Pittsburgh School of Medicine, which has been using the technique for five years, showed that among certain groups, cooling doubled the number of survivors.

Yet many people have never heard of therapeutic hypothermia, and few doctors are using it. For all its promise, inducing controlled hypothermia is a complex procedure that requires doctors to develop and learn a protocol, buy special equipment, and train staff from multiple departments—all for something that sounds entirely counterintuitive. It’s also a procedure that punishes imprecision: Cool a patient a few degrees too far, and you could stop her heart again.

But the U. Penn doctors who are the treatment’s biggest proponents say that not only should the procedure be standard, but that doctors should go even further. They’re running studies on mice and pigs that suggest that it’s better to start cooling before restarting the heart. Soon they will start testing this idea on humans with a machine that would let emergency-medical technicians run a “frozen slushee” IV into patients. In Becker and Abella’s ideal world, at least 15 percent of the 166,000 people who have a cardiac arrest outside the hospital every year will be frozen and paralyzed before they even reach the ER.