February 11, 2008

Hypothermia May Help With Severe Head Injuries

Second of two parts

Her skin cold to the touch, Anna Kindt lay in the hospital as frigid saline was pumped into her veins for more than 10 days.

A crack about one-third of an inch wide ran along the top and right side of Kindt's skull, just one of several fractures to her head and face.

Her car looked just as bad, a collapsed roof and a crushed side.

While passing another car on the shoulder of a road near Hartland in August 2006, Kindt lost control of her Honda Civic, which turned into a front yard and bounced off a couple of trees before coming to a rest.

Flight for Life transported her to Froedtert Hospital, where doctors faced the daunting task of preventing her brain from swelling and killing her or rendering her severely disabled.

One possibility was to remove part of her skull. Another was to put a cooling catheter into one of her veins, bring her body temperature down to 91 degrees, keeping her brain and body in a state of hypothermia.

When doctors started cooling Kindt, 21, of Waukesha, she became part of a small fraternity of head injury patients to undergo hypothermia therapy.

She spent 32 days in the hospital, including about 10 days in a state of hypothermia, sedated and under the influence of a paralyzing drug that prevented her from shivering.

"She was in a coma," said her mother, Nina Kindt. "She was cold. (But) it seemed like she knew we were there."

Doctors say hypothermia therapy has become the standard of care as a way to protect the brains of people who have suffered a cardiac arrest.

It's also being used more in head injury cases, although clinical trials supporting its use have been mixed.

At a few area hospitals, doctors have used the therapy on a handful of head injury cases.

Whether it becomes the standard of care for those types of cases will depend on clinical trials, said Michel Torbey, an associate professor of neurology and neurosurgery at the Medical College of Wisconsin who practices at Froedtert.

Those trials using hypothermia in adults and children who have suffered brain injuries are taking place in the U.S. and in other countries, but it could be a few more years before the results are known.

For years, animal research and some studies in humans have hinted that putting head trauma patients into hypothermia might be beneficial.

However, a 2001 study in the New England Journal of Medicine cooled interest in the use of hypothermia in brain injury cases.

The study, involving 392 comatose patients aged 16 to 65, found that cooling them to 91 degrees within eight hours of their injury and maintaining them at that temperature for 48 hours did not provide any benefit.

About 57% of patients who were cooled and a similar percentage who were not cooled either died or recovered with severe disability or in a vegetative state. And there were more complications among those who got hypothermia therapy.

It was a setback for the use of the therapy in head injury cases.

Signs of help

But encouraged by animal studies, the same group of researchers pressed on, this time looking at a group of 102 brain injury patients who, because of cold outdoor conditions, already were in a state of hypothermia when they were admitted to the hospital.

The researchers found that if hypothermia was continued in the hospital, the patients were significantly more likely to have a good neurological outcome (good recovery and only moderate disability) than a poor outcome (severe disability, vegetative state or death).

In patients who were 45 or younger, the effect was even more pronounced. Among those who did not get hypothermia therapy, 76% had a poor outcome, compared with 52% who got hypothermia therapy in the hospital.

"We kept seeing patients who did dramatically better than anyone expected," said Guy Clifton, lead author on both studies and professor and chairman of the department of neurosurgery at the University of Texas Health Science Center in Houston.

The finding led researchers to theorize that if cooling could be started early, it might be effective.

Now Clifton and other groups of researchers are doing hypothermia clinical trials on children and adults who have had brain injuries with the goal of cooling them to about 91 degrees within four hours of their injury.

"Essentially what we are doing is cooling as quickly as possible," Clifton said.

It is believed that cooling protects the brain in a couple of ways.

When the brain is injured, such as in an auto accident or fall, it begins producing chemicals that can be harmful to brain cells. Hypothermia slows the production of those chemicals.

A cool brain also needs less oxygen.

At the same time, injury to the brain produces swelling that can be damaging or deadly. Hypothermia is known to reduce swelling.

As a result, some hospitals now use it to help decrease swelling.

Reducing the stay

At UW Hospital and Clinics in Madison, about 20% of head injury patients now get hypothermia therapy, said Gregory Trost, a professor of neurosurgery and vice chairman of neurosurgery. He said hypothermia can reduce the amount of time a patient spends in the hospital.

Such patients usually are kept in a state of hypothermia for three to seven days.

"It's just one other therapy that we can try," he said.

As a doctor in residence in St. Louis, William McCullough had experience with a clinical trial in which hypothermia was used in brain injury cases.

"We saw evidence of what were presumed to be good results," said McCullough, a neurosurgeon with Midwest Neurosurgical Associates who practices at Aurora St. Luke's Medical Center in Milwaukee.

But the evidence remains mostly anecdotal, he said. St. Luke's does not use the therapy in brain injury cases, he said.

At Froedtert it has been used on a handful of brain injury patients, Torbey said. He said it can reduce pressure in the brain by as much as two-thirds.

"We can pretty much bring them to normal pressure," he said. "The question is: Is it changing outcomes?"

Signs of improvement

There is no way of knowing whether hypothermia helped Kindt recover, but her initial prognosis was bleak.

"They told us there was a 20 percent chance she'd live, and if she did we'd be feeding her and she would have to be taken care of," said her mother, Nina.

Instead, her daughter has recovered dramatically, although her personality has changed somewhat, her mother said.

She has less patience and she is more likely to be overly crabby or happy about things, her mother said.

Anna Kindt said she also has some lingering memory problems and she is taking a drug used for ADHD to help with her memory.

About half her memories from 2006 seem to be gone, she said.

"All of 2006 is in pieces," she said.

A former competitive gymnast, Kindt has recovered her physical function.

"I can do back handsprings and handstands," she said. "I can hold those for a good five minutes."

She's now studying massage therapy and doing well in school, she said.

"I should be dead or mentally retarded," she said. "(Hypothermia) saved my life. I beat science. Science can't explain me."