Lowering body temperature may aid in recovery
Emergency crews may one day have a potent new weapon against spinal-cord injuries — the one used on the Buffalo Bills’ Kevin Everett after a tackle seemed to leave him paralyzed.
The novel treatment, injecting cold saline in his veins minutes after the injury to lower his body temperature several degrees, has gotten some of the credit for his recovery.
Everett, 25, lay motionless on the field after driving his helmet into an opposing player on Sept. 9. The next day his orthopedic surgeon called the injury “catastrophic” and said the chance of full recovery was bleak.
But a day later, Everett awoke and moved his limbs, and doctors said he will walk again. He was moved to a Houston Rehabilitation center Sept. 21.
“That it actually occurred in a human being instead of just (laboratory) rats … is encouraging,” said David Allgood, 41, of Louisville, who was paralyzed at 16 in a diving accident.
While cooling patients to limit damage from a spinal-cord injury is considered experimental, it could be routine one day if ongoing clinical trials replicate its success in animal tests, medical experts said.
“If my loved one or whatever had brain injury or stroke, or spinal cord injury … I would think that mild cooling in the right hands would be a very good thing to do. But it’s not something that’s universally accepted,” said W. Dalton Dietrich, scientific director of the Miami Project to Cure Paralysis, at the University of Miami (Fla.). The project has pioneered research into cooling the body to lessen damage from an injury.
The technique, called inducing Hypothermia, has been found effective in treating some serious conditions — stroke, brain injuries and cardiac arrest.
And lowering patients’ temperature during surgery has made possible some difficult brain operations, including in Louisville.
But experts, including Dietrich, cautioned against concluding the technique accounts for Everett’s recovery.
“To be honest, we don’t know if it was hypothermia that made a difference,” he said.
Everett’s good outcome could be due to several other factors, doctors and spine researchers said.
They credited the speed with which his orthopedic surgeon, Dr. Andrew Cappuccino, used multiple techniques to limit the damage.
In addition to the cold saline, Cappuccino gave Everett a steroid drug minutes after the injury, a standard treatment that is believed to work best if done immediately.
And he performed surgery quickly after the accident to stabilize Everett’s spine and remove pressure on the spinal cord.
“He pulled out all the stops,” said Edward Hall, director of the University of Kentucky’s Spinal Cord and Brain Injury Research Center.
Another possibility is that Everett’s injury wasn’t as bad as first believed. Louisville surgeons noted that many patients gradually recover movement if their spinal cord is badly bruised but not crushed.
“He may not have had a devastating injury,” said Dr. Christopher Shields, a neurosurgeon and clinical director of the Kentucky Spinal Cord Injury Research Center at the University of Louisville.
Also, Everett had advantages most patients don’t have — athletic neck muscles, a doctor on the sidelines, and a specially equipped ambulance, complete with a backboard adapted to accommodate a football helmet.
The most important step by Cappuccino probably was operating quickly to remove pressure on the spinal cord, Shields said.
Supported by research
That idea is supported by a study he and other researchers at U of L and Norton Healthcare’s Leatherman Spine Center performed using rats. It was published in the journal Spine in 1999.
The study found that the faster the spinal cord is freed of pressure after an injury — for example, by removing blood or bone fragments from the spinal canal — the better the recovery of movement.
A study by the same researchers a year later found that cooling a moderately injured spinal cord can aid recovery.
But the cooling technique researchers used on rats can’t be duplicated on humans, said lead study author Dr. John Dimar, an orthopedic surgeon.
Researchers exposed each rat’s spinal cord and placed a reservoir of cool liquid over it for 72 hours. But a human spinal cord can’t be exposed that long because infection will occur, Dimar said.
Dietrich, who has been studying hypothermia for more than 20 years, believes it can help spinal-cord patients. He said an ongoing clinical trial at the Miami Project has confirmed that properly done cooling is safe but hasn’t yet proven its effectiveness.
Hypothermia slows the metabolism, allowing cells to survive longer when deprived of oxygen. Animal tests have shown that cooling limits the swelling, inflammation and toxic-chemical release that follow a spinal-cord injury, causing further damage.
Doctors have known for decades that a drop in body temperature could help certain patients survive.
“If you drown in a lake in the summer, you’re pretty much dead,” said Dr. Jonathan Hodes, a Louisville neurosurgeon. “If you drown in a lake in the winter, you’ve got some chance of survival without neurological damage. And that’s attributed to cold basically shutting down your systems.”
Early attempts to cool patients had poor results, though.
As far back as the 1940s, aneurism patients were put in a room so cold that nurses wore parkas and gloves, Shields said. The idea was to delay brain swelling by inducing something like hibernation.
Doctors eventually concluded the practice was just “delaying the inevitable,” he said. Also, patients were Prone to pneumonia, and rewarming caused other problems.
A few degrees may be enough
But those early attempts involved sharply lowering the body temperature. In recent years, researchers have learned that a decrease of only a few degrees greatly lessens complications.
Doctors use various methods to cool patients, from placing cooling blankets around the body to circulating cold liquid inside a Catheter placed in an artery.
Hodes said he sometimes places a sterile bag of ice on a patient’s brain while doing surgery to repair an aneurism, a weak spot in a blood vessel.
On rare occasions, Hodes has placed brain-surgery patients at Baptist Hospital East on a heart-bypass machine, enabling him to drop body temperature to the low eighties. That can buy an extra 25 minutes to reconstruct an artery without causing a stroke.
“He lowered my body temperature to that of a dead person,” said Kenny Woosley, a patient of Hodes who had life-saving brain surgery to repair three aneurisms several years ago.
“Medical technology today is truly incredible, that they are able to do stuff like that,” said Woosley, 52, of eastern Jefferson County.
While some uses of hypothermia are rare or still experimental, one is becoming standard.
In 2003, the American Heart Association recommended cooling cardiac patients whose hearts have been restarted by emergency personnel. Studies had shown that lessened the chance of brain damage.
Based on that advisory, some U.S. ambulance systems have started carrying cold saline.
In Louisville, Metro EMS may start carrying cold saline next year for certain cardiac-arrest situations, EMS director Neal Richmond said.
But that will be worthless unless hospitals are prepared to keep cooling those patients after arrival. Richmond said he is conferring with hospitals. Representatives of several Louisville hospitals said they will cooperate and have the needed technology.
For spinal-cord patients, though, use of cooling by ambulance crews may be years away. It is unlikely to become the norm until published human studies recommend it.
If that happens, doctors are likely to add cooling to their arsenal even if the benefit is marginal, Dimar said.
“The goal of every neurosurgeon and orthopedic surgeon is to try to restore as much neurological function that we can,” he said. “If we have to throw in marbles and the kitchen sink … we’re going to try it.”
By Patrick Howington