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Prescription coma

Medically induced comas are in the news because of some high-profile cases. But what are they, and why do doctors use them?

By SUSAN ASCHOFF
Published January 30, 2006

The last thing Drew Hixon remembers before a collision on a football field severely injured his brain is reading to elementary school students with his teammates.

Two days before the game.

"I don't remember any of that day," says Hixon, 23, a Tennessee Tech receiver who was injured in a Sept. 11, 2004, game against the University of South Florida. Hixon caught a pass. Two defenders tackled him. He lay motionless at midfield while, in the stands, his mother prayed he'd get up.

Doctors at St. Joseph's Hospital put Hixon into a medically induced coma for a week to buy time to save his life. His mother, Rebecca Hixon, would wait six weeks at his bedside for her son to come back.

"We didn't understand fully what was happening," she says of those first harrowing hours. "They would show me the pictures (of his brain) and I didn't know what I was looking at."

A medically induced coma is an intensive response to a severe injury. In recent weeks, comas have been prescribed for Israeli Prime Minister Ariel Sharon after he had a massive stroke and for Randal McCloy Jr., the sole survivor of a West Virginia coal mine explosion.

In October 2004, doctors put Wisconsin teenager Jeanna Giese into a coma in the first known case of recovery from rabies without vaccination.

Doctors have been inducing comas for more than two decades to treat brain infections, tumors, stroke and trauma. Intravenous drug cocktails quiet the brain's electrical messaging and its malfunctioning metabolism.

A coma "buys time to address all issues, to maintain good blood flow, to limit damage," says Dr. Kevin Sierra, a critical care physician at St. Joseph's Hospital.

"If you're putting someone in a coma, it's a dire situation," says Dr. Erasmo Passaro, director of the Comprehensive Epilepsy Program at Bayfront Medical Center in St. Petersburg.

Giese, the 15-year-old rabies victim, survived. McCloy, the 26-year-old miner, suffered carbon monoxide poisoning - oxygen starvation - and likely brain damage while awaiting rescue. He emerged from his coma Wednesday. Sharon, 77, who suffered a cerebral hemorrhage and underwent multiple brain surgeries, remained unconscious 31/2 weeks after his stroke.

Ideally, the patient will be weaned off the coma-inducing drugs within 24 to 48 hours, he says. "The longer you have to do it, the poorer the outcome."

The patient must be strong enough to regain consciousness.

"They put him in the coma," says Rebecca Hixon, "but he kinda had to come out on his own. It was very, very, very gradual. It was not like on a TV show."

One day the eyelids fluttered; the next day, they fluttered a little more.

"C'mon, Drew. Try," she coaxed.

Hixon had to relearn how to sit, speak, write. His first memory of consciousness is of sipping through a straw, and a therapist cautioning him to slow down.

Drew Hixon's recovery is a happy ending to an always perilous story. There is little medical personnel can do for initial damage to the brain. What they want to stop is a cascade of subsequent problems caused by lack of blood flow, insufficient oxygen and a disruption of the brain cells' exchange of fluids and chemicals. Any and all can be fatal.

The brain controls heart rate and breathing, body temperature and blood pressure. It deciphers the rush of information gathered by eyes, ears, nose, mouth and skin. It directs the body's movement. In a human, it is what gives us reason, dreams, speech, tears and laughter.

In its 3 to 4 pounds of delicate tissue, there are 100-billion nerve cells, or neurons, gathering and transmitting electrochemical signals along axons extending from each neuron like wires in a computer. Neurons can also pass messages along projections called dendrites.

When the brain is shaken, for example, in a car accident, the axons may pull or tear, inevitably killing the cell. Metabolic processes break down. Tissue is bruised.

"If you get punched in your arm, the arm is going to swell," says TGH's Malek. In the brain, swelling within the closed box of the skull compresses blood vessels, cutting off circulation. Without oxygen, the brain dies.

"A stroke is not just localized to one part of the brain," says Dr. Andrea Gabrielli, associate professor of anesthesiology and surgery in critical care medicine at the University of Florida.

With swelling, more pressure is needed to get blood through the vessels to the entire brain. If there is bleeding, the bleeding damages cells, which leak fluids, causing further damage, he says.

Since the lethal threat to the brain is lack of oxygen, a medically induced coma reduces the amount needed by subduing brain activity.

"It's very much what a bear will do: In the winter there's no food, so he just goes to sleep," Gabrielli says.

In such cases, the injury is more severe than a concussion. The coma is deeper than sleep. The EEG, or electroencephalogram, a graph of brain waves obtained through electrodes attached to the scalp, shows a flat line that spikes much less frequently than normal, Passaro says.

Doctors want to see lots of flat stretches. "Every time (the line) spikes, I'm burning oxygen. Reduce the electric activity of my brain and you reduce oxygen consumption," Gabrielli says.

Passaro says that for a patient experiencing uncontrolled seizures, a coma is induced if "you've tried other medicines, and there is (still) continuous electrical seizure activity." There may be no physical jerks or spasms, but the brain is under assault.

Medicine is experimenting with hyperbaric oxygen, or oxygen administered under pressure, and hypothermia, the lowering of body temperature, to achieve the same effects as in a barbiturate coma, but these methods carry their own risks.

Families of patients in medically induced comas, frightened by the respirator and other life support and desperate for a sign their loved one will recover, may want what the treatment is purposely suppressing. "When we put our hand in his hand he'd squeeze it," Rebecca Hixon says of her son. These were simply reflexes, she learned.

"The longer he was under the more concern they had. We sang, we prayed, we read Scripture, we talked to him about the day, we'd hold his hand," his mother says.

In December, Hixon graduated with a degree in finance. He lives with his parents in Leesburg, Va., and is looking for a job. He still deals with muscle stiffness and short-term memory loss. He has to write things down. Therapists tell him recovery from a serious brain injury can take at least two years.

"I don't think about it. I never ask, why me?" says Hixon. "Looking back, I feel I'm a better person for it, a stronger person.

"I can say I made it through."

- Susan Aschoff can be reached at aschoff@sptimes.com or 727 892-2293.

[Last modified January 27, 2006, 10:48:05]