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New treatments provide clues to injured brains

by Ruth SoRelle, MHP

Claudia Robertson, MD, Jason Ferguson, Shankar Gopinath, MD

Jason Ferguson will never forget Dec. 17, 2002, although he remembers nothing about what happened that day.

In the early morning hours, Ferguson was returning from a late night gig as a music engineer when he lost control of his truck on a feeder to the Southwest Freeway. The truck was totaled and Ferguson thrown onto the street. Injuries to his brain almost killed him.

Had the accident occurred a decade earlier, he might not have survived. Today, new treatments, techniques and instrumentation for monitoring the status of patients with brain injury provide clues about what is going on in the injured brain. Much of that new knowledge came from work done by Baylor College of Medicine experts in the Center for Neurosurgical Intensive Care at Houston 's Ben Taub General Hospital .

From the outside, a brain injury may not be readily apparent. It is the violence inside that can rip apart blood vessels and sever nerves. Propelled by an impact, the brain ricochets from one side of the skull to the other. Nerves rip. Blood vessels tear and leak blood into spaces called ventricles. And that is only the immediate problem.

In the period after the injury, a blood clot can form between the skull and the dura or lining of the brain, between the dura and the brain itself or deep in the middle of the brain. Often these clots lead to dangerous increases in pressure within the skull and require emergency surgery. If the brain twists and turns during impact, the axons or pathways through which messages travel from one part of the brain to another become damaged. As tissues die, cells and chemicals associated with inflammation rush to the injury to clear away the damage. Sometimes, they clear away healthy tissue as well.

Where brain matters
Treating people with brain injury means wrapping them in a technological cocoon that stabilizes the brain environment while the body attempts to repair damaged tissue. In Houston, that cocoon is in constant renewal on the fourth floor of Ben Taub General Hospital, under the supervision Claudia Robertson, MD, medical director of the Neurosurgery Intensive Care Unit, and Alex Valadka, MD, chief of neurosurgery, their colleagues, fellows, residents, students, nurses and staff.

A framed banner at the entrance to the suite puts you on notice that you are in the Neurosurgical Intensive Care Unit, "where brain matters."

The caring begins even before the patient passes through the hospital door when emergency medical services teams pick up victims of head injury and deliver them to the hospital's legendary trauma center. While the patient's injuries are still being assessed, a member of the neurosurgical team arrives to help determine whether or not the injury requires immediate surgery.

"Even a CT scan can look normal when the patient has severe trauma to the brain," said Shankar Gopinath, MD, an assistant professor of neurosurgery at BCM. His training to work with brain-injured patients began six years ago under the supervision of Robertson at BCM.

Patients who do not need surgery are transferred immediately to the neurosurgical intensive care unit, where the care is of 21 st century caliber.

The blue-black areas in  the brain scan , left,  of a patient who has had a contusion or injury to the right temple area shows very low blood flow in the contused brain, while the blood flow to the rest of the brain is normal. This scan  on the right is from a patient who has reduced or no blood flow to the entire right side of the brain.

Closed system
For decades, those who treated head injuries could only guess at what was going on within the closed system of the brain and skull. New probes that measure pressure or test brain chemistry have shed light on the mysteries inside the skull. BCM physicians have pioneered many of these advances at Ben Taub.

When Robertson came to Ben Taub about 20 years ago, roughly half the brain injury patients in the unit did not survive. Today, approximately 70 to 75 percent live. Research at the county hospital is responsible for much of that.

Until recently, physicians believed that patients with brain injury should receive no fluids. They were trying to eliminate potentially damaging edema or swelling. As a result, brain injury patients often went days without nourishment.

Research by BCM researchers at Ben Taub showed the fallacy. Patients recovering from brain injury needed at least 40 percent more calories than normal. In other words, patients need to be fed a lot, and do not need to be dehydrated.

Another common treatment in previous years was reducing pressure inside the skull by "hyperventilating" patients -.but this treatment reduces the pressure by decreasing the blood flow and therefore oxygen delivery to the injured brain.

Monitoring the amount of oxygen getting to the brain with a probe in the jugular vein is better, said Robertson. Treating everyone for a problem that affects only a few can expose some patients to harm. Choosing those who need more oxygen by keeping tabs on their individual status is the method of choice today.

"We are seeing a marked drop in the use of hyperventilation to treat increased pressure," said Robertson. "Twenty years ago, every patient was hyperventilated for 10 days."

The biology
Recognizing the individuality of each patient was only a beginning in improving care. Robertson and her colleagues worked hard to understand the biology of the injured brain.

"Edema is an issue," she said. "While the brain is in the acute injury phase, it is important to monitor intracranial pressure. You only use treatment in patients in whom that pressure is elevated. If you treat everyone, you are exposing some people to possible harm to correct a condition they don't have."

The original monitors of intracranial pressure were fluid-filled catheters inserted into the ventricles of the brain. New devices are miniature pressure transducers that need to be inserted no more than a centimeter into the brain, said Robertson. They are more easily placed and have lower risk of complications than the larger, more invasive catheters.

Understanding the biochemistry of the recovering brain is another important issue, said Robertson. Microdialysis allows her to determine what chemicals are accumulating in the brain. A probe consisting of a dialysis fiber enclosed in plastic tubing is implanted in the brain. It records molecular transfer of neurotransmitters and other chemicals within the brain and gives physicians a biochemical picture of what is happening. The brain releases a chemical called glutamate after injury. Glutamate kills neurons. Swelling or edema can shut off the blood flow, and more cells die. Inflammation that occurs after several days can release cell-killing chemicals. If the brain is becoming more inflamed and injured, chemicals called cytokines are recruited to the area. Ultimately this type of monitoring may allow physicians to direct treatment at underlying injury processes, and monitor the results of this treatment.

Preventing damage
"You always hope to find an earlier predictor of the brain's becoming more damaged," said Robertson.

Preventing damage is her main aim. Most patients in the unit are sedated soon after their arrival to reduce the risk of damage arising from complications such as increasing pressure within the brain. Draining cerebrospinal fluid or administrating a drug called mannitol (which acts to relieve edema) also work to relieve increasing pressure.

After an injury, a patient's body can no longer regulate blood flow to the brain accurately, said Robertson. For example, when a normal person stands up quickly, the blood flow to the brain and blood pressure increase automatically as a compensatory mechanism.

"Can we use technology to measure autoregulation of blood pressure in the brain to identify people at risk of brain damage from lack of blood flow?" she said. The ability to regulate pressure is lost quickly in the first 48 hours after injury.

'We are trying to understand that," she said.

Improving care
Improving care can prove simple and difficult at the same time. When Robertson wanted to reduce the problems associated with transporting patients to a CT scanner on another floor, the answer was simple. Put a CT scanner in her unit. Making that happen was another matter that required the combined efforts of BCM's department of neurosurgery and the Harris County Hospital District.

Today, the portable CT scanner sits in the middle of the quiet, efficient neurosurgical intensive care unit. It saves seriously ill patients from a trip to the radiology suite downstairs. Moving patients attached to monitors and intravenous tubing through the hospital corridors and in elevators is a perilous task and not one taken lightly.

Patient beds are oriented with the heads toward the middle of the room. When someone needs a scan, the CT scanner is rolled to the bedside and the patient carefully moved onto it.

"It is really a great tool," said Robertson.

Most often it is used to determine whether a patient has bleeding in the brain that can only be fixed by a visit to the operating room.

It also provides the physicians with the ability to look at how blood is flowing - or not flowing - within the brain. Robertson and her staff refer to such images as they attempt to determine whether treatments are working to bring blood to areas where flow is reduced.

The amount of healing depends on the extent of the injury and the success of physicians such as Robertson and Gopinath in preventing damage.

"We continue to monitor the patients' progress for six months after the injury," said Robertson. "Some leave the hospital in awful shape and come back talking and walking."

Re-entering the world
The Institute for Rehabilitation and Research or the Harris County Hospital District's Quentin Mease Hospital , both staffed by BCM physicians, provide the retraining needed to continue recovery.

Ferguson is proof that such treatment can work.

He remembers little about his sojourn in Ben Taub. Like most patients, he was sedated for the majority of the time. Nurses and physicians remember him, though. They were heartened when he walked in recently, hale and hearty, to thank them for their care.

"This is why we are here," said Robertson.

"He's a miracle walking around. It shows the power of research," said Gopinath.

For Ferguson , the injury was life changing. He is not fully recovered, but he volunteers at a local hospital and church every week, anxious to give back. He is planning a return to school and wants to work with others who have had severe injuries. He has become an advocate for patients like him.

He is lucky, he said.

"I get better every day."

Because Ben Taub is the county hospital, many people think the work done there benefits only those without funds or health insurance. That is not true, said Robertson. All kinds of people occupy the beds on the unit.

"You see everyone here - lawyers, doctors, a guy off the street, "said Robertson, gazing around the quiet unit. "This is a microcosm of Houston itself."

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