Reporting from Los Angeles and Tucson — The bullet that passed through Rep. Gabrielle Giffords' brain tore through only one hemisphere before exiting, missing the crucial central parts of the brain that control most bodily and cognitive functions.
The bullet entered through the back of her head, passed through the left hemisphere of her brain and exited just above her left eye, Dr. Michael Lemole, chief of neurosurgery at University Medical Center in Tucson, said Sunday at a news conference.
Giffords is being kept in a medically induced coma and is not able to speak because she is intubated, but when she is periodically awakened, she is able to respond to simple commands, such as squeezing her hand and showing two fingers.
"We are very encouraged by that," Lemole said. Her ability to follow those commands "implies a very high level of functioning in the brain," he said.
"If she can hear requests and move her fingers, particularly showing two fingers and raising her thumbs, her receptive language functions are good and her hearing is intact," said Dr. Neil A. Martin, chairman of neurosurgery at UCLA's Reagan Medical Center.
"The best thing is if she is asked to do this and can raise her right fingers and thumb," which are controlled by the brain's left hemisphere, he said. "That's the first thing a neurosurgeon would want to know."
The Tucson doctors refused to say which hand Giffords was able to use. She is not able to open her eyes.
When the shooting occurred, two trauma teams were available at the hospital: the night trauma team was just turning duty over to the day team, and both responded to the emergency, said Dr. Randall Friese.
He told CNN that when he examined Giffords, "she did not speak. She did not open her eyes. She did squeeze my hand very aggressively."
Dr. Peter Rhee, the trauma director at the hospital, who served as a military physician in Afghanistan and Iraq, said the first thing doctors did was a primary survey to make sure they knew she was not going to die. The team looked for things that could kill her immediately, such as an inability to breathe, collapsed lungs, blood in her lungs or holes in major blood vessels.
They would, for example, ask her show them two fingers. "That takes special brain power to do," Rhee said. "She was able to give us that. That was enough for us to know she was alive inside there, she was not dead. That was what gave us so much optimism and why we rushed through this process so quickly."
Then they did a secondary survey, which took about five minutes. They got intravenous lines going and made rapid decisions about whether they needed to control her breathing. They took about 10 minutes to get her intubated and secure the tubes so they wouldn't be pulled out. Then they took images with a CT scanner, which took about 20 minutes.
The surgeons removed the bone that was shattered by the bullet and additional bone around the entry wound to allow room for swelling of the brain caused by the injury, a process known as a craniectomy. The extra bone, about half the skull on the left side of her head, will be stored in a freezer and reimplanted later, most likely in about six to eight weeks.
Such swelling is normal from the shock of an injury, Martin said, and is no different from the swelling of an ankle or knee after a sprain. The only problem is that the brain is compressed within a compartment.
Intracranial pressure will probably be monitored with an implanted catheter, he said, but doctors will also check by manually feeling the exposed brain. If it is "rock hard," they may have to remove more bone.
Lemole said surgeons had to remove some dead tissue from the bullet path. "I'm happy to say we didn't have to do a whole lot of that," he said.
Giffords is in the intensive care unit and probably will remain there for at least a week. She is being given fentanyl for pain and propofol to keep her in a coma. Physicians stop the propofol periodically to wake her up and check her reflexes.
The team most likely has an EEG monitor attached to her to watch for seizures, which are typical in the aftermath of brain injury.
Doctors will monitor her for fevers and other evidence of infections, as well as for signs of leakage of cerebrospinal fluid and any signs of stroke.
It will be several days, at least, before physicians will be able to more fully assess the effects of the injury on her cognitive abilities. "This is very early in the course [of treatment]. We don't know what's going to happen, what her deficits will be in the future," Rhee said.
The team will not be able to test for subtle functions of the brain like memory or finer details of language function until the coma is resolved, she is fully awake and breathing tubes are removed.
Maugh reported from Los Angeles and Mehta from Tucson.