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Congresswoman Gabrielle Giffords has survived incredible trauma to the brain, a bullet straight through the left lobe. Her doctors say she's responding to commands when she's brought out of heavy sedation. That has encouraged the doctors who've made optimistic statements about her chances of surviving and recovering.
But as NPR's Jon Hamilton reports, the risky period can go on for a week or more for someone with an injury like Giffords'.
JON HAMILTON: Most people who get shot in the head die before they reach the hospital. For the ones who do make it, there is a great risk that their brain will swell up so much that critical areas are damaged. But at a press conference in Tucson today, Michael Lemole, the chief of neurosurgery at University Medical Center, said so far, swelling hasn't been a problem for Giffords.
Dr. MICHAEL LEMOLE (Chief of Neurosurgery, University Medical Center): That swelling can sometimes take three days or five days to maximize. But every day that goes by and we don't see an increase, we're slightly more optimistic.
HAMILTON: Neurosurgeons at other institutions say that while there is reason for optimism, there is no guarantee that Giffords will survive and make a full recovery.
Bryan Oh is a surgeon at Memorial Hermann-Texas Medical Center in Houston, the home of one of the busiest trauma centers in the country. He spoke from a phone in one of the hospital's operating rooms.
Dr. BRYAN OH (Neurological Surgery, Memorial Hermann-Texas Medical Center): She still got shot in the head with a high energy missile. She still very well could die. You know, I would say over the next few days is where the rubber hits the road.
HAMILTON: Doctors have removed a piece of Giffords' skull that will allow her brain to swell without putting as much pressure on blood vessels and critical structures.
But Oh says it's still too soon to know whether that will protect her brain completely from the swelling.
Dr. OH: The peak swelling date could be around, you know, post-update three or four, which we're like getting into right now. It can go on even for a week or 10 days afterwards. It depends on how bad her injury was.
HAMILTON: On the other hand, Oh says he's treated patients with similar injuries who have made remarkable recoveries.
Dr. OH: I've dealt with one recently, a similar case, and the guy ended up of course, it was on the right side of his brain but almost the exact same trajectory that I'm guessing that she had. And after about two and a half, three weeks, he was talking and interactive.
HAMILTON: Other neurosurgeons say one reason to be optimistic is that the injury to Giffords isn't as bad as it could have been.
Keith Black is chairman of neurosurgery at Cedars-Sinai Medical Center in Los Angeles.
Dr. KEITH BLACK (Chairman of Neurosurgery, Cedars-Sinai Medical Center): The bullet only went to one side of the brain, so it didn't go to both sides. It didn't cross the midline where you have all of the deep critical, you know, thalamic and brainstem structures that are very important for consciousness.
HAMILTON: Also, the bullet was from a relatively small caliber handgun, reportedly a nine millimeter, and it followed what her doctors called a high trajectory.
Black says a high trajectory means a smaller chance that a person shot in the left side of the brain, which is usually important to language, will lose the ability to communicate.
Dr. BLACK: Because the language areas are lower down. So if the bullet is higher, it's going to be away from her language areas.
HAMILTON: Black says the trajectory that's good for language can be bad for walking, though.
Dr. BLACK: The motor areas that control the leg can be in that region. So, you know, we would want to hope that it's also avoided those leg areas.
HAMILTON: Black says tests of higher mental functions are hard to do until a patient can talk, which they can't do as long they are heavily sedated and breathing through a respirator.
Dr. BLACK: The next big step for her is going to be getting off the respirator. You know, when they wake her up and if she can support, you know, her respirations and you don't get into any problems with the oxygen level and the blood dropping, or the carbon dioxide going up too high that can cause more brain swelling, that would be very good.
HAMILTON: Black says the prospects for that will be much clearer in a day or two.
Jon Hamilton, NPR News.