Trauma surgeons spent two hours on Saturday following an often-performed drill developed from extensive experience treating gunshot wounds in foreign wars and violence in American homes and streets. On Saturday, that drill really began outside a supermarket, with paramedics performing triage to determine the seriousness of the wounds in each of the 20 gunshot victims.
Ms. Giffords, 40, was taken to the University Medical Center in Tucson, where, 38 minutes after arrival, she was whisked to an operating room. She did not speak at the hospital.
As part of the two-hour operation, her surgeons said on Sunday, they removed debris from the gunshot, a small amount of dead brain tissue and nearly half of Ms. Giffords's skull to prevent swelling that could transmit increased pressure to cause more extensive and permanent brain damage. The doctors preserved the skull bone for later replanting.
Since surgery, they have used short-acting drugs to put Ms. Giffords in a medical coma that they lift periodically to check on her neurological responses.
They said early signs made them cautiously optimistic that Ms. Giffords would survive the devastating wound.
"Things are going very well, and we are all very happy at this stage," Dr. Peter Rhee, the director of medical trauma at the hospital, said at a news conference.
Dr. G. Michael Lemole Jr., the hospital's chief of neurosurgery, was more cautious. "Brain swelling is the biggest threat now," Dr. Lemole said, "because it can take a turn for the worse at any time."
Such swelling often peaks in about four or five days, then begins to disappear.
The doctors said that it was far too early to know how much long-term functional brain damage, if any, Ms. Giffords would suffer. They also say they will carefully monitor her over the next few days as she faces a number of potential complications, like infections, that can hamper her recovery. Full rehabilitation could take months to years. Long-term complications could include seizures.
The optimism expressed Sunday was based on Ms. Giffords's ability to communicate by responding nonverbally to the doctors' simple commands, like squeezing a hand, wiggling toes and holding up two fingers. The tests are part of a standard neurological examination after head injuries. In Ms. Giffords's case, the doctors were encouraged because the simple tests showed that she could hear and respond appropriately, indicating that key brain circuits were working.
"If she's following commands, that's great and a very big step toward recovery," Dr. Eugene S. Flamm, chairman of neurosurgery at Montefiore Medical Center in the Bronx, said in an interview. Dr. Flamm is not involved in Ms. Giffords's treatment.
Functional neurological recovery from a gunshot wound depends on a number of factors, including the specific area of the brain that is injured, the number of bullets, their trajectory and velocity, and luck.
Ms. Giffords was shot once in the head, according to Sheriff Clarence W. Dupnik of Pima County, Ariz., and the doctors who treated her said that tests showed the bullet did not cross the geometric center line dividing the brain's left and right hemispheres.
"That's very good because bullets that affect both hemispheres have a much higher mortality because the swelling affects both sides," said Dr. Flamm, who has treated many gunshot wounds in his career, including 25 years at Bellevue Hospital Center in Manhattan, 11 years as chief of neurosurgery at the University of Pennsylvania in Philadelphia and 11 years at Montefiore.
In traversing the left side of Ms. Giffords's brain, the bullet went through what is the dominant side in about 85 percent of people, whether they are right- or left-handed, Dr. Flamm explained.
"It sounds simple to raise fingers and squeeze hands," he said, "but the ability to do it is a very good sign in a brain-injured patient because it shows that the dominant hemisphere was not knocked out."
The doctors in Tucson did not cite the bullet's trajectory — that is, whether it entered at the top of the back of the skull and exited at a lower point or whether it went straight through.
If the bullet went through the visual area in the occipital part of the back of the brain, it could affect the right side of Ms. Giffords's peripheral vision, Dr. Flamm said, adding, "It is hard to piece that together without more information." Ms. Giffords is unable to speak because she is connected to a ventilator and unable to open her eyes, which doctors have covered with patches.
It is usually several weeks before doctors can fully evaluate cognitive function in a patient who has suffered a gunshot wound to the brain, and the body has a significant capacity to compensate for serious injuries.
Although Ms. Giffords's ability to follow commands is encouraging, her doctors said that it would take several weeks to know what her recovery would be. That is a caveat that Dr. Flamm well understands. "I can understand the impatience of wanting to know it now," he said. "But even if I wanted to know and examined her myself, I wouldn't be able to answer that question at this stage."
http://www.nytimes.com/2011/01/10/health/10medical.html?_r=1&nl=todaysheadlines&emc=tha23
