Rep. Gabrielle Giffords remains in intensive care at Memorial-Hermann hospital in Texas, where a buildup of fluid in her brain has slowed her transfer to a rehabilitation center but not caused great concern about her medical condition.
Doctors have inserted a small drain in Giffords' skull to remove the fluid. Experts say it is not uncommon for someone suffering a tramautic brain injury to have such fluid accumulation, caused when the brain bleeds or swells.
"Presure built up perhaps too quickly for the brain to accomodate," said Dr. Jonathan Fellus, who specializes in brain injury at the Kessler Institute for Rehabilitation in New Jersey. Fellus said that when left untreated, fluid could be deadly for brain injury patients.
Giffords' doctors are confident that she has passed the most critical period for complications and say that the fluid is not keeping Giffords from receiving three hours of physical therapy daily.
Still, it could be weeks before they determine whether the catheter to drain the fluid can be removed or if it is more serious, requiring a permanent shunt that would likely remain in place for the rest of her life. Until then, she will not be transferred to TIRR (The Insitute for Rehabilitation and Research), the nearby Houston facility that specializes in brain injuries.
"No one expects her to go rapidly to TIRR," trauma surgeon Dr. John Holcomb said. "We just have to wait and see if the fluid buildup issue resolves itself."
Holcomb said that the fluid buildup, which doesn't appear to be infected, was down a little on Saturday and that she was a little more alert and responsive.
Giffords was brought by a specially equipped private plane from Tucson to Houston's Hobby Airport Friday, and immediately was transported to the Texas Medical Center's intensive care unit by medical helicopter.
Before departing for Houston Friday morning, Giffords left the Tucson, Ariz., hospital where she had been treated since suffering a gunshot to her head in an attack two weeks ago. She was the last shooting victim to leave the hospital.
Cheered by crowds of well-wishers, Giffords, 40, was taken by ambulance to a nearby Air Force base where the private plane was ready to carry her to Texas.
Giffords was accompanied to Houston by her astronaut husband, Capt. Mark Kelly, her doctors, and her mother, Gloria Giffords.
Along her roughly 10-mile route to the Air Force base, crowds of supporters stood on the curb, cheering and waving flags and signs as her motorcade passed by. Giffords' ambulance was escorted by a squadron of military veterans on motorcycles.
"We could hear applause in the ambulance with Gabby, and she responded very well to that, smiling and even tearing a little bit," said Dr. Randall Friese, one of the doctors who treated Giffords in Tucson. "It was very emotional and very special."
At a press conference in Houston late Friday afternoon, Giffords' medical team said that the trip went flawlessly and that while she has a long road ahead, she has great potential for rehabilitation.
Now that her Tucson team has handed over responsibility for Giffords' care, they said their goodbyes and will return to Arizona.
"I'm going to miss her a lot," said Tracy Culbert, the nurse who cared for Giffords over the last two weeks in Tucson and accompanied her on the plane. "She's a very gentle person, and her personality is coming out with touches. ... I'm very lucky to know her."
Giffords' husband, Kelly, who lives in Houston, said Thursday that she soon would be "back at work" and predicted she would be walking around in a couple of weeks.
"I'm extremely hopeful that Gabby will make a full recovery," he said. "She is a fighter like nobody else I know."
In other signs of progress, Giffords was taken outside Thursday for the first time since the attack so she could get some sunlight. She stood up Wednesday for the first time with assistance and looked out of a hospital window.
Giffords already has been able to scroll through an iPad, one of many steps described by her doctors as "fantastic achievements forward."
The Associated Press contributed to this report.