Trauma specialist Dr. Peter Rhee, right, speaks during a press conference Sunday morning at UMC about Rep. Gabrielle Giffords. At left is Chief of Neurosurgery Dr. Michael Lemole, who also operated on Giffords. Dean Knuth/Arizona Daily Star

Rep. Gabrielle Giffords was in surgery within 38 minutes of arriving at University Medical Center with a gunshot "devastating wound" to the head that required the removal of half her skull, doctors said at a news conference this morning.

Doctors said Giffords is sedated and remains in critical condition, though she is responding to simple commands. She is in a medically-induced coma and doctors called her medical condition ‘very precarious,' but said they remain cautiously optimistic about her prognosis.

Giffords was shot on the left side of the head and the bullet traveled from the back to the front, said Dr. G. Michael Lemole Jr., one of the neurosurgeons who operated on Giffords. The left side of the brain controls speech and right side strength on most people..

Giffords remained on a ventilator today. He said her eyes are swollen shut.

While doctors said Giffords was responsive they were cautious of overstating her condition, saying several times she was in critical condition.

Lemole says surgeons worked to reduce pressure from swelling in the brain by removing bone fragments.

Giffords was shot by a gunman on Saturday as she met with constituents outside a grocery store.

Six others were killed, and 14 wounded, including the congresswoman.

Dr. Peter M. Rhee said he expects to have a better idea about Giffords' prognosis in the next few days.

Doctors credited several reasons for her survival, including good luck and the fact that paramedics got her to surgeons quickly.

"This is about as good as it is going to get," said Dr. Peter Rhee, a trauma surgeon. "When you get shot in the head and the bullet goes through your brain, the chances of you living is very small and the chances of you waking up and actually following commands is even much smaller than that. Hopefully it will stay that way."