"Trauma care is optimism translated into action," said Dr. Russell Nauta, chairman of surgery at Mount Auburn Hospital in Cambridge, Mass., where the wounded transit police officer, Richard Donohue, remains in stable but critical condition.
Doctors and emergency responders approach each patient as someone who can be saved regardless of how severe the injuries appear.
And some were very bad.
"The legs came hanging on muscles and skin," said Velmahos, who did three of the four initial amputations at Massachusetts General in the early hours after the bombing. A fifth patient at the hospital had to have an amputation Thursday. Doctors had judged there was a 5 percent chance the woman's leg could be saved, so they didn't amputate right away.
"We restored the blood supply to the leg, but all the muscles and nerves were destroyed," so the leg had to be removed, he explained.
Of the remaining five patients at the hospital with severe leg injuries, "I'm very confident that they will all keep their legs, and even more, that they will have functional legs," he said.
Although doctors are optimistic, some patients still have life-threatening wounds. Complications can range from blood clots to infections. A few still have injuries that could require amputation, said Dr. Michael Yaffe, a trauma surgeon at Beth Israel.
"We have to see how these are going to heal" over the next few weeks, he said. "Blood supply is key .<!p>.<!p>. The two biggest enemies we will face in the next two weeks are maintaining a good blood supply and preventing infection."
So far, the progress has been in the right direction.
"Every day they're a little better," Yaffe said. "A lot of them have a long road of recovery ahead."