LAS VEGAS (REUTERS) - When Dr Jay Coates pulled up to work at the University Medical Center of Southern Nevada on Sunday night (Oct 1), the surrounding streets already were cordoned off and ambulances filled with shooting victims lined the driveway.
Inside the trauma centre, staff worked to evaluate and treat dozens of patients with high-velocity bullet wounds - victims of the deadliest mass shooting in modern US history.
"It was like a war zone," said Coates, one of two senior surgeons who worked on Sunday night duty as the city's emergency personnel struggled to keep up with the flood of victims. "We were just trying to keep people from dying."
The fusillade of bullets fired by a lone gunman from the Mandalay Bay hotel into a crowd of 22,000 at a country music festival killed at least 59 people and sent more than 500 to area hospitals, severely straining the city's emergency response system and putting the hospitals into overdrive.
At University Medical Centre, the state's only level-one trauma centre - which means it is staffed around the clock with surgeons and trauma nurses and personnel - virtually every available employee hustled back to work to be confronted with unimaginable carnage.
Toni Mullan, a clinical nursing supervisor for the trauma unit, had just gotten home after a 12-hour shift when she was called back.
"Chaos, that's what I saw," she said of her arrival.
Coates said that by the time he reached the centre there were already more than 70 medical staff at work, and eight or nine surgeons helped evaluate patients to determine who was most in need of surgery.
The most critically wounded sometimes had up to 20 people around their bed working on them.
"It was a trauma bay full of at least 70 people and patients stacked everywhere. It was controlled chaos," Coates said. "At one time we had eight operating rooms going at the same time."
The trauma centre had received 104 patients by early afternoon on Monday, most suffering gunshot wounds.
"It was all hands on deck. Word travelled very fast," spokesman Danita Cohen said.
Last year, the trauma centre had a training drill in which staff practised receiving patients after a fictional mass shooting at a concert.
"This is what we do, we were prepared for this," Mullan said.
Across town, the scene at Sunrise Hospital was similar. "I have never seen a scene like the one I just saw this morning," US Representative Ruben Kihuen of Nevada, whose district includes parts of the Las Vegas area, told NPR after visiting Sunrise.
"There were about 190 people taking up every single bed possible, every single room possible, every single hallway possible," Kihuen said. "Every single nurse, every single doctor from all over the city came and are assisting a lot of these victims."
Friends and relatives searched frantically for news on the injured, but the sheer volume of patients slowed the process. At Sunrise, Kihuen said, more than 90 of the 190 patients had no identification.
Las Vegas police urged family members not to flood local hospitals in search of the missing, and telephone hotlines were set up to help locate missing loved ones.
Police asked those wanting to donate blood not to go to the hospitals, because the staff were overwhelmed with patients, and referred them to several area clinics.
Paul Hwangpo, a Las Vegas Uber driver, said he had spent the day ferrying tourists and residents to the clinics to give blood. One had a six-hour wait, the other four hours, he said.
Mullan said that emotionally the most difficult moments were when it came time to fill out paperwork for patients she knew only as Jane or John Doe.
"When we have families coming up looking for loved ones...that's overwhelming. I'm human. I cry. I'm sad for the loss," she said.
But Mullan said she was proud of the way hospital staff had responded. "I've been a nurse for 30 years, and on the most tragic moment I've ever been involved in I was most proud to be a nurse," she said.