Transcript for Las Vegas hospitals were inundated with victims of mass shooting

the limits tonight the mgm resorts owner of the mandalay and other hotels offering help to guests and employees. But they also tweeted this today, saying we are in need of certified trauma kocounselors. And after an urgent call for blood donors, hundreds showing up to help. But even at one hospital here in Las Vegas tonight, they reported that at least 14 of the victims were brought there for help, died after arriving at the E.R. It is incredible scene unfolding here tonight, and ABC's linsey Davis is outside university medicalcenter in Las Vegas. Reporter: Tonight, the race to treat the injured. Shots fired from mandalay bay, there's many people down. Reporter: Concert-goers became first responders overnight, pushing the wounded any way they could to get them help. So many rushed to area hospitals. It was non-stop surgery after surgery until 4:30 or 5:00 this morning. Reporter: Hospitals and doctors overwhelmed with hundreds of patients. We brought extra trauma surgeons, extra critical care nurses, extra, even, you know, evs folks to make sure we were keeping our trauma center clean to be able to move our patients through quickly. Reporter: Nevada's governor today made an urgent plea. We need blood. So if anybody can contribute blood. Reporter: And now, so many are responding to his call. I heard this happened, the least I could do, give me blood and I'm o-negative, so, my blood is actually the universal giver. Reporter: Some reportedly waiting up to five hours to donate. You can see -- I don't even know if you can see how far this line goes. It is incredible. Linsey Davis joins us tonight. And some of the doctors we learned had just received some training that proved critical in their response here? Reporter: That's right, David. Many of those doctors recently had just undergone training with a physician who was on-call in Orlando the night of the pulse nightclub shooting and he was able to share with them what worked and what they could have done better. David? Linsey Davis live here in lhlas Vegas tonight.

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