Transcript for Doctors test rare treatment on COVID-19 patients
And as we come on tonight, a new and grim milestone in this country. The number of deaths has now topped 16,000. And in New York state, more cases than any other country in the world outside the U.S. And we did learn today of new research indicating just when the virus might have arrived here in New York City, here for weeks before the first reported cases. We're going to drill down on that in just a moment here. The death toll tonight in this country, more than 16,000 people in the U.S. It's staggering when you think about these numbers. More than 7,000 lives lost in New York state alone. Scientists have long pointed out that the death toll often lags behind the surge. Patients in the hospital, of course, for days or weeks, then dying from this. You can see that death toll right there in New York steadily rising and those new highs three days in a row. But I wanted to show you something else tonight, because there is a glimmer of hope. Look at this. Also from New York state, and it shows the rate of increase of new cases in the state steadily falling in recent days. Of course, let's hope that holds and that it will eventually be reflected in the death rate. We can hope. Scientists say this shows that the social distancing is working. Tonight here, we're going to take you inside a New York City hospital where doctors are using a rare treatment to save the lives of patients in their 30s and 40s when ventilators simply aren't enough. And the threat now spreading to new hot spots including new York's Long Island. Staff at sonybrook hospital cheering as a convey of nurses from elsewhere arrived today. Emergencies tonight in Philadelphia, Baltimore, Washington, D.C. And parts of Louisiana. In Detroit and south Florida. And the heartbreaking images in so many places across America tonight. The long lines for food. The new unemployment numbers out tonight, more than 16 million Americans now out of work, needing help. When will the checks arrive? And will millions of Americans have to be tested for antibodies, will that be one way to help get this country back working, back to some sort of what Dr. Anthony Fauci said about this today. And we begin tonight with ABC's whit Johnson here in New York. Reporter: Tonight, the battle to save lives growing more desperate. Making considerably more progress. Reporter: Inside this icu, at maimonides hospital in Brooklyn, doctors deploying a rare treatment on covid patients in their 30s and 40s still failing on ventilators. In this current epidemic, it's used as a last resort when ventilators are not enough. Reporter: Heart surgeon Dr. Paul Saunders, a covid survivor himself, performing "Ecmo", temporarily drawing blood out of the body to help oxygenate red blood cells in patients whose lungs aren't functioning. With such limited resources, we have to be very careful as to who we're going to offer this to. And making sure those patients are ones that really have a good chance of a good benefit. Reporter: Emotions running high for nurse Mary Kate Funaro. Working in the same icu where her father, a doctor, was being treated for the virus. He's now back home, feeling better. Unfortunately I was not able to go inside his room, didn't want to cross contaminate. Between other covid-19 patients and him. So I waved to him from outside the glass. Reporter: But in New York state, the death toll reaching new heights by the day. Coronavirus killing nearly 800 people in just 24 hours. We've lost over 7,000 lives to this crisis. That is so shocking and painful and breathtaking, I don't even have the words for it. Reporter: Overwhelmed hospitals scrambling this week to move patients to facilities with more room, stacking some patients on bunks in large trucks to be transported. The virus surging in New York's suburbs. In suffolk county, Long Island, covid-19 claiming the lives of two nurses. Construction of a 1,000-bed field hospital now under way. Today, dozens of nurses from upstate arriving to help. New research now suggests the virus was circulating in the new York area by mid-february, weeks before the first confirmed case. Researchers suspect that travelers brought it mainly from Europe, not Asia. New York was seeded before they really knew what was going on, and that's why they're in the difficult situation that they're in right now. Reporter: Back in early March, we heard from Americans who said they weren't screened on their way back from Italy, a growing hot zone at the time. As of right now, we have not experienced any sort of extra check based on anything regarding the coronavirus. Reporter: Tonight, the government is taking its first step toward getting more Americans back to work. The CDC issuing new guidelines for essential workers who have been exposed to the virus. But are asymptomatic, like temperature checks before shifts. Wearing face masks. And practicing social distancing at work. The pandemic still sweeping across the country. In Illinois, the death toll topping 500. The virus exploding behind bars of the cook county jail in Chicago. At least 350 inmates and staff infected. Most of the inmates haven't been tested. And a devastating toll for nursing home residents. In New York state, more than 1,200 dead and thousands infected. At one home in Richmond, Virginia, 39 residents have died from the virus, now the deadliest known outbreak in the country. It appears that it's a death trap. It appears that way. In the sense that we can't see him, we can't go and take him out. Reporter: Don't, tonight, doctors are closely watching cases in D.C., Baltimore and Philadelphia, where Mike and Kelly dewan saw first-hand how quickly the virus spreads. Within days of a birthday dinner for his daughters, ten members of the family were sick. The entire family, grandparents too. But Mike deteriorated quickly. Labored breathing. Like, I can't get a deep breath, I can't breathe. Reporter: After 17 days on a ventilator and that experimental ebola drug, Mike woke up and is now recovering. I think about it every day. Reporter: And a special day for Paul Saunders, that doctor in Brooklyn we just met today. His colleagues greeting him with cheers. His first full day back in the icu, after defeating coronavirus himself, now continuing the fight to save others. Thank you very much. Totally unexpected and undeserved. He said that was unexpected, undeserved but we all know it is very deserving. They applauded him and continue to do so even after he said that. A powerful moment today. Whit Johnson with us from mt. Sinai hospital tonight. And I know a battle for those doctors every day. But New York is really siege some glilers of home tonight. The rate of hospitalizations also slowing. Reporter: David, the number of hospitalizations is beginning to flatten considerably, so, they want to see that trend continue and then decline, a sign that New York state could be nearing its apex, but as you mentioned earlier, that painful death rate still very high, officials are hoping that will soon come down, as well. David? All right, whit Johnson leading us off tonight. Thank you.
This transcript has been automatically generated and may not be 100% accurate.