What are ventilators and how long do coronavirus patients need to stay on them?

Hospitals around the world are trying to obtain more ventilators as the coronavirus pandemic spreads, media outlets reported.

Part of the reason, said New York Gov. Andrew Cuomo, is that coronavirus patients are being hooked up to the breathing machines for up to 21 days, CNN reported.

Most coronavirus patients are usually on ventilators for one to two weeks, Dr. Joshua Denson, a pulmonary medicine and critical care physician, told NBC News.

That’s why Cuomo is stockpiling ventilators, saying the worst is yet to come in New York City, which has more than 25,000 confirmed cases and more than 350 deaths as of Friday evening.

To help provide more ventilators to hospitals, President Donald Trump on Friday invoked the Defense Production Act, requiring General Motors to begin production on the ventilators, according to Politico.

Trump has previously said he doesn’t “believe” Cuomo needs as many ventilators as he has requested, The New York Times reported.

“I don’t believe you need 40,000 or 30,000 ventilators,” Trump said, according to The New York Times. “You know, you’re going to major hospitals sometimes, they’ll have two ventilators. And now, all of a sudden, they’re saying, can we order 30,000 ventilators?”

Coronavirus can damage air sacs in the lungs and doctors decide to put patients on ventilators when their “lungs are so damaged that a patient is not getting enough oxygen,” The New York Times reported.

A ventilator supports people with respiratory conditions by helping them breathe, The Guardian reported. Doctors will look for “respiratory failure” signs before putting someone on a ventilator.

“The breathing rate will increase, they’ll look distressed, the CO2 in the blood goes up and they can become sedated and confused,” David Story, deputy director of the University of Melbourne’s Centre for Integrated Critical Care, told The Guardian.

Ventilators help by pumping air into the patients’ lungs through a tube that has been inserted into their windpipes, according to NBC News.

The American Thoracic Society says the time patients -- not just those with COVID-19 -- may need be on ventilators could be a few hours or days, while others may need the breathing assistance for longer, without specifying time.

Eighty percent of people don’t require hospitalization when they get the coronavirus, according to NBC News. Of the 20 percent who are hospitalized, 13.8 percent of people had “severe disease” and 6.1 percent had “critical illness, including respiratory failure.”