New York City emergency-medicine physician Dr. Cameron Kyle-Sidell sparked controversy when, two weeks ago, he posted a YouTube video claiming that ventilators may be harming COVID-19 patients more than they’re helping.

“We are operating under a medical paradigm that is untrue,” Kyle-Sidell warned. “I believe we are treating the wrong disease, and I fear that this misguided treatment will lead to a tremendous amount of harm to a great number of people in a very short time.”

Weeks later, claims from Kyle-Sidell and like-minded doctors continue to spark impassioned debate within the medical community, with some doctors moving away from the use of ventilators and others defending the current standard of care. What’s clear, though, is COVID-19 patients on ventilators aren’t doing as well as doctors would hope—and health care experts are scrambling to fix it.

Mechanical ventilation always comes with risks: a tube must be placed into a patient’s airway to deliver oxygen to their body when their lungs no longer can. It’s an invasive form of support, and most doctors view it as a last resort. Under the best of circumstances, up to half of patients sick enough to require this type of ventilation won’t make it.

But for COVID-19, the numbers are even worse. Only a small portion of COVID-19 patients get sick enough to require ventilation—but for the unlucky few who do, data out of China and New York City suggest upward of 80% do not recover. A U.K. report put the number only slightly lower, at 66%.

Doctors like Kyle-Sidell (who TIME could not reach for comment) argue these numbers are so high because physicians are ventilating patients as though they have a condition called acute respiratory distress syndrome (ARDS), when they in fact have a different type of lung damage that may not respond well to mechanical ventilation. A group of European physicians submitted a letter to the American Journal of Respiratory and Critical Care Medicine, published March 30, detailing COVID-19’s discrepancies from typical ARDS and calling on doctors to avoid jumping to unnecessary mechanical ventilation. Other physicians say mechanical ventilation can help some patients, but doctors are jumping to it too quickly, potentially subjecting patients to unnecessary traumatic treatment when they could use less-invasive respiratory supports like breathing masks and nasal tubes.

But Dr. David Hill, a pulmonary and critical care physician who treats COVID-19 patients in Waterbury, Conn. and serves as a volunteer medical spokesperson for the American Lung Association, says arguments against COVID-19 ventilation have been over-simplified. It may be less that ventilators aren’t the proper treatment for coronavirus, and more that they’re not a panacea for a pandemic that has pushed the health care system to its breaking point, Hill argues.

“You have really sick people, [while] the people who have the best training are in short supply and ventilator management is not simple,” Hill says. If a dedicated lung specialist were available for each patient, he believes, outcomes would probably be better. They could make the subtle adjustments required for effective long-term ventilation, or try less-invasive options and only move to intubation when absolutely necessary. But with many hospitals nearly at capacity, last resorts can become first resorts.

High ventilator mortality rates in New York City suggest “a health care system failing, and not a ventilator hurting people,” Hill says. (He says telehealth consultations with pulmonology experts could provide stop-gap support for emergency-room doctors.)

Few doctors are saying COVID-19 patients should never be ventilated, but there is a growing subset that thinks it’s happening too quickly. Dr. Nicholas Hill (no relation to Dr. David Hill), chief of pulmonary, critical care and sleep medicine at Tufts Medical Center in Boston and a past president of the American Thoracic Society, says he’s avoiding mechanical ventilation when he can, and finding success with some non-invasive options like flipping patients onto their stomachs, which can trigger better blood flow to the lungs.

He says some doctors are intubating early because they fear that less-intensive forms of ventilation, like high-flow nasal oxygen, can aerosolize a virus, putting health care workers at risk of getting sick. “This is more theoretical fear than a real fear,” Hill says, since there’s not strong evidence that COVID-19 spreads this way.

Tufts’ Hill also points out that patients sick enough to require intubation tend to be those who are older and have underlying conditions. These patients are not only the most likely to experience COVID-19 complications, but also the least likely to do well on an invasive form of support. “That raises the question of whether we should think more about intubating a patient who is very unlikely to do well on a breathing machine,” he says.

Then there’s the issue of how to treat patients who do end up on ventilators. Tufts’ Hill agrees that COVID-19 patients do not behave exactly like they have ARDS, a type of respiratory distress that occurs when fluid builds up in the lungs’ air sacs. The lungs usually get stiff when a patient has ARDS, requiring high-pressure ventilation to support them. But that’s not happening with many COVID-19 patients, Hill says, leading some doctors to fear that the extra pressure is actually damaging the lungs.

Even stranger, some COVID-19 patients who show very low blood oxygen levels still appear to be breathing fairly comfortably, raising even more questions about how much support they need.

Dr. Ken Lyn-Kew, a pulmonologist at National Jewish Health in Colorado, agrees that there are some differences between classic ARDS and COVID-19, but he emphasizes that there’s a lot of variation among COVID-19 patients he’s treated. He says most still meet the criteria for an ARDS diagnosis. In his view, coronavirus patients likely have ARDS plus other issues, but they still have ARDS. With so much unknown, and with treatment protocols being updated on the fly, he thinks it’s too soon for doctors to go off-book and avoid conventional protocols like mechanical ventilation.

“The world is not a dichotomous, black-and-white place, but a lot of people are having trouble with that,” Lyn-Kew says. “We might be able to do better, but in the absence of data on the way to do that, we need to follow our societal guidelines and 25 years of research.”

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Write to Jamie Ducharme at jamie.ducharme@time.com.