How many coronavirus patients on ventilators survive? Scientists race for an answer
Scientists are racing to answer a fundamental question about death and the coronavirus that has driven President Donald Trump to promote an unproven drug cocktail for the critically ill.
Trump grew convinced earlier this month that it was worthwhile to experiment with hydroxychloroquine and azithromycin — two drugs that are approved for other uses, but remain untested on coronavirus patients — after asking his aides for the odds of survival on the most extreme measure of using a ventilator.
“One of the reasons that I keep talking about hydroxychloroquine is that the question that nobody ever asks, and the question that I most hate the answer to, is: ‘What happens if you do have a ventilator? What are your chances?’” Trump asked. “It’s not a very high percentage. So I want to keep them out of ventilators.”
But recent studies on mortality among ventilated patients reflect a far more nuanced picture.
Leading scientists in the field told McClatchy that research is ongoing among governments, hospitals and universities to better understand the true mortality rate for the most critically afflicted.
That number is currently unknown, said Albert Rizzo, chief medical officer for the American Lung Association.
“If you’re sick enough to be on a ventilator, you’re automatically in a critical situation,” Rizzo said in a phone interview. “The chances of you surviving that event are limited. But they’re not necessarily as limited as people are talking about.”
ONLY THE SICKEST GET VENTILATORS
In a controlled environment, scientists would collect the data necessary to answer Trump’s question by giving a ventilator to every patient who needs one, overseen by nurses and doctors trained to operate them and equipped with the personal protective equipment needed to use them.
The pandemic has defied their ability to collect this data in a controlled manner because of the chaos of dealing with shortages of equipment. Instead, scientists must account for several distorting variables.
In Washington state, where the first American outbreak unfolded outside of Seattle, the mortality rate for those on ventilators at the outset of the crisis was close to 100%.
But that was based on data from patients concentrated at a nursing facility, filled with elderly individuals with “comorbidities” – diseases or health defects unrelated to the coronavirus that made a patient’s success on the ventilator less likely.
Andrew Luks, a pulmonary and critical care physician and professor at the University of Washington School of Medicine, said the rate of success in Washington has increased since the disease began affecting a more representative portion of the wider population.
“The simple fact that you’re put on a ventilator does not mean that your outcome is going to be universally poor,” Luks said. “What the ventilator does is buy the body time to recover, and in particular, buys the lungs time to recover.”
Because coronavirus patients often require an extensive amount of time – seven days to four weeks, in some cases, to overcome the disease while on mechanical ventilation – survey data remains low only six weeks into the U.S. epidemic.
In China, however, where the virus has raged since December, a trend has appeared similar to what was witnessed in Washington state, in which early data painted a more dire picture than later, more comprehensive surveys.
One report examining cases from the first month of the outbreak in Hubei province found that 97% of critically ill patients on mechanical ventilation had died. Another early report found 81% mortality among ventilated individuals in Wuhan, where the coronavirus originated.
But a study released at the end of March by the Chinese government’s center for disease control and prevention found the mortality rate for COVID-19 patients admitted to intensive care units was far lower, between 49% and 61.5%, and that those who were provided with intubated ventilation may have received it too late to make a difference.
“The frontline physicians taking care of critically ill patients in Wuhan suggest that intubation and invasive ventilation may have been adversely delayed in some patients,” according to one medical analysis of the Chinese government report.
In Britain, the Intensive Care National Audit and Research Centre recently released its first tranche of data on mortality rates for patients with COVID-19, the disease caused by the novel coronavirus, admitted throughout the month of March to intensive care units, where most patients require forced oxygen for help breathing.
The audit found that 79% of critical COVID-19 patients who had entered ICUs were still there fighting off the disease after weeks of breathing through mechanical ventilation.
“I’ve heard 85 percent do not survive, but I’ve also heard 55 percent do survive,” Rizzo said. “It’s hard to put a number on it.”
The Chinese and British data suggest the survival rate could ultimately be on par with other forms of acute respiratory distress syndrome (ARDS), in which patients need the help of mechanical ventilation because they are unable to breathe on their own.
Mortality rates remain high where the outbreak is first peaking in the United States. Doctors in New York City, the center of the U.S. epidemic, have said that roughly 80% of coronavirus patients on ventilators have died.
But that may be due to public health policy more than the disease itself.
“If you have a higher threshold to put someone on a ventilator, it’ll look like a less successful intervention because you’re only putting the sickest on ventilators,” said Jason Poston, a pulmonary and critical care physician and professor at the University of Chicago. “And the ventilators may be more or less the same from one location to the next, but the context in which they’re used is different from one place to the next.”
Shortages of trained staff, personal protective equipment, and ventilators all factor into a hospital’s decision to set a threshold for who receives ventilation and who does not.
The greater the shortages faced by a hospital, Poston notes, the more likely that hospital is going to reserve its ventilators for patients entering the ICU at a late stage of need, already suffering from respiratory failure or cardiac arrest. That, in turn, is likely to result in an inflated mortality rate.
The White House declined to comment.
‘THERE’S RISK’
In early April, reports began to emerge of doctors across the country questioning whether ventilators were actually doing more harm than good for coronavirus patients — possibly leading to higher death tolls.
At the University of Chicago, where some of the nation’s leading medical experts are deploying helmet ventilation to avoid the adverse effects of more traditional, invasive procedures, Poston said that forced air from traditional ventilators has “repeatedly demonstrated to harm the lungs” among ARDS patients.
“We’ve known for many decades that mechanical intervention is not a benign intervention. There’s risk when it’s introduced,” Poston said. “One of our operating principles is to do everything we can to keep people off the ventilator.”
Rizzo, of the American Lung Association, said that some pulmonologists performing ventilation on coronavirus patients had been assuming that COVID-19 would have the same effect as ARDS in stiffening a patient’s lungs — a process that makes it harder for that patient to breathe, but also makes the lungs more durable to ventilation.
“This COVID-19 infection may not be leading to that stiff lung, and therefore the patient may not necessarily need high-flow, high-pressure ventilators,” Rizzo said. “Ventilation may still be necessary, because you’re dealing with patients who may be very weak and may still need help breathing, but just with less pressure.”
The Trump administration on Tuesday announced a ventilator loan program called the Dynamic Ventilator Reserve that aims to make 60,000 ventilators in hospitals around the country available to other hospitals when they are needed most. The unused ventilators will be managed by the nation’s major health care systems in a public-private partnership, the White House said.
At an event announcing the loan program, Trump said his administration had commissioned the production of “high quality” ventilators.
“I was told it makes a big difference, the level of quality of ventilator,” he said. “They’re obviously more expensive. More detail, harder to build, but I hear they are more effective quite a bit.”
Medical experts are continuing to experiment with different tactics in real time, trying less invasive ways to provide patients with oxygen before turning to ventilators increasingly in short supply.
Questions over the precise effects of ventilation underscore how little is yet known about the novel coronavirus.
But doctors say that one new factor could drastically change the numbers. The sooner a proven, therapeutic medicine is identified, approved and brought to market, the greater the chance doctors will have of alleviating the worst symptoms faced by COVID-19 patients, eliminating the need for ventilation.
Trump has repeatedly advocated hydroxychloroquine — a drug that has been approved by the Food and Drug Administration to treat malaria, but has not gone through clinical trials to test its impacts on coronavirus patients — as a potential treatment, citing anecdotal reports of success.
“I’m not a doctor — I’m just saying, we hear great results,” Trump said earlier this month when discussing the drug.
Despite questioning the effectiveness of ventilators on the critically ill, the president has repeatedly emphasized the important role ventilators serve throughout the crisis.
“The scariest day of my life was about a month ago when, after a long day of meetings, my team told me that we were going to be needing 130,000 ventilators,” Trump told reporters Tuesday in the White House Rose Garden. “Due to our early and aggressive action, the skill of our healthcare workers, and the resilience of our healthcare system, no hospital in America has been forced to deny any patient access to a ventilator.”
But Trump’s focus on a drug cocktail that has not been proven to help COVID-19 patients — or to help mitigate the use of ventilation — has put him at odds with the scientists on his team.
Medical experts on the White House coronavirus task force say that randomized trials must take place before the drug is officially approved for use on COVID-19 patients.
And scientists at the National Institutes of Health and in the U.S. Army have said that hydroxychloroquine is only one of over 100 possible therapeutics under scrutiny.
“Ideally, what is happening now is, we are buying time for patients with these ventilators,” said Luks. “But even if the survival rate is low, that in and of itself is not a justification for using a medication that right now has no evidence in its treatment of COVID-19.”
This story was originally published April 15, 2020 at 11:06 AM.
