A ventilator can help patients unable to breathe on their own, but the
experience of COVID-19 patients has been sobering for doctors. Taechit
Taechamanodom/Getty Images
Most coronavirus patients
who end up on ventilators go on to die, according to several small studies from
the U.S., China and Europe.
And many of the patients
who continue to live can't be taken off the mechanical breathing machines.
"It's very concerning
to see how many patients who require ventilation do not make it out of the
hospital," says Dr. Tiffany Osborn, a critical care specialist at
Washington University in St. Louis who has been caring for coronavirus patients
at Barnes-Jewish Hospital.
That concern is echoed
by Negin Hajizadeh, a pulmonary critical care doctor at the Donald and
Barbara Zucker School of Medicine at Hofstra/Northwell on Long Island, N.Y.
"We have had several
patients between the hospitals across the Northwell system that have come off
the breathing machine," Hajizadeh says. "But the vast majority are
unable to."
The largest study so far to
look at mortality among coronavirus patients on ventilators was done by the
Intensive Care National Audit & Research Centre in London.
It found that among 98 ventilated patients in the U.K., just 33 were
discharged alive.
The numbers from
a study of Wuhan, China, are even grimmer. Only 3 of 22 ventilated
patients survived.
And a study of 18
ventilated patients in Washington state found that nine were still
alive when the study ended, but only six had recovered enough to breathe on
their own.
All the early research
suggests that once coronavirus patients are placed on a ventilator, they will
probably need to stay on it for weeks. And the longer patients remain on a
breathing machine, the more likely they are to die.
"We're not sure how
much help ventilators are going to be," Osborn says. "They may help
keep somebody alive in the short term. We're not sure if it's going to help keep
someone alive in the long term."
Patients need a ventilator
when their lungs can no longer deliver enough oxygen to keep the body going.
And it's an extreme measure, Osborn says.
"We give sedation so
the person goes to sleep. Then we provide a paralytic that stops their
breathing," she says.
Next, a long plastic tube
is inserted through the trachea and vocal cords. That allows a machine to
deliver small puffs of highly oxygenated air to the lungs.
Unfortunately, Osborn says,
"the ventilator itself can do damage to the lung tissue based on how much
pressure is required to help oxygen get processed by the lungs."
And coronavirus patients
often need dangerously high levels of both pressure and oxygen because their
lungs have so much inflammation.
Another risk from being on
a ventilator is that the tube carrying air and extra oxygen to the lungs
provides a pathway for dangerous germs. Many ventilated patients get a new lung
infection, a problem known as ventilator-associated pneumonia.
Ventilators have been seen
as critical to treating coronavirus patients because the devices are very
successful when used to treat common forms of pneumonia, says Hajizadeh.
A ventilator alongside medical supplies and a stretcher is displayed
before a news conference at the Javits Center in New York City on March 23. John
Minchillo/AP
"We treat patients for
several days, and then we get the antibiotics into the body and the patient
recovers," she says. "Unfortunately with this COVID-associated
pneumonia, there are no treatments that we know work for sure."
Also, the coronavirus often
does a lot more damage to a person's lungs than pneumonia associated with the
flu. "There is fluid and other toxic chemicals, cytokines we
call them, raging throughout the lung tissue," she says.
In some patients, the
damage is so bad that even ventilation won't help. So doctors have sometimes
tried an even more extreme measure called extracorporeal membrane
oxygenation, or ECMO, which delivers oxygen directly to a patient's
bloodstream.
But this is still a stopgap
measure. "Remember, ECMO too is a life-supporting treatment,"
Hajizadeh says. "So it's a bridge while we are allowing the lung to heal
itself from a pneumonia."
But lungs don't always heal,
no matter how much help they get from a machine, Osborn says. So people need to
be diligent about social distancing to keep the virus from spreading.
"I know that at times
it gets frustrating," she says. "But it's really important not only
for yourself and your family but for the other people you care about to shelter
in place until this is over."
Osborn should know. When
she's not caring for patients at the hospital, she's living in a camper to
avoid putting her family at risk.
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