WEDNESDAY, April 15, 2020 (HealthDay News) -- Mechanical ventilators have become a symbol of the COVID-19 pandemic, representing the last best hope to survive for people who can no longer draw a life-sustaining breath.
But the ventilator also marks a crisis point in a patient's COVID-19 course, and questions are now being raised as to whether the machines can cause harm, too.
Many who go on a ventilator die, and those who survive likely will face ongoing breathing problems caused by either the machine or the damage done by the virus.
The problem is that the longer people are on ventilation, the more likely they are to suffer complications related to machine-assisted breathing.
Recognizing this, some intensive care units have started to delay putting a COVID-19 patient on a ventilator to the last possible moment, when it is truly a life-or-death decision, said Dr. Udit Chaddha, an interventional pulmonologist with Mount Sinai Hospital in New York City.
"There had been a tendency earlier on in the crisis for people to put patients on ventilators early, because patients were deteriorating very quickly," Chaddha said. "That is something that most of us have stepped away from doing.
"We let these patients tolerate a little more hypoxia [oxygen deficiency]. We give them more oxygen. We don't intubate them until they are truly in respiratory distress," Chaddha said. "If you do this correctly, if you put somebody on the ventilator when they need to be put on the ventilator and not prematurely, then the ventilator is the only option."
Experts estimate that between 40% and 50% of patients die after going on ventilation, regardless of the underlying illness, Chaddha said.
It's too early to say if this is higher with COVID-19 patients, although some regions like New York report as many as 80% of people infected with the virus die after being placed on ventilation.
These critically ill patients die because they are so sick from COVID-19 that they needed a ventilator to remain alive, not because the ventilator fatally harms them, said Dr. Hassan Khouli, chair of critical care medicine at Cleveland Clinic.
"I think for the most part it's not related to the ventilator," Khouli said. "They're dying on the ventilator and not necessarily dying because of being on a ventilator."
'People don't come back from that'
However, mechanical ventilators do cause a wide range of side effects. Those complications, combined with lung damage from COVID-19, can make recovery a long and arduous process, Chaddha and Khouli said.
New York City lawyer and legal blogger David Lat spent six days on a ventilator last month, in critical condition at NYU Langone Medical Center after he was diagnosed with COVID-19.
"This terrified me," Lat wrote in an opinion piece in the Washington Post. "A few days earlier, after my admission to the hospital, my physician father had warned me: 'You better not get put on a ventilator. People don't come back from that.'"
Lat survived, and he thanks the ventilator -- but he also is struggling to recover his ability to breathe.
"I experience breathlessness from even mild exertion," Lat wrote. "I used to run marathons; now I can't walk across a room or up a flight of stairs without getting winded. I can't go around the block for fresh air unless my husband pushes me in a wheelchair."
Mechanical ventilators push air into the lungs of crucially ill patients. The patients must be sedated and have a tube stuck into their throat.
Because a machine is breathing for them, patients often experience a weakening of their diaphragm and all the other muscles involved with drawing breath, Chaddha said.
"When all these muscles become weaker, it becomes more difficult for you to breathe on your own when you're ready to be liberated from the ventilator," Chaddha said.
Precise measurements needed
These patients also are at risk of ventilator-associated acute lung injury, a condition caused by overinflating the lungs during mechanical ventilation, Khouli said.
Doctors have to precisely calculate the amount of air to push into a person's lungs with every mechanical breath, taking into account the fact that a large part of the lung could be full of fluid and incapable of inflation. "The amount of volume you need to deliver would be usually less," Khouli said.
"If the settings are not managed correctly, it can cause an additional trauma to the lungs," Khouli said.
Ventilated patients also are at increased risk of infection, and many are at risk of psychological complications, Chaddha said. A quarter develop post-traumatic stress disorder, and as many as half might suffer subsequent depression.
"It is not a benign thing," Chaddha said. "There are a lot of side effects. And the longer they are on a ventilator, the more likely these complications are to happen."
That's why ICUs are becoming more cautious in their use of ventilation, using oxygen and breathing dilators like nitric oxide to keep people drawing their own breath for as long as possible.
"The ventilator is not a drug. The ventilator is just supporting the body while the body deals with the inflammation caused by the infection," Chaddha said. "You can't say you're putting someone on a ventilator and you expect them to improve the next day. That's not the case."
The U.S. National Heart, Lung, and Blood Institute has more about ventilator support.
SOURCES: Udit Chaddha, M.B.B.S., interventional pulmonologist, Mount Sinai Hospital, New York City; Hassan Khouli, M.D., chair, critical care medicine, Cleveland Clinic, Ohio; Washington Post