What’s the Difference Between a Ventilator and a CPAP Machine?

Ventilators have been the subject of many news headlines recently, recognized as the last line of life-saving defense against the novel coronavirus. Before the outbreak of COVID-19, hospitals in the United States had a median of about 20 ventilators per 100,000 people, according to a 2018 survey conducted by the NCBI. That’s enough to serve patients on a regular basis, but with the coronavirus relentlessly attacking people’s respiratory symptoms, there aren’t nearly enough to go around.


Ventilators essentially “breathe” for people who aren’t able to do so on their own. The machine gets oxygen into the lungs, and then takes out the carbon dioxide from inside.

Lungs have blood vessels interwoven throughout, which carry oxygen into the blood stream, and expel carbon dioxide. COVID-19 causes lungs to become inflamed, and often they fill with fluid, which makes the exchange of oxygen and carbon dioxide difficult or impossible.

To hook a ventilator up to a patient, a ten-inch long tube is placed into a patient’s mouth or nose, and intubated through the windpipe, and a pump on the ventilators blows air and oxygen into the lungs. Some patients need a tracheostomy, where a hole is surgically cut in the trachea, and a tube is inserted into the lungs through that hole.

Ventilators allow healthcare providers to perfectly adjust the volume of oxygen supplied, and the amount of pressure needed, so doctors can analyze whether a patient is getting better or worse.

The trouble is, ventilators don’t do anything to cure patients; they simply aid in crucial lung function, keeping patients alive until doctors can cure the underlying illness or issue.


Continuous Positive Airway Pressure (CPAP) Machines work by forcing pressurized air through the airway to keep it open and free from obstruction. It’s typically used to assist with obstructive sleep apnea, a disorder that causes breathing to repeatedly pause during sleep. That occurs when a person’s throat muscles relax, and block the airway during sleep. Many people with sleep apnea snore, and can occasionally awake gasping or choking.

Man with sleep apnea and CPAP machine

Similar to the at-home ventilators, CPAP machines have masks that cover either your nose and mouth or solely your nose. Over time, the machine can lower blood pressure, reduce heart problems, and, of course, make sure you get a better night’s rest. The machine does have some minor side effects, like increased nightmares, abdominal bloating, irritation of the skin, nasal congestion, or dry nose and sore throat.

Using CPAP Machines Instead of Ventilators

As doctors and patients worldwide try to fend off panic over the lack of ventilators, governments and companies alike are scrambling to create alternatives. In the United States, emergency plans have developed for hospitals to use CPAP machines when ventilators are not available.

There’s a big problem, though: scientists say devices like the CPAP that use masks have the potential to aid the spread of infectious disease by aerosolizing the virus. Doctors in Washington state believe that may have contributed to an outbreak at a nursing home there, where residents were treated with CPAP machines before doctors realized the patients had COVID-19.

The American Society of Anesthesiologists warned against that very issue, saying CPAP machines may increase the risk of infectious transmission, and so patients with acute respiratory failure should always be intubated (using a ventilator) rather than trying out a CPAP.

Another issue is that while ventilators allow doctors to fine-tune the treatment, CPAP machines provide constant pressure and continuous air flow.

There are machines called Bilevel Continuous Positive Airway Pressure Machines, or BiPAPs, which push air in and then lower the pressure so the carbon dioxide can be exhaled. Those can function like ventilators, but don’t get past the issue of the face mask creating aerosols.

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