What is a ventilator and how does it work?
Ventilators are an essential part of treating severe cases of COVID-19 — when it's life or death
As COVID-19 cases continue to rise, and with no end to the pandemic in sight, questions about life-saving ventilators abound.
The coronavirus that causes the illness binds to receptors on cells in a person's airway and lungs, and in severe cases, it's the respiratory system that will struggle to do its job oxygenating a patient's blood.
It's in those cases that a ventilator can make the difference between life or death.
But what is a ventilator, exactly? How does it work, and how are COVID-19 cases different from other instances when a ventilator is used? CBC explains.
What is a ventilator?
In the simplest terms, a ventilator is a machine that helps a person breathe.
Ventilators shouldn't be confused with respirators, which are simply masks to breathe through that filter out dust, viruses, or other things that could be harmful.
Watch: Medical technicians stand beside a ventilator and explains how it works
According to Tina Hsu, a respiratory therapist (RT) at Vancouver General Hospital and educational director with the B.C. Society of Respiratory Therapists, a ventilator pushes air into the lungs and allows air to escape.
"The ventilators we're talking about here [in terms of COVID-19 patients] are going to be the ICU critical care ventilators," said Hsu. "Those ventilators are connected to medical air and medical oxygen."
The medical air tank is a mix of 21 per cent oxygen and 79 per cent nitrogen.
How does a ventilator work?
"There will always be some kind of pressure and some kind of flow happening — inhalation and exhalation. The ventilator measures everything," said Hsu, adding that the exhalation is passive as the lungs sort of spring back, pushing the air out.
A ventilator will have regulators to set the right mix of air and oxygen and a fan or turbine that manages the flow to the patient. The patient will be intubated, meaning a tube will be inserted beyond the vocal cords into the airway, or trachea, and sealed to ensure the air goes where it's supposed to.
Air will pass through a humidifier and into the patient's lung, before being released through a separate tube. According to Hsu, most of the sensors the machine uses to analyze the patient's breath will be on the tube going in.
In the case of COVID-19 patients, filters are added to the tubes exiting the lungs to keep the virus from entering the environment.
How are COVID-19 cases different from other times ventilators are used?
Ventilators are commonly used during sedation, in intensive care situations, or generally when there's something wrong with the way a patient's lungs are working.
According to Hsu, the way COVID-19 patients are treated is similar to another condition called acute respiratory distress syndrome (ARDS).
But Hsu said an ARDS patient has a stiffening of the lung, causing it to spring back more quickly, which isn't seen in COVID-19 patients.
"We can't give as many breaths a minutes as we would like. If we put in a breath it might take a little longer to get it out again before we can do the next breath," she said.
How long can someone stay on a ventilator?
"Longer is worse," said Hsu. "But we also know with COVID, sooner is better. If we wait to put people on a ventilator, we might wait until it's too late."
She said B.C. hasn't seen many severe cases yet, and a lot of them are still on ventilators, but it seems to require between a day and two weeks to treat coronavirus cases.
"Some people are on long-term ventilators for their whole life," for example, some people who are quadriplegic, said Hsu. In such cases, a tracheostomy, or hole in the neck, is used, whereas COVID-19 cases would have a breathing tube.
What are the risks of using a ventilator?
"The lungs are very delicate," she said. "A lot of what we do is trying to not cause further damage to the lungs."
People get lung inflammation and scarring from being on high levels of oxygen for too long, said Hsu, and there's a risk of physically damaging the lung tissue with too much pressure.
She said the breathing tube can also cause pneumonia independent of COVID-19, and complications can arise from just being immobile for days on end in a hospital bed.
Can anyone operate a ventilator?
In North America, ventilators are nearly exclusively operated by RTs in larger hospitals.
Europe and China don't use RTs, according to Hsu, but it's a job in some Asian and Middle Eastern countries.
She said in smaller hospitals, or at times when an RT isn't available, a physician could run a ventilator. In some long-term care facilities, nurses will operate them.
Does B.C. have enough ventilators?
In areas of the world that have already been hit very hard by the pandemic, the ventilator supply has been an issue.
In British Columbia, health officials have done modelling to determine how the province's supply is expected to hold up. Health Minister Adrian Dix said there are currently 1,272 in the province, with more on order.
In most health regions, officials expect there will be enough, even if B.C. suffers a severe outbreak on the level of Northern Italy. But B.C.'s Northern Health region, for example, could be undersupplied with the current stock.
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