A ventilator is a device that supports or simulates the process of breathing by pumping air into the lungs. It is sometimes called an avent or breathing machine.
Doctors use ventilators if a person cannot properly breathe on their own. This may be due to undergoing general anesthesia or an illness that negatively impacts his or her breathing.
There are different types of ventilators, and each provides a specific level of support. Which type a doctor utilizes depends on the person’s respiratory condition.
People require ventilation if they are suffering from respiratory failure. When this occurs, a person cannot take in sufficient oxygen and may not be able to adequately expel carbon dioxide. It can be a life-threatening condition.
Four types of ventilator support are face mask ventilators, mechanical ventilators, manual resuscitator bags, and tracheostomy ventilators.
A face mask ventilator is a non-invasive method of supporting a person’s breathing and sustaining proper oxygen levels. A mask fits over the nose and air blows into their lungs and airways.
Mechanical ventilators are machines that completely take over the breathing process. They are used when a person cannot breathe on their own.
Mechanical ventilators work via a tube in a person’s throat, forcing air into the lungs and expelling carbon dioxide. This tube is inserted using a procedure called intubation. Intubation is a procedure where you are usually sedated, and your doctor puts a tube down your throat, and into your trachea (windpipe). A mechanical ventilator regulates the pressure, humidity, and temperature of the air.
The tube in the airway causes discomfort, quite often rendering a patient unable to talk or eat. That’s why another tube may be inserted into a vein to feed the patient nutrients, or if the person is going to be on a ventilator for a long time, insert a nasogastric feeding tube that goes directly into the stomach or small intestine through a surgically created opening.
Manual resuscitator bags allow people to control the airflow of their ventilator with their hands. This piece of equipment consists of an empty bag, or “bladder,” that a person squeezes to pump air into the lungs.
It can be attached to a face mask ventilator, or, if the patient is intubated, a doctor can attach one to the tube inserted in their throat.
This can be useful if there is a power outage. It can also be a life-saver as a temporary procedure until one reaches a hospital.
People who have undergone tracheostomies can also receive ventilator support through this opening. A tracheostomy is a surgical procedure where a doctor creates an opening in the windpipe and inserts a tube, which allows air to flow in and out of the lungs, thus enabling a person to breathe without using their nose or mouth. Instead of attaching a ventilator through a tube inserted through the mouth, doctors insert it directly into the trachea.
Patients whose oxygen levels remain low despite being on a ventilator may be able to receive Extracorporeal Membranous Oxygenation (ECMO) in specialized centers. This expensive and rare therapy can circulate the blood outside of the body to provide additional oxygen.
So, how does a mechanical ventilator work? Kenneth Lutchen, Dean of the College of Engineering and a professor of biomedical engineering at Boston University explains:
“Think of the lungs as an elastic balloon. You can expand the balloon by having the pressure at the opening (mouth) be greater than the pressure on the other side of it. Normally we breathe by having our muscles expand the chest which lowers the pressure around the lungs inside the body so that the lungs expand.”
“But if the lungs fill up with fluid or become highly inflamed, both of which can happen in coronavirus, then the negative pressures that occur with normal breathing are not sufficient to expand the lungs enough and insufficient O2 and CO2 exchange will result.
The alternative is then to ‘push’ air into the lungs using a ventilator which creates a positive pressure at the mouth— the inlet—to the intubation tube—large enough to push enough fresh air in and out each breath. Hopefully, this can keep the blood O2 and CO2 levels close to normal until the inflammation and fluid buildup subsides and the person can breathe on their own again.”
Ventilation, like many medical procedures, involves some risks, particularly mechanical ventilation. The longer a person requires mechanical ventilation, the higher the risks.
Possible complications of using a ventilator include:
Atelectasis, a condition where the lungs do not expand fully, reducing the amount of oxygen that enters the bloodstream.
Aspiration, or breathing foreign substances into the airways.
Lung damage, which can happen as a result of high air pressure or high oxygen levels.
Pulmonary edema, which occurs when fluid builds up inside the air sacs in the lungs.
Pneumothorax, which involves air leaking from the lungs into the space just outside of them, causing pain, shortness of breath, and in some cases, lung collapse.
Infections, which can include sinus infections and, sometimes, pneumonia, airway obstruction,
long-term vocal cord damage as a result of intubation, blood clots or bed sores as a result of lying in one position for long periods, muscle weakness, and delirium, which can lead to psychological trauma or post-traumatic stress disorder.
According to Jerry King, RRT, an assistant professor in the School of Health Professions at the University of Alabama at Birmingham, “In COVID-19 cases, ventilators are often needed for weeks, sometimes for over a month. While a ventilator might save your life, it is certainly not a pleasant experience.”
