How Do Ventilators Work?

you understand it better. As the United States and the rest of the world scrambled to cope with the COVID nineteen pandemic, hospitals are faced with a critical shortage of ventilators, the bedside devices that help patients who have difficulty breathing on their own. So we wanted to talk today about

what ventilators are and how they work. U S hospitals have about a hundred and sixty thousand ventilators, with another twelve thousand, seven hundred available from the federal government's National Strategic Stockpile, but it's feared that that will be nowhere near enough to cope with all the people who could

become seriously ill from the virus. All of this has suddenly focused attention on a piece of medical equipment that most of us probably haven't given much thought to any more than we think about breathing itself, but for someone who can't get air into their lungs, the device, which ranges in price from twenty to fifty dollars according to The Washington Post, can be a lifesaver. Ventilators assist patients

who have a number of different conditions. We spoke by an email with Dr Paul F. Courier, director of the Respiratory Acute Care Unit for the Division of Pulmonary and Critical Care at Massachusetts General Hospital. He said they can be used to help people breathe during routine surgery under anesthesia, or also when patients are sick and have difficulty breathing due to their illness. A small proportion of people who become infected with COVID nineteen may develop inflammation in their lungs.

Courier explained. An even smaller proportion of these patients can develop respiratory failure, which is best treated with a ventilator. But we also spoke by email with Kenneth Lutchen, dean of the College of Engineering and a professor of biomedical engineering at Boston University. He said, 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 with novel coronavirus, then the negative pressures that occur with normal breathing are not sufficient to expand the lungs enough, and insufficient oxygen and carbon dioxide exchange will result. The

lucchen continued. 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, oxygen, and carbon dioxide levels close to normal until the inflammation and fluid build up subsides and the person can breathe on their own again.

A ventilator is a boxing mechanical device with a digital display on top that typically sits on a cart next to a patient's bed. As the National Heart Long and Blood Institute website explains the patient is connected to the device by a breathing tube that's inserted through their nose or mouth down the throat, which is held in place by tape or a strap that fits around the head. The tube in the airway can cause some discomfort and

also affects the patient's ability to talk and eat. That's why the care team may insert another tube 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 feeding tube that goes directly into the stomach or small intestine through a surgically created opening. Having a tube down your throat isn't exactly pleasant, but it is important electionics blamed Without intubation, Several things can threaten the

ability of the ventilator to do its job. Perhaps the most important is that if the ventilator just blew into the mouth, the delivered volume may not all go into the lung. Some of it could leak out the nose, which is connected to the mouth, or can end up expanding the cheeks of the person rather than going into the lung. To get all of this to work, hospitals depend upon the expertise of highly trained professionals called respiratory therapists.

We also spoke via email with Timothy R. Myers, a respiratory therapist and chief business officer of the American Association for Respiratory Care. He said, the respiratory therapist determines the appropriate settings to match the patient's respiratory needs based on the underlying disease condition. From that point, they provide constant monitoring, an assessment, and modify the setting as the patient's condition

improves or worsens. This would include non invasive monitoring and measurements from blood analysis to look at oxygen and carbon dio side levels. This requires a lot of careful management because lungs are pretty complicated. While it's useful to think of the lungs as a balloon for illustrative purposes, in reality, Myers explained their quote more like a network of millions of balloons that must transfer gases between the lungs and

the circulatory system. When the lungs are damaged or diseased, each lung and the millions of balloons require gas entry in and out differently than when they're healthy. Each patient is unique. In recent years, there have been some advances and how ventilators are used. Courier said research has shown that using low breath size and low pressures improves outcomes. Also, patients with severe respiratory failure may at times be turned on their stomachs while on the ventilator, a process called

prone positioning, which can often improve their oxygen levels. Finally, for some patients whose oxygen levels remain low despite being on a ventilator, they may be able to receive extra corpore membranous oxygenation. In some very specialized centers, this highly intensive therapy can circulate the blood outside of the body to provide additional oxygen. Luchen's research focuses on developing safer

mechanical ventilators, he said. Initially, the ventilator is working to save a life by keeping proper oxygen and carbon dioxide levels, but it does this by pushing air in and exposing the lung to abnormal pressures, often larger pressures to help expand a stiffer and or narrower lung. Also, a ventilator is programmed to give the exact same breath every time, where normal breathing varies a little from breath to breath

and we periodically take a big breath. He explained that injuries can occur from those large, repetitive pressures, which could eventually prevent the ventilator from providing enough gas exchange. That's why Luchen is working with lead investigator Balisuki, a professor of biomedical engineering at Boston University, on a concept called variable ventilation, in which the ventilator delivers variable breaths similar to a natural breathing pattern, to avoid repetitive abnormal pressures

in the same location when a person breathes. Trials and animals have shown that this type of ventilation is less likely to cause injuries, but it hasn't yet been tested in humans. With the current shortage of ventilators, manufacturers are ramping up production. Medtronic, one of the world's major ventilator makers, is gearing up to double its output by adding shifts to keep its Irish manufacturing plant running around the clock.

But manufacturers face a challenge in increasing production because ventilators must be built with great care. Today's episode was written by Patrick J. Tiger and produced by Tyler Klang. For more on this and lots of other topics, visit how stuff Works dot com. Brainstuff is production of I heart Radio. For more podcasts for my heart Radio, visit the iHeart Radio app, Apple Podcasts, or where ever you listen to your favorite shows.