Speaker 1: Welcome to brain Stuff, a production of I Heart Radio.
Speaker 1: Hey brain Stuff, Lauren Vogelbaum here. This episode is part
Speaker 1: of our ongoing series surrounding the novel type of coronavirus
Speaker 1: identified in twenty nineteen, which causes what's therefore being called
Speaker 1: COVID nineteen. Because everything is a little less scary when
Speaker 1: you understand it better. As the United States and the
Speaker 1: rest of the world scrambled to cope with the COVID
Speaker 1: nineteen pandemic, hospitals are faced with a critical shortage of ventilators,
Speaker 1: the bedside devices that help patients who have difficulty breathing
Speaker 1: on their own. So we wanted to talk today about
Speaker 1: what ventilators are and how they work. U S hospitals
Speaker 1: have about a hundred and sixty thousand ventilators, with another
Speaker 1: twelve thousand, seven hundred available from the federal government's National
Speaker 1: Strategic Stockpile, but it's feared that that will be nowhere
Speaker 1: near enough to cope with all the people who could
Speaker 1: become seriously ill from the virus. All of this has
Speaker 1: suddenly focused attention on a piece of medical equipment that
Speaker 1: most of us probably haven't given much thought to any
Speaker 1: more than we think about breathing itself, but for someone
Speaker 1: who can't get air into their lungs, the device, which
Speaker 1: ranges in price from twenty to fifty dollars according to
Speaker 1: The Washington Post, can be a lifesaver. Ventilators assist patients
Speaker 1: who have a number of different conditions. We spoke by
Speaker 1: an email with Dr Paul F. Courier, director of the
Speaker 1: Respiratory Acute Care Unit for the Division of Pulmonary and
Speaker 1: Critical Care at Massachusetts General Hospital. He said they can
Speaker 1: be used to help people breathe during routine surgery under anesthesia,
Speaker 1: or also when patients are sick and have difficulty breathing
Speaker 1: due to their illness. A small proportion of people who
Speaker 1: become infected with COVID nineteen may develop inflammation in their lungs.
Speaker 1: Courier explained. An even smaller proportion of these patients can
Speaker 1: develop respiratory failure, which is best treated with a ventilator.
Speaker 1: But we also spoke by email with Kenneth Lutchen, dean
Speaker 1: of the College of Engineering and a professor of biomedical
Speaker 1: engineering at Boston University. He said, think of the lungs
Speaker 1: as an elastic balloon. You can expand the balloon by
Speaker 1: having the pressure at the opening mouth be greater than
Speaker 1: the pressure on the other side of it. Normally, we
Speaker 1: breathe by having our muscles expand the chest, which lowers
Speaker 1: the pressure around the lungs inside the body, so that
Speaker 1: the lungs expand. But if the lungs fill up with
Speaker 1: fluid or become highly inflamed, both of which can happen
Speaker 1: with novel coronavirus, then the negative pressures that occur with
Speaker 1: normal breathing are not sufficient to expand the lungs enough,
Speaker 1: and insufficient oxygen and carbon dioxide exchange will result. The
Speaker 1: lucchen continued. The alternative is then to push air into
Speaker 1: the lungs using a ventilator, which creates a positive pressure
Speaker 1: at the mouth the inlet to the intubation tube large
Speaker 1: enough to push enough fresh air in and out each breath.
Speaker 1: Hopefully this can keep the blood, oxygen, and carbon dioxide
Speaker 1: levels close to normal until the inflammation and fluid build
Speaker 1: up subsides and the person can breathe on their own again.
Speaker 1: A ventilator is a boxing mechanical device with a digital
Speaker 1: display on top that typically sits on a cart next
Speaker 1: to a patient's bed. As the National Heart Long and
Speaker 1: Blood Institute website explains the patient is connected to the
Speaker 1: device by a breathing tube that's inserted through their nose
Speaker 1: or mouth down the throat, which is held in place
Speaker 1: by tape or a strap that fits around the head.
Speaker 1: The tube in the airway can cause some discomfort and
Speaker 1: also affects the patient's ability to talk and eat. That's
Speaker 1: why the care team may insert another tube into a
Speaker 1: vein to feed the patient nutrients, or if the person
Speaker 1: is going to be on a ventilator for a long time,
Speaker 1: insert a feeding tube that goes directly into the stomach
Speaker 1: or small intestine through a surgically created opening. Having a
Speaker 1: tube down your throat isn't exactly pleasant, but it is
Speaker 1: important electionics blamed Without intubation, Several things can threaten the
Speaker 1: ability of the ventilator to do its job. Perhaps the
Speaker 1: most important is that if the ventilator just blew into
Speaker 1: the mouth, the delivered volume may not all go into
Speaker 1: the lung. Some of it could leak out the nose,
Speaker 1: which is connected to the mouth, or can end up
Speaker 1: expanding the cheeks of the person rather than going into
Speaker 1: the lung. To get all of this to work, hospitals
Speaker 1: depend upon the expertise of highly trained professionals called respiratory therapists.
Speaker 1: We also spoke via email with Timothy R. Myers, a
Speaker 1: respiratory therapist and chief business officer of the American Association
Speaker 1: for Respiratory Care. He said, the respiratory therapist determines the
Speaker 1: appropriate settings to match the patient's respiratory needs based on
Speaker 1: the underlying disease condition. From that point, they provide constant monitoring,
Speaker 1: an assessment, and modify the setting as the patient's condition
Speaker 1: improves or worsens. This would include non invasive monitoring and
Speaker 1: measurements from blood analysis to look at oxygen and carbon
Speaker 1: dio side levels. This requires a lot of careful management
Speaker 1: because lungs are pretty complicated. While it's useful to think
Speaker 1: of the lungs as a balloon for illustrative purposes, in reality,
Speaker 1: Myers explained their quote more like a network of millions
Speaker 1: of balloons that must transfer gases between the lungs and
Speaker 1: the circulatory system. When the lungs are damaged or diseased,
Speaker 1: each lung and the millions of balloons require gas entry
Speaker 1: in and out differently than when they're healthy. Each patient
Speaker 1: is unique. In recent years, there have been some advances
Speaker 1: and how ventilators are used. Courier said research has shown
Speaker 1: that using low breath size and low pressures improves outcomes. Also,
Speaker 1: patients with severe respiratory failure may at times be turned
Speaker 1: on their stomachs while on the ventilator, a process called
Speaker 1: prone positioning, which can often improve their oxygen levels. Finally,
Speaker 1: for some patients whose oxygen levels remain low despite being
Speaker 1: on a ventilator, they may be able to receive extra
Speaker 1: corpore membranous oxygenation. In some very specialized centers, this highly
Speaker 1: intensive therapy can circulate the blood outside of the body
Speaker 1: to provide additional oxygen. Luchen's research focuses on developing safer
Speaker 1: mechanical ventilators, he said. Initially, the ventilator is working to
Speaker 1: save a life by keeping proper oxygen and carbon dioxide levels,
Speaker 1: but it does this by pushing air in and exposing
Speaker 1: the lung to abnormal pressures, often larger pressures to help
Speaker 1: expand a stiffer and or narrower lung. Also, a ventilator
Speaker 1: is programmed to give the exact same breath every time,
Speaker 1: where normal breathing varies a little from breath to breath
Speaker 1: and we periodically take a big breath. He explained that
Speaker 1: injuries can occur from those large, repetitive pressures, which could
Speaker 1: eventually prevent the ventilator from providing enough gas exchange. That's
Speaker 1: why Luchen is working with lead investigator Balisuki, a professor
Speaker 1: of biomedical engineering at Boston University, on a concept called
Speaker 1: variable ventilation, in which the ventilator delivers variable breaths similar
Speaker 1: to a natural breathing pattern, to avoid repetitive abnormal pressures
Speaker 1: in the same location when a person breathes. Trials and
Speaker 1: animals have shown that this type of ventilation is less
Speaker 1: likely to cause injuries, but it hasn't yet been tested
Speaker 1: in humans. With the current shortage of ventilators, manufacturers are
Speaker 1: ramping up production. Medtronic, one of the world's major ventilator makers,
Speaker 1: is gearing up to double its output by adding shifts
Speaker 1: to keep its Irish manufacturing plant running around the clock.
Speaker 1: But manufacturers face a challenge in increasing production because ventilators
Speaker 1: must be built with great care. Today's episode was written
Speaker 1: by Patrick J. Tiger and produced by Tyler Klang. For
Speaker 1: more on this and lots of other topics, visit how
Speaker 1: stuff Works dot com. Brainstuff is production of I heart Radio.
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