We are now many weeks into an international lockdown caused by the coronavirus pandemic. This situation has introduced us to a whole new vocabulary and given us a whole new level of respect for frontline workers. A friend of mine, Ewan Goligher, is a doctor and scientist who has dedicated his career to the intricacies of mechanical ventilation (specifically, characterizing the mechanisms and impact of injury to the lung and diaphragm during mechanical ventilation). He was willing to take a bit of time to answer a few of the questions I’ve had about COVID-19, about the importance of ventilators, and a few other related topics. I hope you find it as enlightening as I did!
When we’ve talked in the past you’ve told me a little bit about your background as an expert in mechanical ventilation. I probably mostly tried to change the subject, but here in the midst of a pandemic caused by a respiratory disease, suddenly I’m riveted. So thanks for the opportunity to chat. Acknowledging that I’ve got basically no knowledge of virology, biology, or other key fields, what should someone like me know about this virus and the disease it causes?
The coronavirus (properly called SARS-CoV-2) is a member of a family of viruses that can cause severe, life-threatening respiratory failure. Related viruses are responsible for SARS (caused by a virus named SARS-CoV-1) and MERS (Middle East Respiratory Syndrome). SARS-CoV-2 appears to be more infectious than the others and can be transmitted by someone without any symptoms of infection. SARS-CoV-2 causes an illness referred to as COVID-19. COVID-19 is primarily a respiratory tract infection, potentially leading to serious pneumonia and life-threatening respiratory failure. COVID-19 is also associated with heart failure, blood clots in the veins and arteries, strokes, and kidney damage. The mortality rate from COVID-19 is probably somewhere between 0.5-3%, although it’s possible that the number is smaller. Patients who are older and those with chronic medical problems, especially cardiovascular disease, seem to be at higher risk of severe illness. Although we’ve already learned a lot about COVID-19 in a short time, there is still a great deal to learn.
We are hearing from some that this disease is extremely serious and from others that it’s relatively minor. Compared to other conditions and diseases you treat, how serious is COVID-19?
A lot of comparisons are drawn between COVID-19 and influenza. Both viruses can cause life-threatening respiratory failure but for most people they cause an unpleasant but not serious viral illness with fever and headache and cough and prostration. However because it is so highly infectious and hard to contain, COVID-19 can cause an unprecedented number of infections which may in turn lead to very large volumes of patients requiring hospitalization and life support. The sheer potential volume of cases is what makes COVID-19 especially serious. When health systems are overwhelmed, they can’t properly treat all the usual health problems that our populations experience. There is one other unique feature: SARS-CoV-2 infects the inner lining of blood vessels and a range of vascular complications have been described in patients with COVID-19 including strokes, heart attacks, and a very high rate of blood clots in the lungs and veins. Other features continue to emerge. COVID-19 should be regarded as a very serious public health problem.
As I recall it, you’ve spent most of your medical career researching better outcomes for people who need mechanical ventilation. (See! I did listen at least a little.) In the very early days of the pandemic, we heard constant references to the importance of ventilation, but it didn’t take long before we began to hear about studies warning that ventilation was harming as much as helping. Where do we stand on that?
A mechanical ventilator is a glorified pump—it pushes oxygen and fresh air into the lungs and uses pressure to keep the lungs inflated. Patients need a ventilator once their own breathing muscles can no longer adequately inflate the lungs. The lungs are, however, quite delicate, and it’s easy to damage the lungs further with pressure from the ventilator. On the other hand, vigorous breathing efforts by patients in respiratory distress can also damage the lung, and some people think that this problem of excess breathing effort is an important contributor to lung failure in COVID-19. Once you are on a ventilator, the ventilator can do all the breathing ‘work’ and allow you to relax your diaphragm and respiratory muscles completely. However, these muscles weren’t designed to get a ‘vacation’ and they waste away very rapidly. This weakens them and makes it harder to get patients off the ventilator. So the ventilator can save your life, but it can also do a lot of damage, and we are working hard to understand how best to apply the ventilator generally, and in COVID-19 in particular.
In the early days of the pandemic we heard concerns that there would not be enough ICU beds and not enough ventilators. As I understand it, those fears were realized in a few areas (.e.g. Northern Italy and New York City) but not in others, including Toronto. To what do you attribute that?
Because COVID-19 is transmitted by asymptomatic carriers and has a relatively prolonged incubation period (up to 14 days), the infection can spread widely before people start getting sick. Until patients began coming to hospital with COVID-19 in Milan and New York, it was widely believed that you were only at risk of COVID-19 if you had contact with someone who had recently travelled to/from China—community-based spread had not really been recognized. By the time the patients started coming, the infection had already spread widely. Social distancing measures were quickly implemented thereafter, but for Milan and New York it was already too late. The epidemic was much less burdensome in other centres like Toronto, probably because of early and rigorous efforts at physical and social distancing. We were in the fortunate position of seeing the outbreak develop elsewhere in North America and Europe and reacting before spread became overwhelming. This is not to downplay the seriousness of the pandemic in Canada—thousands of people have died and the healthcare system had to be almost completely redeployed. That said, we were prepared for much, much worse, and our experience has been nowhere near that of New York City.
Based on your experience with the disease, in what ways does it affect the lungs, and how seriously?
Most patients with COVID-19 infection will have a relatively mild illness that feels like a bad flu (by the way, this can still be very unpleasant). Patients who develop pneumonia (where the virus infects the lungs directly) will experience some difficulty breathing and need to be admitted to hospital for oxygen therapy. Interestingly, this pneumonia seems to primarily affect oxygen levels more than it increases lung stiffness—this means that some patients may have low oxygen levels but feel very little shortness of breath. As the pneumonia progresses, patients may no longer be able to breathe on their own or maintain an adequate oxygen level, so they will be put on a ventilator to assist their breathing. COVID-19 is associated with a hyperactive clotting system leading to the formation of small and large blood clots. When these clots form in the veins, they can block blood flow through the lungs, and this may be an important cause of lung failure. Once patients are on the ventilator for COVID-19, they have a very serious illness, and the risk of death probably ranges somewhere between 30-50%. People spend a lot of time debating the mortality rate for COVID-19, and this is uncertain because the denominator (the total number of cases) is uncertain. From a public health point of view what really matters is the total number of deaths, rather than the mortality rate per se. Major cities like New York and Milan and Paris have seen a massive deluge of very sick and dying patients and health systems have been nearly overwhelmed. This is (hopefully) a once in a generation healthcare crisis.
Is it affecting only elderly people, or are you seeing it affect younger people as well?
While severe illness is certainly more common in older people, I have cared for critically ill patients in their 20s, 30s, and 40s. One of the disturbing and tragic features of COVID-19 is the way that clusters of infection occur within families. Multiple people across generations from the same family may be on life support at the same time. Certain populations are at high risk of infection—we’ve all heard about the tragic outbreaks in long-term care homes. We should also be aware that other marginalized populations—the homeless, prisoners—are at very high risk. I’ve seen quite a few homeless people with COVID-19 or other acute illness because the social safety net is breaking down with social distancing efforts.
From your perspective as a critical care doctor who is tending to those who have been most affected by the disease, what do you want people to know and to do so they don’t end up being your patients?
My advice would be that of our public health experts: maintain appropriate social distance, wash your hands ‘religiously’, and make sure you cover your hands and mouth when sneezing or cough to avoid spraying droplets. We should be especially careful to make sure that seniors are protected from exposure. We should also take care of ourselves—get exercise, eat a healthy diet (avoid the risk of gaining significant weight during self-isolation). Good physical condition will increase your ability to survive the infection if you do become seriously ill. Finally, there is a lot of concern about the long-term mental health impact of this whole crisis. I’d encourage everyone to maintain regular routine of spiritual disciplines and physical exercise, stimulate the mind with good reading, and seek regular interactions with family, friends, and church connections.
You work in an environment where you’re exposed to people who have an infectious disease. Then you go home to a family you want to protect. Are you afraid? Should you be? What precautions are you taking?
It’s definitely on my mind a lot. Many of the heroes with whom I get to work (nurses, respiratory therapists, other doctors, etc) are isolating themselves from their families in order to be available to care for patients. We are constantly washing our hands. We use personal protective equipment when we have contact with patients, and it’s painstaking and time-consuming to take it off properly in a way that doesn’t contaminate ourselves or others. People are putting their cell phones in small lunch bags so that the phones don’t get contaminated (and we need the phones with us). We are required to wear masks all day long at work—this is primarily to protect others from us, rather than protecting us from others, in case we develop asymptomatic infection. I change clothes with great care (and lots of hand washing) at the hospital and again at home. My family is young and healthy and thankfully the virus doesn’t seem cause serious illness in children, so I don’t feel it necessary to isolate completely from them. At the end of the day, we are in God’s hands—that’s not grounds for recklessness, but it relieves us of the need to be paranoid or governed by fear.
You’ve expended a lot of effort over the past few years in battling against the rise of physician-assisted suicide. Are there ways in which you’re now seeing that issue play out?
The pandemic has occasioned a brief reprieve from political and moral discussions over the expansion of euthanasia in Canada. If anything, it’s been refreshing to see the public imagination primarily focused on saving lives, rather than ending them. I think the pandemic has been a harsh reminder that life is a gift to be treasured, not something we can take for granted. There’s also been an appropriate emphasis on the need to ensure good palliative care for those who are dying of COVID-19, and the recognition that high quality palliative care needs to be made much more widely available. Whether we will see any shift in our attitudes about the ethics of euthanasia over the longer term remains to be seen; personally, I doubt significant shifts in values will occur, as these debates are driven by fundamental worldview conflicts.
Ewan Goligher MD, PhD is an Assistant Professor in the Interdepartmental Division of Critical Care Medicine at the University of Toronto and a Scientist at the Toronto General Hospital Research Institute. His research program focuses on characterizing the mechanisms and impact of injury to the lung and diaphragm during mechanical ventilation and on the use of innovative clinical trial designs to test lung and diaphragm-protective ventilation strategies.