How the Modern ICU Was Galvanized By a Polio Epidemic

; Hannah Wunsch, MD, MSc


August 15, 2023

This transcript has been edited for clarity.

Eric J. Topol, MD: Hello. This is Eric Topol for the Medscape Medicine and the Machine podcast. We have a phenomenal guest today: Professor Hannah Wunsch from the University of Toronto, who authored a book called The Autumn Ghost. I had the chance to review her book in the June 6 issue of Nature. Welcome, Hannah.

Hannah Wunsch, MD: Thanks so much. It's such an honor to be on your podcast.

Topol: In The Autumn Ghost, how you were able to go back in history 70 years, in Denmark, and dig up all this stuff about polio? It's hard enough to do currently. But you did it in detail. You included photos of some of the kids who were hit, poetry that some of the patients wrote, the news clippings, going back to 1952 and thereabouts, the interphysician warfare, the egos. How did you do it?

Wunsch: It was a bit of a treasure hunt. I loved it for that. You start scratching the surface and digging, and you never know what threads you're going to get to pull and where they might lead you. For me, the real thrill was getting to find the people who were there, who were eyewitnesses, and also digging up film footage. You can't see that in the book, but I used it as resource material. There is film footage of the epidemic.

The Danes are famous for their great archival material, and records in general in their city archives. They had a book of all of the deaths in 1952 in the one hospital where these events took place. Paging through that, I could reconstruct so much of this. But at the end of the day, it was getting to talk to people who were there.

Topol: Wow. That was the Blegdam Hospital in Copenhagen?

Wunsch: Yes. It's pronounced "Bly-dam" in Danish. It was the infectious disease hospital for the city of Copenhagen and the surrounding areas and became the epicenter for this now famous polio epidemic in 1952.

Topol: Are you of Danish descent?

Wunsch: Not at all. I don't speak a word, and I'm terrible with languages. So, I would say in many ways, the hardest thing for me was not speaking with people, because everybody there speaks English but [I was] dealing with archival material in Danish.

You'll appreciate this as someone who loves artificial intelligence (AI). I was able to read huge swathes of material in Danish with Google Translate; I was much more careful with anything that ended up in the book, in which case I asked people to help me translate. So, my interest in the events there, and in Denmark and Copenhagen, was through the events of this epidemic and my interest in the medical history.

Topol: How long did it take to do all the research?

Wunsch: I think it was 3-4 years in total. In a weird way, I was helped by COVID because, although we were very busy in the hospital — I work in the ICU — there were also long stretches of downtime when I was at home, not doing normal activities. And a lot of older people became familiar with Zoom.

So I was able to do a lot of interviews with people during the COVID lockdown, because everybody was at home with nothing else to do. And people who wouldn't have been facile with that sort of technology before the pandemic were able to hop onto Zoom and allow me to interview them. I was able to do a fair amount of preparation work before I even went over to Copenhagen to do research in person. It was an odd silver lining to COVID.

Topol: We're going to talk a bit more about the parallels between COVID and polio, but before we do that, what I didn't know was the world of the intensive care unit (ICU) and how it was basically born because of polio. I had no idea.

As you portrayed it, it was remarkable what they discovered about positive pressure ventilation. Back then, all these medical and dental students were hand-ventilating the patients around the clock because there was no such thing as a mechanical ventilator. Something like 50 of these students would be breathing for the patients, basically, with an early Ambu bag or whatever.

I had no clue about all this. Or that it was thanks to polio that we have such a thing as an ICU, an appreciation for blood gases, mechanical ventilators, the interdisciplinary team, the respect for anesthesiologists. Can you take us through that? I don't think a lot of people really know how this all came together.

Wunsch: Even in my own specialty, which is critical care medicine, a lot of people didn't know this story, which is the origin story for the specialty. To put it into context, other people and factors at play were also pushing things in this direction. It's important to recognize that although I tell sort of a single story, it's never quite that simple.

But in the early 1950s, one of the things I had to appreciate and understand was just how little there was to do for people who were critically ill. There were iron lungs for people who had polio with respiratory failure. But with bulbar polio — difficulty swallowing, all of that — it was 90% mortality for those patients.

I stumbled on this story in a book called The Rise and Fall of Modern Medicine 20 years ago. It tells this story as an important pivotal moment in medical history when there's a major epidemic of polio in Copenhagen. They've seen a lot of polio over the years, but nothing like this. It was a particularly virulent strain, and it was just hitting an enormous number of people. By the time the epidemic was over, 1 in 200 boys aged 1 to 4 had been paralyzed by polio. The hospital had one iron lung, but they also recognized that iron lungs were not the solution because so many patients had bulbar polio.

The book is about early innovation, but it's also about modern innovation and the important factors involved for something to occur, like this major leap in figuring out how to keep people alive. In this case, it was bringing in an anesthesiologist by the name of Bjørn Ibsen.

At that point in time, anesthesiology was barely a specialty in Denmark. Anesthesiologists had been recognized only a year or two earlier, and they certainly were not involved in the care of polio patients. That was the domain of infectious disease doctors, maybe neurologists, but certainly not anesthesiologists.

Ibsen was the one who came in and suggested, Let's do a tracheostomy on your patients. I think carbon dioxide retention is killing them. If we take the techniques of the operating room, where we keep people alive with ventilation, and apply them to patients with polio, I think I can save many of your patients.

So, the crux of the story is what it took for them to let him try this. You alluded to the involvement of ultimately 1200 medical and dental students when they realized they had a technique that worked — positive pressure ventilation — but they didn't have ventilators yet. It still gives me shivers every time I imagine being one of those students sitting at the bedside. They did it in 6- to 8-hour shifts, 24 hours a day, for months. At one point, they kept 70 patients alive this way. It's a great story, but it's also an important story for people to understand how recently we didn't have these basic interventions that we consider part and parcel of modern medicine.

Topol: The transformation of modern medicine by polio is so incredibly well captured. I want to read a couple of passages because this is a Medicine and the Machine podcast. The machine here is mechanical ventilation and related life support.

Ibsen said, "That I could save the patient's life with such a simple method was one of the most incredible moments of my life. We had our first polio patient under control."

And then later, "The legacy of these polio patients continues in the care provided to millions of patients with a wide array of medical conditions across the globe who breathe with the help of mechanical ventilation and receive the complex multidisciplinary care delivered in ICUs worldwide." That is the story you told that is just so extraordinary.

Now I want to connect the dots, because what you didn't do was just get into the tech stuff. You brought out the humanity. That blew me away, because you had pictures and stories of the patients. You included poetry written by Rosa Abrahamsen, opening many chapters with it, and tracing her life. Another patient who was central was Vivi Ebert.

She had bulbar polio and was able to live 20 years longer, from age 12 to 32, because of the support she had. With so many patients, you brought out the humanity of what this meant. This was what made the book quite extraordinary to me. It wasn't just technology and innovation and the polio story. It was how you so vividly portrayed these people.

Wunsch: When you work in the ICU, you always have to be careful that you do remember that these are human beings in the beds. There is so much technology surrounding them that it's easy to see the tubes and the machines and think about everything that's going on around the individual. I think the biggest struggle we've had is to ensure that we continue to remember that we are caring for individual humans in those beds.

That's true of all medicine. I know that something you care about deeply is how we keep that humanity in the role of physicians. To me, there is nothing more fundamental in terms of a connection than the idea of sitting at the bedside, literally having that life in your hand, in terms of hand-ventilating someone and that connection to a patient.

But with polio in particular, these people were awake. They were not asleep. They weren't critically ill in the way we often think of modern critical illness, where they need heavy sedation or paralysis. These people were, and sometimes still are, of course, fully interactive. So it was a phenomenal experience for the patients, the medical students, everyone involved, because there was so much human connection actually involved with this birth of machinery.

Topol: That was startling, how well you got into that. It was a theme of the book. Another part, of course, is the story of the role that Denmark played with the vaccine, because of Statens Serum Institut there. Of course, everyone knows about the Salk vaccine in 1955.

But maybe you could comment on that, because unlike SARS-CoV-2 and COVID, where in 10 months we went from isolating the pathogen to having a vaccine, with polio, it took 47 years. Denmark was making monkeypox vaccines, of course, in the recent outbreaks. They have a long history of science and expertise in this area that you wrote about in the book.

Wunsch: I felt it was important, although the focus of my book was not the story of the vaccine. That's been told phenomenally well in other books. It's also what people associate with polio. I wanted to make it clear that polio's legacy went beyond the vaccine.

But I also felt it was important to tell that story because it runs in parallel. As they were treating people with polio, they were also desperate for a vaccine and for prevention. That runs throughout, all the fits and starts of the vaccine. You alluded to Denmark's place in medical history, and science and technology, and given the size of the country, it really had an outsized influence in many ways with the expertise and developments that have come out of Denmark over the years.

They had a smooth rollout of the vaccine, thanks to one individual, Herdis von Magnus, a woman who was in charge of the vaccination planning in Denmark. She was in close contact with Salk and Sabin in the years leading up to the development of the vaccine. They were ready to go as soon as the announcement came about the success of the big trials that were done in 1955. They didn't have the problems the United States had with oversight of the quality of the vaccine. The Cutter incident in the United States set back the vaccination drive.

First of all, Denmark's effort was centralized. It's a small country. They had one facility that made vaccines, and so their oversight it was a lot easier. But they also just had phenomenal scientists who were meticulous in the way they approached the development of their vaccine and the way they communicated with other scientists. Their involvement in these things is an important legacy of Denmark.

Topol: They come out looking quite strong, very impressive

Wunsch: That said, one of the things that also comes out is the feeling that the medical culture is very hierarchical in Denmark compared with the United States. There were definitely side aspects to medical care and medical culture. They were behind in terms of having anesthesiologists recognized as a specialty compared with the United States.

So, some things were well developed. Other things were maybe not quite as strong in that regard, and the medical culture was one of them.

Topol: The COVID pandemic and polio warrant some comparison because, as you brought out in The Autumn Ghost, there was a miscue about how polio was transmitted, which of course happened with COVID.

Everyone was writing about large droplets with COVID, but it turns out it's airborne, and there was great resistance to that theory. So that is glaring, along with the fact that a lot of polio is asymptomatic, which people don't understand.

Wunsch: Regarding the symptomatology, it is striking that you get asymptomatic transmission of both viruses. They are similar in that way. It was hard to track polio initially, and they struggled with how it was transmitted, who was at risk, who was going to develop symptoms, and who wasn't. Part of what made it feel so terrifying was this sense that they never knew who was going to be struck with paralytic polio vs who would just have cold symptoms vs who would not even know they had it.

And of course, that's been a struggle with COVID. All these people who are carrying it around and are not aware that they've got the virus, and how much harder that has made it to contain or to know who is at risk. The parallels are strong in that regard. And then the way polio was transmitted. They had all kinds of theories about how it was transmitted. What's really interesting is, if you bring up polio, there's so much buried memory. It's not talked about much anymore.

But as soon as you mention it to people of a certain generation, you get all kinds of memories and stories of people they know who had polio or people in their families who had polio, or even just the experience of the fear of polio. One memory I heard over and over again was of parents shutting windows in the middle of summer, not allowing any air to enter, because they were so afraid that polio was going to get into the house. And of course, once you know how it's actually transmitted, you realize how crazy that was.

It brings back the memories of all the handwashing and some of the things we did at the beginning of COVID when we didn't have the understanding, and how much fear that creates when you don't fully understand the transmission.

To your point, scientists understood that polio was transmitted by the oral-fecal route before the general public did. That's clear. You get the same challenge where, even once it's transmission is established, getting that information out to the general public in a way that they can accept and understand can be as big a challenge as establishing how it's transmitted.

Topol: There is also the parallel about how you ventilate patients with polio — the discovery, as we discussed, about positive pressure ventilation and mechanical ventilators. Here, the idea that for COVID, all these people were coming in, and maybe they shouldn't have been intubated and received mechanical ventilation, and then seeing the benefits of a prone position. As a critical care physician, was this discovery of the benefit of a prone position new with COVID? Or did we know about this before?

Wunch: We knew about this before, certainly. There have been many trials of proning in patients with acute respiratory distress syndrome. It had been established that this was probably beneficial for at least some subset of patients.

The uptake of it wasn't great, though. The concept of proning someone who was not intubated was also known if you go back in the literature, but really it was not embraced at all before COVID. The concept of proning for severe respiratory failure in general was out there, but not well-established. COVID pushed people to establish protocols and improve the skills needed to safely prone people in a way that we hadn't seen before. My feeling is that the medical innovations, barring the vaccine issue in COVID, were relatively incremental. They were refining things that we already knew.

In fact, some of the issues around whether or not to ventilate were a bit of panic in the beginning. We needed to change our assessment of patients. And rather than trusting clinical assessments of whether the patient needed intubation, it was this mindset that we must intubate them early. We can't put them on noninvasive ventilation because that will aerosolize things. And we changed what we would normally do for people in ways that were not helpful.

A lot of what we did for patients in COVID was exactly what Bjørn Ibsen was doing for patients back in the early 1950s. It was just good, basic critical care with some refinements, and some medication changes and things like that helped improve outcomes. I look around the ICU and see lot of extra gadgets and monitors, but really, the basics of what we're doing haven't changed in 70 years.

Topol: I also wanted to touch on the tens of millions of people who are affected with long COVID. With polio, there's this peculiar post-polio syndrome that many people are still not aware of, which can happen 20, 30, or 40 years later What is post-polio syndrome, and what might be the root cause?

Wunsch: I learned all about this as I was writing this book. I had heard the term but didn't really know what post-polio syndrome was. I discovered, as I interviewed patients who had been cared for in 1952, that pretty much every one of them was telling me about post-polio syndrome and their struggles now. Those who had paralytic polio experienced increasing weakness, but also other symptoms.

That's the part that has taken people by surprise. It's a lot of fatigue. There can be pain and weakness in the limbs or in parts of the body that they didn't associate with the polio itself, suggesting that there may have been injury to other nerves and limbs that they weren't aware of.

Technically, it starts about 15 years after you've had polio. For most people, it seems more like 30, 40, or even 50 years later that they started to get these symptoms. It is this kind of slow deterioration. I interviewed one man who had been in an iron lung in the United States in the 1950s and who is now back on a ventilator after having had what he felt was a full recovery from polio and leading an active life. Pretty much everyone I spoke to needs walkers or canes or were in a wheelchair after having been fully mobile for most of their lives.

There are some different theories about what causes it. The predominant theory is that the nerves that are left to take over as much function of the muscles as possible get metabolic fatigue over time. That's what these patients are experiencing when their bodies get toward the end of life.

Some have also wondered whether the polio is recurring or whether it's an autoimmune reaction. I don't think there's as much evidence or support for those theories, but we don't fully know. It is a diagnosis of exclusion, which is not a term people like.

But they're clear that you need to rule out other things that might cause people to become weak and fatigued over time. Every time I talk about my book to medical audiences, I always make sure that I talk about post-polio syndrome. It's the piece that is in many ways most relevant to caregivers now, because it's something that is still affecting our patients. To be honest, I've started to wonder how many patients who have unexpectedly struggled to get off a ventilator have perhaps had polio in the past, and we just never thought to ask. Could this be manifestations of post-polio syndrome? We're sometimes taken by surprise when someone doesn't do well after surgery or they have a respiratory complication, or they don't wean from the ventilator as we would expect.

I wonder if we're underestimating how often it's at play. That's something that's changed in my thinking about current care. But I know for those who know they've had polio and have post-polio syndrome, they're concerned about doctors knowing about this syndrome and being aware of it, because it does make them more susceptible to things. They're sensitive to anesthetics, for instance. If you don't have a provider who understands that, it can be potentially catastrophic.

Topol: Another dimension of the book is educating not just the public, but the physician community about this, because it's not out there. There is not a lot of awareness. It's critical that we know about it now. You also brought back memories for me in this book. I wrote about this in the last part of my Nature review of this wonderful book of yours. When I was at the University of Virginia, in college, I worked the night shift as a respiratory tech and I worked in the ICU. Most of the patients there were on Engström ventilators, which I think you called the Cadillac or something of ventilators.

Wunsch: The Rolls-Royce of ventilators.

Topol: That was the ventilator in 1974. But I had no idea where these ventilators came from. I just assumed they'd been around for centuries, because I was just a 19-year-old. I saw people who were so sick but who, like Lazarus, came back to life. That's what inspired me to go into medicine. Mechanical ventilation helped those patients for sure. Over time, I would see them on the night shift and days later, when I thought they were dead, they were getting extubated, and I thought, wow, this is amazing. So, it had an impact on my career as well.

Before we wrap up, I want to ask you about your next project is, because this one had to take a lot out of you. This was a feat to do this book. Every physician, no less the public, should read this. It is a phenomenal book. But are you ready for another 3- to 5-year project like this and a new book?

Wunsch: Yes. I've got the bug. I discovered I love writing, and I love the idea that there are so many important lessons out there in medical history. Much of the public doesn't understand where things come from, let alone physicians or other healthcare providers. I'm interested in finding those stories that haven't yet been told but are important moments.

I'm turning my attention, at least for the moment, to tuberculosis, because I believe there are stories to be told. Despite all the books about tuberculosis out there, some important stories need to be highlighted. That's what I've started scratching at, as I return to full-time work and continue to think and talk about polio.

The juxtaposition of the two diseases is fascinating because polio isn't eradicated. It is still there. Yet, where most of our time and attention needs to be in terms of the actual disease is in thinking about the long-term consequences of polio and post-polio syndrome. You allude to this in your review. We don't know with COVID-19 what those long-term consequences could be because viruses are nasty in that way, as we've learned from Epstein-Barr virus and multiple sclerosis and all kinds of other things.

There are all these relationships that are murky and hard to track. I'm hoping AI may help us in the future, that we'll be able to see these signals for problems down the road with patients who had COVID. I'm not talking about long COVID. I'm talking about something further down the road, maybe different, that is triggered by COVID, similar to those long-term consequences of the polio virus.

Tuberculosis is not a disease I know that much about either. But you start reading about it and you think, oh my god, it was everywhere, and it's still everywhere. Yet, we're not talking about it and, as multidrug resistance takes hold, how scary that is, that we are so far from eradicating tuberculosis.

I know there is a vaccine in the pipeline, and it will be fascinating to track and see whether it will make a difference. It is interesting to go from this disease, polio, that I thought of as a dead disease — I didn't learn about it in med school, I didn't need to know about it — to this disease, tuberculosis, that is still a huge burden in most of the world. The opportunity to educate people about that while telling the history is my next task.

Topol: You're prescient. During the pandemic, as you know, we saw polio, come back in New York State, and in other places. Because of some of the anti-science anti-vaxxers out there, it's inevitable we're going to see more polio outbreaks.

We have very little in terms of control of tuberculosis around the world, and even the prospects for a vaccine don't look like anything is imminent. That's a big challenge. Are you going to anchor that in one particular place in the world? Or will this be more of a global coverage of tuberculosis?

Wunsch: I'm definitely interested in those single-event moments. I'm interested in the early history of the development of the treatments for tuberculosis. So I'll leave it slightly vague for now, as it's still early days.

You alluded to the fact that it's the individual stories that are so fascinating. It's the individual people you get to follow in these stories. I want to make medical history feel exciting and as if it's fiction, rather than textbook. That's my goal in telling the early history of the treatments and trials for tuberculosis.

Topol: You've matched up a rarefied talent of telling stories, making history exciting, and transmitting your real humanitarian connection with medicine. I look forward to your future books and works. You're a real gem. We're so lucky to have had you on Medicine and the Machine today. We'll be following your career with great interest.

Wunsch: Thank you so much. It does feel like my book fits well with Medicine and the Machine, as it is about that sort of early moment as humans and machines got combined. It's been an honor to speak to you about it.

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