Science from the Field: The Power of Respiratory Muscle Training with Bernie Bissett

Bernie Bissett Podcast Imt Training

Welcome back to BMedical Science from the Field podcast series, where we shine a light on some of the amazing work being done here in our own backyard of Australia to further the fields of sleep and respiratory medicine. This episode, we had the pleasure of chatting with professor Bernie Bissett, an Aussie legend in respiratory muscle training.

Sarah: Now, I’m a sucker for an origin story of our passions, so I want to know what drew you to specialise in respiratory research, and particularly, respiratory muscle training?

Bernie: Well, I would consider myself an accidental researcher, in fact, because my direction and my career pivot into research was not something I planned. I certainly saw myself as a physiotherapist working in intensive care. I loved my work. I was very much a clinician. And my desire to do research was always driven by seeing what was happening to our patients in intensive care, particularly those that became very dependent on the ventilator to breathe, and realising that them being stuck on a ventilator for sometimes weeks, dare I say months, was a really difficult outcome for them.

I wanted to do more to set them free from that ventilator dependence. It was way back in 2004. I was working in the ICU at Canberra Hospital and had a long-term ventilator dependent patient. One of the consultant doctors there said to me, ‘Hey, Bernie, have you heard about inspiratory muscle training? There’s a couple of case studies being published about strength training for breathing muscles.’

When I was at uni the vaguely glossed over the fact you could train breathing muscles, and was covered with a caveat that there’s no evidence that it does anything, so they’re not going to bother spending much time on it in the curriculum.

Boy, were they wrong.

It’s so exciting that way down the track, we now have a ton of evidence. At the time I got my hands on the couple of case studies that were available and thought, ‘That’s just basic strength training principles, but we’re applying it to the inspiratory muscles’.

And so given that these muscles behave just like any other muscles, it made sense to me, because we’re obviously putting effort into strengthening people’s arms and legs and trying to get them back to sitting and standing and walking. Why weren’t we applying the same principles to their breathing muscles?

Because we know for sure that anybody who’s on a ventilator for more than a few days, their breathing muscles do just naturally weaken, because the machine does part of the effort of breathing for them. It’s that disuse atrophy that we know is par for the course, unfortunately. And that weakness could be contributing to their ventilator dependence. Well, that to me was a fixable problem that belonged in the wheelhouse of physiotherapists.

I don’t even remember how we got our hands on an IMT device. We mail ordered it and had it posted out to us at the physio department. And I remember standing in the storeroom with this device and it had a mouthpiece. Now a mouthpiece was no good to me because my patients had a breathing tube or a tracheostomy. So I had to figure out how I was going to connect that, and I remember rifling through the storeroom in the various boxes going, what connector would work here?

I found a very simple corrugated plastic tubing. I took the mouthpiece off the device and attached the tubing. I went, “Oh, you little ripper!” I could just attach this directly to somebody’s tracheostomy or ETT. If I set it at the right setting, I could get them to breathe against that resistance.

This could totally work. So, in the early 2000s, this is what we did. We kind of went rogue; we didn’t ask anyone’s permission. We just started trying this with a few of our patients. We were very sensible about it, ensuring that the patients we worked with were awake, alert, and able to follow instructions.

I explained it to them like this: “You know how lifting weights makes your arms and legs stronger? This is like lifting weights for your breathing muscles.” With the first few patients, I coached them through it and figured out the settings we would use. I looked at the case studies and thought, “Let’s apply good strength training principles.” Just like with peripheral muscles, I decided we should work at least 50 percent of their maximum strength.

We didn’t want to waste our time with very low settings. We could vary the intensity from low to high. At low intensity, they could only just complete six breaths per set before needing to go back on the ventilator. That was our approach: basic strength training principles, nothing particularly rocket science there.

Through trial and error, we found that about five sets, or a total of around 30 breaths, was the limit for what someone who was ventilator-dependent could handle. By about 2007, we had done this with quite a few patients. One patient, who had undergone post-op abdominal surgery and had been on the ventilator for a couple of weeks, showed clear improvement. We could chart how his tolerated training pressure increased over time.

Encouraged by this success, we decided to write it up and publish it as a case study.

Sarah: I think what’s great about that too, is because you’re coming from a clinical background, like you’re being able to put in information that’s going to be useful to clinicians. So not just coming out from that research perspective, like being able to put an info that we can use straight away.

Bernie: Absolutely. One case study isn’t going to change the world. We didn’t claim that this training guaranteed better outcomes. Instead, we reported that we did this training with one guy, and his training pressures improved over time. His ability to tolerate time off the ventilator also improved. Everything was moving in the right direction.

Beyond that, we decided to collect data on more patients to determine whether this training was safe. It was a bit of a wacky idea, removing ventilator-dependent patients from the ventilator for even just six breaths at a time and then putting them back. It felt a bit cowboy, really. I was fortunate to have strong support from the doctors and nurses I worked with in the ICU. They understood what we were doing and why.

We collected data from about 200 treatments, measuring details like oxygen saturation, blood pressure, heart rate, and patient experience. We published a case series of about 10 patients, showing that none of these parameters significantly changed before and after the training sessions. It was boring, and boring is good in this situation. It meant that the training didn’t compromise their medical stability. Meanwhile, their strength and tolerated training pressures were improving.

Around this time, Dr. Anna Ditschke suggested that the only way to prove this actually works is to do a randomised controlled trial. She wisely suggested that I enrol in a PhD program, which would open doors of support. This included Dr. Jenny Peratz at the University of Queensland, a world expert physiotherapist in intensive care with specialised experience, particularly with burns and unstable patients, making her an ideal advisor for our work.

The other advantage of doing it as a PhD program was that it opened doors in terms of funding, support for conferences, and access to journal articles without hitting paywalls. All those barriers that clinicians face just disappeared. I enrolled in the PhD program in 2010, and it took six years to complete because I did it part-time. The PhD ended up being a randomised controlled trial of this same kind of training. We proposed two trials: one starting while patients were ventilator-dependent and another for those who couldn’t do the training on the ventilator but had residual weakness afterward.

It was important to me, even back in 2010, to measure not just ventilator settings and monitor data, but also the patient experience. This included the sensation of breathlessness, quality of life, and functional activities. This was so novel at the time that it was hard to find other studies measuring these aspects.

I was fortunate to work in an ICU where the doctors understood that minimal sedation maximised our chances of doing early rehab interventions. We invested effort in different quality of life surveys and asked patients to rate their perceived exertion (RPE) at various activity points to capture this data.

Long story short, we completed one of the randomised controlled trials within the PhD. We showed that just two weeks of daily inspiratory muscle training (IMT) following ventilator weaning didn’t just make their breathing muscles stronger. Compared to those who didn’t do the training, the IMT group also showed significant improvements.

I remember presenting these findings at a big conference in the US. It was a big deal, with many of my physio and medical idols in the audience. I was the only non-medical person presenting in a session filled with doctors. I delivered the best presentation I could, and while it seemed to go well, some of the questions were challenging. One question was, “Of course, your quality of life improvement was a fluke finding. No physio interventions are ever adequately powered to show quality of life improvements.”

I remember scratching my head and thinking, “I’m not sure it’s a fluke.” It makes sense to me that if your breathing experience improves, it flows into every aspect of your quality of life.

And maybe even just the sense of improving—like last week I could only train at 17 and now I’m training at 34—that sense of progression may actually be quite profound for our ICU patients. For them, everything else might be progressing incredibly slowly, and they may not have a sense of progress and achievement. It seemed to me that the inspiratory muscle training gains they made counted a lot. From a psychological point of view, from the perception of “I can get better, I am going to beat this,” I think we underestimated how powerful that would be. These criticisms came from people I really respected, so I wondered whether it was a fluke finding or not.

I’m excited to say that when we completed the second RCT, where we measured the same kind of quality of life measures across two different metrics to ensure it was a real finding, we saw significant results again. When we started the inspiratory muscle training during ventilator dependence and continued for at least one week beyond, the quality of life improved significantly for those who did the training compared to those who didn’t.

I cannot dismiss this as a fluke finding. Giving these patients the opportunity to strengthen their breathing muscles and feel a sense of progress in their training made their lives better. Even if no other metric improved, that’s a pretty good return on an investment that takes less than 10 minutes a day and is really low risk. This intervention doesn’t require a lot of therapists’ time but can empower our patients to kickstart their recovery from a vulnerable and dependent time in their life.

The randomised controlled trials we did were crucial. It was essential to show the outcomes and benefits. These were small studies, each with 70 patients at a single centre. From that, we started to see really good signals of benefit, but the question remained whether this would translate to other centres and sites. It has been heartening to see a global shift towards embracing this potential.

However, we wondered what would happen with six weeks of training. Typically, strength training programs show initial improvements, but optimal recovery usually takes six to eight weeks. Many of our patients weren’t fully recovered, so we thought, let’s design a multi-centre study that starts training in ICU and continues for six weeks, measuring the difference and benefits.

Multi-centre studies are more challenging and require more organisation, but they also allow us to prove this isn’t just a “Canberra special.” We wanted to maintain patient-centred measures, but many ICU patients are on the ward or at home by the six-week mark. We had to consider how to empower patients to continue using this technology at home and how to follow up with them. We needed to design measures that could be done over the phone and keep track of patients without losing them to follow-up, encouraging them to keep training.

I’m pleased to say we’ve been planning this study for over two years. We have 23 sites around Australia and New Zealand engaged. Our first step is launching an audit to measure the usual practice of physiotherapy in these centres, establishing a baseline for comparison with usual care. Long-term studies can see a change or creep in usual practice, making group comparisons difficult, so we need to understand usual care and check it at the end of the study.

The interest, enthusiasm, and engagement from physios around Australia and New Zealand have been thrilling. Our study team sees this research not just as a way to answer important questions but also as an opportunity for hospitals to change practices, learn new clinical and research skills, and learn together. It’s fabulous to be a part of that.

Sarah: It’s exciting to hear that it’s taking off here in our corner of the world. In Australia we punch above our weight in terms of research, but it’s always exciting to hear when we’ve got big things like this that are going to impact clinical practice everywhere.

Often when I talk to researchers, one of the big challenges that we discuss is how to transfer the learnings from the research setting into a clinical setting. Obviously you went about it from the other direction. You were in the clinical setting and pulling in, and this is obviously something you really excel at.

What are some of the most pressing respiratory related concerns that you think we have today? And how can we take those learnings from respiratory research into the mainstream?

Bernie: That’s a really good question. So, the work we did in intensive care, which has been our primary focus, has led to inquiries from people with various conditions asking if breathing training could help in other areas. One interesting area is long COVID. Many patients battling long COVID experience breathlessness, one of the top four most common symptoms. People are keen to try anything to reduce this breathlessness because it significantly affects their daily activities, work, study, and caregiving roles.

There are studies, particularly from the UK and parts of Europe, showing that high-intensity inspiratory muscle training for long COVID patients improves not only their breathing strength but also reduces breathlessness and enhances their quality of life. These studies measured exercise tolerance through tests like the six-minute walk test, and those who underwent the training could walk further. This demonstrates the meaningful impact of this training, translating to everyday benefits.

At our long COVID clinic at the University of Canberra Hospital, we offer inspiratory muscle training to our breathless patients. Similar to ICU patients, these individuals often struggle with even simple activities like walking to the mailbox. This training, which can be done sitting in a lounge chair in front of the TV, helps them make progress and provides hope that they can improve their condition.

Another community interested in this training is athletes. There is a significant connection between breathing muscle strength and the oxygen utilisation of these muscles relative to peripheral muscles. Endurance athletes, including Olympic rowers, runners, cyclists, and swimmers, are keen on improving their breathing muscle efficiency. Even a small improvement can free up extra oxygen for their peripheral muscles, which can make a significant difference in their performance. Studies have shown that even a two or three percent improvement can be crucial, especially when competing for a gold medal. As I often tell my physio students, a two or three percent improvement can be the difference between taking home the gold medal or not.

Sarah: I guess this is a bit of left of centre, but because you’ve done it, do you have any tips for clinicians out there that maybe want to be implementing things like this that aren’t already in their standard practice in their hospitals or their clinics?

How do you get past some of those barriers if you’re trying to bring some of the research into your clinical practice?

Bernie: Yeah, that’s such a great question. How do you get the doctors to turn down sedation so that you have half a chance of doing this? It’s not easy, but some of the things that clinicians have told me over the years that have helped are going to the staff in the area that are having resistance—maybe that’s doctors, maybe it’s other colleagues—and presenting them with a clinical practice guideline on how to do this. Here’s a step-by-step guide that is based on evidence, on studies, and has been shown to be safe and effective.

We tried really hard to put out a document just like that. I think it was published back in 2016. We published it open access so that clinicians could literally walk into their boss’s office and say, “Hey, here’s this thing that we want to do. Here’s a step-by-step guideline. This is what’s being recommended.” They’re not proposing to do something completely wacky; they’re trying to implement something that has been shown elsewhere. In our experience, people have found that kind of document helpful.

Another kind of document that can be helpful is if you can get your hands on the internal documents that other hospitals are using for that technology. For example, a lot of people ask, “What’s your protocol? What’s your credentialing process to say that someone’s safe to do that technique if it’s a bit different?” Often, it’s just a little checklist of the things that a more senior clinician has watched them do. The generosity among hospitals that I’m aware of is huge. “Here’s our standard operating procedure, or here’s our guideline, you can have it.” If you can go into your section and say, “Here’s what’s being used, we can adopt it and put our hospital’s spin on it,” you’re rarely having to invent these things from scratch.

Other things we have done include making videos. Some of our clinicians, bless them, have created little videos. “Here’s this particular machine that we’re using. This is how we do it. You press this button here.” One of my gorgeous physios at Canberra Hospital put together a how-to-use the electronic inspiratory muscle trainer. That was used quite a lot by our junior physios learning it. Next thing I knew, I was sending his little how-to video to lots of different hospitals, saying, “Hey, have a look at Tony talking you through how to do it.” It was very low tech, but just having those how-to steps is really, really helpful.

Researchers should remember that doing your RCTs and studies to prove something works is important, but we mustn’t forget the translation value of publishing those step-by-step guidelines. It can be hard to find a journal that’s interested, which is a bit sad, but when you find a journal that sees the value of that, you can make a big difference. We very strategically published our step-by-step guideline in Australian Critical Care and published it open access. I know that it’s now one of the most downloaded papers of that journal because it was meeting that need for, “Okay, we’ve seen the studies that it works, but how do you do it in practice?”

Thinking back to why I started doing this in the first place, I love going to different parts of the world and having people in Singapore or Ireland say, “Oh yeah, we used your how-to guidelines so that we could bring it into our unit.” That’s great. The crazy idea that we had in Little Canberra Hospital in the early 2000s is now benefiting patients in other parts of the world.

One of my honours students asked, “How has practice changed in the last few years?” I wouldn’t for a second claim that it’s just because of what we have done, but I had a sense that things were shifting. Compared to a study in 2015, where they said about 5 percent of physios responding to a survey were using inspiratory muscle training, we found that it was up to 63 percent of ICU physios that responded to our survey. That’s a pretty massive change within about five or six years. When you hear that the time required between evidence and actual practice changes is around 17 to 20 years, I’m pretty excited that physios around the world seem to be in touch, interested, looking at the evidence, and willing to evolve their practice much faster than that. That gives me hope that our patients around the world are going to benefit from being in touch with what the evidence is saying and being willing to adapt and evolve over time. I think that’s great.

Sarah: What researcher papers are getting you excited at the moment?

Bernie: I think it’s interesting to see where people are going with early mobilisation rehab in ICU. There are some controversies around how far we push the envelope on that. I’m really interested to see how people interpret evidence and some of the dodgy ways that evidence can be interpreted around that. I’m watching that with great interest. I’m really excited to see how the conversations around long COVID are switching over to, or maybe we need to be thinking about, post-viral conditions more broadly, that some of the challenges people have with their breathing around long COVID.

It’s not because long COVID is special, but within our community, there’ve been people recovering from all kinds of different viruses. And we need to be really thinking about that small subgroup that really struggles in our community after lots of different illnesses and thinking about how we can better meet their needs. So I’m really interested in how that direction is going. I think we’re seeing a shift more broadly in the literature away from just focusing on the numbers on a machine and what those numbers are saying. We’re seeing a big shift towards what matters to our patients and our consumers. We’re seeing much more consumer-led research, which gets me excited. We’re actually talking to our survivors, for example, of ICU or different conditions, and going, yeah, but what should we be managing? What should we be measuring? That’s going to make a difference to real people. So I guess I’m excited about seeing that shift. Generally speaking, I’m excited to be part of a profession, particularly physiotherapy, that prides itself on being evidence-based and we can keep looking at that evidence and changing what we do over time.

It would be incredibly boring to be part of a health field where you didn’t change, right? Like imagine if I was still doing the same techniques that I learned back in the late 1990s, and I was still doing exactly the same treatments to patients now. Oh, that would be snore-worthy, I think. So it’s very exciting to be able to be part of that conversation. So yeah, I’m very optimistic and hopeful that our next wave of health professionals and researchers will be more patient-focused, more consumer-focused and keep asking questions about things that matter to people rather than just what the machines can do. Which I think even within my lifetime, I’ve seen that pendulum start to swing, which is exciting.

Sarah: I love how from the very beginning you’ve been asking those questions, not just of the numbers, but also of the impact on people’s lives and those quality of life measurements. For the future of respiratory medicine, particularly regarding the impact on overall well being and healthcare, what do you think the future looks like?

Bernie: Oh my goodness, I would love to think that we will continue to see the evolution of technology and how it will enhance clinicians’ ability to connect with patients, particularly in rural and remote locations, to monitor treatment and provide feedback in an individualised way. It will be really exciting to watch the new apps that are coming out, which can connect with devices to inform about someone’s training. Imagine if, in our current study, we could connect with people who’ve been discharged to rural New South Wales—patients who would normally have been lost to follow-up. What if we could still connect with them in a real way and monitor their training and give them feedback?

I think technology is going to be really exciting to augment and supplement what clinicians can do. I don’t ever think we’ll be in a situation where robots are in charge. Robots have the potential to be amazing, but the smart evolution of technology will increase the ability to communicate in a really individualised way between clinicians and patients, particularly in rural and remote settings.

Even just for Canberra Hospital—obviously, Canberra is not a big city—many of our patients we care for go home outside our metropolitan borders. Historically, respiratory physiotherapists used to be very hands-on. You might be cupping their chest or doing something else in a hands-on way. But once they go home, it was like, “Oh, well, good luck with that.” Now, we’re incorporating more techniques, more machines, more things that we can offer people that they can take home and continue for life. For example, we can now get somebody started on some breathing training while they’re an inpatient.

Based on the evidence, we can suggest things they can take with them to continue at home, maybe even continue their training two or three times a week for life. And we can say to them, hands on heart, because the evidence has shown us, if you keep doing this kind of training in this way, you can reduce your rate of hospitalisation because of your lung disease by about 30%. That’s a pretty big motivator, you know?

So, I think our ability to follow up or connect with them if things do deteriorate would be fantastic to see in the future. It should be a really easy thing for often metropolitan-based clinicians to connect with patients outside those borders and to offer them more than just “good luck with that.” That’s where I’d love to see us evolve too. I don’t think that we saw Telehealth really make some progress during COVID obviously, but what we still hear from our patients very often is Telehealth is good once you’ve already got a relationship established with somebody and you’ve connected and maybe had some hands-on contact. Follow-up by Telehealth seems much more palatable than just an entire model of Telehealth.

So, yeah, I see somehow that Telehealth could be our continuation of the conversation with people if they’re going home from hospitals in our big cities.

Sarah: Amazing. Thank you so much for taking the time to speak with us today.

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Professor Bernie Bissett
Canberra Hospital & UC

A physiotherapist by background, she has worked in Sydney, London and Canberra, but has spent 20 years of her career focused on using respiratory muscle training to accelerate recovery for intensive care patients. She is also involved in research about recovery from Long COVID, and works closely with clinicians to enable evidence based practice and consumer-centred research. She has shared her work around the world, and in the last 3 years has been an invited speaker in New Zealand, Spain and Kuwait. When not busy with research or teaching, you will find her lifting heavy things in time to music, or walking her two Cavoodles in the Canberra sunshine.