Snoring kills (ABC Radio 31 July 2008)
The quiet hero of snoring therapy has just received a Clunies Ross Award, yet another recognition for physiologist Professor Colin Sullivan of Sydney University. His work began over thirty years ago and has led to a global, multibillion dollar industry based on masks directing airflows over the user's face. But is it true that apnoea, when people stop breathing as they snore, is behind most of today's vascular disease? And what next in this immensely important research?
Robyn Williams: What a dreadful noise. Why do we do it? And how did humans survive out there in the forest, advertising their presence to all rampaging carnivores that they were there, asleep, ready to be devoured. Hello Robyn Williams with In Conversation. And today's chat is about more than snoring. It's about apnoea, those moments when breathing actually stops, damaging our physiology in the process. Henry VIII had apnoea, as did Churchill, Brahms, Rosie O'Donnell and Billy Connelly so I'm told by our producer, Nicky Phillips, and she should know.
But for the last 30 years there's been an effective treatment. The man behind it is Professor Colin Sullivan from the University of Sydney, and this was the turning point way back.
Colin Sullivan: Well I remember it very clearly. The study was done in my laboratory, where I am still, at the University, and the patient was really very ill with the condition, he was 43 and he had severe sleep apnoea. I in fact recommended tracheotomy for him but the family refused outright.
So he agreed to try this experimental method and in fact my first two PhD students who were involved with it; Dr Faiq Issa and Dr Michael Burton Jones. and we brought him in to the lab and set him up on a bed that I had set up there, or a bench, and put on the mask. In fact it wasn't a mask, it was a pair of prongs attached to quite a large-bore tube, which I literally glued on with silastic material, which is a medical silastic, and we started recording, turned on the pressure and very quickly, like within minutes, he was asleep, we let him sleep with severe apnoea, repeated obstructions, his oxygen would go down to 50%, just turned up the pressure...
Robyn Williams: The flow of air.
Colin Sullivan: We turned up the flow because what it's doing is increasing the pressure, so turned up the flow of air and then there was this absolutely normal trace and it was spectacular. The excitement was very hard to recreate, it was incredibly exciting so we waited and I decided well I'll drop the pressure again, it could have been he's gotten better spontaneously. We dropped the pressure-back came the apnoea, let it go for a few minutes, increased the pressure, stopped it again, decreased it-so we did this through several cycles. And I remember thinking well the next thing I need to know is if it's going to work all night. So we decided to leave him on it all night. So we went through until about 6.30 in the morning and he slept for the rest of the night.
I'll never forget the look on his face when he woke up, because he was bright and alert and that day he was under my care in the hospital, he went back to the ward and he was awake all day for the first time. So it was a fantastic night and the physiology was very clear, it's one of those, sort of, moments when you absolutely see what's occurring.
Robyn Williams: And you wrote a paper straight away?
Colin Sullivan: That's right and I sat down in my office while we were doing this and drafted the first draft of the paper. I was going to send off that paper but decided that it might be a one-off, I didn't think it would be, but I would wait until I got several other patients. So we had four other patients and I trialled them first before sending off the paper.
Robyn Williams: Professor Colin Sullivan. And that work has led to a huge industry, many prizes and membership of both scientific academies and, just now, a Clunies Ross award. But let's go back to a time when our fathers snored like walruses, to a time of Franklin Delano Roosevelt, who also had apnoea by the way. Was there any treatment at all and did it matter?
Colin Sullivan: Certainly not until the 1990s when I started working in the area, I remember the day, it was 1975, I was doing a PhD in physiology with Professor David Reid and our interests were how breathing was controlled. And he got me interested in the area because of an interest in the sudden infant death. However, I remember it was in November, another colleague of mine did the first sleep study on a patient and we became aware of sleep apnoea through that, through some literature that had been published several years before but it was still very unknown. So between that period and well into the 1980s people were not aware of the disorder, even though we'd become aware of it and no one was aware of just how extensive it was.
Robyn Williams: And that question of snoring-and then when you stop breathing which is what apnoea is-was that thought to be just a normal process, that's the way you slept at night?
Colin Sullivan: Colin Sullivan: Absolutely, I think snoring at least was believed to be essentially normal, people had written, and talked, and joked about snoring forever, and because it's so common people assume that it is normal. However, the stopping breathing, which again would have been and was reported, was thought—I would think that people would have seen their partners or father etc. doing that and thought it was part of ageing etc. So I think that's probably one of the reasons why people didn't take it seriously. I think the other reason is that because all of the events occur during sleep, certainly at that time in the 1970s the medical approach to sleep was the patients are all right and you can leave them alone.
Robyn Williams: Well, look, this has puzzled me for a long time because if you go back further than 10,000 years, during 100,000 years when we were wandering around the plains or the forest—and it struck me about babies as well, if you've got screaming babies in the forest and you're surrounded by sabre tooth tigers or whatever, you're not going to last. Similarly if all the men are snoring around the campfire then you're advertising your presence and it's a risky business. Is it likely that snoring is a modern thing and we didn't do it way back as primitives?
Colin Sullivan: No I don't, I think it's occurred as part of the evolution if you like of our upper airway and it's probably in part a consequence of our developing speech capacity-because the upper airways are actually a muscular tube which depends on muscle tone to stay open. So I don't think it's a modern phenomenon. Certainly there are references to snoring and obstruction in ancient literature, so I don't think it's recent at all. Some people in a semi-humorous way have suggested that snoring was protective, in the sense that if you're in a cave and making this incredible noise it sounds more like a lion than a human.
Robyn Williams: Keeps the beasts away.
Colin Sullivan: Yes, that's right. But no, I don't think so. I think certainly in our time one of the major risk factors for developing snoring and obstruction is course obesity but it's not the root cause. You have to have a small airway to begin with and it also involves the loss of muscle tone in sleep. But in modern times of course it's part of the obesity epidemic that we are facing.
Robyn Williams: Yes indeed, well of course with babies going around in ancient days meant that they did not cry as much, probably hardly at all, and I'd infer from what you said that slimline cave men or Neanderthals or whatever would tend to snore rather less. But bringing us to the modern day, lots and lots of men especially have snored a lot, and in the old days when you were first working, when the realisation came that it was a problem, the first sorts of treatment were surgical and fairly drastic, weren't they?
Colin Sullivan: Yes they were. The first treatment for obstructive apnoea was a tracheotomy, which was to make a hole in the windpipe and essentially bypass the upper airway. The first people to do that did it in the late 1960s, 1968; at that point it was thought to be a rare phenomenon a rare disorder. However during the 1970s a small number of centres started to identify patients and use tracheostomy to treat it.
Robyn Williams: That's pretty drastic.
Colin Sullivan: It is drastic and in fact I went overseas to Canada where I worked on how sleep interacts with breathing—really driven by these new findings for us in the 1970s-but I returned to Sydney University and Prince Alfred in 1979 and my task then was to look after respiratory patients with respiratory failure. But I also began looking at people who had sleep apnoea. And we found really severe cases, few of them-in that first year I found two—but they were so bad we did do a tracheostomy and it was life-saving but it wasn't a treatment you'd use for people who had less severe problems.
Robyn Williams: No. Did they lose their voice in the process?
Colin Sullivan: Yes, but what we would do was put a tracheostomy tube which also had a voice part, so they could just block the tube in the daytime, but it's a drastic treatment. The other treatment that began to be used in the 1980s was surgical reduction of the pallet, so that the surgeon would go in and literally ream out parts of the upper airway in the throat region.
Robyn Williams: The flap at the back.
Colin Sullivan: That's right. And that was really introduced by a Japanese surgeon, first in Japan, and then he went to the US where they started to do it. And as this disorder started to be recognised, people thought well this is going to be the treatment—and of course it doesn't work.
Robyn Williams: It doesn't work, I remember Norman Swan did a Health Report on the topic and showed in fact that it was a very mixed success if anything. Then you found there was a way of using what's now called CPAP, a flow of air over the nose. How did that come about and how were dogs involved?
Colin Sullivan: Well I remember very clearly my research in Canada involved working with sleeping dogs, and the person I went to work with, Elliot Philipson, had developed a model where he could study dogs' breathing during sleep. In fact the dogs he had he made a tracheotomy so that these dogs had a hole in the front of their neck, which in fact was only used when he was doing the study, so it was allowed to just close up and when the dog ran around, it could still breath and eat. And what he would do was then put a tube in to measure air flow during sleep and measure how it changed.
And I worked with him on looking at how if your oxygen level fell, if your CO2 level rose, and also blocking it, so creating if you like an experimental model of what sleep apnoea is.
When I came back to Sydney I decided I wanted to see rather than doing a tracheostomy to make a mask and do the same experiments in the dogs with a mask. So in fact I made masks for the dogs so that I could measure their breathing asleep and block the airway and see how they would respond reflex wise. So that's the background to that but at the same time I started looking for patients and also that involved doing all-night sleep studies. At that time there were no sleep laboratories, so in fact I had to find an area, I remember I used my good colleague Dr Sandra Anderson's lung function laboratory. So I would go and rearrange it sort of after hours...
Robyn Williams: She's the asthma lady?
Colin Sullivan: That's correct...and have to clean it up in the morning otherwise I'd be in trouble.
Robyn Williams: You were working some pretty odd hours yourself, weren't you?
Colin Sullivan: Very odd hours. But also we didn't have the tools. The instrument that really opened this up was the oximeter, a device which measures how much oxygen is carried in the red cells, and it's done by measuring-at that time the colour change in the earlobe-mostly now the finger probe. You see them all the time in hospitals but in those days that technology had just been developed. But that then allowed us to measure oxygen levels continuously in a non painful way that allowed people to sleep.
And that showed for the first time what was happening during snoring and apnoea, which were often spectacular falls in the level of blood oxygen. But that was everything, to do those studies, I had to put them together myself and I was seeing, as I started to see patients with this really very serious disease, once you see someone obstructing and having falls in oxygen levels, the tracheostomy wasn't an attractive treatment, we used it but we saw it as a lifesaving treatment.
So I was looking at a way of controlling the upper airway closure and I remember when it occurred to me I was looking at what at that time people believed was the mechanism and there were a number of mechanisms being proposed. One was that the airway was being sucked closed and another one that it was reflex constriction of the airway, so that no one was absolutely sure, although tracheostomy clearly solved the problem. And it occurred to me if I could splint it—the pressure—now although the idea is simple it wasn't so simple to think about how to do it.
Robyn Williams: Well let me ask you about the question of snoring, because lots of people snore but not necessarily all of them have apnoea, the stopping of breathing. Are many people just more or less safe snorers?
Colin Sullivan: I think that's a fair comment, yes there are, but snoring is graded from very mild to quite severe to obstructive and we don't know really where the threshold is. Although we do know that once you start snoring, snoring tends to progress-we understand why it progresses too because snoring actually damages the tissue. But we unequivocally know that once you have sleep apnoea that it is a major risk factor. It is actually a cause-what we now know is it causes high blood pressure, it causes heart attack, it causes stroke, and there is very clear evidence it itself is a causative mechanism in the underlying disease that leads to those, that's the vessel disease, atherosclerosis.
But when we come back down the severity, so for instance if you are a heavy snorer and people are commenting on it it's very likely you are going to have numbers of apnoeas-it might be 7 or 8 in the whole night-when you come back down the scale of severity we don't really know where the line is that puts you at risk. However, it is very clear that snoring gets worse with age. There are big epidemiological studies now that do link the history of snoring and outcomes and if you have a history of long snoring you're much more likely to have a stroke, heart attack, etc. But those epidemiological studies show the link, they don't actually show the individual, if you as an individual are snoring a little bit, what is your level of risk. In the mild end the answer is I don't know.
Robyn Williams: Well of course a person we haven't mentioned so far is Professor Peter Farrell, who became head of ResMed, the great company that made use of some of these ideas. And he is famous for saying things which are startling. He's not a person who is given to understatement and I remember him saying something like apnoea being the cause of something like 90% of cardiovascular diseases like blood pressure and stroke and so forth. Would you put it on that scale?
Colin Sullivan: It's certainly up there, I wouldn't put a figure on it like that because it's very difficult to dissect out the various elements. There is no question though now that we know that when patients are treated for snoring and apnoea their risk of cardiovascular disease drops dramatically. There are a series of studies done over long term where they've used CPAP both as the treatment if you like-and it is if you like a tool to understand the underlying disorders. But there is no question now if you have a control group untreated and a treatment group there is a huge difference after something like 8 years in the number of people having heart attacks, strokes etc.
So there's no question about the link. I wouldn't though put a number of 90% on it, we know when you go the other way when you look at patients who have had heart attacks, who have had strokes, a very high proportion of them have sleep apnoea and have had it for years. So it's a very important link but that's not a figure that's really justifiable at present.
Robyn Williams: Well let's look at the way the technology came to be, on the face of it you wouldn't necessarily imagine that people would be comfortable lying there in bed with a face mask on and a machine blowing air at them. How cumbersome was the first model, was it really monstrously offputting in the beginning, and how did people respond?
Colin Sullivan: Well no, not really, not given the severity of the condition. I think we originally made masks for people, we hand made them and they were made designed around the person's own nose, so it was a bit like making a dental apparatus, if you like. We had to make a mould of the nose etc. Now those masks actually were very comfortable and the machines we used to produce the air flow and pressure were really off the shelf, machines used for other purposes which were also very effective. But they were big and produced far too much air and we had to leak a lot of that air-yes, they were noisy but people would put them outside the room etc. But you're quite right, I think the notion of actually wearing something during sleep was quite alien, not only to most patients but to doctors. However of course the technology development has been an improvement in the masks, improvement in machines, intelligent machines, and that of course has been a major development—but of course it's still the same device.
I think one of the interesting things about this treatment is that unlike say breakthroughs in other areas like diabetes, or gastric ulcers for instance, or if we think about the bionic ear and hearing loss-all those areas the disease was known, whereas at the point where I first used this as a method to try and understand the disorder, the disease was really virtually unknown.
So the device was spectacular in that it taught us so much about the disorder because we would literally turn off the obstruction and in those years my science was all about looking at what happened to control the breathing, the blood pressure, the various blood hormones for instance. We'd measure them before and then literally turn the disease off overnight and measure them after and we saw major changes. So in fact it's an experimental tool to unravel a disorder, it was actually spectacular if you like.
Now it took a long time before people accepted it as a treatment. In a way the fact of the experimental tool and the fact that it is a very safe treatment preceded our knowledge of the disease and it played a pre-role in the development of the whole area. Also when the treatment became available people started to look for the disease and as they looked they'd see more and more happen.
Robyn Williams: Now what about long term users, because obviously this has been going on for a long time, so have you been able to see whether patients kind of become recidivists-they get their apnoea back again-or does the treatment last indefinitely?
Colin Sullivan: Well first of all it doesn't cure the apnoea it actually controls it, so it's a physical therapy that stops the key event which is obstruction which leads to all the consequences. By and large if people start to use it and accept it early, many of them will actually continue to use it over years. The first patient I put on died only recently, he died of another disorder, malignancy, and he actually used it every night virtually for 30 years until his death a few months ago and that's representative of a very large core of people.
Probably the main reason people would use it is because of the immediate benefit they get, so the fact that they can sleep all night and wake up fresh and function well-they tend not to use it because of the long term benefits, although they are there, that it will stop you having hypertension, it will prevent you having a heart attack, and will prevent you having a stroke. That is actually a much more recent drive to use it but the reason people use it is because perhaps unlike some other diseases they've got immediate feedback, they feel terrible in the morning, they can't function very well, their mind's sleepy, their mind isn't focused—use the treatment, have a wonderful sleep, wake up really fresh and function really well.
So there are certainly a lot of people who can't use it, no question about that but there is a large percentage of people who will use it every night and use it long term
Robyn Williams: What stops them using it?
Colin Sullivan: Well I think it is the inconvenience, although that's improved dramatically with the development of masks and machines. I would say that if you don't have the problem you wouldn't want to use it. The treatment-I like to compare it to the need for glasses, if you didn't need glasses you wouldn't use them, but it's so inconvenient not to, so CPAP is a little bit like that. The people who don't tend to use it are those who don't quite have the level of symptoms, but to be frank you wouldn't use it if you didn't have to.
Robyn Williams: Now what do you think of the fact that it's become a multi-million dollar industry and that ResMed, with which you have some association, is virtually dominating the world market with extraordinary success?
Colin Sullivan: Well I'm absolutely delighted at what's happened, that it has actually spawned what is a huge global industry. ResMed isn't the biggest; the other biggest company is in fact called Resprionics (?) who were just several months ago bought out by Phillips for some huge amount but ResMed is a close second. But it also has spawned an industry with all the diagnostic technology etc. I don't know what the absolute numbers using it are but it's in the order of 3 to 4 million people use this treatment every night so it's quite extraordinary. ResMed of course is now Australia's biggest medical device company I think they're looking at annual revenues this year in the order of a billion US dollars so it's a big business.
Robyn Williams: I hope you got some of the action.
Colin Sullivan: Oh, I was a foundation shareholder so I was very fortunate in that.
Robyn Williams: I don't suppose, Colin, you snore yourself do you?
Colin Sullivan: Unfortunately I do now; it's a function of age in very large part. My mother snored quite badly and she in fact had obstructive apnoea I recall, I didn't know what it was at the time, though unfortunately I do, I've put on a bit more weight than I should have and trying to keep fit.
Robyn Williams: So you're not on the device yet?
Colin Sullivan: I try them regularly but I'm not on the device on a regular basis no.
Robyn Williams: Well congratulations, I think it's a marvellous story and a classic example of the way that original science can link with industry and make a difference.
Colin Sullivan: Thank you.