Physiology practical demonstrations - Spirometry

In this short video, Terry Gleave (University of Liverpool, UK) gives a demonstration of a clinical test of the respiratory system using a Bendict-Roth Spirometer; a device used to analyse lung volumes. This video has been adapted from a Massive Online Open Course (MOOC), titled 'Physiology: The Science of Life', which ran in 2018 and 2019. The course was developed in partnership between The Physiological Society and the University of Liverpool and was hosted on FutureLearn. Transcript: So we've got a Benedict-Roth spirometer. And it was one of the ways before we moved into a digital age where we'd be able to look at the air volumes, the lungs, looking at your static volumes, so things like tidal volume, inspiratory capacity, expiratory capacity reserves, and also vital capacity. So what we're going to do is use a Benedict-Roth spirometer to look at your breathing. What you're going to do is sit, relax, pop the mouthpiece in. Before you do, pop the nose clip on because we want to make sure that all of the ventilation that's going on is actually coming through your mouth. If you want to, put yourself comfortably and offer yourself up to the mouth piece. That's it. And you'll notice that nothing is moving, nothing is changing at all. You are able to breathe. And what's happening is you're breathing through the atmosphere. So there's a set of valves underneath and it allows us to breathe through the atmosphere rather than the gas that's contained within the bell. The reason that it operates it this way is so that you've got an opportunity to just get used to the breathing pipes, probably a good two inches in diameter. But essentially, you will be allowed to breathe through that and there shouldn't be any issue. If you're feeling uncomfortable or nauseous at any point, please just back away from the machine, but stay seated, You don't need to ask for permission. So we'll set the Kymograph going. It rotates in at two and a half millimetres a second. So it will allow us to do some analyses later, if we so wish. And what I will do is I'll move the valve over to the spirometer. And if everything is working, that should be moving up and down. Right, so what you can see, is, as you're breathing in and out, you've got the bell moving up and down. And that is a direct reflection of the changes in lung volumes as a consequence of the pressure and volume changes that are happening actually in the lungs. The chart recorder is linked to a pen on the balance side of the tin, the drum. And so it allows us to see directly what's going on with the inhalation and exhalation. We call it tidal volume, because it's almost ebbing and flowing. And you can see it on that side. So what I'm going to ask you to do, as you carry on breathing like that, you're breathing normally, you've got some good tidal capacities, when I ask you to, and I'll tap you on the shoulder to give you an indication, I want you to take the biggest possible breath in you can. So if you can do that now for me, please. And then blow that out. Now stop and go back to normal breathing there, please. And what we've done there is we've looked at inspiratory volume. And it'll give us an idea of an inspiratory capacity and an inspiratory reserve. And if you can do the same, but given your maximum exhalation. And then go back to normal, and then normal breathing. What that one has now given us is your in-and-out maximum ventilation. So it gives us the vital capacity. And then just keep breathing normally. And thank you very much. I'll put you back onto the atmosphere. And then I can stop the drum. And that's it.