The First Response in an emergency

Light-based sensors can give us important information about a patient's condition - such as their heart rate, or how much oxygen is in their blood. Laura Brooks has been to see how a new light-based device could help save lives in an emergency...

James - This is James Baker. I'm a partner at Cambridge Design Partnership and I look after electronics and connected products.

Laura - This week, Cambridge Design Partnership (CDP) received two awards for developing a wearable medical device that could help medics save lives on the battlefield.

James - At the point of injury, the battlefield medic faces a very challenging situation. They're trying to rescue somebody, they're trying to keep them alive, and there's many distractions, there's probably significant danger.  And the process that they go through is to look at breathing and heart rate and base the kind of care that they give off those readings. But measuring those parameters is quite challenging and whilst they're measuring them they're not providing care.

Laura - A challenging situation indeed! But CDPs First Response Monitor could support medics in their difficult task. The gadget uses light based sensors, among other techniques to measure a casualty's vital signs...

James - A little piece of focus technology that can give them those important parameters and let them concentrate on providing care brings real benefit and helps them to improve the casualty outcome.

Laura - The little monitor is only about the size of the top joint of my thumb. It has a small display screen on the front  and a clip on the back - a bit like a clip on an earring except that instead of clipping onto your earlobe, it clips onto your nose...

James - It needs to clip onto the nose because we're interested in measuring both heart rate and breathing rate. The heart rate can be measured using an optical technique but the breathing rate we do by looking at changes in temperature and humidity that are influenced as you breath in and out.

Laura - Can you talk me through how it works?

James - Yes. We shine light into the tissue of the nose and that gets bounced around and diffused and reflected inside the tissue and some of that gets reflected back to the device. And looking at the amount of light that gets reflected back, it's influenced by the amount of blood that's in the tissue of the nose, so that gives you a signal that's related to the heart rate with blood being pumped into the nose and then moving out again.

Laura - Is that similar to how fitness trackers work that people might have at home?

James - It's  exactly the same technique, so on many fitness trackers you'll see a light on the back that's contacting the skin and its using exactly the same technique to measure heartrate.

Laura - That's neat, I always wondered how they work. So what else can you sense with this device?

James - Staying with the optical technique, if we actually use two slightly different colours of light shone into the tissue of the nose, we can look at the fact that blood cells change colour dependent on how much oxygen they're carrying. So looking at the ratios of those two light wavelengths that come back to us, we can actually determine the oxygenation state of the blood.

Laura - So you record all of this data from the patient - what do you then do with that data?

James - There's multiple levels of how we use and display that information. The primary method of display is that those three parameters are shown on the device itself - there's a nice little bright OLED display on the device.

On the next level we can actually communicate that information off to a wireless device, such as a mobile phone or a tablet and that allows us to do two things; we can show for a single casualty how those parameters have changed or trended over time, but it also allows us to monitor multiple casualties so you can start thinking about which one of my patients needs my attention most urgently.

Laura - You've got your smartphone here - can you show me how it works?

James - Certainly! So you can see on this front page we're currently connected to one device and we're showing those three parameters of respiration, heart rate, and SPO2 for that one device.  We could have multiple devices connected to that front page.

Or, alternatively, you can dive more deeply into the information from any one device - so I'm pressing that one - and it's brought up some graphs that are looking at those instantaneous parameters but it's also showing me graphs of how those parameters have changed over time.

So you can see, for example, the breathing graph had me breathing at about twenty two breaths per minute but now you can see where I've taken the device off and it's now trended down to zero breaths per minute. I think if the device was still attached, that would be a big alert for you to actually go and have a look more closely at me.

Laura - James told me that this kind of monitoring also answers another key challenge in treating casualties in dangerous situations - how to keep information about the patient with the patient while they are transported to safety for further treatment. Since the wearable monitor stays with the casualty the data that it records is automatically passed on to rescuers and is available to whoever is caring for them next. Once more, James thinks the monitor could give lifesaving assistance in a range of different scenarios...

James - We originally started by investigating military uses but we see lots of opportunities for this in all sorts of civilian first response situations as well, such as disaster relief or anywhere there's a multiple casualty situation.

It can bring real benefit where you have first responders - people on the scene - who have some level of medical skill but they're not the professional emergency services, and they're trying to deliver care whilst they're waiting for the emergency services to arrive. This is a device that can give them a real insight into the immediate health of the patients. So you can see on the example here we've got three casualties being monitored and it's drawing our attention to casualty one. It's showing that their blood oxygenation is dropping below a bound that we've set as considered to be acceptable saying this person needs immediate attention from you.

Laura - What's next then for this device - will we be seeing medics on the frontline using these anytime soon?

James - We've been through a process of checking this concept with various battlefield medics and we're getting great feedback that this could be really useful to them on the battlefield. So we know there's a market for it and we have a device that shows our concept works, and the next stage for us is looking for investment, building on the work we've done to date and getting towards a product that we could sell in volume into that market.