SAFA Skysailor Magazine

SKY SAILOR 27 September | October 2019 So, what is there in the way of wrist watch type devices? Again, there are lots out there, but I purchased two for evaluation. The first operates via an app on a mobile phone, whilst the second gives a reading on the device itself. The unit that runs through the app is a Bakeey C1 Plus. It doesn’t come with a charging cable, so you’ll need to get one of those too (available on Ebay). The app is available via the Apple App Store or Google Play and is accessed by scanning a QR barcode in the instruction leaflet that comes with the device. Once charged, you can connect to the app via a Bluetooth pairing. The date and time will be picked up from your phone. There’s a touch sensor that cycles through the various screens of the unit. It will receive emails, SMS messages, phone calls and does a heap of other things. Here’s what the cardio functions look like: Figure 2: Bakeey C1 cardio functions Once you have the app loaded and the Bluetooth connection on, you can control the device from your phone. I won’t go into all the ins and outs and what- nots of the app; I’ll leave that fun stuff up to you to explore. But here’s what the screen looks like with the cardio functions in view, and a before and after of the Blood Oxygen screen (Figure 3). To take a measurement, tap the Measure button. You’ll feel the device give a little vibration and within a few seconds, the result will appear on your app screen. The same goes for measuring your pulse rate and blood pressure. This is probably a good set-up if you fly with your mobile phone in your cockpit. Battery life on the device is about a week to 10 days. What if you don’t want your phone in the cockpit, or you don’t have a dedicated phone for the cockpit? That’s where my third device comes in, an oCare Pro 100. This is a wrist watch type unit that can run independent of a mobile phone app, and it comes with a power adapter and charging cable. Battery life on this unit is pretty bad, you’ll need to charge it every one to two days. It is not very versatile – it can only function as a clock or give your pulse and oxygen saturation readings. Figure 4: oCare Pro 100 To take a measurement, you press the upper of the two buttons. The unit is sensitive to movement while reading, so this could be a problem if you are working the controls at the same time. How do they stack up? I took all three up to the summit of Hobart’s Kunanyi/Mt Wellington, where the elevation is 1271m or 4170ft. Now, a caveat: This is not an adequate altitude to give a thorough test of these units, but given I’m constrained by winter flying conditions in Hobart (i.e., basically nil opportunities), it is what it is. 2 With all three running at the same time, I was getting oxygen saturation levels of 93 to 96% from the CMS-50D, 96 to 98% from the oCare Pro 100 and 97 to 98% from the Bakeey C1. Pulses were around the 79 to 81 mark from all three units. What sort of numbers should we be looking for? At the extreme end of things, if you see 60% or somewhere close to it, you’re in BIG trouble, as in your death is imminent. Normally, we would expect to see 96 to 99%. Up to 10000ft (3030m), we would expect to see 90 to 97%. This stage of hypoxia is referred to as the ‘Indifferent’ stage. The next stage, ‘Compensatory’, runs from 10000 to 15000ft (3030 to 4500m); we would expect 80 to 90% saturation. Next comes the ‘Disturbance’ stage, at 15000 to 20000ft (4500 to 6000m) and 70 to 80% saturation is expected. Finally, is the ‘Critical’ stage: 20000 to 23000ft (6000 to 7000m), with saturation values of 60 to 70%. This is really dangerous territory – next stop is death. Recommendations? I’d say the gold standard is the CMS-50D, but it is impractical for use in flight. Between the other two, it comes down to how you rig your cockpit and clothing. If you can access your wrist to press the button, the oCare Pro 100 would suit. If not, and you run a phone in your cockpit, the Bakeey C1 suits. Either way, something is better than nothing if you spend a lot of time inhabiting higher altitudes. Notes: 1 Phil Hystek was present see [ youtube.com/ watch?v=VCnNA6RQm4g] 2 I’m looking into chartering a Cessna for a spin up to altitude for a proper evaluation. References: [britannica.com/science/hypoxia ] [avmed.in/2011/03/flying-into-thin-air-under- standing-hypoxia] [flightsafetyaustralia.com/2014/08/do-not-go- gentle-the-harsh-facts-of-hypoxia] [faa.gov/pilots/training/airman_education/ topics_of_interest/hypoxia] [youtube.com/watch?v=6yQFcXpFwX8 ] Figure 3: Bakeey C1 – Da Fit app cardio functions