Withings is very much a “personal health” monitoring company. Originally they produced a WIRED BP monitor, which was great, assuming you owned an iPhone, for everyone else… not so much. Withings now have a Wireless Blood Pressure Monitor which plays nicely with other phones. So lets take a look at the monitor, but also look at what MATTERS with regard to BP monitoring
The Withings Wireless Blood Pressure Monitor looks good, and is nicely compact. That might not mean a lot to many people, but compared to the usual BP monitors available over the counter, it’s great! Plus of all the kit in my medical bag, the BP monitor takes up the most space, so I’m very pro anything that reduces this!
Yes there ARE wrist based BP monitors which are smaller, but there are several papers supporting the inaccuracy of these monitors. One reason can be seen if you look at how blood pressure is measured
Measuring Blood Pressure
Your blood vessels are a tube. The blood inside them exerts a pressure on the wall of the vessel. This IS blood pressure. Have you ever had your blood pressure taken and though “Ouch that’s a bit tight!” before suddenly the pressure dropping? The reason this happens is the cuff that is put around your arm has to be pumped to a pressure ABOVE that of your blood vessel. As soon as this happens, the blood vessel collapses, so there is no blood flow, and no sound of blood flow (Korotkoff Sounds)
Inside the blood pressure monitors is essentially an electronic stethoscope. With monitor “listens” to the woosh sound of blood going through the vessel. When the blood pressure cuff inflated more than the pressure of the vessels, the woosh disappears as the blood is momentarily stopped flowing through the vessel by the cuff squashing it. At this point, the machine starts to release the cuff pressure, “listening” again for then the noises, the blood flow restarts. When the noise of the blood flow returns , the machine records the pressure in the cuff, as this will be the same as your systolic blood pressure. The top number, e.g. 120 on blood pressure recordings of 120/80
Rice University has a very nice graph of BP cuff vs pressure
As the pressure in the cuff eases off further, the noise of the blood flow will disappear, which again the monitor listens to. This is the bottom number, e.g. 80 on our previous 120/80 recording.
So why not a wrist monitor
Everyones bicep is fleshy. You can squeeze it, and give it a jiggle round. This makes it easy for the blood pressure cuff to squeeze and stop the blood flow in the vessels in the upper arm, and accurately record your blood pressure.
Now have a look at your wrist. There is a LOT more going on down there. Not a lot of muscle, few bony bits, and a plethora of ligaments and nerves under the skin running near the blood vessels. To put it simply, it’s just a harder part of the body to accurately squash…AND listen to the changes in blood flow noises. Similarly, it’s much easier just to relax your arm, when you have a blood pressure taken, whereas there are lot of ways you can position your fingers and hand which may affect the blood pressure readings.
The upshot, we don’t use them in clinic, as the upper arm is a more reliable measurement, and at home is harder to get wrong. Hence Withings choice for an upper arm cuff.
True blood pressure
People get worried about their blood pressure. ‘I was doing my readings, and they were getting higher and higher, the worst was 155/99!!!”
But the important question is what is a persons OVERALL or average blood pressure.
Think about the average speed cameras on the motor way. The signs say 50mph, and you decide to overtake someone who is dead set on going nowhere, by doing 38mph. You over take, but push a little too hard and reach 60mph for a few moments. You ease off, and carry on at 50mph for the rest of the journey. You DID break the posted speed limit briefly, but your average will still be very close to 50mph. Blood pressure is ENTIRELY the same when it comes to home blood pressure monitoring. It’s the over all picture that matters.
SO when a patient comes in saying “Doc my BP is high”, unless there reading in clinic is astronomically high, eg. 180/110 AND I’m worried about it, it will still be a case of confirm that blood pressure over the next week or so at home, using average blood pressure readings. Partially because I dont know what has gone on before the patient came into the room. They might be anxious, had difficult getting in on time, scratched their car, run over a cat/horse/ex-husband, there is a plethora of things which, like hitting the accelerator a little bit too strongly, can make a blood pressure look dramatically different to what’s actually going on.
For that, we do home blood pressure monitoring. Get the patient to take their blood pressure THREE times in the morning when at rest, and record ONLY the LOWEST reading, and then the same again in the evening. The crucial bit being record only the LOWEST readings on a chart
Those blood pressures are averaged over a 5-7 day period, to tell us what is going on with the patient. The averages go some way to reducing all the variability that comes with the user operator aspect of their recordings, one particular issue is people looking at their blood pressure results as they are being recorded – you can a much more stable reading if they are done blindly.
The Withings unit, while costly does address several of these points. SO after going on about what pressure IS, lets actually look at the Withings Wireless Blood Pressure Monitor!
The Withings Wireless Blood Pressure Monitor is a very tasteful white exterior with a shocking green interior to the cuff. It’s certainly not something you are going to have difficulty finding.
The new device is identical to the original wired unit, save for, well the lack of wires!
You have the soft touch side of the Velcro cuff inside the unit.
The aluminium part containing the pump and pressure monitor, and a very discrete micro USB connector
The aluminium bar also houses the 4xAAA batteries, included with the monitor.
The cuff is always curled up, and the inner part contains a stiff plastic section which you have to prize open in order to slip your arm into, or conversely pull up your arm.
Inside the cuff is a very important detail for the use of the monitor. A label with the arm circumference information, 22-42cm
This is important, as if you arm is smaller, or larger than this circumference, the machine will read too low, or high respectively. This is the reason why in hospital, we have a wide range of blood pressure cuffs – note the largest is a THIGH cuff, not an arm cuff.
Now different manufacturers use different ranges of cuff size anyway, so there is no hard and fast rule. But looking at the Withings Wireless Blood Pressure Monitor, because of the wide range it covers, I’d want to consider a slight caution if you are at either extreme ends of the cuff.
Using the Wireless Blood Pressure Monitor
GP’s LOVE apps which monitor your health. They do so much of the work for us in terms of plotting the graphs and calculating the average values. They also help the patient by allowing them to easily see their measurement trends. Withings gives a broad brush stroke over view of your health in their app, from which you can drill down further into the specific data
The unit is powered on from a small power on the end of the metal tube (which for some reason sounds a little sinister written down…anyway)
At which point follow the instructions on the Withings App to detect and install the cuff
After installed the unit self calibrates, after which it is ready to be used.
As long as your phone is switched on, pressing the unit power button will actually open the Withings app to the reads screen, which is really very handy.
From here you can do a straight forward check of your blood pressure, by pressing the start button, or by using the cog in the top right, access Auto Mode.
Auto Mode, as shown above allows the unit to take more accurate readings, by taking 3 pressures each spaced a user selected time apart. All you have to do is sit there, with the metal bar of the unit in line with your arm, and let the unit do it’s thing over the next 20-30 secs
The only times I’ve has issues with measurements not working is if the velcro has not been secured, or the metal bar not aligned properly, so the unit cannot detect my pulse.
You can also load up the unit and do single BP readings:
After each recording, you have to opportunity to put any notes – e.g. bike ride last night, or how you are feeling, and see if there is any correlation
The recordings can be viewed immediately in either numerical or graphical form. With colours responding to the low, healthy, borderline and unhealthy ranges of BP
But going back to monitoring your own blood pressure, you can both look at the trend, but also, assuming your practice has an email for such things, send a copy of the data to you GP
This can make your interactions with the GP much more time efficient, as in the button of the above picture is an “activate” toggle which automatically send you BP readings, every day (Please no!!) every week (Useful if planning a medication change) or every month (Useful for long term monitoring)
This is very much the start of tele-health, as with this data, the patient is saved from having to manually collect the data, and organise appointments, and a lot of time is saved on the GP side with appointments and paperwork enabling more time to be easily put to looking after the patients BP most effectively.
The Withing Wireless Blood Pressure Monitor isnt cheap at £70 from Amazon (not affiliated, just showing where) when you look at the standard kit available in Boots etc
However for a one off cost, and ease of use of monitoring I’ve very impressed – most importantly the blood pressure readings compare very accurately with the practice Omron meters.
I think if you have an interest in monitoring your health, in a minimally fussy way, with Withings is great. However can do EVERYTHING that the Wireless Blood Pressure Monitor does on lower cost models, and still input the data manually into the Withings App, so you can still send the data recordings into your GP.
I love toys. The Withings Wireless Blood Pressure Monitor is very good, but the one issue holding it back is the cost. It’s very hard to say to a patient there is a £70 bit of kit, when there is a £20 available which does the same, but with a little less style and automation.
If you can afford it. The Withings Wireless Blood Pressure Monitor is the one to buy, the integration and ease of use is very slick, the integrated BP bladder is great as well, no faffing around with tubes! On the odd occasion I’m feeling a bit rough after a previous bike ride/run the next day, it takes under a minute to check the BP with this unit, giving me an idea if it’s a hydration issue, or I’m just feeling a bit off – more times that not I’ve found I’ve felt grotty with a BP of 104/76 – and need to pay more attention to my own post exercise hydration.
If money is more of an issue, it’s harder to justify, as a lot of the work and benefit that Withings gives from a BP monitoring perspective is also as a result of their free app
7/10, although at £50, it would be an 8 pushing a 9/10