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Comment by laarc | Hacker News Reader

I was hoping the product would pivot to passive blood pressure monitoring. I want my blood pressure to be recorded every few seconds, logged and cross-referenced against what I did, ate, and drank. For correlation purposes, knowing those things can be as simple as snapping a photo.

Smart people apparently claim that blood pressure is one of the most reliable indicators of how long you'll live. If so, then it's always seemed strange it's (almost) never measured.

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Now that would be a cool product. Lots of datapoints. I'm skeptical about the claim - yes, it's important, but there are so many variables that feed into it, and I need to be convinced that constant, 24 hr monitoring of BP would enable better management than spot tests, home BP management and the occasional 24 hr ambulatory monitoring.

It's a very consumer-targeted technology, although it would certainly find a place in emergency departments and ICUs. I am at a loss to think of ways as to how we would actually capture the data, although better minds than mine I hope come up with ways.

The problem is that to get a good read on arterial pressure you either need to do it the old fashioned way (occlude the artery and record that pressure, then slowly drop it until it's constantly flowing again - see [0]) - or you need to stick a cannula into an artery, as we do in ICUs, and measure pressure using a transducer.

Even technologies that stress their 'passivity' (see [1]) and try to capture this market use the old fashioned way. I don't see that changing anytime soon - you could try and somehow monitor the stretch of a small artery maybe using some variation of current o2 saturation sensors, coupled with advanced computer models of flow rate and variation in small arterioles, but that is a world away and would seem to me to be highly subject to variation/sensitivity.

My prediction is that this won't be possible until we are commonly implanting biometrics in people, but I guess we will wait and see!

[0] https://en.wikipedia.org/wiki/Korotkoff_sounds [1] http://www.visimobile.com/

It seemed promising to do some experiments with sewing a BP sleeve into a shirt, then setting up an Arduino to trigger it to inflate/deflate. It should be possible to record the result digitally. It'd be slightly uncomfortable, but even if it's only once per hour, it's still better than zero per hour. The noise would be annoying, but I have some ideas for how to make it quiet. But would anyone actually want such a thing?

Thanks for batting around the idea with me, and for the valuable references. I didn't know there was any other way to measure BP than the old-fashioned way.

You're describing creating an ambulatory blood pressure cuff. I've had one attached to me and you get used to it fairly quickly, although it failed to measure blood pressure when I was active (I was cycling for a few of the readings, which you think would keep your arm fairly still and not cause a problem) Cool to make it yourself though! Have a look at these further links. The australian prescriber article you may find particuarly useful

http://www.racgp.org.au/download/documents/AFP/2011/November...

http://www.australianprescriber.com/magazine/20/1/18/20

https://en.wikipedia.org/wiki/Ambulatory_blood_pressure

My mom is terminally ill and recently started experiencing orthostatic hypotension, so I just picked up an Omrom armband blood pressure monitor that is trivially easy to use and stores the last 100 measurements for two people.

http://amzn.com/B00KPQB2SS

It's still not what you want, but it looks like things are moving in the direction you suggest. That said, I'm wondering if it is even possible to do what you suggest without being inconvenient to the user. Having an armband inflate and tighten around my arm every few seconds with become infuriatingly annoying. Are there alternatively ways to measure blood pressure that are imperceptible?

What I'm looking forward to seeing is conductive textiles making their way into compression clothing so we can measure heart rate all the time. i.e. a wearable EKG shirt. The use case would be older people at risk for a heart attack and heart fail so we can detect problematic heart abnormalities that are predictive of failure.

I'm guessing I got downvoted for linking to the product on Amazon. What's the appropriate way to link to something like that so that it doesn't get downvoted?

I think your comment was informative, your manner of linking was fine, and that you should ignore the downvote(s) in this case. I guess it might be slightly clearer to use the full "amazon.com" in the URL, and I suppose someone might argue that it's safer to indent it two spaces so it's plain text rather than an active link, but seems good to me as it is. Maybe someone clicked the wrong button, didn't like something else about your wording, or was just in a bad mood.

You know, when I saw your original comment, it was so helpful that I wanted to respond to you and say thank you, but I suppressed my instincts because I thanked someone else, and it felt like the community would react badly to me saying "Thank you so much!" to every single person.

But now I see that the community actually downvoted your comment rather than rewarded it. Darn.

For what it's worth, and even though this reply is very late: Thank you so much for your time and for the thoughtful and helpful reply. The links, specifically, were the reason it was helpful to me.

Here's what England's NICE say about diagnosing hypertension. COmpare the difference between ambulatory measurement, and home measurement.

We know that most people can't even take their medication properly (many organ transplants fail because people don't comply with the medication regime, for example) so easier blood pressure monitoring would probably be useful. Especially if you combine it with something that can lower blood pressure.

http://www.nice.org.uk/guidance/cg127/chapter/Key-priorities...

> Diagnosing hypertension

> If the clinic blood pressure is 140/90 mmHg or higher, offer ambulatory blood pressure monitoring (ABPM) to confirm the diagnosis of hypertension. [new 2011]

> When using ABPM to confirm a diagnosis of hypertension, ensure that at least two measurements per hour are taken during the person's usual waking hours (for example, between 08:00 and 22:00).

> Use the average value of at least 14 measurements taken during the person's usual waking hours to confirm a diagnosis of hypertension. [new 2011]

> When using home blood pressure monitoring (HBPM) to confirm a diagnosis of hypertension, ensure that:

> for each blood pressure recording, two consecutive measurements are taken, at least 1 minute apart and with the person seated and

> blood pressure is recorded twice daily, ideally in the morning and evening and

> blood pressure recording continues for at least 4 days, ideally for 7 days.

> Discard the measurements taken on the first day and use the average value of all the remaining measurements to confirm a diagnosis of hypertension. [new 2011]

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