As a person who had a hypertensive crisis late last year, nothing boils my blood (yes, a pun, I am fine now) more than how people measure blood pressure incorrectly in doctors offices and even hospitals. There are many different things than can increase a BP measurement above the "baseline" including talking, moving around, not having rested but also just waking up, not being in a supported position, only a single value, etc. Most of the major health agencies (AMA,AHA,CDC, etc in the US) have recommendations on how to do it properly, but in medical situations like doctors offices and hospitals, these are rarely done as they take too much time. A single measurement is not sufficient and can result in misdiagnosis.
A more reliable way to measure a continuum would make a difference, but I imagine it would still require time to collect as BP is a dynamic value that changes with behavior, posture and activity.
I'm a resident physician and I deny having my BP taken in outpatient clinics.
The techniques used are ridiculously inappropriate:
"Ok, Mr. So-and-so, come with me." calls the nurse, as the pt who is irritated for having to wait 30 minutes quickly gets up to walk along unknown hallways, while rushing to finish a phone conversation, stressed and not knowing where to turn next..."Ok, now we're going to weigh you on this scale" while the pt thinks 'oh man, I've probably gained weight', followed by "ok, now we're going to measure your blood pressure." 'I don't want BP meds...let me try to relax...breathe slooowly...but I don't want the nurse to notice I may be trying to cheat this sudden examination.'
That's why the most appropriate way nowadays is to measure it at home, and keep a BP log.
It's frustrating. I usually bike to the doctor's office, and every time I warn them that they're going to get a systolic 10 higher than if they'll wait until the end of the appointment. They don't wait. The tech-taken entry gets put in the EMR. The doctor takes my BP again at the end, says "oh, great" and that reading gets ignored. :p
As a sibling comment noted, I ended up deciding to just watch my BP at home every now and then. It turns out it's fine and it reduced my metaphorical blood pressure to monitor it myself.
As an adult with a congenital heart defect and white coat hypertension, I can relate. Once, a nurse took my blood pressure and immediately freaked out as I was sitting calmly on the exam table. She took it again in the same arm, then hurriedly took it in each of my other limbs before throwing her hands up.
Often, I would arrive at the cardiology office having made my way through downtown traffic to find a parking space and walk across the pedway. Then I'd find a seat as far away as possible from all the noisy children there to remind me that I should be dead. No wonder my BP is higher than usual. And you're the one freaking out?
I got so used to nurses tossing out every recommendation for measuring BP that I started taking it myself at home before visits just to prove the point. Eventually, as I grew older, my BP rose to a point where it actually needed to be addressed. I am now on medication. But I have yet to find a nurse anywhere that has taken time to follow even one recommendation for properly taking BP.
I had hypertension for about 15 years and after quitting drinking and smoking no longer do. I still suffer from white cost hypertension regularly and frequently have to tell nurses to just press the button again - second time drops back to normal range with a drop of about 20/10.
This would be the best use of the "AI Pin" fiasco of a device;
Create an AI pin that takes in all the activity associated with the BP monitoree, including telemtry for environment, movement, and diet. if I had a pin that did this (and recorded all audio for the day, and snapped pictures when I wanted and transcribed all audio via whisper and I had a full searchable day-runner...
Yay!
EDIT: The above desire is fully capable of a phone - except battery life...
I have a boatload of old phones. It would be interesting to just build a mini-build for an android phone to simply be a daily recorder. to capture audio/video only and run a slow app that will transcribe all audio to text on the device (even if it does so once its on lan, then it connects to an endpoint running locally on your docker desktop fast api to capture the audio that auto uploads as soon as on home lan. Sorts the files and pics and everything onto the NAS with simple txAI workflow to ffmpeg as needed.
> A single measurement is not sufficient and can result in misdiagnosis.
During an acute care stay, a single blood pressure is a drop in the bucket. It averages out on the long term, and it’s not taken out of context of a clinical presentation.
I would take pressures manually, question unusual values, repeat on the spot and after some time had passed.
Yeah I was told I had high blood pressure, was about to be put on a bunch of medication and then I decided to get a second opinion. The hospital I went to gave me a 24 hour monitor and it came back I had perfectly fine blood pressure.
Totally agree and I think the malpractice comes from laziness and a lack of interest in their patients. If they cared, they would do it correctly per the guidelines they hand out to patients themselves! By which I mean these:
https://www.heart.org/en/news/2020/05/22/how-to-accurately-m...
It is especially bizarre to me when they don’t listen to patients and make medical decisions like deciding prescriptions and dosage amounts based on false readings.
This approach has been tried before. Bill Softky describes a startup he'd worked for using a similar sound-transduction continuous non-invasive blood-pressure monitoring technique. It ... had problems:
Our non-invasive device was supposed to measure blood pressure just as accurately [as an arterial line], but without the cutting, using specially-sculpted sonic vibrations and fancy algorithmic analysis, which was my job. The overall challenge was like measuring the pressure inside a bottle without opening it. Our device worked fine, in that our algorithmically-estimated blood pressure moved up and down, beat to beat, in lockstep with the actual blood pressure. The problem was that our estimate also moved up and down at other times as well, say when the patient moved her fingers, rotated her arm, or took vaso-constricting drugs like nicotine. I spent most of a year understanding these problems, and understanding they couldn’t be solved before our funding ran out. That was when an old-timer taught me an important lesson of measurement: it’s fairly easy to calculate a signal which correlates with what you want to measure, the way our vibration-estimate correlated with actual blood pressure. It’s much harder, though, to calculate a signal which does NOT correlate with what you DON’T want to measure, like arm motion.
It’s just a blurb from a college PR team. As someone that came from academia, they don’t have to have solved any of that because these are generally pretty worthless. It can be as small as someone in a lab discovered how to do the smallest thing and the college wants to run with it to look good.
They tested on the carotid artery. I don't know whether they're concerned with addressing issues of wearing this while active. It seems more likely that it will be used in a clinical setting.
Looking at the diagram I’d suspect they use accelerometer information from both the wrist watch and the upper arm mounted sensor to remove the effects of arm motion. At simplest it could only check when the arm is in a neutral position. But I’d expect they did something more complex/better than that.
I guess it's not considered reasonable to keep your arm still when measuring BP, or to measure it only during intervals of minimal movement? Doesn't seem like a showstopper to me.
One of the key applications for this technology is during surgery, when (ideally) nothing is being moved.
Interesting. I recall working on some devices that implemented something called Pulse Arrival Time [1] which the biomeds on the team told me "isn't blood pressure, but it can be used for the same purposes."
Does this technique have an advantage over PAT? How true is the statement that "PAT can be used for the same purposes?"
There’s a company called Biobeat that sells a patch you put on your chest for continuous 24-hour blood pressure measurement [1]. From what I’ve heard it’s in clinical use and works.
I've always wanted a Garmin linked ear-cuff device that uses the earlobe for heartrate and blood pressure and then doubles as music playback or alerts from the watch. You could even do body temperature from the earlobe reliably.
This believe this blood pressure watch has been approved in a few European countries. It requires you to calibrate against the normal approach every month. I think they are trying to get it approved in the US by next year.
They’ve just received approval for a monitor that needs no calibration at all, although it’s not commercially available yet, and will probably take another half a decade to reach the US.
Huge deal for humans moving forward. ~5-8yrs too late for me (2-5yrs for product dev, 3yrs since a hemorrhagic stroke that was likely caused by serious blood pressure).
I was 40 at the time and never measured my blood pressure (and certainly never when exercising). After the event I measured it all the time. During the 8th time of sitting in a chair, rolling up my sleeve, I thought, the Apple Watch has BP sensor, right?
That question sent me on a quest only to find that humans had not yet figured out a way to measure blood pressure on-the-go.
This is quite an old problem. A quick search of PubMed yields 4834 results for "noninvasive blood pressure monitoring". Caltech has a weird definition of "first".
Edit: To clarify, plenty of things have been tried besides the cuff, but most patients who need something more sophisticated than that are already sick enough to be in the ICU, where an a-line can be placed. This is really a solution in search of a problem.
Aside from the home use, If this could be proven to be just as accurate as arterial lines this would be a huge benefit to patients in the ICU or undergoing major surgery where continuous blood pressure is needed. I hate putting in A-lines.
Yes, the concept is sold as a huge benefit in patient quality-of-life.
A-lines mean you can't just get up and move, or even roll over in bed. Non-invasive measures can simply be unclipped, or made fully mobile in the first place.
The problem is having a non-invasive method which works, which has been the sticking point until now.
A year or two ago, I interviewed a developer who worked for one of the companies trying to build these types of optical blood pressure sensors. I have high blood pressure so I was keen to learn more. The gist of his message was that even in excellent conditions, it was very inaccurate.
> This measurement requires three parameters—a measurement of the artery's radius, the thickness of the artery's walls, and the tension or energy in the skin of the artery.
I've been thinking a lot about continuos health parameter monitoring lately. For the last 100 days or so I have been running a personal health experiment and collecting multiple data points during the process. I guess some use the term "bio-hacking", not sure if it applies.
The experiment has included multiple fasting periods, with a maximum of 7 days as well as changing one variable at a time in categories such as diet and exercise. The results have been very interesting and I intend to continue on this path until at least the end of the year.
As part of the data collection I have been taking my blood pressure a minimum of twice a day, sometimes more. Also blood glucose, ketones and (consumer) EKG.
The first thing that jumped at me was the inaccuracy or variability of these measurements. I even got a Dexcom continuous glucose monitor. Interesting but useless for my purposes. The thing produced 20% error with respect to finger poke measurements. And, then again, when I got a calibration kit to check my finger poke meter, the calibration range is approximately +/- 18%. In other words, unless you hit extremes it feels like these measurements are almost useless. You can kind of tell you are going up or down, yet don't really know where you are.
The same, of course, has been true of blood pressure measurements. I went through three consumer machines. I can't say any of it is accurate because there are too many variables. I have run multiple experiments with regards to where and how to measure BP. All I can determine are relative changes by effectively measuring under as close to the same conditions as possible twice a day, morning and evening (both before meals).
During the last month or so I have been using a protocol I learned from one of Andrew Huberman's presentations (can't remember which one or I would post a link). I believe he was interviewing a researcher who explained the process they use during their studies. In simple terms, they take three measurements and then average. The first is after 15 minutes sitting, feet on the ground, back supported, no movement, no speaking, no activity. The second and third are at 5 minute intervals under the same conditions. In other words, the entire process takes at least 25 minutes.
After adopting this approach I have been seeing wildly different numbers with respect to the single measurement protocol I had been using for two months. In addition to that, the standard deviation of the computed values are much tighter now.
This experience, so far, has made me wonder about just how many people might be misdiagnosed and put on medication every year because of bad data. I can see the value in having more data, of course. Yet, continuous data is only good if it is accurate to within a reasonable margin.
> how many people might be misdiagnosed and put on medication every year because of bad data
Another variable that causes this is the patient. They don't like the medication or don't take it properly but tell their prescriber that they are taking the medication correctly (age, culture, dementia etc). The prescriber then adjusts the dose.
I have reverse white coat hypertension: having a health professional care about me reduces my BP appreciably when they measure it. Placebos work very well on me, if delivered by an obvious competent authority like a nurse practitioner or GP.
I still take the hypertension meds: it's cheaper than paying somebody that highly trained to be nice to me.
> The new patented technique, called resonance sonomanometry, uses sound waves to gently stimulate resonance in an artery and then uses ultrasound imaging to measure the artery's resonance frequency, arriving at a true measurement of blood pressure.
BP monitoring requires a pressurized cuff which restricts (stops) arterial flow. The readings are the pressure of the cuff as it deflates when the blood starts flowing and when it can no longer be detected.
coldcode|1 year ago
A more reliable way to measure a continuum would make a difference, but I imagine it would still require time to collect as BP is a dynamic value that changes with behavior, posture and activity.
hereme888|1 year ago
The techniques used are ridiculously inappropriate:
"Ok, Mr. So-and-so, come with me." calls the nurse, as the pt who is irritated for having to wait 30 minutes quickly gets up to walk along unknown hallways, while rushing to finish a phone conversation, stressed and not knowing where to turn next..."Ok, now we're going to weigh you on this scale" while the pt thinks 'oh man, I've probably gained weight', followed by "ok, now we're going to measure your blood pressure." 'I don't want BP meds...let me try to relax...breathe slooowly...but I don't want the nurse to notice I may be trying to cheat this sudden examination.'
That's why the most appropriate way nowadays is to measure it at home, and keep a BP log.
dgacmu|1 year ago
As a sibling comment noted, I ended up deciding to just watch my BP at home every now and then. It turns out it's fine and it reduced my metaphorical blood pressure to monitor it myself.
nulbyte|1 year ago
Often, I would arrive at the cardiology office having made my way through downtown traffic to find a parking space and walk across the pedway. Then I'd find a seat as far away as possible from all the noisy children there to remind me that I should be dead. No wonder my BP is higher than usual. And you're the one freaking out?
I got so used to nurses tossing out every recommendation for measuring BP that I started taking it myself at home before visits just to prove the point. Eventually, as I grew older, my BP rose to a point where it actually needed to be addressed. I am now on medication. But I have yet to find a nurse anywhere that has taken time to follow even one recommendation for properly taking BP.
teamspirit|1 year ago
samstave|1 year ago
Create an AI pin that takes in all the activity associated with the BP monitoree, including telemtry for environment, movement, and diet. if I had a pin that did this (and recorded all audio for the day, and snapped pictures when I wanted and transcribed all audio via whisper and I had a full searchable day-runner...
Yay!
EDIT: The above desire is fully capable of a phone - except battery life...
I have a boatload of old phones. It would be interesting to just build a mini-build for an android phone to simply be a daily recorder. to capture audio/video only and run a slow app that will transcribe all audio to text on the device (even if it does so once its on lan, then it connects to an endpoint running locally on your docker desktop fast api to capture the audio that auto uploads as soon as on home lan. Sorts the files and pics and everything onto the NAS with simple txAI workflow to ffmpeg as needed.
xattt|1 year ago
During an acute care stay, a single blood pressure is a drop in the bucket. It averages out on the long term, and it’s not taken out of context of a clinical presentation.
I would take pressures manually, question unusual values, repeat on the spot and after some time had passed.
HPsquared|1 year ago
m463|1 year ago
does this mean your arm is not relaxed when measuring?
They always measure my blood pressure in a jury-rigged way resting on not an armrest, but some uncomfortable bracket of the blood pressure device.
bamboozled|1 year ago
Turns was scared of doctors.
unknown|1 year ago
[deleted]
blackeyeblitzar|1 year ago
It is especially bizarre to me when they don’t listen to patients and make medical decisions like deciding prescriptions and dosage amounts based on false readings.
dredmorbius|1 year ago
Our non-invasive device was supposed to measure blood pressure just as accurately [as an arterial line], but without the cutting, using specially-sculpted sonic vibrations and fancy algorithmic analysis, which was my job. The overall challenge was like measuring the pressure inside a bottle without opening it. Our device worked fine, in that our algorithmically-estimated blood pressure moved up and down, beat to beat, in lockstep with the actual blood pressure. The problem was that our estimate also moved up and down at other times as well, say when the patient moved her fingers, rotated her arm, or took vaso-constricting drugs like nicotine. I spent most of a year understanding these problems, and understanding they couldn’t be solved before our funding ran out. That was when an old-timer taught me an important lesson of measurement: it’s fairly easy to calculate a signal which correlates with what you want to measure, the way our vibration-estimate correlated with actual blood pressure. It’s much harder, though, to calculate a signal which does NOT correlate with what you DON’T want to measure, like arm motion.
<https://www.linkedin.com/pulse/monster-monetization-bill-sof...>
I'd be exceedingly curious as to how the CalTech team have solved that non-correlation problem.
Mistletoe|1 year ago
mhb|1 year ago
They tested on the carotid artery. I don't know whether they're concerned with addressing issues of wearing this while active. It seems more likely that it will be used in a clinical setting.
Timothy055|1 year ago
CamperBob2|1 year ago
One of the key applications for this technology is during surgery, when (ideally) nothing is being moved.
ryukoposting|1 year ago
Does this technique have an advantage over PAT? How true is the statement that "PAT can be used for the same purposes?"
[1]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6912522/
bjornsing|1 year ago
1. https://www.bio-beat.com/cuffless-blood-pressure-monitoring
ck2|1 year ago
The first way has been done in studies for years, maybe even a decade ago.
Earlobes.
I'll search for the papers later and link them.
https://scholar.google.com/scholar?q=earlobe+blood+pressure
https://www.todaysmedicaldevelopments.com/article/wearable-b...
I've always wanted a Garmin linked ear-cuff device that uses the earlobe for heartrate and blood pressure and then doubles as music playback or alerts from the watch. You could even do body temperature from the earlobe reliably.
pkaye|1 year ago
https://aktiia.com/
ryeights|1 year ago
https://aktiia.com/uk/regulatory-approval-no-need-for-calibr...
Psst… the bracelet is available in the US if you use a UK freight forwarder, & download the app from the EU app store…
benterix|1 year ago
hm-nah|1 year ago
I was 40 at the time and never measured my blood pressure (and certainly never when exercising). After the event I measured it all the time. During the 8th time of sitting in a chair, rolling up my sleeve, I thought, the Apple Watch has BP sensor, right?
That question sent me on a quest only to find that humans had not yet figured out a way to measure blood pressure on-the-go.
Congratulations on this effort!
queuebert|1 year ago
Edit: To clarify, plenty of things have been tried besides the cuff, but most patients who need something more sophisticated than that are already sick enough to be in the ICU, where an a-line can be placed. This is really a solution in search of a problem.
Herodotus38|1 year ago
dredmorbius|1 year ago
A-lines mean you can't just get up and move, or even roll over in bed. Non-invasive measures can simply be unclipped, or made fully mobile in the first place.
The problem is having a non-invasive method which works, which has been the sticking point until now.
_qua|1 year ago
kekeblom|1 year ago
trentnix|1 year ago
ryeights|1 year ago
unknown|1 year ago
[deleted]
unknown|1 year ago
[deleted]
spoonfeeder006|1 year ago
Or perhaps is that enough the case on a certain lower frequency band, where variations in those quantities are much smaller than the wavelength?
amelius|1 year ago
Ok, so now instead of 1 variable, there are 3?
robomartin|1 year ago
The experiment has included multiple fasting periods, with a maximum of 7 days as well as changing one variable at a time in categories such as diet and exercise. The results have been very interesting and I intend to continue on this path until at least the end of the year.
As part of the data collection I have been taking my blood pressure a minimum of twice a day, sometimes more. Also blood glucose, ketones and (consumer) EKG.
The first thing that jumped at me was the inaccuracy or variability of these measurements. I even got a Dexcom continuous glucose monitor. Interesting but useless for my purposes. The thing produced 20% error with respect to finger poke measurements. And, then again, when I got a calibration kit to check my finger poke meter, the calibration range is approximately +/- 18%. In other words, unless you hit extremes it feels like these measurements are almost useless. You can kind of tell you are going up or down, yet don't really know where you are.
The same, of course, has been true of blood pressure measurements. I went through three consumer machines. I can't say any of it is accurate because there are too many variables. I have run multiple experiments with regards to where and how to measure BP. All I can determine are relative changes by effectively measuring under as close to the same conditions as possible twice a day, morning and evening (both before meals).
During the last month or so I have been using a protocol I learned from one of Andrew Huberman's presentations (can't remember which one or I would post a link). I believe he was interviewing a researcher who explained the process they use during their studies. In simple terms, they take three measurements and then average. The first is after 15 minutes sitting, feet on the ground, back supported, no movement, no speaking, no activity. The second and third are at 5 minute intervals under the same conditions. In other words, the entire process takes at least 25 minutes.
After adopting this approach I have been seeing wildly different numbers with respect to the single measurement protocol I had been using for two months. In addition to that, the standard deviation of the computed values are much tighter now.
This experience, so far, has made me wonder about just how many people might be misdiagnosed and put on medication every year because of bad data. I can see the value in having more data, of course. Yet, continuous data is only good if it is accurate to within a reasonable margin.
lostlogin|1 year ago
Another variable that causes this is the patient. They don't like the medication or don't take it properly but tell their prescriber that they are taking the medication correctly (age, culture, dementia etc). The prescriber then adjusts the dose.
ggm|1 year ago
I still take the hypertension meds: it's cheaper than paying somebody that highly trained to be nice to me.
2-3-7-43-1807|1 year ago
That's invasive - gently or not.
ruckfool|1 year ago
patrickhogan1|1 year ago
anon115|1 year ago
rrrix1|1 year ago
BP monitoring requires a pressurized cuff which restricts (stops) arterial flow. The readings are the pressure of the cuff as it deflates when the blood starts flowing and when it can no longer be detected.
jkid|1 year ago
[deleted]
oezi|1 year ago
unknown|1 year ago
[deleted]