Let's measure blood pressure accurately!

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Junfeng
Posts: 26
Joined: Mon Dec 28, 2015 7:33 am

Let's measure blood pressure accurately!

Post by Junfeng » Mon Dec 28, 2015 8:41 am

Welcome to this forum, established to discuss topics and share experience on accurate blood pressure measurement. Here, you can but not limited to

  • Ask questions on Accutension and Accutension Stetho.
  • Report App bug.
  • Share your experience on using Accutension.
  • Request new features you want to see in the Accutension and Accutension Stetho App.
  • Share your experience on blood pressure measurement, whether it is accurate or not and which model.
  • Discuss general topics related to blood pressure such as monitoring and measurement.
Let's measure blood pressure accurately and control the blood pressure below the target.[/size]
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Smartphone auscultatory blood pressure measurement - hearing is believing.

nathanbhoffman
Posts: 2
Joined: Sun Jan 10, 2016 5:42 pm

Re: Let's measure blood pressure accurately!

Post by nathanbhoffman » Sun Jan 10, 2016 5:47 pm

So I just received my Accutension Stetho and downloaded the iOS App for my iPhone 6s and iPad Air2.
When I try to register, it asks me for the QR Code on the Manual, but I did not receive a manual. I do not have a QR code to scan.
How do I register using the App?
I would like to try out the product, but I don't know how I can do that without registering.
Please advise.

User avatar
Junfeng
Posts: 26
Joined: Mon Dec 28, 2015 7:33 am

Re: Let's measure blood pressure accurately!

Post by Junfeng » Wed Jan 13, 2016 12:04 am

Maybe the manual is missed and we will send you an e-manual with the code. Don't worry about that. Thanks!
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Smartphone auscultatory blood pressure measurement - hearing is believing.

mr_coffee
Posts: 2
Joined: Sat Mar 05, 2016 6:20 pm

Re: Let's measure blood pressure accurately!

Post by mr_coffee » Sat Mar 05, 2016 8:26 pm

I have not had this unit for long, but - in theory - like it very much. In use... I think I'd much prefer the unit which includes the cuff and whatever other method tracks the air pressure in the cuff over the digital display of my automatic cuff. As a programmer, I look at the display during the use of the device as more of a "screen saver" or just as a way of displaying feedback of ANY kind to the user to let them know the device is working... I would NOT count on these numbers to be accurate or to be used as the basis of an actual reading. I would imagine the manufacturer was more concerned with the accuracy of the final readout as opposed to the "real-time" pressure gauge during use. And I use this last phrase extremely loosely... as the digital display - at least on my kit - updates once per second or second and a half, and certainly doesn't iterate through every number. This data is therefore extremely lossy... and it's difficult to know if my true reading is the number I'm seeing, or a number I'm not seeing because the frame corresponding to my pulse does not match up with the moment the display has updated to the correct information.

I can also verify that - if my automatic pressure kit is 100% accurate - I would not be able to validate its results by the "real time" display of information during deflation, as very often the final result that is on the display matches exactly none of the numbers that were shown on display during deflation. So, even if the display is perfectly correlated to actual pressure, the refresh rate of the display is nowhere near fast enough to provide a true reading during deflation. I can't say if the use of the accutension stethoscope helps me to identify an inaccuracy in its final reading, or if it just shows me how far off the "real time" display is from the final reading, whether the final reading is accurate or not is still unknowable.

The instructions included with the accutension stethoscope do not include instructions on how to check your blood pressure with a manual blood pressure kit. It certainly should, as this is critical information to have in order to get any value out of this device. Having learned how to - at this point - I have determined that the digital display of my automatic blood pressure kit has too low a refresh rate to have any real value, but that's all I've determined. I feel I would much better benefit from having a manual sphygmomanometer to take a video of using this same device, eliminating all guess work or need to read the result quickly... and the peaks of beats in the waveform included would make this particular task incredibly easy. The difficulty would only be in managing the phone and the rest of the equipment at the same time, which is - by far - the most difficult part of the current arrangement. If you were to sell a nifty little stand to sit the analogue dial and my phone on to where they were in an ideal position to get a great video of the analogue dial, I'd absolutely order it. Otherwise, I'd absolutely buy the version of this which includes the cuff, as I assume it uses the phone to display the pressure values in real-time... except actual real-time, and iterating through many more numbers more quickly so that the accuracy of the display would no longer be an additional issue.

Sometimes... when clicking "record" in the app, the app itself minimizes instead of doing what is expected. I'm not sure why or how, but it's done this to me at least 3 times.

Sometimes, after plugging everything in... the phone records from it's built-in mic instead of from the steth. I'm not sure why, but I have to unplug everything, restart the app and plug everything back in to fix it. Simply unplugging and replugging isn't enough by itself, the app itself also needs restarted. It would be nice - if for this reason if for no other - to have some kind of "test" button or something like it... like I know I'm not going to do an actual recording, but I need to hear something on my headphones to know everything is working. For now, I'm just doing a test record and then retesting when I'm really ready... but maybe something in the instructions should be telling me to be ready for that since about 1 of every 3 times, the phone is using the wrong input for sound.

It would be cool if the app had a shortcut for the phone's built-in light... for some reason the display is too dark to read - even on the video - when trying to get a standing reading... the phone sort of has a solution to that built-in, it's just not accessible while using the app in any quick and easy way.

It would be nice to be able to trim or crop the video... since the peaks of the pulse are nearly invisible if any part of the inflation sounds are included in the video. Either that... or an ability to "zoom in" to the quieter parts. (zoom in isn't the correct phrase.... more like "exaggerate"... just make the smaller peaks more obvious if needed, no actual change to the sound file is needed, but any ability to modify how the waveform is displayed should be fine here)

There should be a method to "mark" peaks of the sound of the pulse in the waveform. Marking any consecutive two would give the app enough information to provide a very accurate heart rate as well. Marking more than one should average the results, improving the accuracy of this reading. Really, I don't see any reason this wouldn't happen automatically using software other than that additional sounds could be misappropriately marked as heartbeats... but giving the user the ability to manually point them out would certainly solve this problem... and timing would be part of the video so wouldn't have any discrepancy to worry about. This, or any indication of time along the drawn waveform would at least give anyone curious enough all they needed to mathematically deduce their heart rate.

The base around the plug on the steth itself is too large around and my iPhone's case interferes with it. The adapters, however, do not have this issue. I think a future model of this might benefit from a thinner base for the plug like the adapters have.

I like the idea of getting a more accurate reading, of storing the result and having the ability to play it back. I would love to purchase the version with the cuff if/when it becomes available again, but for now feel I'd have a higher degree of certainty about the readings if I exchanged my automatic device with a manual one. Now that I know how to use one, that certainly seems to be the way to go. I think this is a great idea overall, I just have no faith in the numeric reading I see during cuff deflation on my automatic kit. I have no idea what standard - if any - those numbers are being held to, but based on the slowness of update, it was not a concern during the manufacture of the kit I have. I feel the only way to get the full value of your product, I'll need to supplement it with a manual unit or with your version of the automatic cuff.

If you make the other unit (with the cuff) available again, please let me know. If you devise a clever accessory for holding the phone and manual analogue dial... please let me know. I'll - of course - update my app regularly, but if you guys decide to devise a Pro version with some of the crazy features I was talking about... please let me know. Also, thanks for forcing me to learn how to properly test blood pressure. This experience has been educational - if nothing else.

User avatar
Junfeng
Posts: 26
Joined: Mon Dec 28, 2015 7:33 am

Re: Let's measure blood pressure accurately!

Post by Junfeng » Fri Mar 11, 2016 7:18 am

Hi @mr_coffee,

Thank you very much for your feedback on Accutension Stetho! Here are some explanation on your questions.

1. whether your blood pressure monitor displays the real time pressure of your cuff. We tested several brands and 10 models. We found the screen displays the cuff pressure with slight delay (around 0.1-0.2 second). That means the number displayed slightly later than the pulse is the pressure on the pulse. The pressure drop per pulse is around 3mmHg, so even if there is one pulse difference, the error caused is around 3mmHg. Considering 15% people could get errors bigger than 10mmHg. It is still very valuable to capture the big error. Actually, we have captured very big inaccuracy on some individuals with Accutension Stetho. The cuff pressure during deflation is continuous but only the pressure on the pulse (when a medical professional hears a Korotkoff sound) is used for blood pressure determination. So the displayed pressure on the pulse is exactly what we need. The refresh rate of an automatic blood pressure monitor is the pulse, so it is not low because the pressure during the pulse has no meaning on the blood pressure.

2. Agree that the manual can be further improved to include the explanation of Krotokoff sounds and manual BP measurement method. There are a lot of instructions on the web and maybe a link to those is good.

3. The stand for a manual manometer is a good idea. We can consider making a 3D drawing so that people can print it out with a 3D printer. The design of Accutension Stetho is for people to screen out those individuals who get big errors (higher than 10mmHg). It is not a chance of low possibility. Around 15% people get such big errors according to both rigorous research and users comments on Amazon. It is a severe problem with low awareness in the public. We want to use an easy product to help people to do a personal check! It is like a health check. People need to pay to have a health check. No matter the health check find any issue or not, it is valuable.

4. On the plug and un-plug issue. We will check further how the phone picks the right mic input source. We haven't found this phenomenon in the past. We will try to repeat the scenarios you encountered and fix.

5. The build-in light idea is a great one! We will study further.

6. Crop the video. Currently we suggest the user to hit the record button when the cuff starts to deflate and hit the button again immediately after the BP readings appear on the automatic BPM. The crop the video feature might complicate the app and operation.

7. The base around the plug. We will improve in next generation.

8. Thank you so much for your interests in the cuff and we will inform you once it is available.
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Smartphone auscultatory blood pressure measurement - hearing is believing.

mr_coffee
Posts: 2
Joined: Sat Mar 05, 2016 6:20 pm

Re: Let's measure blood pressure accurately!

Post by mr_coffee » Fri Mar 11, 2016 7:09 pm

1. Appreciate the additional information on this. I found my monitor (A&D Company, Tokyo, Japan, Model UA-851) is not off by the more significant discrepancies you've discussed here. I'm a Peritoneal Dialysis patient so check my pressure every morning in part to determine the glucose level of fluid to use for the next treatment... any major discrepancies would certainly have an undesirable effect. The only discrepancies I'm seeing so far seem to be within the unit's margin of error anyway... a test 5 minutes before or after a different test could affect results by 1-5 mmHG in either direction for either number whether I use this revised method to double-check the accuracy or not, so I found it's results to be within an acceptable range.

2. A link or QR code would have been great, yeah. I found the instructions on a few sites... a video version was helpful, the written instructions were easier to follow... although I have yet to find anything spell out the part about "you'll only hear a heartbeat for a short period of time" and that the beginning and ending of this is what you're listening for. If you make your own instructions, I'd mention this since - from my limited consumer standpoint - this part is sorcery. Possibly a single sentence or two explaining why this would even be true (it's not as though the heart wasn't beating before or stopped beating after the test... why don't we always hear it?).

3. Yeah, a 3D design would be sweet. I don't have a 3D printer... but if I can get someone from a school to let me borrow a shop class for a few minutes over the summer, I might be able to bend a piece of acrylic to accomplish this task also... I'm guessing it would need to be semi heavy to keep from scooting around the desk, but I don't know. Well... we'll see which comes first... your automatic model or my purchase of a manual sphygmomanometer... then I'll figure it out.

4. it may only be with the adapter in use... but it happened a few times for me. My phone could just have been acting up... sometimes they just need to be restarted, so I can't put all the blame on your software... if you can't make it do the same thing, I wouldn't worry about it.

6. MIGHT... but might be worth it. It depends on how coordinated the user is. I found it difficult to work out the timing of the button press of the auto kit and the "button" press on the phone... this is more to remedy the "I messed it up" thing than to be an intricate video editor. Even a kind of "fake" zoom in... maybe by the same gesture you use to zoom into images on a phone? over the waveform graphic to make the peaks taller... instead of a crop would be ok... so long as you aren't listening to it... since if you start recording during inflation... it's kind of deafening.

8. I do look forward to this model. Can't wait!

This was my first purchase of any device being sold within a crowdfunded campaign. Well worth the price, I'm far more likely to do something similar in the future. Thanks for the response!

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Junfeng
Posts: 26
Joined: Mon Dec 28, 2015 7:33 am

Re: Let's measure blood pressure accurately!

Post by Junfeng » Thu Aug 25, 2016 7:29 am

Hi @mr_coffee,

The Accutension Stetho App was updated to fix some bugs and also implemented some features you mentioned in the post. Please have a try. Thanks!
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Smartphone auscultatory blood pressure measurement - hearing is believing.

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