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Oscillometric blood pressure measurement
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- เผยแพร่เมื่อ 8 มี.ค. 2014
- biosignals.bern...
Automatic blood pressure monitors use the small pressure changes while deflating the cuff to determine both the systolic and diastolic blood pressure. In this clip we emulate an automatic blood pressure monitor with a standard manually operated cuff. To be able to record the pressure we have added the same sensor which is inside of the automatic blood pressure monitor and plotted its readings together with the ECG.
1st trace: Einthoven II, 2nd trace: pressure, lowpass filtered (5Hz), 3rd trace: pressure, highpass (0.5Hz) and lowpass (5Hz) filtered and amplified by x50.
The omron blood pressure monitor reported before filming at 10am 92/61,91/59 and after filming at 6pm 103/72,95/66. The plot at the end was recorded a week later and the blood pressure monitor reported: 89/66, 88/62, 108/73 and 100/65.
The demonstrator in this video is beautiful. Glad I had to study this tonite !!
Thank you for letting us listen to your heart and Korotkoff Sounds. Keep on Cuffin!!!
This video and all channel is simply amazing!!! :)
Accutension lets you see the oscillation and hear the Korotkoff sounds on your phone.
Interesting! So you let an app listen to the stethoscope while measuring the blood pressure. Stupid question: you could just listen to a normal stethoscope while the automatic blood pressure monitor does its job, isn't it? No need to have that special stethoscope and the app? Certainly a good idea in itself to cross check the readings of the automatic blood pressure meter with a stethoscope.
BPM biosignals Use of normal stethoscope to measure BP requires some skills. Accutension stetho simplifies that. You will not need to remember the number in real time and you can also playback to double confirm.
Amazing! Never know this
What I don't get is, when the cuff pressure is greater than systolic pressure then the artery is collapsed and so it would seem to me that no oscillations could be measured. Therefore the cuff pressure at which oscillations appear could be measured as the systolic pressure. Similarly, when the pressure in the cuff is lower than the lowest pressure in the artery, diastolic pressure, then no oscillations could be measured. Could you explain what I am misunderstanding here?
I'd say it's not just the artery underneath but I guess the whole arm expands / changes shape a bit when the heart beats. Remember these changes are tiny. Even pinching the cuff on the edges when inflated with the pressure wave hitting it will cause some change. I reckon the same when it's nearly empty but then the air transmits the small changes when the arm expands a bit.
What you described in you comment is what happens during a routine blood pressure check in the doctor's office or clinic. In this setting the examiner listens with a stethoscope for the Korotkoff sounds. Just think back to the last time you had your blood pressure checked. During a polygraph exam, the cuff on your arm is measuring blood volume. The cuff is usually inflated to 70-90 mm Hg. At this pressure you can hear the Korotkoff sounds but would not be able to determine a complete blood pressure reading.
Thanks for the video, can you please mention the part number for the pressure sensor...
www.biosignals.org.uk/nonelec_blood_pressure/
I really like they demonstration. I have a quick question how do you calculate the corresponding changes in pressure (p'*50)?
It's just the difference between two samples.
you are my god. i admire you so much.
thank you so much for the video. I would like to ask you, what program did you use to show the actual pressures? thank you
It's called 'comedirecord'.
@@BPMbiosignals thank you. May I ask you another thing. In matlab file when filtered the data, you calculated Wn ( cutoff frequency ) = fc/(fs*2) " from your matlab code: [bhp ahp] = butter(4,0.5/1000*2,'high');" while, I know that: Wn = fc/(0.5*fs). Can you please explain me why? Thank you so much. your videos are great!
not sure where you get that info from. That filtering is done with comedirecord and that's done in C++.
She has amazing artery sounds.
can i know if you can share the theory for the waveform shown at 2:36? appreciate.
biosignals.berndporr.me.uk/doku.php?id=nonelec:pressure
what type of pressure sensors you have used. Can you please share its circutry
biosignals.berndporr.me.uk/doku.php?id=nonelec:pressure
Problem with this over 100 year old method is, when you increasingly block the blood circulation, the natural effect is the body tries to maintain circulation so what is really measured is the hearts ability to build up pressure and maintain circulation.
The use of automatic machines have only exacerbated the problem.
Pumping up the cuff to high preaaure over 200 mmhg also creates a lot of stress on a human being and the stress implications are difficult to mitigate and assess between individuals.
Also, a well trained arm with a strong bicep muscle on an athlete is quite a different subject than a soft upper arm on your 80 y o mother, which is much easier to compress to cut off the blood circulation. As opposed to the well trained person with a high muscle tone.
This is very well known but simply ignored by the "medical society"
A lot of doctors understand this but still use this flawed method for reasons that hardly need to be explained.
It's a great shame and a travesty.
This doesn't make any sense. A body builder still has soft arteries that get compressed easily by pressures higher than their systolic blood pressure. Sure, if they're deadlifting 100s of kg at the point you check their BP, your going to have to pump it much higher and taught tendons may block the pressure transfer, but flaccid tendons and muscles aren't going to resist the pressure.
🙏🏿🌞🗽🌋