Blood Pressure Measurement using Korotkoff Sounds

Need some guidance on the topic "Blood Pressure Measurement using Korotkoff Sounds". The components I'm gonna use for the project are Arduino Uno, stethoscope, sphygmomanometer, and sound sensors. I need a detailed explanation on how to do the project and on what software(s) must be used.

That's a big ask, @JennYoung. Just checking, is this a college assignment, or something?

Hi, @JennYoung
Welcome to the forum.

Please read the post at the start of any forum , entitled "How to use this Forum".

Can you please tell us your electronics, programming, arduino, hardware experience?

Will you be analysing sound waveforms?

Thanks.. Tom... :smiley: :+1: :coffee: :australia:

Please provide a detailed description of the project.

This is more like a medical research than a college assignment. You need something more beefy than an UNO to do sound processing

Well, I wouldn't have thought so. As far as I know, blood pressure measurement by this means is totally sorted and has been for decades. Isn't this how all the popular blood pressure machines work? It sounds too basic and simple to be a research project.

How about without the sounds:
"Blood pressure monitor (BPM) using oscillometric method with MPX5050GP pressure sensor has been successfully fabricated and calibrated."

The taking of blood pressure using the 5 Korotkoff sounds is always recgonized as more accurate.

Simple and distinct sounds should be able to be plotted.

However we have entered the age where "Arduino" no longer means UNO.

While the UNO cannot handle this there are other chips that might.

The answer to the question is really what chip can detect the sound and identify it.?


I think the OP was very clear in the request.

The mechanics of pumping air into the cuff then bleeding it off and watching the pressure is simple enough. Any arduino can do that easily.

The sound sensor can use the stethoscope listed in the question.

Sound detection and characteristics are the bit where a microphone needs to be selected. Frequency sensitivity etc.

Sound patterns seems to me to be the only part that would require some processing muscle.

As a wild guess the OP posted on other forums and someone offered that the RPi has the processing muscle.

It would seem the OP needs help in selecting a suitable microphone and also is looking for software to help pick out the characteristics of the sounds that hopefully does not report 'magma displacement'

The job of being the doctors ears will require some major programming I would say, the RPi suggestion would fit the bill for speed and some realtime processing "grunt".

Tom... :smiley: :+1: :coffee: :australia:
PS.. "One ping only"

Well, yes, more-or-less. I had such a machine some - well, I think at least thirty years ago. Probably somewhere lost in my museum now. However ...

No, almost all machines in current use are not strictly sphygmomanometers, but oscillotonometers. Those I see in theatre are double tube devices - now that I mention it, I have assumed they were double bladder but probably they use one tube for inflation and the other for the oscillotonometric determination for better accuracy. I must check this. :grinning:

You really should not require advanced frequency analysis to detect Korotkoff sounds though ambient noise and particularly noise introduced by the mechanics of the cuff will always be a problem, So a common Arduino (Nano, please do not refer to UNOs) should suit with some analog microphone processing.

(You do not need an actual stethoscope - the microphone is directly attached to the cuff with a sound absorbent backing,)

That's fascinating! Thanks, @Paul_B.

The ones I had in mind when I spoke so imprecisely are the small battery-powered ones that you find in the GP's surgery - I believe Omron is a common brand. They have a single cuff, of course. So would they be sphygmomanometers rather than oscillotonometers? I'm going to read up on the latter - I didn't even know they existed until I read your post!

Almost all machines are single cuff - I was just musing about those integrated into the theatre/ ICU monitors which have two hoses - I will look into this tomorrow.

The Omron HEM-907 is a popular model, certainly in Australia where they were supplied to most GPs here some years back as an initiative (the singularly most useful such) by a drug company (whose name presently escapes me - while there is a HEM-907 sitting on another table here as a result of my wife's recent piqued interest in her BP, it is a spare I purchased and does not have the drug company's imprint).

An actual ausculatory sphygmomanometer has a microphone attached to the cuff which needs to be accurately placed over the brachial artery in the cubital fossa. Very few machines have this compilation - I have not seen one in many years - so they are basically all oscillotonometers.

This is a fascinating discussion, and I was concerned it might be drifting off-topic, but I don't think it is, really. So, Omrons et al work by detecting the pulsing changes in pressure in the cuff, whereas the OP's project does, literally, require a microphone to listen to the Korotkoff sounds and some DSP to extract useful information. Not really a job for Arduino, then.

As you say, she has left the room after her first post, so perhaps has come to the same conclusion. It's a bit discourteous not to even acknowledge the interest shown, though.

Well, I can assure you the machine I fondly(?) recall existed prior to DSP as I understand it, and the "whooshing" sounds in question should be reasonably obvious, so I think a microphone amplifier and level detector are the main interface required.

The other faltering thread here on the "sound level alert" would probably indicate a suitable device if we could ever figure it out. :worried:

Oh, of course, if all the OP wants is to hear the whooshing sounds, then why use any kind of microcontroller? I just assumed she wanted to do some kind of processing in the digital domain to the detected sounds, hence including an Arduino in the parts list.

post #8

There are 5 distinct sounds.
the 'whooshing' is when the diastolic pressure is equal to, or just higher than, the cuff pressure, and on the contraction of the heart, the highest pressure is forced past the cuff zone and the compressed artery.

At the lowest pressures, the systolic, the standing pressure of the artery is found. it is the point where the heart is at rest between beats.

Two very different sounds.

Since the OP asked about a stethoscope as part of the project, we may assume that someone trained would be placing the stethoscope properly.

a note about the OP and project
#1) I would not be suprrized if this turned out to be an XY Problem
#2) the OP my be in the States and away for the 3-day weekend,
#2a) OP may have posted elsewhere (a Pi forum perhaps) and gotten a tutorial for this project and has all the answers needed.

Of no interest at all. :yawning_face: What matters is only if there are any such sounds. Systolic BP is indicated by the appearance of the first sound, and diastolic by the cessation of the last sound.

What do you mean? Got it backwards I gather?

Good luck! :roll_eyes:

Since we are talking about sensors i will agree.

A point i made in a previous post is that the microphone has to be selected that can hear those sounds and have a signal output that is recognized above the noise.

No sign of the OP, I wonder why? :wink: