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An open-source stethoscope that costs between $2.5 and $5 to produce

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Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#51

Post by M95D »

devilbunny wrote: post #43
Lalabadie wrote: post #37

Earlier quoted context omitted.

The pressure cuff + stethoscope combo is called a sphygmomanometer. It's a pretty fascinating piece of technology: A heartbeat is only audible in the earpiece when the cuff is compressing between someone's systolic and diastolic pressure. To use it, you get the cuff pressure high enough that you stop hearing a heartbeat in the earpiece. Start releasing pressure slowly. As it comes down, take note of where on the dial…

And if you use a mercury sphygmomanometer, you can actually see those pulses appear and then disappear. (It's harder to see them with a gauge-based one.)

The pulses you see are no substitute for a stethoscope. You see them later and they dissappear sooner than what you hear with a stethoscope.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#52

Post by lukko »

Lalabadie wrote: post #37
sonofhans wrote: post #25

Earlier quoted context omitted.

Years ago I had my blood pressure taken by a nurse; this was when they did it manually, squeezing the pressure cuff bulb by hand and listening with a stethoscope. The doctor came in later, saw the numbers and frowned, and took my pressure again. She (both were women) ended up with a reading much more within my normal range. I asked, joking, “So are you just better than her?” “No,” my doctor replied, “She’s better. Sh…

The pressure cuff + stethoscope combo is called a sphygmomanometer. It's a pretty fascinating piece of technology: A heartbeat is only audible in the earpiece when the cuff is compressing between someone's systolic and diastolic pressure. To use it, you get the cuff pressure high enough that you stop hearing a heartbeat in the earpiece. Start releasing pressure slowly. As it comes down, take note of where on the dial…

It does feel magical, especially when the first sound comes in. More details here [0].

[0] https://en.wikipedia.org/wiki/Korotkoff_sounds

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#53

Post by harvey9 »

sonofhans wrote: post #25
colinbartlett wrote: post #2

I was shocked to see that a "brand name" stethoscope is $100+ and even generic ones are $30.

Years ago I had my blood pressure taken by a nurse; this was when they did it manually, squeezing the pressure cuff bulb by hand and listening with a stethoscope. The doctor came in later, saw the numbers and frowned, and took my pressure again. She (both were women) ended up with a reading much more within my normal range. I asked, joking, “So are you just better than her?” “No,” my doctor replied, “She’s better. Sh…

If the nurse got a reading well outside normal range she should have repeated it to confirm, especially if it was inconsistent with your overall presentation.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#54

Post by conception »

nomel wrote: post #48
filoleg wrote: post #46

Earlier quoted context omitted.

A commercially sold hospital stethoscope is a legally marketed medical device made under a manufacturer quality system, with labeling/instructions, device listing/registration obligations, adverse-event/complaint processes, cleanability expectations, liability, warranty, consistent materials, and repeatable acoustic performance. An open-source 3D-printed stethoscope is a cool project, but unless it is produced and co…

What standard exactly, for a stethoscope? I know nothing of this, but it looks like stethoscopes are Class 1 medical devices with 501(k) exemption, and fall under the "Good manufacturing practices" guidelines of Quality System Regulation (21 CFR 820), but that seems pretty squishy.

CFR 21 being labeled squishy is a first for me.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#55

Post by sandworm101 »

I seem to remember a major issue re 3d-printing medical things. Early in the pandemic LTT organied an effort to print some PPE face shields for hospitals. It was all rejected. The microscopic holes left in the print material meant it could not be properly sanitized.

A stethoscope touches both patients and providers. This may be a place where smooth non-printed material may be the only sanitary choice.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#56

Post by krispykrem »

Here is an interview with one of the researchers behind this project:

https://logicmag.io/bodies/tarek-loubani-on-3d-printing-in-g...

It explains the project and its motivations. It's been a while since I read it (2019), but at the time I found it really fascinating and inspiring.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#57

Post by conductr »

colinbartlett wrote: post #2

I was shocked to see that a "brand name" stethoscope is $100+ and even generic ones are $30.

If it’s your everyday carry used in your profession, just pay for a nice one. It’s really not that much.

If someone showed you how to create a functional $30 monitor, you’d still pay more for a nicer commercial one

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#58

Post by projektfu »

colinbartlett wrote: post #2

I was shocked to see that a "brand name" stethoscope is $100+ and even generic ones are $30.

There are cheap, generic scopes (Sprague-Rappaport types) that are very sensitive but the double tube also causes a lot of noise. There are knock-offs of the Littmann scopes in the market. Then there are the scopes doctors usually buy, which are Littmann, Harvey (made by Welch-Allyn) and Heine, and a few smaller makers. No marketer of a high-quality scope wants to sell it at a $30 or less price point, and if you're going to go higher, might as well place it in the same market as the Littmann ($115+). I'll be honest, for emergency medicine use, the Littmann lightweight scope is good enough and cost about $45 when I bought it. But if I actually want to hear the subtleties in a chest, I'll use my personal scope (a Littmann Cardiology IV). Why choose this one? I already know it and they are very consistent. It doesn't feel cold to the patient and it has the right level of sensitivity without much noise. It is a little heavy. If a dog is bucking around, it can go flying and hurt if it hits someone.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#59

Post by andrewla »

stronglikedan wrote: post #19

The thing is that I can get just as good if not better ones (metal) for $7 all day long, and not have to spend time sourcing and assembling materials, and I don't even have to leave my house to do it.

When my kids were little they had a toy doctors set and the fake wooden stethoscope broke; replacing it with a real one was significantly cheaper than paying Melissa and Doug for a new one.

Re: An open-source stethoscope that costs between $2.5 and $5 to produce

#60

Post by dzhiurgis »

projektfu wrote: post #58
colinbartlett wrote: post #2

I was shocked to see that a "brand name" stethoscope is $100+ and even generic ones are $30.

There are cheap, generic scopes (Sprague-Rappaport types) that are very sensitive but the double tube also causes a lot of noise. There are knock-offs of the Littmann scopes in the market. Then there are the scopes doctors usually buy, which are Littmann, Harvey (made by Welch-Allyn) and Heine, and a few smaller makers. No marketer of a high-quality scope wants to sell it at a $30 or less price point, and if you're g…

How long do they last? Looks like pretty solid piece of equipment, but are they damaged easily or simply clap out after few years?
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