I posted this a few weeks ago but think it relevant to what you are saying Red bar

"The STETHOSCOPE
Your doctor will probably use a stethoscope to listen to the back and front of your chest to check for any crackling or rattling sounds. They may also tap your chest and listen to the sound that is produced. If your lungs are filled with fluid, they will produce a different sound compared with normal, healthy lungs.

How do doctors check chest infections using only a stethoscope?

By
Alveolar Tan, studied Medicine and Healthcare

Oct 4, 2014

Before answering this question, we must first know that lungs are filled with airs.
In normal lungs, the air ways are smooth. So when a person inhales or exhales air, there forms laminar flows. As we all know, the fluid meets a lesser resistant force when in a laminar flow, so the auscultation will be "clear".
When there are chest infections, the body will react to these invaders. The capillaries will dilate, and the plasma will exudate. So the air ways will not be smooth any more. There are fluids in it. Thus, when a person inhales or exhales, the air will have to pass through the exudated fluids. I think we all have the experience to exhale air in water, when sounds will generate. In auscultation, we call it "bubble sound"， or the lesser sound we call "rales". With theses sounds, their locations, and the entensity, a clinical practitioner can get some hints about whether there are infections, to make sure of it, they can suggest some other examinations.
By the way, there are "dry rales" in auscultation. This is because the air ways are narrowed. So the air flow will form trebulent when passes through. Thus we can hear the sound.

RAPAPP"looks" at these SOUNDS in the lungs and records, compares and provides some possible observation, without the doctor.
Results can then be remotely relayed to a doctor or hospital who can analyze the patterns generated by the lungs. Conclusions made and if need be call the patients in for further examinations.
SOUND really futuristic.
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