I am not a nurse or a doctor but just a hearing aid dispenser from the Netherlands, so sorry for my broken english. I regulary get this question and as the only audiologist in the Netherlands I do sell a special stethoscope from a US company cardionics.
This stethoscope comes in different ways. I did fit many of them. Sometimes using an Oticon streamer, Phonak iCom or Widex Dex to get the sound into the hearing aid. Don’t try to use the bluetoothconnection with a jabra or something, just connect it with an audio cable to the input of the streamer. Especialy Agil had good results with the power bass which only is used in the audio program of the streamer. You have to tweak the settings then, reduce ambient sound, no spatial noise and so on. Widex music program is excellent too, starting at 70Hz, but unfortunately this program is only used by the microphone and not by the Mdex.
Another way is to use a silhouette cable. This cable has one or two induction coils which can be placed next to the hearing aid when it has induction possibility.
Whe the fitting is an open fit, these options do not have enough low frequenties, the I suggest just to put a headphone. It has amazing results, the benefit is that you do not really close the fitting then like you do when using a conventional amplified stethoscope which will give you extra amplification of low ambient sounds from the surrounding when the hearing aid is still on but when you close the ear channel with the convetional stethoscope earpieces.
When you are student, I suggest to ask if the automatic switch off can be lengthened. You can also connect two headphones or record the sound to your PC
In the US Cardionics has a webshop.
cardionics.com/e-scopeelectronicstethoscope.htm
Good luck, greetings from Holland