Hearing Aids and Stethoscopes - Can you use hearing aids with Stethoscope? the short answer is yes. There is an adapter from a company called Microsonic See http://www.microsonic-inc.com/index2.php?section=61 You can reach them at 800 523 7672
The short description is The Anesthesiologist’s earmold uses a standard receiver ring and a male stethoscope adapter that connects to a listening device. Electronic stethoscope and conventional stethoscope adapter molds are also available. The conventional stethoscope mold is made of soft thermoplastic Synth-A-Flex II.