Some Universities & Airlines offer courses for Doctors/Nurses to train them how to help during a medical emergency onboard. A course I took years ago was “Onboard Medical Emergencies” given by McGill University and Air Canada.
Was a great course, lasted a day long and we spent 2 hours in their motion simulator doing role playing! All the topics mentionned here were addressed: Good Samaritain law, Medical kits, aviation physiology, etc…
Their website is: http://www.onboardme.com
For those who wants a great course on that subject, I really recommend it. I would do it again anytime!