In regards to an EM physician working on a rig, it is not an unheard of practice, but it is fairly uncommon. The main reason is that the EM physician has a skill set that is most effectively utilized in the setting of an emergency department. We can function in the field, however, most would be at a disadvantage there. Most of the things that we can do better than a medic out in the field (their environment) would be done in the ED (our environment).
On occasion, there are times when a physician would be beneficial in the field. I am thinking of the emergent amputation in order to facilitate extrication from an accident. An on-site emergency physician *could* be of some benefit at the scene of a mass-causalty incident, however, we would be of the greatest help to the patients by being in our environment.
Most of the EM physicians that I know that still run on a rig were EMTs/Medics once upon a time. Most would function to the level of their malpractice coverage. It is a sad fact, but we live in society of litigation and that determines what is done at times. As GarrettMccarthy wrote, there usually a set of protocols used by EMTs/Medics written by their Medical Director (known henceforth as “Doc A”). Doc A bears the liability if something goes wrong with the medics under him.
The EM physican on the rig (known henceforth as “Doc B”), will have 2 choices. If Doc B doesn’t want liability, then he/she would have to follow the protocols established by Doc A and function as a Medic. Doc B has a second option. If the rig’s online medical control (the “go-to” people on the radio for answers that aren’t covered by protocols) gives the OK, Doc B could assume direct medical control. That would allow Doc B pretty much free reign to do what he/she wants to do in the field, but it comes at a cost. By assuming direct medical control, they also assume liability. That is something that most EM physician’s malpractice insurance wouldn’t cover.
Where am I going with this? Good question! (mental note: Don’t try for insightful answers after getting off of a 10 hour flight).
The short answer is: the EM physician on a rig would function as an EMT and follow established protocols if they don’t want so assume liability. If they are willing to assume liability, then they can function as an EM physician in the field.