What happens if there is a major injury on a spaceflight? I know that Astronauts/Cosmonauts are trained to do first aid and one crewman has further training.
I presume there is a procedure to decide what can be handled in space and what they need to send down? Who decides? Mission Control? Commander?
On Apollo 15, James Irwins heart issues were not communicated to the Commander, David Scott, which pissed him off no end. Irwin did a major deep space spacewalk after the issues arose, which Scott said he would have disallowed had he known. In that case they could not have come down faster anyway.
What about on the Mir/ISS or earlier in Salyut or Skylab? On the later I presume it means end of mission, but on MIR and ISS? If on ISS someone feels ill and has to go down, does that mean his/her expedition colleagues also have to go down?