A century ago, NO HOSPITAL in the world had air conditioning, fifty years before that NO HOSPITALS had electricity and few had running water. And although morphine was readily available, IT WASN'T USED BY DOCTORS WITH THE INTENT OF KILLING THEIR PATIENTS.
Go back and do the research for yourself, the Hippocratic Oath was DELIBERATELY CHANGED in the early 1960s and that is when doctors first started talking about euthanisia. Yes, there is a history of severely injured people being euthanized on battlefields, but this was done by soldiers, not doctors.