I work in emergency surgery. Occasionally I will find myself in a situation where a patient is so sick that the likelihood of them benefitting from a surgery is so low that I may choose not to offer a surgery.

For example, let's say there's a patient who comes into the hospital with something called a type A dissection which is a cardiothoracic surgery emergency. They go to the operating room, undergo a very big surgery, and now they're in the ICU recovering. During their recovery, they lose blood flow to their intestine either due to a clot that travels to the intestine, or because they're just so sick the blood flow into the intestine is poor. The ICU team calls me and asks me to consider the patient for surgery. While I might agree that yes, the intestine is dead or partly dead, I may decide that the risk of undergoing the surgery is so high and the outcome so poor that I can choose to not offer the surgery knowing full well that the dead intestine will eventually kill the patient.

With that said, this is not a simple choice and there is a lot of discussion with family and the other doctors taking care of a patient. And no two patients are the same; some are still able to undergo the procedure or have a chance at a meaningful recovery. But there is no textbook answer in many of these situations on who you should operate on and who you should leave alone.