"How often do autopsies turn up a major misdiagnosis in the cause of death? I would have guessed this happened rarely, in 1 or 2 percent of cases at most. According to three studies done in 1998 and 1999, however, the figure is about 40 percent."
It's disturbing to learn how thin the evidence is for a lot of modern medical operations. For example, the recommendations for certain cancer screenings have actually been reduced in recent years after it was found they were causing net harm.
This is especially true for severe cases like this, people in the ICU, etc.
If someone is in the ICU for multi-system organ failure, gets an infection, and then dies of multi-system organ failure, did the infection kill them? Was it a contributory cause? The same sort of question arises as in this case.
Does it? I'm definitely not a doctor, but it seems like a very difficult question to answer.
Even with perfect information, it seems unlikely there is always a simple/single answer. I would naively expect things like (and I'm making a bit up here, because I'm really not a doctor) "not enough oxygen reached his cells, because his lungs were bad at refreshing the air in them, his heart was bad at pumping blood in circles, his veins and arteries were in bad shape due to diet, and he wasn't moving around much because he had a cold further reducing circulation".
But also, we don't have perfect information. We have this set of measurements we could make without harming the patient, or consuming too much time on really expensive equipment like MRIs. Many of those measurements are no doubt themselves subject to some degree of interpretation error and confounding factors.
Maybe I underestimate our doctors, or overestimate the problem, but it doesn't sound easy to me.