Not a doctor...but wouldn't a cardiac ejection fraction of 10% show as a low and intractable blood oxygen level on the patient's first ER visit? Especially with:

> For the past four days, he said, he had been coughing up blood and finding it harder and harder to breathe.

Then:

> The emergency room doctors [...] sent him home with asthma medicine and an inhaler.

Which sounds like a recipe for his acute decline to continue - possibly fatally - unless those asthma meds kicked in extremely fast.

Again, not a doctor. But my sense is that the ER rather bungled things, before the A.I. cavalry suddenly came over the hill.