'The patient is Code 3 critical. Her frail, 90-year-old body is failing. How much should I do to save her life?'

"This … is the end … of my life.”

These would be my patient’s only words — an economy of phrasing made necessary by an all-consuming air hunger. She had just arrived in the emergency room, Code 3 critical, after a lights-and-sirens ambulance transport from her nursing home. Awake, alert and intensely...