It's probably more accurate to refer to him as the father of modern surgery, but I was thinking of William Harsted, who - alongside many other innovations (such as championing anesthetics and sterile surgical environments, both of which are alarmingly recent inventions) - created the residency system that's still used for training hospital staff today.

He demanded insane hours of his staff, which he was easily able to handle himself due to his cocaine habit, and which have been kept to this day (a law was passed attempting to cap it at 80 hours a week, but it's widely ignored) because studies show that shortening medical shifts results in worse patient outcomes.

It turns out minimizing shift changes is critical - the doctors/nurses who've been observing the patient are more aware of what's going on and can spot any changes in behavior or subtle warning signs of danger, whereas their replacements can only go by what's on a patient's medical chart and what they're told during handover.