I don't know much about how hospitals work, do doctors even have "managers?" I would figure the doctors would be the ones coming up with and using the checklists.

It's complicated. Doctors employed by hospitals report to two sets of managers. There are other doctors who serve as medical department heads and the chief of medicine. But those doctors are also accountable to non-physician business managers for administrative and financial issues. And then independent self-employed doctors may have privileges at the hospital and see some patients there but don't have managers in the traditional sense.