Delirium can happen despite textbook medical care. The only way to truly avoid it may threaten access to care:
It appears that the surest way to avoid incurring CMS’ proposed financial penalty for delirium occurring in the hospital would be to avoid admitting sicker patients who are most likely to become delirious. This, of course, is a perverse incentive that could make care less accessible for those who need it the most, and would violate hospitals’ fundamental mission to care for the sick.
The Happy Hospitalist also chimes in.