Nursing in many states is challenged by unsafely high patient:staff ratios, excessive documentation requirements (on extremely slow user interfaces), and the need to vigorously double-check physician's orders (dangerous drug interactions, over-dosages, etc).

medical residents will routinely do back to back 24 hour shifts with no sleep and even the ICU attendings will do a week of every other day 24 hour shifts.

The 16 hour rule only applies to interns. Once you reach second year the rule is 80 hours a week averaged over four weeks. This means that 100 hour weeks still do happen.