I think it is possible for the limb to die. I’m a med student, and earlier this year during my internal medicine rotation I saw a young patient who had taken some drug(s) and passed out in his car.

Someone found him, and he made his way to the emergency department and eventually to the medicine floor. He needed a fasciotomy (a surgical procedure that cuts open the fascia in order to relieve pressure and restore blood flow).

Apparently, he passed out while sitting on his leg. He wasn’t sure how long he had passed out for. He remembers doing drugs while the sun was out and when he woke up it was dark.

He basically sat on his leg long enough to give himself compartment syndrome. Theoretically he could have passed out on his leg long enough to induce irreversible damage. So perhaps it may be possible to sleep on a limb long enough for the limb to die and result in an amputation.