We had brought a large body-sized far-infrared heating pad to warm her, as well as smaller one for her chest. I kept her under blankets and turned up the room thermostat to 80F. We did this to take the edge of the chills and shakes, as well as to reduce energy requirements by the body to raise core temperature.
(The picture below is of the far infra-red heating pad in black, covered with towels, that we used to pre-warm the body)