The heating pads that Sather used were an external warming method — they added heat to the body surface rather than directly to the core.

This approach carries more risk of afterdrop than active core warming, but it was what was available, and in Jean Hilliard’s case, it worked.

The fact that it worked suggests that either the afterdrop phenomenon was manageable in her specific case, or that the peripheral warming from the heating pads was sufficiently gradual that the return of cold peripheral blood to the core did not overwhelm the cardiac system.

Given that her heart was already at 12 beats per minute and her cardiovascular system was profoundly depressed, the margin for cardiac error was extremely small.