The shift is, at its core, a shift in default assumption.

Before the accumulation of cases like Jean Hilliard’s, the default assumption in emergency medicine was that a patient who appeared dead — no visible pulse, no visible respiration, unresponsive — was dead unless there was specific evidence to the contrary.

The evidence of apparent death was taken at face value.

The medical understanding of hypothermia’s effects on the body’s vital signs — the way it mimics death while actually preserving life — has moved the default assumption.

For patients whose apparent death is associated with hypothermia or cold exposure, the presumption is now that they may not be dead, and that aggressive efforts to rewarm and resuscitate are warranted before a declaration of death is made.