Environmental Medicine

Carbon monoxide binds haemoglobin far more avidly than oxygen, so oxygen carriage collapses while the arterial oxygen tension and the pulse oximeter both stay deceptively normal.

In hyperthermia the hypothalamic set-point is normal and heat load simply outstrips heat loss, so antipyretics have nothing to act on and physical cooling is the only disease-modifying treatment.

Accidental hypothermia is a core temperature below 35°C: cooling leaves an irritable myocardium that handling alone can tip into arrest, while protecting the brain enough that prolonged resuscitation still works.