The Quarterly journal of medicine
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The pathophysiology of afterdrop of core temperature during rewarming in patients with induced or accidental hypothermia remains controversial. We studied the effect of cooling and rewarming in four female patients with acquired poikilothermia and in four normal females. Exposure to cold air (16.5 degrees C) induced shivering and adequate vasoconstriction in normal individuals, without a fall in rectal temperature (Tr; 36.3 +/- 0.2 degrees C [mean +/- SD]); subsequent heating (40 degrees C) induced a rise in Tr to 37.0 +/- 0.3 degrees C and generalized sweating. ⋯ The basal metabolic rate was decreased by 71-82% in all patients during steady-state hypothermia and remained lowered during normothermia in two patients. We conclude that during hypothermia three of the four patients showed severe disorders of peripheral vasomotor function and shivering response. These data provide evidence for thermal conduction as the major mechanism of afterdrop during hypothermia.