An Effect of Injury on Thermoregulation in Man

Abstract

SUMMARYThe effect of trauma on human thermoregulation has been studied using a behavioural test and the vascular response to cold exposure. It was confirmed, in controls, that a pleasurable temperature for the hand (Thand) depended on core temperature (T7) to which it was negatively related. Shortly after moderately severe fractures in a leg this relationship was lost and in the patients the slope of this regression line was not significantly different from zero and they usually chose a Thand towards the upper end of the normal range irrespective of T7. This effect was not imitated in controls by removing 500 ml blood but Thand was increased by occluding the circulation to one leg. Naloxone did not alter Thand in controls but when given in a suitable dose it reduced the rise in Thand during a short period of limb ischaemia. Immersing one hand and forearm in water at 17°C reduced the blood flow through the contralateral forearm and hand. The reduction in flow was positively related to the initial rate of flow in both controls and injured but the slope of the regression line was significantly less after injury. It is concluded that thermoregulation is affected by trauma in man.

Do fever and anapyrexia exist? Analysis of set point-based definitions

“…One can notice that the strategy shown in Fig. 1, D-I, represents exactly what happens with thermoeffector thresholds in the so-called anapyretic states (18,25,28,31,33,37) and during the later phases of fever (40; also see test 1 above). This strategy is characterized by a wide interthreshold zone formed by a drastically decreased T thr-cold at the low end and a slightly decreased (D and G), normal (E and H), or even increased (F and I) T thr-heat at the high end and represents the poikilothermic type of T b regulation (6).…”

“…Similarly, it has been found in many (for review, see Refs. 9 and 34), but not all (18,31,37), cases of anapyrexia that the fall in T b is also achieved by coordinated behavioral (e.g., seeking a cooler environment) and autonomic responses; the autonomic responses involved are aimed at increasing heat loss (e.g., skin vasodilation) and decreasing heat production (e.g., inhibition of thermogenesis). In other words, both fever and anapyrexia can occur as the result of several effector responses all aimed at changing T b in the same direction.…”

Thermoregulatory Response to Chemical Toxicants and Other Insults

“…Most of the human data indicate relatively minor reductions in core temperature when subjected to a variety of insults, suggesting that regulated hypothermic responses are probably not operative in large mammals as is observed in rodents. It is possible that the CNS thermoregulatory centers of large species respond to insult in a coordinated manner, 42 but more work is needed to verify the mechanisms.…”