Studies in children provide a model to re-examine the metabolic response to burn injury in patients treated by contemporary burn protocols

It is clearly important to assess what events, if any, are associated with periods of increased oxygen consumption during the first 24 h after a burn. Since patients are sedated, fasted and nursed in a thermoneutral environment many of the factors known to raise oxygen consumption have already been minimized. This is particularly so in children who are asleep because even activity has been eliminated and measured V̇o 2 is likely to be close to basal. One major influence on V̇o 2 at this time may be the early development of fever (described earlier). In all patients the pattern of rectal and acral temperature was plotted and its relationship to changes in V̇o 2 compared. Although there are slight differences between patients, this general pattern is typical of the changes which occur in most of the patients studied. Depending on the timing of measurements it is possible in some cases to determine the order of the changes which are seen. For example, T(ac) changes first, very soon followed by a rapid increase in T(r) over a period of just 2-3 h. The fall in T(ac),in most cases, is maximal before T(r) reaches a peak. With the method of indirect calorimetry used in this study it is difficult to assess whether the rise in V̇o 2 precedes the rise in T(r), simply because of the timing of the measurements but one would expect that it might. Further studies are in progress to confirm this. From these studies the characteristics of the early changes in oxygen consumption and metabolic rate have been examined. The rise in V̇o 2 during the early postburn period can be attributed to a thermoregulatory change in central set-point temperature. We can confirm that both efferent mechanisms operate at this time; heat conservation in acral regions together with a rise in oxygen consumption and metabolic heat production.