Metabolic correlations

Metabolic correlations

72 Blood flow to surface wounds Doppler blood flow probes have been implanted around the external iliac arteries of goats prior to excision of the sk...

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Blood flow to surface wounds Doppler blood flow probes have been implanted around the external iliac arteries of goats prior to excision of the skin of one hind limb. Compared with the measurements made before excision of the skin and in the uninjured limb after the excision (with a blood flow of 107 -+ 19 ml per min), the blood flow in the injured leg was supranormal by the fourth postoperative day and remained at between 70 and 90 per cent above the uninjured leg blood flow for the next 2 weeks (at 186 -c 27 ml per min). The increase in the blood flow in the injured leg coincided with the development ofa highly vascularized wound. Studies of substrate turnover indicated that the elevated blood flow to the injured leg was not the result of increased oxygen consumption but was associated with increased glucose uptake (7.8 f 1.1 mg per min v. 2.7 k 0.6, P < O.OOl), and lactate release (3.6 f 1.3 mg per min v. 1.1 f 0.7, P
Burns No.

7/Vol.

1

LABORATORY STUDIES Frozen allografts Frozen allografts (human cadaver skin stored at - 196 ‘C) may serve as an excellent biological membrane but it is not a satisfactory product for longer term (intermediate) allografiing. The method of thawing (microwave oven v. water bath) appeared to have little effect on the ultimate viability and outcome of the frozen allografi. Wachtel T. L., Ninnemann J., Fisher J. C. et al. t&9:9) Viability of frozen allogmfis. Am. J. Surg. 138,

Thermal conduction in skin The maximum permissible temperature any material may attain without causing pain or a bum on contact with bare skin was determined from over 2000 observations of pain threshold during contact with materials at elevated temperatures. Six materials were used representing a range of thermal properties from good conductors to good insulators. Time to pain threshold was converted to time to threshold blister on the basis of the relationship between pain and bum established earlier for radiant and convective heating. Calculated times to blister were used to predict the material temperatures causative of ‘touch bums’. Experimentally produced threshold blisters at the predicted temperature-times verified the predictions. Graphs and equations were generated for determining safe temperatures for any material in contact with bare skin for I-5 s solelv from a knowledae of its thermal properties. Conversely the thermal in&a (Kpc) of the optimal material for a specific use and skin contact can be predicted from a knowledge of the maximum material temperature and length of contact time anticipated. Stall A. M., Chianta M. A. and Piergallini J. R. (1979) Thermal conduction effects in human skin. )4viat.‘Space Environ. Med. 50,778. Metabolic correlations A study is reported of the correlations between insulin, human growth hormone, cortisol, glucagon, free fatty acids, triglycerides and glucose in patients with a wide range of burned areas. When the injury was of only moderate severity (with a mortality probability up to 0.34) there appeared to be a loss of glucose regulation in conjunction with insulin resistance without significant interplay of the other factors studied. In contrast, patients with a mortality probability above 0.47 showed correlations between glucagon and glucose (which was negative) and cortisol and free fatty acids, indicating a significant role for hyperglucagonaemia in these patients. Discriminant function analysis was used to include all significant variables into a probability model, and only insulin, glucose and glucagon appeared in the optimal classification equation. _ Volenec F. J., Clark G. M., Mani M. M. et al. (1979) Metabolic profiles of thermal trauma. Ann. Surg. 190; 694.