EFFECT OF HYPEROXIA AT 1-ATA AND 2-ATA ON HYPOXIA AND HYPERCAPNIA IN HUMAN SKIN DURING EXPERIMENTAL INFLAMMATION

Transcutaneous Po-2 and Pco(2) measurements and estimates of skin respiration were monitored at different levels of inspired Po-2 in 20 healthy adults during the first 4 days of the tuberculin reaction, a convenient model of acute inflammation. Hyperoxia at 1 and 2 ATA significantly increased transcutaneous Po-2 levels in undisturbed and in inflamed skin but did not fully correct the relative hypoxia at the site of inflammation. Hypercapnia was reduced with O-2 breathing at 2 ATA. The apparent rate of O-2 consumption at the reaction site was raised during hyperoxia, most prominently at 2 ATA. The most intense reactions showed a central relative slowing of laser-Doppler blood flow indicative of microcirculatory impairment. The extent of the relative hypoxia and hypercapnia was greatest in these strongest reactions. The density of lymphocytes and monocytes in biopsies of 48-h reactions was loosely related to the corresponding transcutaneous Po-2 measurements. The present study provides evidence that diffusion barriers, in addition to increased local respiration, can contribute to the apparent hypoxia and hypercapnia of this inflammatory model.