Tissue pO2 and pCO2 estimation with rat subcutaneous gas pockets

Abstract

This study appraises use of gas pockets for estimation of tissue pO2 and pCO2. a) Tensions of O2 and CO2 in rat subcutaneous pockets in the constant composition state were compared with tissue tensions estimated by a special interpolation technique using the pockets; the two types of results were not appreciably different. b) Possible values for venous blood pO2 and pCO2 were estimated by a “blood r” curve; agreement between expected blood tensions and gas pocket tensions supports the hypothesis that pockets closely reflect a tissue region's venous blood. c) Initial composition adjustments after introduction of five different mixtures of O2, CO2, and N2 into the pockets were studied; the results were used to illustrate some theoretical properties of gas pockets in the body. Submitted on April 23, 1962