Tissue pO₂ and pCO₂ estimation with rat subcutaneous gas pockets

¹ Department of Physiology, The University of Rochester, Rochester, New York

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.