The effect of epinephrine on blood and tissue PO2 in the rabbit

Tissue PO2 in the rabbit was measured with galvanic oxygen electrodes chronically implanted in peritoneal and subcutaneous tissues; blood PO2 was measured in arterial and venous blood samples obtained from chronically implanted catheters. The effect of intravenous epinephrine 4 microgram/kg on tissue and blood PO2 was examined in the unanesthetized animal. Basal tissue PO2 values were 43.6 +/- 1.71 mm Hg (mean +/- SEM) for peritoneum and 15.9 +/- 2.51 mm Hg for subcutaneous tissue. These values increased to 112.8 +/- 8.67 mm Hg (peritoneum) and 76.0 +/- 2.24 mm Hg (subcutaneous) after 15 minutes of O2 breathing. Epinephrine led to significant reductions in tissue PO2 during both air and O2 breathing without affecting blood PO2. It is concluded that epinephrine administration alters the relationship between blood and tissue PO2 leading to relative tissue hypoxia despite normal or high blood PO2. These observations are important to an understanding of shock and emphasize the need for further investigation of tissue PO2 as a measure of shock states.