Studies on Peripheral Blood Catecholamine Levels During Hemorrhagic Shock in Dogs.

Summary Peripheral blood catecholamines were studied in dogs during hemorrhagic shock. When determined by the fluorimetric procedure, with values corrected for recovery, epinephrine increased from control levels of 0.4 ± 0.2 μg/1 to 27.6 ±8.7 μg/1; norepi-nephrine increased from 3.4 ± 1.6 μg/1 to 11.6 ± 3.4 μg/1. Thus during hemorrhagic shock in dogs the catecholamines found in the peripheral arterial blood are largely epinephrine (70%); and to a lesser extent nor-epinephrine (30%). Significant quantities of epinephrine-norepinephrine usually appear in the blood when the mean arterial pressure has dropped to about 80 mm Hg. As the pressure is lowered further the circulating catecholamines increase very rapidly. This increase is largely due to epinephrine and to a lesser extent to norepinephrine. Simultaneous estimation showed epinephrine concentration to be greatest in the inferior vena cava followed by the femoral artery and lowest in the femoral vein. These experiments indicate most of the catecholamines in the circulation during hemorrhagic shock in dogs are released from the adrenal medulla and are rapidly destroyed by the tissues.