CARDIAC OUTPUT IN MAN BY A DIRECT FICK METHOD: Effects of Posture, Venous Pressure Change, Atropine, And Adrenaline

Abstract

Serial estimations of cardiac output and right auricular pressure were made by means of a ureteral catheter passed along the left median antecubital vein into right auricle. Normal resting values for arterio-venous O2 differences were lower than those obtained previously by the acetylene method, being 5.3 liters/min. in the recumbent position and 4 liters/min. in the standing position. A fall in right auricular pressure reduced, and a rise in right auricular pressure increased the cardiac output. Acceleration of the heart rate with atropine usually increased cardiac output and caused a fall in right auricular pressure. Intraven. adrenalin increased the cardiac output in doses that did not accelerate the heart or raise the blood pressure. Normal subjects with a high resting cardiac output had a faster heart rate than others.