KETONE-BODY RATIOS OF THE SUPERIOR AND INFERIOR VENA-CAVA AND OF PULMONARY ARTERIAL BLOOD COMPARED TO THAT OF ARTERIAL BLOOD - CENTRAL VENOUS KETONE-BODY RATIO AS A SUBSTITUTE FOR THE ARTERIAL KETONE-BODY RATIO

To investigate the ketone body ratio (acetoacetate/3-hydroxybutyrate) of central venous blood compared to that of peripheral arterial blood, the acetoacetate and 3-hydroxybutyrate concentrations in paired perip heral arterial and central venous or pulmonary arterial blood were mea sured. The ketone body concentrations in superior and inferior vena ca va blood were significantly (P < 0.0001) lower than those in periphera l arterial blood, whereas those in pulmonary arterial blood were almos t the same as those in peripheral arterial blood, These results indica te that ketone bodies were metabolized in the muscles, which reduced t heir levels in vena cava blood, but ketone bodies newly produced by th e liver were transported to the right side of the heart via the hepati c vein, giving concentrations in pulmonary arterial blood that were al most the same as those in peripheral arterial blood, On the other hand , the correlation coefficients (r(2)) Of the arterial blood ketone bod y ratio to the ratio of superior and inferior vena cava and pulmonary arterial blood were 0.897, 0.767 and 0.882, respectively. The ratios o f central venous ketone body ratio/arterial blood ketone body ratio we re 0.89 +/- 0.15 in the superior vena cava, 0.64 +/- 0.18 in the infer ior vena cava and 1.01 +/- 0.15 in the pulmonary artery.