CARDIAC OUTPUT AND RELATED MEASUREMENTS AND PRESSURE VALUES IN THE RIGHT HEART AND ASSOCIATED VESSELS TOGETHER WITH AN ANALYSIS OF THE HEMODYNAMIC RESPONSE TO THE INHALATION OF HIGH OXYGEN MIXTURES IN HEALTHY SUBJECTS

Journal/Book: Vol. 51 No. 1 Pages 72-90 January 1958 (Printed in the U. S. A.). 1958;

Abstract: From the Mayo Clinic and Mayo Foundation Rochester Minn. The Mayo Foundation is a Part of the Graduate School of the University of Minnesota. Received for publication June 10 1957. *Fellow in Surgery Mayo Foundation. **Section of Physiology Mayo Clinic and Mayo Foundation. Reprinted from THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE St. Louis SUMMARY Twenty-six ambulatory healthy subjects with cardiovascular respiratory systems normal in all clinical and laboratory aspects were investigated by the technique of cardiac catheterization. The zero reference point for all pressure measurements was mid-chest at the sternal end of the third interspace. The cardiac index averaged 3.5 and ranged from 2.5 to 4.4 L./min./M.2 and the stroke index 46 with a range from 37 to 63 ml./beat/M.2 The mean and range of values for calculated total systemic total pulmonary and pulmonary "arteriolar" vascular resistances were 1 130 (745-1 570) 205 (90-290) and 67 (44-106) dynes-seconds-cm.-5 respectively. The average pulmonary artery wedge pulmonary artery right ventricular right atrial and antecubital vein pressures were : 15/9 22/12 27/4-10 9/4 and 9/7 mm. Hg respectively while the radial artery pressure averaged 135/71 mm. Hg. The average statistically significant mean pressure gradients from the antecubital vein both cavae and the left atrium to the right atrium were 2 0.5 and 6 mm. Hg respectively. The average systolic pressure gradient of 2 mm. Hg across the pulmonary valve was statistically significant. The pressures during expiration in the right atrium right ventricle pulmonary artery pulmonary artery wedge and radial artery averaged 1 2 3 3 and 4 mm. Hg respectively higher than during the inspiratory phase of the respiratory cycle. The average maximal differences in systolic pressures recorded at different times in the Same individual during cardiac catheterization averaged 2 4 3 and 3 mm. Hg in the right atrium right ventricle pulmonary artery and wedge positions respectively and ranged from 0 to 12 mm. Hg. The effect of the administration of 95 per cent oxygen was investigated in 20 of these subjects. There was a fall in heart rate and an increase in stroke volume with no systematic change in cardiac output under these conditions. In addition a fall in pressure throughout the right heart and pulmonary vascular tree and a rise in systemic arterial pressure were noted. ___MH

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