480 C. R. BARDEEN 



to the estimate given above of 20 per cent from each ventricle, 

 60 per cent of the ventricular content. 



In the prone position we have observations on eight individ- 

 uals. The average output was 27.6 per cent of the cardiac con- 

 tent or 13.8 per cent for each ventricle; 41.4 per cent of the 

 ventricular content. The extremes are 19.2 per cent of the car- 

 diac content, 9.6 per cent for each ventricle, 29 per cent of the 

 ventricular content; and 32.5 per cent of the cardiac output, 

 16.8 per cent for each ventricle, or 50.4 per cent of the ventricu- 

 lar content. The estimates of percentage output of ventricular 

 content are based upon the assumption that one-third of the blood 

 in the heart in diastole is to be found in each ventricle, one-third 

 in the two atria. It is probable however that in the prone 

 position a greater proportion of the blood in the heart in diastole 

 is to be found in the atria and that the percentage output from 

 each ventricle is greater. On the assumption that in the prone 

 position there is an equal amount of blood in each chamber of 

 the heart in diastole the percentage output from each ventricle 

 would average 55.2 per cent, with variations from 38.4 per cent 

 to 62 per cent. 



The 'relation of cardiac output as determined by the method 

 given above, to various factors has been studied in our labora- 

 tories by Mr. E. J. Van Liere. He found no correlation be- 

 tween body weight, height, or build and the proportional amount 

 of blood expelled at each contraction of the heart. Hearts 

 whose diastolic volume was 5 per cent or more above the normal 

 as compared with body weight showed less proportional cardiac 

 output than normal and small hearts. High pulse pressure was 

 accompanied by large relative output in a given position, al- 

 though in the prone position the pulse pressure was higher 

 than in the sitting position while the relative output was 

 smaller. No definite correlation between systolic pressure or 

 pulse rate and output was found under the conditions of the 

 experiment. 



The average left ventricular output sitting was 80.8 cc. per 

 kilo per minute, the average pulse rate 82 making the output 

 approximately 1 cc. per kilo per beat. The average output 



