The Rate of the Circulation of the Blood in Normal Resting Individuals *

Abstract

This paper describes two allied methods for the determination of the rate of blood flow which have yielded consistently reproducible results in untrained subjects. The data obtained in forty experiments on twenty-one normal resting individuals are presented in tabular form. The first method is suitable for use with subjects having practically any type of pathology but in the resting condition only. The second method is inapplicable when the subject has a pulmonary lesion preventing ventilation of part of the alveoli or a cardiac defect permitting mixture of arterial and venous blood. With these restrictions, however, this method should be useful as it can be carried out in a short time, with a high degree of accuracy and under varying conditions of activity.[ETHOD I Several investigators have studied the circulation rate, determining the gases in the mixed venous blood by some procedure in which the lungs are used as an aerotonometer, and those in the arterial blood indirectly from the alveolar air or directly by analysis of blood obtained by arterial puncture. Burwell and Robinson, in a contemporary publication (1) have reviewed the literature of the subject and a complete bibliography will not be given here.The method of Christianson, Douglas, and Haldane (2) is difficult to apply to patients but, in suitable subjects, should yield results of the correct order of magnitude. It consists in the inhalation of. a mixture of CO2 and air (oxygen was used instead of air in a few ex-*The expenses of this research were defrayed in part by the Proctor Fund and by the Tutorial Fund of Harvard University.

The Effect of Digitalis Upon the Output of the Heart in Normal Man

“…Reliable current methods such as those devised by Plesch (1909); Krogh and Lindhard (1912); Douglas and Haldane (1922) ;Field, Bock, Gildea and Lathrop (1924); Burwell and Robinson (1924); all depend upon equilibrium between a gas or gases in the alveolar air and those in the pulmonary capillaries. Under the conditions imposed by pulmonary congestion such an equilibrium may be impossible to attain (Peters and Barr (1921)).…”

“…During the studies, observations were also made of changes in "basal" pulse rate and other changes were recorded. The output of the heart was measured by the method of Field, Bock, Gildea and Lathrop (1924), a method which requires no punctures of blood vessels and therefore lends itself to repeated application to the same subject. It involves the determination by respiratory methods of the carbon dioxide tension in the blood entering and leaving the lungs, and the measurement of the total gas exchange by the gasometer method.…”

The Output of the Heart in Patients With Abnormal Blood Pressures

“…The observations here reported were made by the method of Field, Bock, Gildea and Lathrop (10) with careful attention to the constancy of "standard basal" conditions as described in previous publications (11). In each case, observations were made only after several days of rest in hospital had led to the establishment of a relatively fixed level of bood pressure.…”

Applicability of Rebreathing Method for Determining Mixed Venous Co2 in Cases of Chronic Pulmonary Disease

“…In 1922 Douglas and Haldane (3) showed that the same arteriovenous differences in CO2 content were obtained in a given subject, whether the rebreathing procedure equilibrated CO2 tensions only and oxygenated the blood in the lungs, or whether this procedure equilibrated simultaneously both CO2 and oxygen tensions of incoming venous blood with the rebreathed air. Field, Bock, Gildea, and Lathrop (4) showed that arterial blood drawn during the course of rebreathing a mixture of 6 per cent CO2 and 94 per cent oxygen was fully oxygenated, and that the CO2 tensions in arterial blood and in the rebreathed air were the same. Most workers have been able to demonstrate an equilibrium of CO2 tensions by similar rebreathing technique; Hamilton, Moore and Kinsman (5), however, were unable to establish equilibrium or " plateau " levels of CO2 during rebreathing in experiments with a small number of subjects.…”