A determination of the circulation rate in man at rest and at work : the regulation of the circulation / by Walter M. Boothby from the surgical service and respiration laboratory of the Peter Bent Brigham Hospital, Boston, Mass.

  • Boothby, Walter M.
Date:
[1915?]
Catalogue details

Licence: In copyright

Credit: A determination of the circulation rate in man at rest and at work : the regulation of the circulation / by Walter M. Boothby from the surgical service and respiration laboratory of the Peter Bent Brigham Hospital, Boston, Mass. Source: Wellcome Collection.

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    tions the coefficient of absorption of nitrous oxide for blood has been taken as 0.43, as determined by Siebeck in 1909 for ox blood at 37°. Lindhard and Krogh6 have recently determined the coefficient of absorption of nitrous oxide for human blood at 37° and found it to be 0.405 =*= 0.005. The method used by us in the present study is essentially that given by Krogh in his most recent paper.7 However, as a few changes in the routine of experimentation have been made by us we present our technic in full. EXPERIMENTAL DETAILS Unit of work. The object of our experiments is to show the volume per minute of the circulation between a condition of complete rest in bed to one of severe muscular work. It was necessary to have a method of expressing the amount of work performed by the subject under all the conditions of the experi¬ ments. A mechanical unit, such as kilogram-meters per minute, gives a rough comparative idea of the amount of work performed by the subject while pedaling an ergometer, such as that de¬ scribed by Krogh.8 This unit, however, cannot be used to com¬ pare the amount of work a subject’s muscles would be called upon to perform when sitting at rest on a bicycle, in a chair, or lying in bed; further, it does not take into consideration variations produced in efficiency by a proper position on the seat or the energy expended by the arm muscles exerting a counter pull on the handle bars of the bicycle.* We have, therefore, adopted the physiological unit of the number of cubic centi¬ meters of oxygen consumed per minute. For the study of the circulation rate, the unit of oxygen con¬ sumption per minute is particularly well adapted, for it is one of the chief functions of the blood to transport the gases between the lungs and tissues. In fact the transportation of the other metabolic substances of the blood current, though equally essen- 6 Krogh: See reference 4, p. 550. 7 Krogh: See reference 4. 8 Krogh: A bicycle ergometer and respiration apparatus for the experimental study of muscular work. Skand. Archiv. f. Physiol., 1913, xxx, 375-394.