A STUDY OF INDIRECT METHOD FOR CARDIAC OUTPUT DETERMINATION BY CONTINUOUS GAS-ANALYSIS OF PROLONGED EXPIRATION

• Published in: Japanese Journal of Physical Fitness and Sports Medicine Vol. 22; no. 1; pp. 26 - 32
• Main Authors: SAKAKIBARA, CHIEKO, IKEGAMI, HARUO, YUZA, NOBUO
• Format: Journal Article
• Language: English
• Published: The Japanese Society of Physical Fitness and Sports Medicine 1973
• ISSN: 0039-906X; 1881-4751
• DOI: 10.7600/jspfsm1949.22.26

Theoretical principle of the indirect method for cardiac output determination by continuous gas-analysis of prolonged expiration was introduced and its practical utility and error sources were discussed. Merits and demerits of this method are as followd; 1) No blood sampling nor catheterzation is required. 2) Nonphysiological gas inhalation or injection of dye or other substances are not required. 3) Real time determination of cardiac output is possible when used with online computor processing. 4) Repeated measurement on the same subject is able to perform once every two minute at rest and once a minute during exercise. 5) Measurement during exercise is performed without any dificulty. 6) Several suppositions which used in this method may cause some error, especially anemia and unevenness of ventilation-perfusion ratio are possible two major error sources. Using a gas-spectometer, cardiac output of six subjects was measured by this principle at rest and during exercise of several intensities on a bicycle ergometer. Average values of cardiac output were 4.5, 7.5, 9.4, 12.3, and 14.1 1/min. at rest and during exercise of 150, 300, 450, and 600 kpm/min., respectively. From the results, utility of this method was practically confirmed for application to exercise physiology.