Cardiac output and mixed venous oxygen content measurements by a tracer bolus method: theory

• Published in: Journal of applied physiology (1985) 1997-09, Vol.83 (3), p.884-896
• Main Authors: Clark, Justin S, Lin, Yuxiang J, Criddle, Michael J, Cutillo, Antonio G, Bigler, Adelbert H, Farr, Fred L, Renzetti, Attilio D., Jr
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Blood gas. Hemoglobin. Myoglobin. Hemotissulary gas exchange. Acid-base balance; Cardiac Output - physiology; Computer Simulation; Dogs; Female; Fundamental and applied biological sciences. Psychology; Male; Microcirculation - physiology; Models, Biological; Oxygen - blood; Respiration, Artificial; Space life sciences; Ventilation-Perfusion Ratio - physiology; Vertebrates: respiratory system
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1997.83.3.884

Justin S. Clark, Yuxiang J. Lin, Michael J. Criddle, Antonio G. Cutillo, Adelbert H. Bigler, Fred L. Farr, and Attilio D. Renzetti Jr. Department of Biomedical Engineering and Medical Physics, LDS Hospital, Salt Lake City 84103; and Department of Medical Informatics, Division of Respiratory, Critical Care and Occupational (Pulmonary) Medicine, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, Utah 84132 Received 10 September 1996; accepted in final form 1 May 1997. Clark, Justin S., Yuxiang J. Lin, Michael J. Criddle, Antonio G. Cutillo, Adelbert H. Bigler, Fred L. Farr, and Attilio D. Renzetti, Jr. Cardiac output and mixed venous oxygen content measurements by a tracer bolus method: theory. J. Appl. Physiol. 83(3): 884-896, 1997. We present a bolus method of inert-gas delivery to the lungs that facilitates application of multiple inert gases and the multiple inert-gas-exchange technique (MIGET) model to noninvasive measurements of cardiac output (CO) and central mixed venous oxygen content Reduction in recirculation error is made possible by 1 ) replacement of sinusoidal input functions with impulse inputs and 2 ) replacement of steady-state analyses with transient analyses. Recirculation error reduction increases the inert-gas selection to include common gases without unusually high (and difficult to find) tissue-to-blood partition coefficients for maximizing the systemic filtering efficiency. This paper also presents a practical method for determining the recirculation contributions to inert expired profiles in animals and determining their specific contributions to errors in the calculations of CO and from simulations applied to published ventilation-perfusion ratio ( / ) profiles. Recirculation errors from common gases were found to be reducible to the order of 5% or less for both CO and whereas simulation studies indicate that measurement bias contributions from recirculation, / mismatch, and the / extraction process can be limited to 15% for subjects with severe / mismatch and high inspired oxygen fraction levels. These studies demonstrate a decreasing influence of / mismatch on parameter extraction bias as the number of inert gases are increased. However, the influence of measurement uncertainty on parameter extraction error limits improvement to six gases. multiple inert-gas-exchange technique; ventilation-perfusion ratio 0161-7567/97 $5.00 Copyright © 1997 the American Physiological Society