title: The non-invasive determination of cardiac output in children: a three-breath technique.
abstract: In this study, the cardiac output of 11 children (5 days to 18 yr of age) was measured following cardiopulmonary bypass. Standard dye dilution cardiac outputs and an indirect Fick-CO2 technique were simultaneously determined. A rebreathing maneuver is described to estimate the oxygenated mixed venous PCO2 (PvCO2). This estimate of PvCO2 was combined with the end tidal PCO2 and CO2 production to give a non-invasive Fick estimate of the cardiac output. Non-invasive cardiac outputs correlated well with those measured by dye-dilution (r2 = 0.94) over a range of cardiac outputs from 490-7280 ml/min. All non-invasive determinations were within 15% of the line of identity, and within 22% of averaged replicate dye-dilution values. Our results agree with previous comparisons of indirect Fick-CO2 methods with invasive determinations of cardiac output. These data suggest that the indirect Fick-CO2 technique offers a rapid, non-invasive alternative to invasive monitoring of cardiac output.
mesh_terms: D000293:Adolescent; D002245:Carbon Dioxide / Q000097:blood* / Q000378:metabolism; D002302:Cardiac Output; D002648:Child; D002675:Child, Preschool; D004395:Dye Dilution Technique; D005540:Forced Expiratory Flow Rates; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D010100:Oxygen / Q000097:blood; D012119:Respiration
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen