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Validation and application of single breath cardiac output determinations in manThe results of a procedure for estimating cardiac output by a single-breath technique (Qsb), obtained in healthy males during supine rest and during exercise on a bicycle ergometer, were compared with the results on cardiac output obtained by the direct Fick method (QF). The single breath maneuver consisted of a slow exhalation to near residual volume following an inspiration somewhat deeper than normal. The Qsb calculations incorporated an equation of the CO2 dissociation curve and a 'moving spline' sequential curve-fitting technique to calculate the instantaneous R from points on the original expirogram. The resulting linear regression equation indicated a 24-percent underestimation of QF by the Qsb technique. After applying a correction, the Qsb-QF relationship was improved. A subsequent study during upright rest and exercise to 80 percent of VO2(max) in 6 subjects indicated a close linear relationship between Qsb and VO2 for all 95 values obtained, with slope and intercept close to those in published studies in which invasive cardiac output measurements were used.
Document ID
19870023862
Document Type
Reprint (Version printed in journal)
Authors
Loeppky, J. A. (Lovelace Foundation for Medical Education and Research Albuquerque, NM, United States)
Fletcher, E. R. (Lovelace Foundation for Medical Education and Research Albuquerque, NM, United States)
Myhre, L. G. (Lovelace Foundation for Medical Education and Research Albuquerque, NM, United States)
Luft, U. C. (Lovelace Foundation for Medical Education and Research Albuquerque, NM, United States)
Date Acquired
August 13, 2013
Publication Date
August 1, 1986
Publication Information
Publication: Aviation, Space, and Environmental Medicine
Volume: 57
ISSN: 0095-6562
Subject Category
AEROSPACE MEDICINE
Funding Number(s)
CONTRACT_GRANT: NAS9-12572
Distribution Limits
Public
Copyright
Other