Patent ID: 7018340

Claim:
A method for estimating the cardiac output of an individual, comprising: determining a carbon dioxide elimination (V CO 2 ) of the individual for a before re-breathing period and for a during re-breathing period; calculating a carbon dioxide elimination difference between the carbon dioxide elimination of the before re-breathing period and the carbon dioxide elimination of the during re-breathing period; estimating a partial pressure of carbon dioxide in alveoli (P A CO 2 ) of the individual for the before re-breathing period and for the during re-breathing period based on partial pressure of end tidal carbon dioxide (PetCO 2 ) measurements of the individual during the before re-breathing period and during the during re-breathing period, respectively; converting each estimation of the partial pressure of carbon dioxide in alveoli to a carbon dioxide content (C CO2 ); calculating a carbon dioxide content difference between the carbon dioxide content of the before re-breathing period and the carbon dioxide content of the during re-breathing period; and dividing the carbon dioxide elimination difference by the carbon dioxide content difference to estimate cardiac output.