title: Automation of a noninvasive cardiac output computation from respiratory gases and flow.
abstract: We describe work completed and discuss future work on the automation of a real-time, non-invasive method for calculating Cardiac Output. This method [1] uses concentrations of oxygen and carbon dioxide in the inspiration and exhalation segments of a breath cycle, atmospheric pressure, and total respiratory degrees ow to estimate the relationship between partial pressure of alveolar CO2 and the instantaneous gas exchange ratio (R). Known physiological relationships between R and the partial pressures of CO2 on both the venous and arterial sides of the lung, in conjunction with the Indirect Fick Equation, allows us to determine a patient's breath-by-breath Cardiac Output. This method is now feasible in real-time with the development of a prototype non-invasive metabolic monitor that utilizes a micro- degrees uidic gas analyzerlable to simultaneously measure the constituent concentrations of three-gas mixtures in real-time at a fractional cost of other hardware and methods.
authors.affiliation: University of Wyoming, Laramie, Wyoming, USA.
authors.forename: Brennan G
authors.initials: BG
authors.lastname: Kilty
authors.forename: Cameron H G
authors.initials: CH
authors.lastname: Wright
authors.forename: Jerry M
authors.initials: JM
authors.lastname: Calkins
authors.forename: Steve F
authors.initials: SF
authors.lastname: Barrett