Patent ID: 7815578

Claim:
An apparatus for determining cardiac output to within a constant scale factor comprising a computer system that includes: (a) computer readable media having code comprising computer-executable process steps; and (b) a processor that executes the process steps to: (i) accept an input representing a measurement of an arterial blood pressure signal over a plurality of cardiac cycles; (ii) estimate a function that represents the response of the arterial blood pressure to a single cardiac contraction; (iii) fit the function of step (ii) to an exponential-like function over a time period that begins a selected amount of time following the maximum value of the function; (iv) estimate the time constant of the function of step (ii) as the time constant of the exponential function of step (iii); and (v) determine cardiac output to within a constant scale factor by dividing average arterial blood pressure by the time constant obtained in step (iv).