METHOD AND APPARATUS FOR ESTIMATING THE RELIABILITY OF CARDIAC OUTPUT MEASUREMENTS

According to an aspect, there is provided a method of estimating the reliability of cardiac output, CO, measurements for a subject obtained using an arterial waveform analysis, AWA, technique. The AWA technique is calibrated using CO measurements obtained using a thermodilution CO measurement technique. The method comprises (a) during a first time period in which a first CO measurement is obtained for the subject using the thermodilution CO measurement technique: (i) initiating (203) inflation of a cuff that is at a first location on the subject; (ii) obtaining (205) a first cuff pressure signal comprising measurements of pressure inside the cuff during inflation; (iii) analysing (207) the first cuff pressure signal to derive a relationship between oscillations in arterial volume beneath the cuff and pressure in the arteries; and (iv) estimating (209) a first arterial compliance of the arteries for a range of cuff pressures based on the determined relationship; (b) during a second time period that is after the first time period, repeating (211) steps (i)-(iv) to estimate a second arterial compliance of the arteries; and (c) using (213) a result of a comparison of the first arterial compliance and the second arterial compliance to determine a reliability of CO measurements obtained using the AWA technique during the second time period.