Computation of aortic flow from pressure in humans using a nonlinear, three-element model
article
We computed aortic flow pulsations from arterial pressure by simulating a nonlinear, time-varying three-element model of aortic input impedance. The model elements represent aortic characteristic impedance, arterial compliance, and systemic vascular resistance. Parameter values for the first two elements were computed from a published, age-dependent, aortic pressure- area relationship (G. J. Langewouters et al. J. Biomech. 17: 425-435, 1984). Peripheral resistance was predicted from mean pressure and model mean flow. Model flow pulsations from aortic pressure showed the visual aspects of an aortic flow curve. For evaluation we compared model mean flow from radial arterial pressure with thermodilution cardiac output estimations, 76 times, in eight open heart surgical patients. The pooled mean difference was +7%, the SD 22%. After using one comparison per patient to calibrate the model, however, we followed quantitative changes in cardiac output that occurred either during changes in the state of the patient or subsequent to vasoactive drugs. The mean deviation from thermodilution cardiac output was +2%, the SD 8%. Given these small errors the method could monitor cardiac output continuously.
Topics
age dependencyaortic arctangent pressure-area relationshipaortic input impedancecardiac outputnonlinear modelsimulationstroke volumetime-varying modelaccuracyadultanalytical erroraorta flowaorta pressurearterial pressurearteriosclerosisartery complianceartery diametercalculationclinical articleheart outputimpedancenonlinear systemreliabilitysimulationsystemic vascular resistanceAgedAgingAortaArteriosclerosisBlood PressureBody HeightCardiac OutputFemaleHumanIntraoperative PeriodMaleMiddle AgeModels, BiologicalRadial ArteryRegional Blood FlowStroke VolumeThermodilutionVascular Resistance
TNO Identifier
280623
ISSN
87507587
Source
Journal of Applied Physiology, 74(5), pp. 2566-2573.
Pages
2566-2573
Files
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