Circulation research
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Circulation research · Jul 1976
Continuous determination of beat to beat stroke volume from aortic pressure pulses in the dog.
Present methods for measurement of stroke volume from the aortic pressure pulse are not suitable for beat-to-beat determinations during non-steady state conditions because these methods assume that each systolic ejection is equal to the peripheral runoff during the same beat. We have tested a new method which allows determination of an aortic pressure-volume conversion factor over a wide range of pressures during transient changes in stroke volume and infusions of vasoactive drugs in 6 dogs with chronically implanted aortic electromagnetic flowmeters. ⋯ The total systolic increment (delta PSV) is assumed to describe the pressure-volume characteristics during systole and is related to stroke volume by a constant multiplier that is derived from the indicator-dilution measurements of cardiac output. The values for beat-to-beat variations that were determined by use of the aortic electromagnetic flowmeter and by this aortic pressure pulse method were found to be within the range of measurement errors of stroke volume determined from individual aortic electromagnetic flow pulses.