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The cardiovascular model combines a ventricular pump together with a four element 'Windkessel' model (Stergiopulos et al). The pump is pre- and after-load sensitive and generates a sinusoidal output. The intra-vascular pressure calculations are computed every 5 msecs.
The effect of variation in pre-load on the cardiac output of the model (in a patient with normal contractility and sympathetic tone) is illustrated below. These data were generated from the system itself and recorded using the data recording system.
In addition to exhibiting Frank-Starling behaviour, the cardiovascular model also incorporates some reflex activity. The effect of haemorrhage on blood pressure and pulse rate is shown below. Over a 60 second period, a 70 kg patient loses 1L of blood. As a result, the systolic blood pressure falls from ~115 to ~ 50 and the pulse rate increases from ~ 70 to ~ 115.
Stergiopulos N, Westerhof BE, Westerhof N. Total arterial inertance as the fourth element of the windkessel model. Am J Physiol. 1999 Jan;276(1 Pt 2):H81-8.