A simple volume related model of arterial blood pressure generation.

A single compartment model of the arterial circulation was used to generate an arterial blood pressure waveform from pre-determined stroke volume (SV) and arterial resistance (R). With fixed stroke volume and varying resistances blood pressure waveforms showed mean values proportional to resistance but amplitude lessening with higher pressure; the amplitude of the hypothetical volume waveform of the arterial system was the same for all resistance values. Where SV varied and R changed reciprocally, the waveform when analysed with the PulseCO algorithm gave estimates slightly higher than the input stroke volumes (r 0.9998; y = 0.99x + 5.28 ml). Where SV varied with fixed R mean blood pressure varied with stroke volume; SV estimates were, again, slightly higher than the input stroke volumes (r 0.9994; y = 0.986x + 6.04 ml). Estimates of SV and R from Valsalva manoeuvre BP were used in the model to generate arterial blood pressure. SV estimates closely resembled the original model values (r 0.988; y = 1.0802x - 3.9251). The model appears capable of generating BP waveforms compatible with real BP waveforms since stroke volume estimates closely resemble the original stroke volumes used in the model.