Mathematical modelling of non-invasive oscillometric finger mean blood pressure measurement by maximum oscillation criterion

A mathematical study is performed to assess how the arterial pressure-volum e (P-V) relationship, blood pressure pulse amplitude and shape affect the r esults of non-invasive oscillometric finger mean blood pressure estimation by the maximum oscillation criterion (MOC). The exponential models for a re laxed finger artery and for a partly contracted artery are studied. A new m odification of the error equation is suggested. This equation and the resul ts of simulation demonstrate that the value of pressure estimated by the MO C does not exactly agree with the value of the true mean blood pressure (th e latter being defined as pressure corresponding to maximum arterial compli ance). The error depends on the arterial pressure pulse amplitude, as well as on the difference between the arterial pressure pulse shape index and th e arterial P-V curve shape index. In the case of contracted finger arteries , the MOC can give an overestimation of up to 19 mmHg, the pressure pulse s hape index being 0.21 and the pulse amplitude 60 mmHg. In the case of relax ed arteries, the error is less evident.