Oscillometric blood pressure measurement and simulation

Automated noninvasive blood pressure (NIBP) monitors have been increasingly used to measure BP inside and outside clinical environments. Clinical methods of evaluating the measurement accuracy of such devices require extensive resources. NIBP simulation offers an alternative approach to such evaluation methods. A survey reveals that oscillometric BP monitors are the most widely available, followed distantly by auscultatory BP monitors. A functional PC-controlled oscillometric BP simulator has been designed and built. This simulator permits user-friendly entry of parameters for simulating a wide range of oscillometric BPs. An evaluation performed on nine oscillometric BP monitors using the simulator shows that most of the monitors give statistically different BP readings with respect to the corresponding reference BPs of the simulator, with the mean differences ranging from 1.2 to 18.2 mmHg. This phenomenon may be partly explained by the use of different BP determination criteria. The standard deviations of the differences range from 2.1 to 16.7 mmHg, suggesting varying robustness of the BP determination algorithms used by the monitors.;The survey also reveals the use of a variety of cuff bladder sizes. Two studies were performed to examine the effects of cuff-arm compliance on oscillometric BP measurement and their implications on oscillometric BP measurement and simulation. The first study shows that oscillometric BP determination points may be affected by cuff-arm compliance, which is partly dependent on bladder sizes. The second study shows that the use of long bladders that completely encircle the arm will help reduce oscillometric BP measurement variations caused by the nonlinear characteristics of cuff-arm compliance and those variations caused by the use of different bladder lengths.