Abstract: Current oscillometric devices for monitoring central blood pressure (BP) maintain the cuff pressure at a constant level to acquire a pulse volume plethysmography (PVP) waveform and calibrate it to brachial BP levels estimated with population average methods. A physiologic method was developed to further advance central BP measurement. A patient-specific method was applied to estimate brachial BP levels from a cuff pressure waveform obtained during conventional deflation via a nonlinear arterial compliance model. A physiologically-inspired method was then employed to extract the PVP waveform from the same waveform via ensemble averaging and calibrate it to the brachial BP levels. A method based on a wave reflection model was thereafter employed to define a variable transfer function, which was applied to the calibrated waveform to derive central BP.

Abstract: Various systems, techniques, and embodiments are disclosed for implementing a blood-pressure measurement method that does not require specialized equipment (such as inflatable blood pressure cuffs). The measurement can be taken from arterial locations within a user's finger, via the standard equipment and features of many widely-available consumer mobile devices. Such devices can be programmed to accurately and easily guide a user to press her finger on the screen of a device at a precise location, so that an accurate measurement can be taken. For example, guidance visualizations on a screen (such as finger silhouettes and animations) can be employed on the same screen on which a user presses her finger. Pressure sensitivity and optical camera readings are then used to calculate blood pressure for the user.

Abstract: A method is presented for predicting onset of pulmonary congestion symptoms. The overall idea is to track rising left ventricular filling pressure (LVFP) in heart failure patients by exploiting significant changes in a pulsatile arterial waveform obtained with a mobile device and thereby avert hospitalizations. The stimulus for the changes may be metronomic deep breathing performed by the patient or a natural occurring arrhythmia such as atrial fibrillation or premature beats. For either stimulus, the extent of the amplitude variations depends on where the patient is on the Starling curve. If the patient is on the steep part of the curve, the variations will be large and LVFP will be low. If the patient is on the flatter part of the curve, the variations will be smaller and LFVP will be higher. These variations can be normalized in various ways to arrive at a congestion prediction index (CPI).

Abstract: Current oscillometric devices for monitoring central blood pressure (BP) maintain the cuff pressure at a constant level to acquire a pulse volume plethysmography (PVP) waveform and calibrate it to brachial BP levels estimated with population average methods. A physiologic method was developed to further advance central BP measurement. A patient-specific method was applied to estimate brachial BP levels from a cuff pressure waveform obtained during conventional deflation via a nonlinear arterial compliance model. A physiologically-inspired method was then employed to extract the PVP waveform from the same waveform via ensemble averaging and calibrate it to the brachial BP levels. A method based on a wave reflection model was thereafter employed to define a variable transfer function, which was applied to the calibrated waveform to derive central BP.