The invention describes a measuring system for the continuous non-invasive determination of blood pressure at one or more fingers. The fingers chosen for measurement and the adjacent parts of the palm rest on a supporting surface of a housing, which has the shape of a computer mouse. Inside the housing of the “CNAP Mouse”, i.e. underneath the supporting surface for the hand, the pressure generating system is located. The finger sensors are mounted on the supporting surface for the hand. The forearm and the back of the hand are left free and may be used to place intra-venous or intra-arterial access elements. Since the hand will rest on the supporting surface motion artefacts are largely avoided. Tilting or turning of the sensors is hardly possible since the fit of the sensors and thus the coupling of light and pressure are optimized.

An electronic blood pressure meter includes a cuff that is to be worn on a measurement area, a piezoelectric pump that adjusts a pressure applied to the cuff, a drive circuit that drives the piezoelectric pump, and a controller that outputs, to the drive circuit, a pulse signal defining a driving timing of the piezoelectric pump. The drive circuit includes a switching circuit for switching a connection relationship between respective voltages applied to both ends of the piezoelectric pump in response to corresponding first and second driving signals, and a signal generation circuit that outputs the first and second driving signals based on the pulse signal outputted from the controller. The signal generation circuit has a signal conditioning circuit that adjusts timings of the first and second driving signals so that the phases of the first and second driving signals do not overlap.

A system for non-invasively determining an indication of an individual's blood pressure is described. In certain embodiments, the system calculates pulse wave transit time using two acoustic sensors. The system can include a first acoustic sensor configured to monitor heart sounds of the patient corresponding to ventricular systole and diastole and a second acoustic sensor configured to monitor arterial pulse sounds at an arterial location remote from the heart. The system can advantageously calculate a arterial pulse wave transit time (PWTT) that does not include the pre-ejection period time delay. In certain embodiments, the system further includes a processor that calculates the arterial PWTT obtained from the acoustic sensors. The system can use this arterial PWTT to determine whether to trigger an occlusive cuff measurement.

An apparatus for extracting a cardiovascular characteristic is provided. The apparatus may include: a first sensor configured to measure a vibration signal generated by a pulse wave of a subject; a second sensor configured to measure a pulse wave signal of the subject; a processor configured to perform an operation related to a cardiovascular characteristic on the basis of the measured vibration signal and pulse wave signal; and a main body in which the first sensor, the second sensor, and the processor are mounted.

Systems and methods for optimizing sensor pressure in blood pressure (BP) measurements using a wearable device are provided. An example method includes recording photoplethysmogram (PPG) data using a PPG sensor of a wearable device while a pressure applied by the PPG sensor to a blood artery of a user is gradually increasing, monitoring a pulsating parameter associated with the PPG data, determining that the pulsating parameter has passed a critical value, in response to the determination, causing the increase of the pressure to stop, recording further PPG data using the PPG sensor and electrocardiogram (ECG) data using input plates of the wearable device, analyzing the further PPG data and the ECG data to determine a pulse transit time (PTT), a pulse rate (PR), and a diameter parameter, and determining, using a pre-defined model, a BP based on the PTT, the PR, and the diameter parameter.

Optical ankle-brachial index (ABI) and blood pressure measurement systems and methods are disclosed. The blood pressure measurement system includes a pressure cuff and an optical pulse detector placed on a finger or toe or a reflectance optical pulse detector attached to the skin distal to the inflation bladder of its respective cuff. The ABI measurement system includes a brachial artery pressure cuff, a first reflectance optical pulse detector attached to the brachial artery pressure cuff or a transmission or reflectance optical pulse detector attached to a finger, an ankle pressure cuff; and a second reflectance optical pulse detector attached to the ankle cuff or an optical pulse detector attached to a toe. A computer may also be included in the above systems and methods to detect optical pulses from the detectors and control the inflation and deflation of the cuffs in order to determine blood pressure and/or ABI.

Disclosed herein are in vivo non-invasive methods and devices for the measurement of the hemodynamic parameters, such as such as blood pressure, stroke volume, cardiac output, performance of the aortic and mistral heart valves, arterial blood velocity profile, blood viscosity and the blood flow induced arterial wall shear stress, hypertensive/hypotensive and vasodilation/vasocontraction state and aging status of a subject, and the mechanical anelastic in vivo properties of the arterial blood vessels. An exemplary method requires obtaining the peripheral pulse volume waveform (PVW), the peripheral pulse pressure waveform (PPW), and the peripheral pulse velocity waveform (PUW) from the same artery; calculating the time phase shift between the PPW and PVW, and the plot of pulse pressure versus pulse volume; and determining the blood pressures and power law components of the anelastic model from the waveforms PPW and PVW, the cardiac output and heart valves performances from the waveforms PPW and PUW, and the anelastic in vivo properties of the descending, thoracic and abdominal aorta. The disclosed methods and devices can be used to diagnose and treat cardiovascular disease in a subject in need thereof.

A wearable device can be used for hypertension monitoring. The wearable device can include a motion sensor and an optical sensor. The data from the sensors can be processed in the wearable device and/or by another device in communication with the wearable device to provide an early screening for undiagnosed hypertension. If the screening estimates undiagnosed hypertension for a user, the user can then be notified to seek a proper hypertension diagnosis. The hypertension monitoring can include a first stage to estimate one or more short-term hypertension scores or parameters. The hypertension monitoring can also include a second stage to estimate a long-term hypertension score using accumulated short-term scores/parameters to estimate hypertension.

A method for characterizing the blood pressure of an individual includes placing an optical device on a limb, the optical device having a light source arranged to emit light towards the limb, placing a photodetector facing the limb, and applying compression to the limb of the individual. The compression duration includes an increasing phase, in which the applied pressure increases, and a decreasing phase, in which the applied pressure decreases. During the compression duration, the limb is illuminated with the light source and the intensity of light is detected by the photodetector to obtain a time-dependent function. The method also includes applying low-pass filtering to the time-dependent function.

The invention comprises a method and apparatus for estimating state of a cardiovascular system, comprising a cardiac stroke volume analyzer, comprising: (1) a blood pressure sensor generating a time-varying pressure state waveform output from a limb of the person; (2) a system processor connected to the blood pressure sensor; and (3) a dynamic state-space model; the system processor receiving cardiovascular input data, from the blood pressure sensor, related to a transient pressure state of the cardiovascular system; at least one probabilistic model, of the dynamic state-space model, operating on the time-varying pressure state waveform output to generate a probability distribution function to a non-pressure state of the cardiovascular system; iteratively updating the probability distribution function using output from the blood pressure sensor; and processing the probability distribution function to generate a non-pressure state output related to stroke volume of a heart of the person and arterial compliance of the person.