A wearable device and an airbag preparation method. The wearable device includes a watch body, an airbag, and an airbag cover. The airbag is detachably connected to an end of the watch body, so that a coverage area of the airbag for the watch body is small, thereby reserving space for installing another module on the watch body. The airbag includes a first layer structure and a second layer structure that are superposed. The first layer structure has a first cavity, the second layer structure has a second cavity, and the first cavity communicates with the second cavity.

A sphygmomanometer includes: a sensing cuff that includes a second sheet disposed to face the pressing member's inner circumferential surface and a first sheet facing the second sheet; a fluid storage control part providing a control of supplying and storing the pressure-transmitting fluid into sensing cuff in a worn state wherein the pressing member and sensing cuff are worn on the wrist; and a blood-pressure calculating part calculating a blood pressure based on a pressure of the pressure-transmitting fluid stored in the sensing cuff. The fluid storage control part supplies fluid in the worn state such that the first and second sheets are in contact with each other in a region corresponding to an ulna, a region corresponding to a radius, and a region corresponding to a tendon while first and second sheets are separated from each other in regions corresponding to two arteries that are radial and ulnar arteries.

A wearable blood pressure detecting device is provided. The wearable blood pressure detecting device includes a pulse detecting module, a processing unit, a memory unit, a model selecting unit, and a blood pressure calculating unit. The pulse detecting module is configured to generate a pulse waveform. The processing unit is configured to capture the pulse waveform to generate at least one pulse characteristic value. The memory unit is configured to store at least two blood pressure models corresponding to different pulse characteristic value ranges. The model selecting unit is configured to select a corresponding blood pressure model according to the at least one pulse characteristic value. The blood pressure calculating unit is configured to calculate a blood pressure value by the selected blood pressure model.

Disclosed is a finger cuff that is attachable to a patient's finger to be used in measuring the patient's blood pressure by a blood pressure measurement system. The finger cuff may comprise: a light emitting diode (LED)photodiode (PD) pair; a bladder that exerts pressure on the patient's finger; and a first light pipe that surrounds the LED to guide and focus light emitted by the LED, wherein the patient's finger surrounded in the finger cuff abuts against the bladder such that the bladder and the LED-PD pair are used in measuring the patient's blood pressure by the blood pressure measurement system.

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.

Disclosed is a finger cuff that is attachable to a patient's finger to be used in measuring the patient's blood pressure by a blood pressure measurement system. The finger cuff may comprise: a bladder configured to exert pressure on the patient's finger; and a plurality of light emitting diodes (LEDs) and a photodiode (PD), in which, the PD detects light emitted by the plurality of LEDs. Further, when the finger cuff is placed around the patient's finger, the bladder, the plurality of LEDs, and the PD aid in measuring the patient's blood pressure by the blood pressure measurement system utilizing the volume clamp method.

Devices and methods for non-invasive capillary blood pressure measurement are provided. An device can comprise a front end in contact with the body to compress and decompress the capillaries in the tissue, a pressure control module for regulating the contact pressure between the front end and the tissue, a pressure transducer coupled to the front end for measuring the contact pressure, a capillary sensing module for detecting the capillaries pulsations under the contact pressure modulation, and an algorithm for determining the capillaries pressures from the traces of capillary pulsation signals and the contact pressure signal. The methods include an oscillometric method for intermittent arterial and capillary blood pressure measurement and a volume-clamp method for continuous capillary blood pressure measurement.

An apparatus for measuring compliance of blood vessels includes a photoplethysmography sensor for emitting electromagnetic radiation to the blood vessels, for receiving electromagnetic radiation reflected off the blood vessels, and for producing a measurement signal indicative of the received electromagnetic radiation. The apparatus further includes a pressure instrument for producing mechanical pressure applied on the blood vessels, and a control system for controlling the pressure instrument to change the mechanical pressure linearly with respect to time during emission of electromagnetic radiation to the blood vessels and reception of reflected electromagnetic radiation from the blood vessels. The control system finds, from the measurement signal, a portion whose envelope has exponential change with respect to time and produces an estimate for an exponent coefficient of time during the exponential change. The coefficient is indicative of the compliance, as well as stiffness, of the blood vessels.

The present disclosure relates to a device, method and system for calculating, estimating, or monitoring the physiological parameters of a subject. At least one processor, when executing instructions, may perform one or more of the following operations. A first signal representing a pulse wave relating to heart activity of a subject may be received. A plurality of second signals representing time-varying information on the pulse wave may be received. A blood oxygen level of the subject based on the plurality of second signals may be determined. A first feature in the first signal may be identified. A second feature in one of the plurality of second signals may be identified. A pulse transit time based on a difference between the first feature and the second feature may be computed. A blood pressure of the subject may be calculated based on the pulse transit time.

Disclosed is a finger cuff that is attachable to a patient's finger to be used in measuring the patient's blood pressure by a blood pressure measurement system. The finger cuff may comprise: a light emitting diode (LED)photodiode (PD) pair; a bladder that exerts pressure on the patient's finger; and a flexible circuit electrically connectable to the LED-PD pair and attached to an interior of the finger cuff, wherein the flexible circuit includes a flexible polymer material.