A calibration method includes receiving magnetic field values, which are generated by a plurality of real magnetic transmitters and are measured at multiple positions on a grid in a region containing a magnetic field perturbing element. Approximate locations of the real magnetic transmitters are received. Using the approximate locations, a respective plurality of imaginary magnetic sources is characterized inside the field perturbing element. Using the measured magnetic field values, the approximate locations, and the characterized imaginary sources, there are iteratively calculated (i) actual locations of the real and imaginary magnetic sources in the region, and (ii) modeled magnetic field values that would result from the real and imaginary magnetic sources at the actual locations. Using the calculated locations, and the modeled magnetic field values at the multiple positions on the grid, a magnetic field calibration function is derived for the region.

Medical devices and related systems and methods are provided. A method of estimating a physiological condition using a first sensing arrangement involves obtaining a sensor translation model associated with a relationship between the first sensing arrangement and a second sensing arrangement, wherein the second sensing arrangement is different from the first sensing arrangement, obtaining one or more measurements from a sensing element coupled to the processing system of the first sensing arrangement, determining simulated measurement data for the second sensing arrangement by applying the sensor translation model to the one or more measurements from the sensing element of the first sensing arrangement, and determining an estimated value for the physiological condition by applying an estimation model associated with the second sensing arrangement to the simulated measurement data.

Medical devices and related systems and methods are provided. A method of estimating a physiological condition involves determining a translation model based at least in part on relationships between first measurement data corresponding to instances of a first sensing arrangement and second measurement data corresponding to instances of a second sensing arrangement, obtaining third measurement data associated with the second sensing arrangement, determining simulated measurement data for the first sensing arrangement by applying the translation model to the third measurement data, and determining an estimation model for a physiological condition using the simulated measurement data, wherein the estimation model is applied to subsequent measurement output provided by an instance of the first sensing arrangement to obtain an estimated value for the physiological condition.

Medical devices and related systems and methods are provided. A method of estimating a physiological condition involves obtaining reference measurement data for the physiological condition, obtaining first measurement data corresponding to the reference measurement data from one or more instances of the first sensing arrangement, determining a generative model associated with the first sensing arrangement based on relationships between the first measurement data and the reference measurement data, obtaining second reference measurement data for the physiological condition, generating simulated measurement data corresponding to the second reference measurement data by applying the generative model to the second reference measurement data, and determining an estimation model for the physiological condition based on relationships between the simulated measurement data and the second reference measurement data, wherein the estimation model is applied to subsequent measurement output provided by an instance of the first sensing arrangement to obtain an estimated value for the physiological condition.

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.

In an organ of interest in a patient is emplaced a set of sensors designed to monitor parameters of the organ of interest, including at least nicotinamide adenine dinucleotide level and at least one parameter from among the group consisting of tissue blood flow, blood hemoglobin, and tissue reflectance. Substantially continuously, a vitality index of the organ of interest is computed based at least in part on the parameters monitored by the sensors at the organ of interest. Another point of the patient is monitored continuously for a systemic reference, NADH level and at least two parameters from among the group consisting of blood flow (BF.sub.S), blood hemoglobin, and tissue reflectance. Substantially continuously, a systemic vitality index is computed from the measured systemic parameters. The vitality index of the organ of interest and systemic vitality index are monitored for a divergence in the temporal trend. Based on the detection of the divergence, an alarm is raised to a physician to warn the physician of a change in the patient's condition.

This invention generally relates to methods useful for measuring heart rate, respiration conditions, and oxygen saturation and a wearable device that incorporate those methods with a computerized system supporting data collection, analysis, readout and sharing. Particularly this present invention relates to a wearable device, such as a wristwatch or ring, for real time measuring heart rate, respiration conditions, and oxygen saturation.

A method of measuring a patient's systolic and diastolic brachial blood pressure non-invasively with a brachial cuff considers the shape of a patient's peripheral waveform (e.g., the cuff volumetric displacement waveform) to recalibrate the height of the waveform. The maximum and minimum values of the recalibrated waveform correlate to and closely estimate counterpart values for invasively measured brachial systolic and diastolic pressure.

A gas analyzer for measuring a respiratory gas component includes an emitter that transmits infrared (IR) radiation through a measurement chamber containing respiration gas, and at least one IR detector configured to receive at least a portion of the IR radiation transmitted through the measurement chamber and to generate radiation measurement data based on the received IR radiation. A light source is configured to emit light onto a color indicator, wherein the color indicator is one of a predefined set of colors. A color detector is configured to detect light reflected by a color indicator so as to identify color information. The controllers configured to determine a respiratory gas component concentration within the measurement chamber based on the color information and the radiation measurement data.

The present disclosure relates to a device, method and system (100) 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: receiving a first signal representing a pulse wave relating to heart activity of a subject, receiving a plurality of second signals representing time-varying information on the pulse wave, determining a blood oxygen level of the subject based on the plurality of second signals, identifying a first feature in the first signal, identifying a second feature in one of the plurality of second signals, computing a pulse transit time based on a difference between the first feature and the second feature, calculating a blood pressure of the subject based on the pulse transit time.