68 results about "Plethysmograph" patented technology

A method and an apparatus for measuring a physiological parameter, functioning based on obtaining a first signal derived from electromagnetic energy transmitted through a tissue portion at a first wavelength, the first signal including a signal portion corresponding with motion-related events and a signal portion corresponding with arterial pulsation events, where at the first wavelength water is a dominant absorber of electromagnetic energy in the tissue portion; obtaining a second signal derived from electromagnetic energy transmitted through a tissue portion at a second wavelength, the second signal including a signal portion corresponding with motion-related events and a signal portion corresponding with arterial pulsation events, where at the second wavelength hemoglobin is a dominant absorber of electromagnetic energy in the tissue portion; and combining the first signal and the second signal to generate a combined plethysmograph signal, such that the combined signal has a signal portion corresponding with motion-related events that is smaller than that present in the first signal or the second signal.

A pulse monitoring plethysmograph system for establishing a history of the pulses of the user over an extended period of time, comprises a housing, a piezoelectric sensing element mounted within said housing, and fixed to the housing, a force transmitting member positioned to cause said piezoelectric sensing element to flex in response to an external force and to generate a current, and a transimpedance amplifier. The transimpedance amplifier converts the current generated by the flexing of the piezoelectric element into a voltage signal and an analog to digital converter converts the voltage signal into digital data. A digital memory storing member is provided for storing the digital data and establishing a history of data over an extended period of time.

A method and apparatus are disclosed of utilizing a source of arterial and/or arteriolar pulse waveform data from a patient for the purpose of measuring pulsus paradoxus. The arterial pulse waveform data source described is a pulse oximeter plethysmograph but can be any similar waveform data source, including intra-arterial transducer, blood pressure transducer, or plethysmograph. Through incorporation of the measurements of values, such as the area under the pulse waveform curve, that are time-domain functions of a change in height of the pulse waveform over at least a partial duration of the waveform, embodiments of the present invention represent a significant improvement upon previously described methods of measuring pulsus paradoxus and, further, produce improved accuracy in measurement of the multiple contributing variables generating pulsus paradoxus, in particular the contribution of diastolic events, to the extent that the physical signs so measured can be regarded as “Revised Pulsus Paradoxus.”

The present invention relates to a system for measuring respiratory function of living organisms. More particularly, signals indicative of the change in lung volume, defined as active and passive work, required to breathe and the airflow through the respiratory system of the living organism are obtained and processed as waveforms to provide a signal indicative of the respiratory restriction. The methods of the present invention measure clinical forms of airway obstruction, airway reactivity and lung volume and may be used to continuously or intermittently monitor patients with compromised respiratory function. In a preferred embodiment, a head-out, breath in respiratory plethysmograph system provides the signals indicative of change in lung volume as related to pressure changes in a chamber. Further, flowmetric variables are generated that provide a characterization of airway obstructions.

Disclosed herein are methods and devices for delivering gas to a subject and obtaining plethysmograph readings from a subject. Specifically disclosed herein are masks and helmets which comprise one or more pulse oximeter probes associated therewith. The masks and helmets may be used in particular contexts, including, but not limited to, emergency responder personnel, pilots or subjects of medical attention.

A cough event is differentiated from a sneeze event of a test subject enclosed within a plethysmograph test chamber by measuring air pressure changes during the event, and comparing the pressure changes against criteria indicative of a cough to determine the likelihood that the event is a cough. Air pressure changes are recorded as pressure and/or sound values. A graphical record of a waveform of changes in the air pressure during an event relative to a baseline value is recorded, and a value is calculated that is indicative of the likelihood that the event is a cough based on the sizes of areas between the waveform and baseline during the event, said areas including a first area indicative of the change in air pressure during air inspiration, a second area indicative of the change in air pressure during air compression, and a third area indicative of the change in air pressure during expiration.

A method and system for operating a non-invasive blood pressure monitor that utilizes an SpO₂ plethysmograph signal to determine the initial inflation pressure for the blood pressure cuff of the NIBP monitor. A pulse sensor is placed on the patient's limb distal to the blood pressure cuff such that as the blood pressure cuff is inflated, the pulse signals from the pulse sensor will be reduced. When the blood pressure cuff reaches systolic pressure, the pulse signals from the pulse sensor will be initially attenuated and eventually eliminated, thus providing an indication that the cuff pressure has reached systolic pressure for the patient. The central processor of the NIBP monitor compares the pulse signals during cuff inflation to an average pulse signal and terminates the inflation of the blood pressure cuff upon sufficient attenuation. The use of the SpO₂ plethysmograph signal to determine the initial inflation pressure reduces both the over-inflation of the blood pressure cuff and the under-inflation of the blood pressure cuff which increases the rate at which the blood pressure measurement can be made while increasing patient comfort.

A method and an electronic device for measuring blood pressure are provided. The method includes illuminating, by a PPG sensor included in the electronic device, skin of a user and measuring a PPG signal based on an illumination absorption by the skin. Further, the method also includes extracting, by the electronic device, a plurality of parameters from the PPG signal, wherein the parameters may comprise PPG features, Heart Rate Variability (HRV) features, Acceleration Plethysmograph (APG) features, and non-linear features. The method also includes estimating, by the electronic device, the BP based on the extracted plurality of parameters.

Non invasive measurement of infant lung function during unsedated sleep is achieved by a plethysmograph which comprises of a rigid acrylic box (10) with integral water sealed spirometer (11) and a vacuum-actuated neck seal (20) allowing "head out" monitoring. The neck seal comprises particulate material entrapped in the space between two layers of rubber, which become rigid when a vacuum is applied to the space. Tidal volume, respiratory rate and changes in functional residual capacity (FRC) are able to be recorded during unsedated REM and NREM sleep whilst monitoring with conventional polysomnographic methods. The head out configuration allows additional instrumentation to be used, avoids facial stimulation and allows unimpeded access to the upper airway.

The present invention is an inductance plethysmograph transducer particularly suited for use in respiratory monitoring. The transducer is in the form of a woven fabric providing a substantially flat extensible belt for encircling a portion of a patient for a wide range of patient sizes. The transducer is used for monitoring changes in cross-sectional area corresponding to changes in volume of an expandable organ such as the patient's chest or abdomen. At least one electrical conductor is woven directly into the fabric in a manner that improves the electrical performance of the transducer over the prior art in two ways. First, a high-density weave is used for the fabric that produces many more inductive turns of the embedded conductor(s), thereby increasing the overall inductance change, hence improving the signal to noise ratio, and increasing the expandability of the effective length of the transducer. Secondly, the conductor(s) are oriented within the weave perpendicular to the surface or the torso of a patient being monitored, thus reducing artifact due to body capacitance. In addition to improvements in the electrical performance, the manufacture of the inductance sensor is a single step process that can be carried out on existing looms, reducing the overall cost while improving the flexibility, durability, and ease of use. The present invention is also machine washable making reuse much less labor intensive and therefor much less expensive.

Apparatus, systems and methods are provided for analyzing relative compliance in the peripheral vasculature that generally involve generating a plethysmograph (PG) signal, generating one or more pressure waveforms and comparing the pressure waveform(s) relative to the PG signal to determine compliance indexes associated particular regions of the vasculature. A relative compliance ratio may also be determined by comparing arterial and venous relative compliance indexes. Apparatus, systems and methods are also provided for analyzing a PG waveform that generally involve generating a plethysmograph (PG) signal and comparing amplitude modulation of the PG signal relative to baseline modulation of the PG signal to estimate a relationship between left ventricular end diastolic pressure and stroke volume. The estimated relationship may account for a phase offset for the time between when changes in venous return affect left ventricular end diastolic pressure and stroke volume.

A wearable physiological measuring device has a torso-worn module and a limb-worn module configured to communicate in a wireless way with each other. The torso-worn module is configured to be coupled with a torso of a user to obtain an R-peak from an electrocardiac signal. The limb-worn module is configured to be coupled with at least one limb of four limbs of the user to obtain a pulse wave peak from a plethysmograph signal. There are no physical connections (neither wire nor cable) between the torso-worn module and the limb-worn module. The wearable physiological measuring device is configured to use the R-peak time and the pulse wave peak time to generate a pulse transit time data.

The accuracy of measurements of changes in air volumes within a plethysmograph is improved by addition of a manifold to provide a common source of exterior air to the plethysmograph test and reference chamber. The preferred plethysmograph includes test and reference chambers divided by a common separator wall, pneumotachs in communication with the chambers, and a differential pressure transducer having a first inlet in communication with the test chamber and a second inlet in communication with the reference chamber. The manifold includes an exterior air inlet and a passageway extending between the two pneumotachs and the air inlet. The passageway may be in the form of separate tubes or conduits, or a common housing covering the pneumotachs. Preferably, the distances from the exterior air inlets to the two pneumotachs are approximately the same.

An embodiment of the invention discloses a photoplethysmograph (PPG) and a terminal. The PPG comprises a shell, a cover plate, an optical device for emitting light rays outwards as well as photoelectric sensors for receiving external optical signals; the shell and the cover plate define a closed space, and the optical device and the photoelectric sensors are accommodated in the closed space; the cover plate comprises a first area for the optical device to emit light rays outwards and a second area for the photoelectric sensors to receive external optical signals; and the cover plate further comprises a third area, and a shielding structure is arranged on the third area and used for isolating light rays between the optical device and the photoelectric sensors. By arrangement of the shielding structure in the third area, the PPG improves the isolation between the optical device and the photoelectric sensors, avoids light leakage between the optical device and the photoelectric sensors, improves measurement accuracy of the photoelectric sensors and improves user experience.

Time delays between a feature of a signal indicative of electrical activity of a patient's heart and a feature of a plethysmograph signal indicative of changes in arterial blood volume are used to arrange the operation of an implantable device, such as a pacemaker. Shorter time delays between the feature of the signal indicative of electrical activity of a patient's heart and the feature of the plethysmograph signal indicative of changes in arterial blood volume are indicative of larger cardiac stroke volumes. The time delay can be used to select a pacing site or combination of pacing sites and/or to select a pacing interval set.

Apparatus, systems and methods are provided for analyzing relative compliance in the peripheral vasculature. Such apparatus, systems and methods generally involve generating a plethysmograph (PG) signal, generating one or more pressure waveforms and comparing the pressure waveform(s) relative to the PG signal to determine compliance indexes associated particular regions of the vasculature. A relative compliance ratio may also be determined by comparing arterial and venous relative compliance indexes. Apparatus, systems and methods are also provided for analyzing a PG waveform. Such apparatus, systems and methods generally involve generating a plethysmograph (PG) signal and comparing amplitude modulation of the PG signal relative to baseline modulation of the PG signal to estimate a relationship between left ventricular end diastolic pressure and stroke volume. The estimated relationship may account for a phase offset for the time between when changes in venous return affect left ventricular end diastolic pressure and stroke volume.

A plethysmograph is described that includes a reference chamber having a top wall, a bottom wall, a barrier wall spaced beneath the bottom wall, a continuous side wall having a lower edge, and a first continuous flange with a lower edge below the bottom wall and above the barrier wall; a test chamber having a bottom wall, a continuous side wall with an upper edge, and a second continuous flange extending upwardly from the upper edge, the interior face of one of the flanges including an annular groove with an O-ring in the groove, and the interior face of the other flange being tapered from vertical by up to about 1°; and a manifold having airflow openings in communication with the reference and test chamber and a common exterior airflow opening through a passageway, and a sampling port in communication with the passageway.

The invention discloses a wearable smart T-shirt capable of detecting health data in real time. The wearable smart T-shirt is characterized in that electro-conductive fibers are sewn on the T-shirt; electrocardio inductive sensors, respiratory inductive plethysmograph sensors, elastic gloves, oxyhemoglobin saturation monitors, T-shirt and glove connecting interfaces and a portable compressed oxygen and face mask are connected with a main unit and power supply through the electro-conductive fibers; the electrocardio inductive sensors, the respiratory inductive plethysmograph sensors, an elastic chest band and an elastic bellyband are sewn on the body-fitting face of the T-shirt; the elastic gloves are connected with the T-shirt through the T-shirt and glove connecting interfaces; the main unit and power supply, the portable compressed oxygen and face mask and a first-aid health package are integrated; the first-aid health package is arranged at the waist part of the T-shirt. The wearable smart T-shirt can realize real-time health data monitoring, data integration and wireless transmission, provide acousto-optic and vibrating alarms after data exceeds the early-warning value, and further provide first-aid treatment through the first-aid health package, the portable compressed oxygen and face mask at the first moment.