283 results about "Pulse oximeters" patented technology

A method of producing a diode drive current in an oximeter includes sensing at least a part of a current passing through the diode and converting the sensed current to a sensed voltage, inputting the sensed voltage to a feedback amplifier for stabilizing the current passing through the diode, and eliminating an offset voltage across inputs of the feedback amplifier. A pulse oximeter includes a diode for emitting light flashes, a feedback amplifier having inputs, a feedback capacitor, and an output, the feedback amplifier stabilizing a current passing through the diode, a nulling amplifier having inputs, a nulling capacitor, and an output, the nulling amplifier charging and discharging the feedback capacitor until the inputs of the feedback amplifier are at a same voltage. The operation may include synchronizing an elimination of input offset voltages of the feedback and nulling amplifiers with on or off state of diode current.

A pulse oximeter adaptively samples an input signal from a sensor in order to reduce power consumption in the absence of overriding conditions. Various sampling mechanisms may be used individually or in combination, including reducing the duty cycle of a drive current to a sensor emitter, intermittently powering-down a front-end interface to a sensor detector, or increasing the time shift between processed data blocks. Both internal parameters and output parameters may be monitored to trigger or override a reduced power consumption state. In this manner, a pulse oximeter can lower power consumption without sacrificing performance during, for example, high noise conditions or oxygen desaturations.

A processor provides signal quality based limits to a signal strength operating region of a pulse oximeter. These limits are superimposed on the typical gain dependent signal strength limits. If a sensor signal appears physiologically generated, the pulse oximeter is allowed to operate with minimal signal strength, maximizing low perfusion performance. If a sensor signal is potentially due to a signal induced by a dislodged sensor, signal strength requirements are raised. Thus, signal quality limitations enhance probe off detection without significantly impacting low perfusion performance. One signal quality measure used is pulse rate density, which defines the percentage of time physiologically acceptable pulses are occurring. If the detected signal contains a significant percentage of unacceptable pulses, the minimum required signal strength is raised proportionately. Another signal quality measure used in conjunction with pulse rate density is energy ratio, computed as the percentage of total energy contained in the pulse rate fundamental and associated harmonics.

The present invention relates to novel nasal pulse oximeter probes that are configured to be placed across the septum of the nose. These probes are fabricated to provide signals to obtain arterial oxygen saturation and other photoplethysmographic data. The present invention also relates to a combined nasal pulse oximeter probe/nasal cannula. The present invention also relates to other devices that combine a pulse oximeter probe with a device supplying oxygen or other oxygen-containing gas to a person in need thereof, and to sampling means for exhaled carbon dioxide in combination with the novel nasal probe. In certain embodiments, an additional limitation of a control means to adjust the flow rate of such gas is provided, where such control is directed by the blood oxygen saturation data obtained from the pulse oximeter probe.

A portable, integrated physiological monitoring system is described for use in clinical outpatient environments. This systems consists of a plethora of sensors and auxiliary devices, an electronics unit (100) that interfaces to the sensors and devices, and a portable personal computer (102). Electrodes (106) are provided to acquisition electrocardiographic, electroencephalographic, and neuromuscular signals. Electrodes (108) are provided to stimulate neural and muscular tissue. A finger pulse oximeter (110), an M-mode ultrasonic transducer (112), an airflow sensor (114), a temperature probe (120), a patient event switch (116), and an electronic stethoscope (118) are provided. A portable personal computer (102) interfaces to the electronics unit (100) via a standard parallel printer port interface (258) to allow communication of commands and information to/from the electronics unit (100). Control and display of the information gathered from the electronics unit (100) is accomplished via an application program executing on the portable personal computer (102). Sharing of common data acquisition hardware along with preliminary processing of information gathered is accomplished within the electronics unit (100). The entire system is battery operated and portable. This system, because of its architecture, offers significant cost advantages as well as unique modes of operation that cannot be achieved from the individual physiological parameter measurement devices alone. The system allows for the integration of acquisitioned information from the sensors into a patient's database stored on the portable personal computer.

The invention relates to methods and devices for measuring pulsus paradoxus. The methods herein employ a combination of one or more forms of waveform analysis for the purpose of measuring pulsus paradoxus and diagnosing respiratory distress. The methods also combine measurements of pulsus paradoxus and physician assessments to diagnose respiratory distress. The methods also combine measurements of pulsus paradoxus and percentage oxygenated hemoglobin to diagnose respiratory distress. The devices of this invention employ pulse oximeters, arterial tonometers, finometers, or processors for the purpose of implementing the methods of the invention.

The present invention relates to a novel non-invasive perfusion/resistance status monitor system and methods of using the same, and more specifically, a vascular perfusion status monitor system receiving and processing signals from at least two pulse oximeter probes, where each of the at least two pulse oximeter probes are situated at advantageously different locations in a patient. Novel pulse oximeter probes are configured to be placed, respectively, across the lip or cheek, across the septum or nares of the nose, and on the tongue. These probes are fabricated to provide signals to estimate arterial oxygen saturation. Conventional oximeter probes also can be configured to function according to the novel methods of determining differences in peripheral blood flow and/or resistance described herein.

Systems and methods for determining a physiological parameter in a patient are provided. In certain embodiments, a system can include an analyte detection system configured to measure first analyte data in a fluid sample received from a patient, a medical sensor configured to measure second analyte data in the patient, and a processor configured to receive the first analyte data and the second analyte data and to determine a physiological parameter based at least in part on the first analyte data and the second analyte data. In certain such embodiments, the medical sensor may be a pulse oximeter, and the physiological parameter may include a cardiovascular parameter including, for example, cardiac output.

A pacifier pulse oximeter sensor includes pulse oximeter sensor elements located within the nipple of a pacifier. The pulse oximeter sensor elements may be completely within the nipple material, embedded within the nipple material, nested within the nipple material, or adjacent to the nipple material while not being exposed to the outside environment. The pulse oximeter sensor elements include a light source and a light detector. The pulse oximeter sensor elements communicate with an oximeter through wiring, an electrical connector, and/or wirelessly. An alternative embodiment adds oximeter processing capabilities to the pacifier pulse oximeter sensor.

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 provides a multifunction health device, which comprises a meter and a platform. The meter has two electrodes arranged separately at its two sides or both arranged at its one side, and the meter has another electrode arranged in its bottom. The platform has four electrodes arranged in its top face, and a pressure sensor arranged in its inside. With or without some parts assisting, the single use of the meter can function as an ECG detector, a TENS machine, a thermometer, and a first sphygmomanometer. Connecting with the platform, the meter and the platform can function as an ECG detector, a weight scale, and a body composition estimator. Further, the meter can alternatively connect with a chassis thus functioning as a second sphygmomanometer, a stethoscope, a glucose meter, or a pulse oximeter.

An oversampling pulse oximeter includes an analog to digital converter with a sampling rate sufficient to take multiple samples per source cycle. In one embodiment, a pulse oximeter (100) includes two more more light sources (102) driven by light source drives (104) in response to drive signals from a digital signal processing unit (116). The source drives (104) may drive the sources (102) to produce a frequency division multiplex signal. The optical signals transmitted by the light sources (102) are transmitted through a patient's appendage (103) and impinge on a detector (106). The detector (106) provides an analog current signal representative of the received optical signals. An amplifier circuit (110) converts the analog current signal to an analog voltage signal in addition to performing a number of other functions. The amplifier circuit (110) outputs an analog voltage signal which is representative of the optical signals from the sources (102). This analog voltage signal is received by a fast A/D converter (112) which samples the analog voltage signal to generate a digital voltage signal which can be processed by the digital signal processing unit (116). The fast A/D converter (112) operates at a rate sufficient to take multiple samples per source cycle and may have a sampling frequency, for example, of over 41 kHz. The digital signal processing unit (116) implements software for averaging the samples over a source cycle for improved measurement consistency, improved signal to noise ratio and reduced A/D converter word length.

A disposable digit cover structured to be applied to envelop a portion of a human finger or toe, i.e., digit, for aiding in prevention of the spread of communicable diseases and cross-patient contamination from pulse oximeter probes. The cover is a flexible, tubular structure of material impervious to the passage of infectious agents, and having one open end and an oppositely disposed closed end, and is sufficiently thin and transparent to light to serve as infectious agent barrier between a human digit and a pulse oximeter probe. The covers are stored in a flattened state in a clean condition with a dispensing package containing a plurality of the covers stacked upon each other and secure to the package. The package includes a closeable opening allowing access to the digit covers. The dispensing package is small enough to be carried in a garment pocket.

The present disclosure includes a pulse oximeter attachment having an accessible memory. In one embodiment, the pulse oximeter attachment stores calibration data, such as, for example, calibration data associated with a type of a sensor, a calibration curve, or the like. The calibration data is used to calculate physiological parameters of pulsing blood.

A combined nasopharyngeal airway and pulse oximeter sensor capable of monitoring the posterior pharynx, posterior soft palate or nasal mucosa is disclosed. The nasopharyngeal airway includes a thickened wall section over approximately one-third of its circumference. Pulse oximeter sensor elements may be embedded in the airway. The pulse oximeter sensor elements may include a light source, which preferably emits light at wavelengths around 660 nm (red) and around 940 nm (near infrared), and a light detector. The pulse oximeter sensor elements may be connected to a pulse oximeter monitor (spectrophotometer) or other external device for analysis.