Abstract: A method and a system for ensemble averaging signals in a pulse oximeter, including receiving first and second electromagnetic radiation signals from a blood perfused tissue portion corresponding to two different wavelengths of light, obtaining an assessment of the signal quality of the electromagnetic signals, selecting weights for an ensemble averager using the assessment of signal quality, and ensemble averaging the electromagnetic signals using the ensemble averager.

Abstract: A pulse oximeter sensor having an emitter(s) and a detector, with a layer having a first portion of the emitter and a second portion of layer over the detector is provided. A barrier is included between the first and second portions of the overlying layer to substantially block radiation of the wavelengths emitted by the emitter(s). Preferably, the barrier reduces the radiation shunted to less than 10% of the radiation detected, and more preferably to less than 1% of the radiation detected.

Abstract: Forehead oximetry sensor devices and methods for determining physiological parameters using forehead oximetry sensors. One method includes placing an oximetry sensor on the forehead of a patient, such that the sensor is placed on the lower forehead region, above the eyebrow with the sensor optics placed lateral of the iris and proximal the temple; and operating the pulse oximeter to obtain the physiological parameter. In one aspect, the method also includes providing and placing a headband over the oximetry sensor, or alternately, the sensor is a headband-integrated sensor. The headband has an elastic segment sized to fit around the patient's head. The headband also includes a non-elastic segment that is smaller than and attached with the elastic segment. The non-elastic segment is sized to span a portion of the elastic segment when the elastic segment is stretched. In addition, the non-elastic segment is larger than the portion of the elastic segment it spans when the elastic segment is not stretched.

Abstract: A light emitter drive circuit for an oximeter which utilizes a single inductor for driving multiple light emitters. The inductor is connected to a switching circuit to multiple energy storage circuits, such as capacitors. These are alternately charged up, using the same inductor. Subsequently, the capacitors are alternatively discharged for their corresponding light emitters through he same inductor. Also, the magnetic susceptibility of the LED drive circuit is reduced by using magnetic flux canceling in the inductor. In one embodiment, a toroidal inductor is used with geometric symmetry and its magnetic flux. In other embodiment, a dual core closed bobbin shielded inductor is used.

Abstract: A pulse oximeter method and apparatus which provides (1) a notch filter at a distance between a modulation frequency and a common multiple of commonly used power line frequencies (50, 60, 100 and 120) and also (2) a demodulation frequency greater than a highest pulse rate of a person and lower than any harmonic of 50, 60, 100 or 120 Hz, to filter ambient light interference, while choosing an optimum demodulation frequency that avoids interference from the notch filter or from harmonics of the line interference. Also, ambient light for any low frequency interference, such as power line interference, is measured both before and after each of the light emitter wavelengths and the average of the ambient light is then subtracted from the detected signal.

Abstract: Forehead oximetry sensor devices and methods for determining physiological parameters using forehead oximetry sensors. One method includes placing an oximetry sensor on the forehead of a patient, such that the sensor is placed on the lower forehead region, above the eyebrow with the sensor optics placed lateral of the iris and proximal the temple; and operating the pulse oximeter to obtain the physiological parameter. In one aspect, the method also includes providing and placing a headband over the oximetry sensor, or alternately, the sensor is a headband-integrated sensor. The headband has an elastic segment sized to fit around the patient's head. The headband also includes a non-elastic segment that is smaller than and attached with the elastic segment. The non-elastic segment is sized to span a portion of the elastic segment when the elastic segment is stretched. In addition, the non-elastic segment is larger than the portion of the elastic segment it spans when the elastic segment is not stretched.

Abstract: Forehead oximetry sensor devices and methods for determining physiological parameters using forehead oximetry sensors. One method includes placing an oximetry sensor on the forehead of a patient, such that the sensor is placed on the lower forehead region, above the eyebrow with the sensor optics placed lateral of the iris and proximal the temple; and operating the pulse oximeter to obtain the physiological parameter. In one aspect, the method also includes providing and placing a headband over the oximetry sensor, or alternately, the sensor is a headband-integrated sensor. The headband has an elastic segment sized to fit around the patient's head. The headband also includes a non-elastic segment that is smaller than and attached with the elastic segment. The non-elastic segment is sized to span a portion of the elastic segment when the elastic segment is stretched. In addition, the non-elastic segment is larger than the portion of the elastic segment it spans when the elastic segment is not stretched.

Abstract: In a system for measuring a physiological parameter using at least one wavelength of electromagnetic energy transmitted through living tissue, a method for determining an operational status of the system. The method includes receiving a data signal from at least one sensor, determining whether the received data signal is representative of the physiological parameter by sensing whether the at least one sensor is secured to the living tissue, and generating a status signal representative of the operational status of the system based on that determination. The determination includes measuring an output level corresponding to the at least one wavelength. The determination may also include analyzing a spectrum corresponding to the at least one wavelength to determine a percentage of energy contained in a subset of the spectrum, or monitoring an amplitude of the data signal for a given interval.

Abstract: A method and apparatus for controlling alarms in a medical diagnostic apparatus where an alarm is generated when a measured value for a physiological parameter is outside a specified range. The method continuously calculates a baseline value, and establishes dynamic thresholds that are related to and continuously track the baseline value. The method determines the amount of time the measured value is past the dynamic threshold, and the amount by which the threshold is passed. Alarms are triggered based upon a combination of the amount of time and the amount by which the threshold is passed. Preferably, the combination is an integral or some function of an integral.

Abstract: The invention is directed to a ventilation control system for controlling the ventilation of a patient. The ventilation control system utilizes a user-friendly user interface for the display of patient data and ventilator status, as well as for entering values for ventilation settings to be used to control the ventilator.

Abstract: An optical sensor having a cover layer, an emitter disposed on a first side of the cover, a detector disposed on the first side of said cover, and a plurality of stacked independent adhesive layers disposed on the same first side of the cover, wherein the top most exposed adhesive layer is attached to a patient's skin. Thus, when the sensor is removed to perform a site check of the tissue location, one of the adhesive layers may also be removed and discarded, exposing a fresh adhesive surface below for re-attachment to a patient's skin. The independent pieces of the adhesive layers can be serially used to extend the useful life of the product.

Abstract: A method for determining a physiological parameter in the presence of correlated artifact, including obtaining two digital waveforms, x and y, the waveforms being representative of the absorption of two wavelengths of electromagnetic energy received from a blood-perfused tissue, and where each of the waveforms has a component corresponding to a plethysmographic waveform and a component corresponding to the correlated artifact; calculating several weighted difference waveforms of the form x?R*y, where R is a multiplier, by varying R over a range; evaluating the several weighted difference waveforms using a shape characteristic of the weighted difference waveform; identifying a weighted difference waveform most closely representative of and one most different from the plethysmographic waveform; determining a pleth-based physiological parameter using the waveform most closely representative of the plethysmographic waveform; determining at least one artifact-based physiological parameter using the waveform most d

Abstract: The use of two separate ensemble averagers for processing a detected waveform for use in calculating oxygen saturation and a pulse rate. The ensemble averager used for calculating oxygen saturation operates on a signal which has been normalized, while the ensemble averager for the pulse rate calculation operates on a signal which has not been normalized. The metrics chosen for the two paths through the two ensemble averagers can be varied to optimize the ensemble averaging for oxygen saturation or pulse rate calculations.

Abstract: A laryngeal airway device, having an airway tube which has an internal passage in the airway tube wall for receiving a cuff inflation line, and a dome having an inlet and an outlet, where the dome is connected at its inlet with the distal end of the airway tube. The device also includes an annular spoon-shaped inflatable cuff connected with the periphery of the outlet of the dome; a cuff inflation line configured to be in fluid communication with the internal space of the cuff; and a multi-lobed aperture formed in the dome. The aperture is configured to be in fluid communication with the proximal end of the airway tube. The dome has protrusions forming the multi-lobed aperture, such that a flap is configured to prevent the obstruction of the aperture by a patient's epiglottis when the device is inserted into the patient.

Abstract: A method and apparatus for the application of Blind Source Separation (BSS), specifically independent Component Analysis (ICA) to mixture signals obtained by a pulse oximeter sensor. In pulse oximetry, the signals measured at different wavelengths represent the mixture signals, while the plethysmographic signal, motion artifact, respiratory artifact and instrumental noise represent the source components. The BSS is carried out by a two-step method including an ICA. In the first step, the method uses Principal Component Analysis (PCA) as a preprocessing step, and the Principal Components are then used to derive sat and the Independent Components, where the Independent Components are determined in a second step. In one embodiment, the independent components are obtained by high-order decorrelation of the principal components, achieved by maximizing the sum of the squares of the higher-order cumulants of the plurality of mixture signals.

Abstract: A method for use and an improved oximeter sensor substrate that is conforming to the shape of the patient's forehead. In one embodiment, the present invention is an oximeter sensor, having a substrate with a shape similar to a shape of at least a portion of a patient's forehead and including a section adapted to substantially fit over a portion of a forehead of a patient; an emitter disposed on the substrate at a position located on the section; and a detector disposed on the substrate at a distance from the emitter. In one embodiment, the substrate includes a hat that holds the emitter and the detector in a spaced-part manner against the patient's forehead.

Abstract: The invention is directed to a ventilation control system for controlling the ventilation of a patient. The ventilation control system utilizes a user-friendly user interface for the display of patient data and ventilator status. The user interface includes a graphic representation of a breath cycle that displays the breath cycle currently being ventilated, and is also responsive to changes in ventilation settings to assist the user in evaluation the effect of those changes on the ventilator strategy before the changes are implemented.

Abstract: A method and a device for determining the quality of signal used for measuring a physiological parameter. One embodiment of the present invention is directed towards a pulse oximeter, where the measured physiological parameter includes a patient's pulse rate and blood oxygen saturation. The signal quality, which is indicative of the accuracy and reliability of the measured physiological parameter, is calculated by combining a plurality of signal quality indicators, each of which is an indicator of a quality of the measured signal. The value of the signal quality metric is compared to a threshold and based on this comparison various decisions are made by the medical device. One decision is directed towards deciding whether or not to display the measured physiological parameter, to ensure that only accurate measured values are displayed. Another decision is directed towards providing feedback to guide the clinician to adjust the location of the sensor to a more suitable tissue location.

Abstract: A memory in a sensor is used to store multiple coefficients for a physiological parameter. In one embodiment, not only are the sensor's specific calibration coefficients stored in a memory in the sensor for the formula to determine oxygen saturation, but multiple sets of coefficients are stored. The multiple sets apply to different ranges of saturation values to provide a better fit to occur by breaking the R to SpO2 relationship up into different pieces, each described by a different function. The different functions can also be according to different formulas for determining oxygen saturation.

Abstract: The system and method for detecting disconnection and occlusion of a tubing system of a patient ventilator detects disconnection of the tubing system, opens the exhalation valve, delivers an idle flow of breathing gas to the tubing system, disables breath triggering, and generates an alarm. A reconnection of the tubing system can also be detected, to initiate resumption of pressure supported inspiration. For occlusion detection, the pressure drop in the tubing system is determined by pressure sensors in the inspiratory and expiratory airways of the tubing system. The two pressure drop values are compared, and once occlusion is detected, an alarm is generated, and the ventilator responds to protect the patient from over distension. Abatement of the occlusion can also be monitored in a pressure based occlusion status cycling mode, and the ventilator can revert back to normal ventilation when the circuit occlusion or exhaust port occlusion are not detected.