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 either circuit occlusion or exhaust port occlusion are not detected.

Abstract: A parameter of interest being measured by a sensor is estimated from output response data from the sensor and the known transfer function of the sensor, allowing fast and accurate sensor data from sensors having a dynamic characteristic otherwise precluding assessment of the sensor input. A parameter of breathing gas from a ventilator is determined based upon the known transfer function and a plurality of the sensor output signals at predetermined intervals of time, to provide an estimation of the parameter of interest.

Abstract: A fetal pulse oximeter sensor mounted on a sensor head with an articulating design. A lumen on one side of the sensor has a cable or rod therein to either push or pull that side of the sensor with respect to the main body, thus causing the sensor head to articulate. This can be used, for instance, to apply pressure against the fetus' scalp, with the sensor head, using the articulating mechanism, until an adhesive takes hold. Additionally, the sensor may be held in place on the fetus by an adhesive which is appropriate for a wet surface. The adhesive has the characteristics of having sufficient adhering characteristics to maintain the sensor in place, while at the same time not damaging the fetus' skin upon removal, without requiring suction.

Abstract: An improved infant/neonatal pulse oximeter sensor substrate which is preferably conforming to the shape of the infant or neonate's foot. In one embodiment, the pad conforms to the heel of the infant, with the emitter and detector preferably being mounted in the region of the calcaneus bone. The heel pad can be held in place with a stretchable sock. In an alternate embodiment, the conformable pad is a sock with recesses or pockets cut in it for holding the emitter and detector.

Abstract: An oximeter sensor formed with a housing made of a relatively rigid material into which the oximeter electrical components can be mounted is provided. An overmolded material, of lesser rigidity, is injection-molded over the housing to complete the sensor. In one embodiment the housing is made of plastic, such as polypropylene, and the overmolded material is an injection-molded thermal plastic elastomer, such as Santoprene.TM. (polypropylene with 1 micron size particles of rubber). The housing preferably contains thin portions connecting thicker portions which support the electrical and optical components. These thin portions provide natural bending portions in the final oximeter sensor. By having the thin portions near or at the central, neutral axis of the sensor, flexibility is optimized in the longitudinal direction, while the housing provides stiffness laterally.

Abstract: An improved sensor using a gel. In one aspect, the gel is an oil plasticized thermoplastic elastomer gel. In one embodiment, the gel is mineral oil-based. The gel may be embedded on a support layer. Means for reducing shunted light from the gel are provided, such as substantially opaque material in the gel or breaks in the gel.

Abstract: The ventilator exhalation gas condensate collection and drainage system includes an exhalation filter and a fluid collector vial. Exhalation breathing gas flows through the collector vial for collection of condensate from the exhalation breathing gas. The exhalation filter includes a locking ring that can be turned to secure or release the fluid collector vial. A drain port on the collector vial can be connected to a drain tube, or can be capped by a drain port cap. A clamp on the tube can be unclamped to drain liquid from the collector vial. The collector vial includes a maximum fill line, to indicate when the collector vial should be emptied.

Abstract: The present invention provides an adapter which actively connects a two terminal oximeter probe or monitor to a three terminal monitor or probe. This is done actively, with the alternating drive signals from the oximeter monitor providing a control signal for switching the adapter connections. The adapter connections are preferably made with diodes, transistors, or other active devices.

Abstract: The compression molded aircraft personal service unit and integrated oxygen dispensing system module housings are formed by compression molding of a sheet molding material. The integrated oxygen dispensing system module can be mounted separately in the aircraft, or can be contained in the personal service unit, and includes an oxygen dispensing system module container housing having a multiple release main door, an oxygen generator removably disposed in the oxygen dispensing system module container housing, and one or more oxygen masks. In one embodiment, an external test lever is mounted on the main door, and in an alternative embodiment an internal test mechanism is provided that is operated by a test tool insertable through an aperture in the main door. An improved latch testing system and related capability is also provided.

Abstract: A fetal pulse oximeter sensor in which a sensor head is held against the fetus by the action of a securing means which is remote from the sensor head. The securing means is sufficiently remote so that light detected by the light detector in the sensor head does not scatter through tissue which may be deformed by the securing mechanism. The securing mechanism could deform the tissue by applying pressure, to exsanguinate the tissue, or could attach to the tissue by vacuum, penetration, or glue, etc.

Abstract: A reusable accessory for a sensor (such as a pulse oximeter or a plethysmograph) that allows close conformance between the sensor heads and the patient tissue to be measured. The accessory thus provides both a key advantage of adherent sensors (i.e. close tissue-sensor conformance) and a key advantage of rigid structure sensors (reusability). The accessory provides a structure for mounting the sensor heads, whereby the sensor heads can pivot about their respective points of attachment to the mounting structure within first and second voids, respectively, thereby allowing the sensors to closely conform to the patient tissue. In one embodiment, the mounting structure includes a spring containing two coils, and two frames surrounding the voids and connected to the coils, each frame having an end shaped to fit a portion of a sensor head and onto which a sensor head is mounted.

Abstract: A pulse oximeter display device which displays oxygen saturation data is provided. The device comprises a multicolor display unit which displays oxygen saturation data in first and second colors. A display drive is coupled to the display unit, and a control unit is coupled to the display drive. Limits for oxygen saturation data are set by the control unit. The control unit further provides three signals to the display drive. The first signal is provided to continuously illuminate the display in the first color if the oxygen saturation data is within the limits. The second signal is provided to intermittently illuminate the display unit in the second color if the oxygen saturation data is not within the limits. The third signal is provided to continuously illuminate the display unit in the second color if the limits have not been set.

Abstract: A sensor probe operable to transmit light of a first wavelength for scattering by a tissue sample is described for use with a pulse oximeter designed to operate with another type of sensor probe which transmits light of a second wavelength. The sensor probe includes at least one source of light for transmitting light of the first wavelength for scattering and/or absorption by the tissue sample. At least one detector is included for detecting light of the first wavelength affected by the tissue sample and generating a signal in response thereto. An encoder in the sensor probe transforms the signal to a form which may be employed by the oximeter.

Abstract: A compact pulse oximetry system and method which separates the combined signal into its respective AC and DC components. By separating the signal into AC and DC components, a smaller order bit A/D converter may be used while still maintaining signal accuracy. Instead of using the combined signal to calculate the oxygen saturation content, the system microprocessor computes the Ratio of Ratios using the derivative of the separated AC component of the diffused signal to calculate the oxygen saturation of the measured fluid. To calculate the Ratio of Ratios, a ratio of the derivative value of the separated AC component is used. Instead of taking a single sample between the peak and valley of the signal, the oximeter system samples each value. To decrease the effect of system noise, a linear regression is performed over each sample.

Abstract: A pulse oximeter sensor having an emitter(s) and a detector, with a layer having a first portion over 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: A pulse oximeter sensor with a light source optimized for low oxygen saturation ranges and for maximizing the immunity to perturbation induced artifact. Preferably, a red and an infrared light source are used, with the red light source having a mean wavelength between 700-790 nm. The infrared light source can have a mean wavelength as in prior art devices used on patients with high saturation. The sensor of the present invention is further optimized by arranging the spacing between the light emitter and light detectors to minimize the sensitivity to perturbation induced artifact. The present invention optimizes the chosen wavelengths to achieve a closer matching of the absorption and scattering coefficient products for the red and IR light sources. This optimization gives robust readings in the presence of perturbation artifacts including force variations, tissue variations and variations in the oxygen saturation itself.

Abstract: The present invention utilizes at least three wavelengths of electromagnetic radiation for determining a blood constituent, such as arterial oxygen saturation, in a patient. The detected radiation scattered by the tissue of the patient is analyzed in a manner that compensates for variations in the detected radiation caused by differences in the scattering of the radiation at different wavelengths. In particular, a result is determined which is equivalent to the sum of a first blood constituent estimate using a first pair of the detected signals, and the difference between the first blood constituent estimate and a second blood constituent estimate, using a different pair of wavelengths, with the difference being multiplied by a multiplicative factor.

Abstract: The present invention provides an encoding mechanism for a medical sensor which uses a modulated signal to provide the coded data to a remote analyzer. The modulated signal could be, for instance, a pulse width modulated signal or a frequency modulated signal. This signal is amplitude independent and thus provides a significant amount of noise immunity.

Abstract: A presenting part fetal pulse oximeter sensor which does not penetrate the fetus' skin, and does not rely on a vacuum for attachment is provided. The fetal sensor of the present invention is held in place by pressure applied to the fetus by a number of different mechanisms. In one embodiment, the sensor is held in place against the fetus by a rigid rod, with the pressure being applied by the physician or technician's hand on the rod. This type of a sensor is useful for spot-checking, where continuous monitoring is not needed. In another embodiment, a pre-loaded spring is coupled between the rod and the sensor head to prevent too much pressure being applied by the user.

Abstract: A pulse oximeter sensor that is designed to surround an appendage of the patient, such as a finger, toe or foot is disclosed. The sensor has a reusable member which preferably includes a photodetector. A disposable, flexible member preferably contains the photoemitter and can be wrapped around the patient's appendage to secure it to the appendage and the reusable member. When secured, the photoemitter and photodetector end up on opposite sides of the appendage. The disposable member connects to the reusable member to establish electrical contact. The reusable member is connected to a cable which can be plugged into a sensor monitoring system.