Abstract: A compact pulse oximetry system 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 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 adults. 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: A method and apparatus for a simple pulse oximeter measurement of an area of the body with a small amount of blood vessels by using a counterirritant to profuse the blood and then apply a modern oximeter probe is disclosed. The counterirritant is either applied to the skin immediately before attaching the probe, or, preferably, is contained in an adhesive pad which couples the probe to the skin.

Abstract: The present invention provides a method and apparatus for improved fetal contact with a fetal probe. The easily insertable probe includes a means for adjusting the position of the probe so that a sensor makes firm contact with the fetus. In one embodiment, the position is adjusted via a biasing segment of the probe which rotates about a fulcrum. In another embodiment, the position is adjusted via a bladder.

Abstract: An intrauterine pulse oximetry apparatus and method are provided to measure fetal blood oxygen saturation at sites in a preferred region on the fetus. The sensor of the apparatus is attached to a stiff cable which can be inserted into the uterus past the presenting part and transcervical region of the fetus. The cable may have visual and tactile markings by which the user, without seeing or feeling the sensor, can guide it to an appropriate site on the fetus.

Abstract: An apparatus for detecting movement in patients coupled to pulse oximeters and a method for using the signal generated by the apparatus to filter out the effects of motion from the test results generated by the pulse oximeter are disclosed. In a preferred embodiment, a piezoelectric film located in close proximity to the pulse oximeter's sensor provides a voltage signal whenever movement occurs near the sensor. This voltage signal is processed and the resulting signal is used to correct the oximeter's measurements. In addition to piezoelectric film, accelerometers and strain gauges are also usable to provide a signal indicative of motion.

Abstract: A gas analyzer system and method for detecting and displaying information of gases in a respiratory gas stream, comprising an optical bench including a gas pathway for the flow of a gas stream through the optical bench, a flow shaping inlet at the entrance to the optical bench's gas pathway, two infrared detection channel assemblies for measuring the partial pressures of the gases in the respiratory gas stream, a pressure sensor for measuring the pressure within the gas pathway, a temperature sensor for measuring the temperature within the optical bench, and a flow rate sensor for measuring the gas flow rate through the gas pathway, circuitry for processing the detected partial pressures of the gases and the measured values for pressure, temperature, and flow rate, and for providing output signals indicative of processed measured values, the detected partial pressures of the gasses, and characterization information with respect to the optical bench components; analog input circuitry for processing the signals

Abstract: An apparatus for use in measuring fetal blood flow characteristics. The apparatus includes a non-invasive pulse oximetry probe that is inserted into the uterus between the fetus and the uterine wall. The probe is deformable and is positively attached to the fetal tissue surface using a vacuum pump which causes the probe to deform from a pre-set curvature to the curvature of the fetal tissue surface and to form a gasket-type seal with the fetal tissue surface. The probe is manually inserted into the uterus using a curved insertion tool, and is shaped to fit through a slightly dilated cervix. In a preferred embodiment, the probe includes fetal and maternal ECG sensors and additional sensing devices, and is provided with apparatus for improving the efficiency of the pulse oximetry optics.

Abstract: A gas analyzer airway adapter that permits insertion of a suction tube into the patient without removal of the airway adapter from the patient. The adapter body has three ports. A patient port is formed in the main section of the adapter body and has a fitting that attaches to the endotracheal tube. A sample port is formed in a smaller diameter passage extending from the main body and attaches to the sample intake of a gas analyzer. The central axis of the smaller diameter passage is preferably parallel to the central axis of the main body of the adapter. Finally, a ventilator port is formed in a passage whose central axis extends at approximately a 31 degree angle from the central axis of the main body. A hub/filter assembly is disposed in the smaller diameter passage of the airway adapter, and a longitudinal filter extends into the main body of the adapter. A tube guide is disposed below the filter within the main body of the adapter.

Abstract: An agent gas analyzer that will determine the types and measure simultaneously the concentrations of a plurality of agent gases in a respiratory gas stream of an anesthetized patient, with the analyzer self-determining the agent gas types and concentrations each time gas measurements are made.

Abstract: A backflushing system for an inlet filter in an airway adapter in a gas flow sampling and analyzing system includes a back flush fluid supply conduit and sampling conduit connected to the airway adapter by a single coupling element. Flow of back flush fluid causes material blocking the filter to be washed away into the respiratory conduit for disposal. Flow of backflush fluid is restricted to one way flow through the backflush conduit by a disk shaped valve member mounted in the air way adapter.

Abstract: An improved gas analyzer system (FIG.

Abstract: An improved gas analyzer system (FIG. 1) and method of use for detecting and displaying the constituent gases of a respiratory gas stream, the system comprising an optical bench (109) through which a respiratory gas flows and in which measurements of the gas are taken; analog input circuits (122) for receiving signals output from the optical bench (109); analog processing circuits (124) for processing signals output from the analog input circuits (122); display processing circuits (128) for processing the signals output from the analog processing circuits (124) and other system circuitry; pixel logic circuits/analog outputs (130) for processing signals output from the display processing circuitry (128) and providing analog output ports; a five button panel (148), an alarm-knob board (144), and a speaker driver (152) for operator interface and activation of audible and visual alarms; a CRT driver for driving the CRT; and a power supply (158) for powering the system.