Abstract: A respiration monitor that indicates respiration or loss of respiration by detecting carbon dioxide in expired air in an endotracheal tube comprises a tubular member adapted to receive respired air from an endotracheal tube and having diametrically opposed planar windows substantially transparent to infrared radiation; an infrared analyzer comprising a source means for producing an unmodulated beam of infrared radiation passing through the planar windows and respired air, and a solid state detector means to receive infrared radiation after passage through said windows and respired air and to generate an output signal in response to the presence of CO.sub.2 in respired air, means for detecting the time between signals generated by said detector, and alarm means responsive to a predetermined delay between said signals.

Abstract: An infrared fluid analyzer for the detection of end tidal CO.sub.2. The analyzer is comprised of an IR source that irradiates a chamber filled with gas. CO.sub.2 present in the chamber absorbs the IR radiation at a certain wavelength. An IR detector determines the amount of IR radiation passing through the chamber unabsorbed and produces a signal corresponding to the CO.sub.2 in the chamber. At predetermined intervals a zero gas is reintroduced into the chamber for the system to be recalibrated. A span gas is only needed initially for calibration purposes.

Abstract: The present invention pertains to a photo-acoustic apparatus for detecting energy that exits from the end of an optical fiber waveguide device. The photo-acoustic apparatus includes a housing having an opening through which the end of the optical waveguide device extends into the housing. The gas fills the housing and is capable of absorbing energy that exits the end of the optical waveguide device. The gas increases in pressure corresponding to the energy absorbed by it. There is also a pressure sensor such as a capacitor micorphone disposed in said housing which is capable of sensing the pressure of the gas and producing an electrical signal proportional to the energy which exits the optical waveguide device. Alternatively, a solid absorber is disposed in the housing that absorbs energy that exits from the end of the optical waveguide device. The gas filling the housing, in this case, does not absorb any of the energy.

Abstract: This present invention pertains to a photo-acoustic apparatus for detecting energy that exits from the end of an optical fiber waveguide device. The photo-acoustic apparatus includes a housing having an opening through which the end of the optical waveguide device extends into the housing. The gas fills the housing and is capable of absorbing energy that exits the end of the optical waveguide device. The gas increases in pressure corresponding to the energy absorbed by it. There is also a pressure sensor such as a capacitor microphone disposed in said housing which is capable of sensing the pressure of the gas and producing an electric signal proportional to the energy which exits the optical waveguide device. Alternatively, a solid absorber is disposed in the housing that absorbs energy that exits from the end of the optical waveguide device. The gas filling the housing, in this case, does not absorb any of the energy.

Abstract: The present invention pertains to an apparatus that is capable of correcting for inaccuracies caused by molecular collision broadening in analyzers. The apparatus includes an analyzer for analyzing a fluid. The analyzer is capable of producing an output signal corresponding to the fluid in the analyzer. The apparatus also includes a device for detecting molecular collision broadening in the fluid. The detecting device produces an output signal proportional to the molecular collision broadening. There is also a device for correcting inaccuracies in the analyzer output signal caused by molecular collision broadening. The correcting device is disposed to receive the analyzer output signal and the detecting device output signal, and is capable of producing an output signal corresponding thereto. Preferably, the detecting device includes a thermal conductivity cell and the correcting device is either a voltage control gain operational amplifier or a computer.

Abstract: A liquid separator for removing liquid from a breath sample comprises a liquid trap having a conduit passing the breath sample and opening through a check valve to a reservoir chamber. Sample flow is diverted to the reservoir and ambient air is drawn back through the conduit and check valve to backflush liquid in the conduit to the reservoir. The reverse flow is activated by the presence of liquid in the sample line, periodically actuated by a timer or both. The reverse air flow may be used as a zero calibration gas for an infrared analyzer.

Abstract: An organic fluid detection instrument having great sensitivity to low concentrations or organic fluids in a fluid stream comprise a conduit adapted for the one-way flow therethrough a mixture of an oxygen-containing carrier fluid and organic fluids; a first electrical resistance element disposed in the conduit and carrying a material catalyst for promoting exothermic oxidation reactions of the organic fluid of the mixture; a second resistance element also disposed in the conduit for temperature sensing, consisting of a material with an electrical resistivity that varies with its induced temperature; each element is connected to a pair of electrical leads for operatively producing electrical signals representative of the amplitude of the output signal to be measured; a measuring circuit means is joined to both pairs of leads for processing both a synchronous signal and the second output signal in a manner whereby variations in the differential resistance of the second sensing element serve as a measure of the

Abstract: A liquid separator for removing liquid from a breath sample comprises a liquid trap having a conduit passing the breath sample and opening through a check valve to reservoir chamber. Sample flow is diverted to the reservoir and ambient air is drawn back through the conduit and check valve to backflush liquid in the conduit to the reservoir. The reverse flow is activated by the presence of liquid in the sample line, periodically actuated by a timer or both. The reverse air flow may be used as a zero calibration gas for an infrared analyzer.

Abstract: An infrared fluid analyzer with an improved sensitivity and signal to noise ratio is provided. The device includes a capacitor microphone for detecting absorption by the sample of characteristic infrared wavelength lines, and utilizes an electret material to electrically polarize the capacitive element. Also included are means for controlling the temperature of the infrared radiation source in order to stabilize the output thereof and increase the reliability of the instrument, and means for controlling the temperature of the fluid sample. In a double-beam embodiment of the invention, a gas-free reference cell is provided to further stabilize the instrument.

Abstract: An infrared fluid analyzer with an improved sensitivity and signal to noise ratio is provided. The device includes a capacitor microphone for detecting absorption of characteristic infrared wavelength lines by the sample and utilizes an electret material to electrically polarize the capacitive element in the microphone. The device is used to detect a stoppage of respiration in a person and thereby warn of the presence of an APNEA condition. The capacitor microphone generates a signal each time it detects an exhaled breath. When a timer senses an extended delay between signals, an alarm sounds indicating the presence of an APNEA condition.

Abstract: A double beam infrared analyzer is modulated to separately and alternately project the sample beam and comparison beam into a condenser microphone type detector thereby generating alternate pulsed signals indicating the intensity of the sample beam and comparison beam. The peak comparison beam signal is detected and maintained at a constant value through a feedback circuit controlling the degree of amplification of both the comparison beam signal and the sample beam signal, thereby providing comparison and sample signals that are corrected every cycle for analyzer instabilities.