Abstract:
An improved gas analyzer system and method for detecting and displaying the constituent gases of a respiratory gas stream, the system comprising an optical bench (109) comprising a gas pathway for the flow of a gas stream, a flow shaping inlet, three infrared detection channel assemblies for measuring the partial pressures of constituent gases, and measuring sensitivity changes in the detectors of the three infrared detection channel assemblies, a pressure sensor for measuring the pressure within the gas pathway, a temperature sensor for measuring the temperature within the optical bench, a flow rate sensor for measuring the gas flow rate through the gas pathway; analog processing circuitry (124) for processing the detected partial gas pressures, sensitivity changes, the measured values for pressure, temperature, and flow rate, and display processing circuitry (128).
Abstract:
@ A pulse oximeter is disclosed of the type wherein light of two different wavelengths is passed through human or animal body tissue, such as a finger, an ear, the nasal septum or the scalp, so as to be modulated by the pulsatile component of arterial blood therein, and thereby allowing indication of oxygen saturation. The level of incident light is continually adjusted for optimal detection of the pulsatile component, while permitting accommodation to variable attenuations due to skin color, flesh thickness and other invariants. At significant slope reversal of the pulsatile component to negative (indicating a wave maximum), wave form analysis of blood flow occurs. A quotient of the pulsatile component of light transmission over the constant component of light transmission is measured for each of two wave lengths by direct digital tracking. The respective quotients are thereafter converted to a ratio, which ratio may be thereafter fitted to a curve of independently derived of oxygen saturation. Calibration is disclosed by solving four unknowns at at least four differing saturations. An output of pulse rate, pulse flow and oxygen saturation is given. An incident light source duty cycle is chosen to be at least 1 in 4 so that noise, inevitably present in the signal, may be substantially eliminated and filtered. Provision is made for a local battery-driven low power consumption instrument capable of being substantially independent of ambient light noise.
Abstract:
A pulse oximeter wherein light of two different wavelengths is passed through body tissue, such as a finger, an ear or the scalp, so as to be modulated by the pulsatile component of arterial blood therein and thereby indicate oxygen saturation. A tonal signal is emitted having a pitch proportional to the ratio of oxygen saturation and a sequential repetition proportional to pulse. A visual cue consisting of an array of strobed light emitting diodes is flashed having a total light output proportional to the magnitude of the pulse and a sequential flashing rate proportional to pulse rate. A systematic rejection of extraneous or irregular detected data prevents undue sounding of alarms.
Abstract:
An intravaginal and intrauterine sensor for transillumination of a blood-perfused portion of fetal tissue to measure light extinction. The sensor comprises at least one light source (21, 23) and at least one photo-sensor (20, 22) with a shielding (30). The sensor may be mounted onto a paddle-shaped probe provided with signal connections (25, 26) contained in an insulated cable (27) leading to a measurement device. Alternatively, the sensor may include an opaque suction cup or other attaching apparatus for disposition on a protruding portion of the fetus. Most preferably, the sensor includes a housing.
Abstract:
The oximeter for cooperation with an oximeter probe comprises decoding means responsive to encoded signals for selecting appropriate calibration coefficients for use in calculating oxygen saturation based upon the known wavelength of first and/or second light emitting means (10, 132 and 20, 130, resp.) in the probe. A probe comprises a pair of light emitting means preferably diodes (10, 20, 130, 132) which emit light of narrow wavebands having known characteristic wavelengths through part of a patient onto a photosensor (30, 38). A coding means comprising resistor (40) of coded known resistance or else an eight bit connector (52′) is used to enable the oximeter to calculate the coefficient of extinction of the wavelengths of the LEDs. The resistor, LEDs and photosensor are mounted on self-attaching hook and eye tape (50) for mounting the probe onto the appendage of the patient. The probe is detachably wired to the oximeter, rendering the probe completely disposable. The oximeter is programmed at the factory to calculate the co-efficients of extinction of any LEDS which may be encountered in a series of disposable probes. From the co-efficients of extinction, the pulse rate and degree of arterial oxygen saturation is computed and displayed by the oximeter.
Abstract:
A sensor for trans-illumination of a blood perfused portion of flesh to measure light extinction during trans- illumination is disclosed. The sensor is preferably mounted on a fingertip but any digit or blood perfused portion of flesh will work. The sensor includes a first end for disposition on one side of the trans-illuminated flesh and a second end for disposition on the opposite and opposed side of the trans- illuminated flesh. A light source is mounted to the first side and a photo- sensor is mounted to the second side. If an elongated flexible strip is used, it is provided with adhesive and is suitably windowed that light is allowed to take an optical path through the finger. If no flexible strip is used, the two ends are aligned and secured to the flesh such that the light emitted takes an optical path through the finger. When the adhesive fastener is used, the effect of the light source and photo-detector substrates being integrated into the adhesive fastener is that they become, in effect, a part of the skin. The resulting device is resistant to accidental removal and avoids constriction of blood vessels. Most importantly, the low mass of the sensor itself and its conformance to, so as to effectively become a part of, the skin, prevents relative motion between the light source and sensor and the perfused flesh. This eliminates the common interference associated with the operation of conventional plethysmographs and oximeters.
Abstract:
A pulse oximeter wherein light of two different wavelengths is passed through body tissue, such as a finger, an ear or the scalp, so as to be modulated by the pulsatile component of arterial blood therein and thereby indicate oxygen saturation. A tonal signal is emitted having a pitch proportional to the ratio of oxygen saturation and a sequential repetition proportional to pulse. A visual cue consisting of an array of strobed light emitting diodes is flashed having a total light output proportional to the magnitude of the pulse and a sequential flashing rate proportional to pulse rate. A systematic rejection of extraneous or irregular detected data prevents undue sounding of alarms.
Abstract:
An improved gas analyzer system and method for detecting and displaying the constituent gases of a respiratory gas stream, the system comprising an optical bench (109) comprising a gas pathway for the flow of a gas stream, a flow shaping inlet, three infrared detection channel assemblies for measuring the partial pressures of constituent gases, and measuring sensitivity changes in the detectors of the three infrared detection channel assemblies, a pressure sensor for measuring the pressure within the gas pathway, a temperature sensor for measuring the temperature within the optical bench, a flow rate sensor for measuring the gas flow rate through the gas pathway; analog processing circuitry (124) for processing the detected partial gas pressures, sensitivity changes, the measured values for pressure, temperature, and flow rate, and display processing circuitry (128).