Abstract: A cuvette comprising a housing having a passage therethrough and being adapted to receive blood. The housing has a wall with an outer face. An optical window leads from the outer face to the passage and the optical window is transmissive to an optical signal so that a parameter of blood in the passage can be measured. A magnet is carried by the wall and spaced from the optical window for use in providing information about the cuvette. The cuvette is releasably attachable to an optical head. The optical head includes a plurality of Hall effect transducers which respond to the position of the magnet on the housing so that the position of the magnet can be used to provide information about the cuvette.

Abstract: An adapter cable is used for connecting a pulsoximetry sensor unit to a medical measuring device. The pulsoximetry sensor unit comprises, among other components, two antiparallel-connected, light-emitting diodes, which are activated alternatingly by a pulse current source of the medical measuring device. Between said pulsoximetry sensor unit and said medical measuring device, a plurality of grounding lines extend within the adapter cable. In the case of a short circuit between one of the two supply lines of the antiparallel-connected, light-emitting elements and one of the grounding lines, the fault current is caused to flow in the grounding lines to a first node in accordance with the present invention, said first node being adapted to be connected to a reference potential of the medical measuring device via a first resistor.

Abstract: A method and apparatus for accurately determining a blood parameter that is calculated by measuring the transmittance of light through tissue having blood flowing therein is disclosed. A plurality of transmittance of light measurements are obtained for each transmittance of light parameter. The arithmetic mean of each transmittance of light parameter is calculated from the plurality of measurements. The arithmetic means are used to calculate the blood parameter from known formulations.

Abstract: A sensor for non-invasive measurement of oxygen saturation using the reflection method comprises a red transmitter (55), an infrared transmitter (58) and a receiver (57). The distances between the transmitters and the receiver are selected such that the length of the light path (60, 61) between the red transmitter (55) and the receiver (57) is substantially equal to the length of the light path (62, 63) between the infrared transmitter (58) and the receiver (57). The sensor comprises a further red transmitter (56) which is used for another application at the human body or another tissue characteristics where the depth of penetration at the various wavelengths is different from the shown example. Together with an appropriate oximeter, manual or automatic adaptation is possible. Further signal improvement may be obtained by autocorrelating the received signal, detecting its frequency and cross-correlating it with a pattern function of the same frequency.

Abstract: A sensor for non-invasive measurement of oxygen saturation using the reflection method comprises a red transmitter (55), an infrared transmitter (58) and a receiver (57). The distances between the transmitters and the receiver are selected such that the length of the light path (60, 61) between the red transmitter (55) and the receiver (57) is substantially equal to the length of the light path (62, 63) between the infrared transmitter (58) and the receiver (57). The sensor comprises a further red transmitter (56) which is used for another application at the human body or another tissue characteristics where the depth of penetration at the various wavelengths is different from the shown example. Together with an appropriate oximeter, manual or automatic adaptation is possible. Further signal improvement may be obtained by autocorrelating the received signal, detecting its frequency and cross-correlating it with a pattern function of the same frequency.

Abstract: A method for converting a value for the partial pressure of oxygen (pO.sub.2) in blood at a measurement temperature to a corresponding value at a reference temperature (37.degree. C.). A value for pO.sub.2 is determined by measurements made in a patient's blood stream using a phosphorescent compound that is sensitive to the concentration of oxygen. The phosphorescent compound is illuminated with a short pulse of light, causing it to produce a phosphorescent emission having a rate of decay that varies as the function of the partial pressure of oxygen in the blood surrounding the phosphorescent compound. A detector produces an electrical signal corresponding to the intensity of the phosphorescent emission, and the electrical signal is converted to a corresponding digital value for input to a microcomputer. Also supplied to the microcomputer in digital form is a signal indicative of the temperature at the measurement site where the phosphorescent compound is disposed.

Abstract: A non-invasive method for detecting deep venous thrombosis in a human body wherein changes are effected in the amount of deoxyhemoglobin in the body limb by trapping blood in the venous system for a determinate time period and then releasing the trapped blood in the venous system. During the period that the changes in the amount of deoxyhemoglobin are effected, first and second light sources emit light of two selected wavelengths which penetrate into the deep venous system of the body limb so that the reflectance contributions can be used to measure changes in the flow and amount of deoxyhemoglobin and to thereby detect the presence or absence of deep venous thrombosis.

Abstract: A fiberoptic based sensor for patient care use. The sensor includes a catheter placed transcutaneously into a blood vessel which is connected to an external measuring head. A sensing tip of the catheter includes a pressure sensing element and an oxygen saturation measuring element. Features of the invention include novel tip designs, measuring head features, and approaches for enhancing measurement though correlation of the saturation and pressure readings.

Abstract: A sensor includes a pair of resiliently loaded jaws for receiving a finger, the sensor including a pair of fiber optic light transmitting guides secured in fixed spaced relation to one of the jaws for sensing blood in the finger tip. A control unit includes a light generator for transmitting light modulated at first and second frequencies to one of the guides via a light guide transfer section. The finger pulse modulates the received transmitted light. The modulated light is sensed by the other guide and returned to a receiver in the control unit via the transfer section for separating and demodulating the different frequency signals. The control unit includes a calculating unit which has two branches for processing and then combining by dividing the processed demodulated signals for determining the oxygen content of the blood from the relative magnitudes of the pulse-dependent modulation factor of the wave reflected from the finger.

Abstract: An apparatus for calibrating a pulse oximeter which can improve the repetitivity of measured values for calibration tests and which can calibrate the pulse oximeter with a high reliability. A tissue model having a light-absorbing characteristic approximated to that of the tissue of a living body is inserted into a space between a light-emitting section and a light-receiving section of a measuring probe that is connected to the pulse oximeter, and a blood model having a light-absorbing characteristic that is approximated to that of the blood is moved within the tissue model so as to enter into or exit from the space between the light-emitting section and the light-receiving section.

Abstract: The present invention relates to the noninvasive measurement of blood hematocrit and hemoglobin content using differential optical absorption of two or more wavelengths of light during blood volume changes. The method is also useful for noninvasive measurements of other blood analytes, such as glucose, where variations in hematocrit or blood hemoglobin concentration cause errors in the measurement.

Abstract: A pulse oximeter of the present invention is to provide a greatly simplified in construction and a simplified procedure for performing arithmetic operations.

Abstract: Under the present invention, a method and apparatus are provided for compensating for the effect temperature variations have on the wavelength of light emitted by the oximeter sensor light source (40, 42). In pulse oximetry, LEDs (40, 42) are typically employed to expose tissue to light at two different wavelengths. The light illuminating the tissue is received by a detector (38) where signals proportional to the intensity of light are produced. These signals are then processed by the oximeter circuitry to produce an indication of oxygen saturation. Because current oximetry techniques are dependent upon the wavelengths of light emitted by the LEDs (40, 42), the wavelengths must be known. Even when predetermined combinations of LEDs (40, 42) having relatively precise wavelengths are employed, variations in the wavelength of light emitted may result. Because the sensor (12) may be exposed to a significant range of temperatures while in use, the effect of temperature on the wavelengths may be significant.

Abstract: A hinge clamp mechanism and sensor for performing pulse oximetry tests, as well as for performing other diagnostic procedures that can be conducted on a human body part, such as a finger. More particularly, the hinge clamp mechanism utilizes one or more slots, pins and springs to enclose the body part being tested. The hinge clamp relies on a movable pivot point connecting upper and lower portions of the device and the biasing force of one or more cantilevered leaf springs to enable the upper and lower body portions of the device to conform to the upper and lower surfaces of the body part, and to evenly distribute the gripping pressure of the device over the upper and lower surfaces of the body part.

Abstract: A noise insensitive pulse transmittance oximeter (11) is disclosed. Two LEDs (21 and 23) are included in the pulse transmittance oximeter. The LEDs alternately emit a red light pulse and an infrared light pulse. A detector (13) detects corresponding red transmittance pulses and infrared transmittance pulses that are indicative of the amount of light transmitted through tissue having blood flowing therein. A microprocesser (29) determines the peak and valley values of the red transmittance pulses and infrared transmittance pulses over a cycle. The difference between the peak and valley values for the red transmittance pulses and infrared transmittance pulses are calculated by the microprocessor. The microprocessor generates control signals that vary the intensity of the LEDs until the differences between the peak and valley values of the red transmittance pulses and infrared transmittance pulses are substantially equal.

Abstract: Disclosed is an integrated lead frame pulse oximetry sensor which includes a thin metal lead frame to which is connected light emitting diodes and a photodiode chip for the purpose of emitting light and detecting light respectively. The thin metal frame is deformable to attach to perfused tissue. The lead frame has a very low mass which diminishes its acceptability to motion induced artifact.

Abstract: A gas sensor using optical fiber technology to measure gas concentration in a test volume. In one embodiment, the sensor incorporates a gas enriching polymer which absorbs and concentrates carbon dioxide (CO.sub.2) from the test volume surrounding the sensor. The polymer is wrapped around the core of an optical fiber which guides radiation with first selected wavelengths to the polymer. The radiation propagates into the polymer and reacts with the carbon dioxide in the polymer. Determination of CO.sub.2 concentration in the test volume is made by measuring the amount of attenuation of the radiation after reacting with the carbon dioxide in the polymer. In another embodiment, the polymer is capable of absorbing oxygen from the test volume and oxygen concentration is measured using fluorescence quenching.

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: An apparatus for photo-optically detecting transducer motion using a photodetector resiliently suspended inside the transducer housing and photo-optically coupled to a light source. During movement the inertia effect of the photodetector along with the resilient suspension system causes the changes in the photo-optical coupling between the photodetector and the light source. The inertia effect of the photodetector is enhanced by adding a mass to the photodetector. Either the magnitude or the phase of the photodetector output is monitored to detect movement. In another embodiment, a light emitter is resiliently suspended so that movement induced changes in the position of the light emitter alter the coupling of light to one or more light detectors.

Abstract: A probe for a reflection-type oxymeter which measures a blood oxygen saturation of a subject, the probe including a light emit device emitting at least two lights having different wavelengths toward a body portion of the subject, a light detect device detecting the lights reflected by the body portion of the subject, a housing supporting the light emit and detect devices, and an elastic member secured to the housing, the elastic member including an adhesive portion, the adhesive portion being spaced from the body portion of the subject with the housing contacting the body portion, the adhesive portion being elastically deformed and adhered to the body portion so that the housing is pressed against the body portion with a pressing force within a predetermined range due to an elastic return force of the deformed adhesive portion.

Abstract: Systems and methods for non-invasive blood analysis are disclosed in which blood is illuminated at a plurality of discrete wavelengths selected from the near infrared spectrum. Measurements of the intensity of transmitted or reflected light at such wavelengths are taken, and an analysis of transmittance or reflectance ratios for various wavelengths is performed. Changes in the ratios can be correlated with specific near infrared (IR) absorption peak for the analyte which varies with concentration of the analyte (the data wavelength) and the a second (reference) wavelength being sufficiently removed from the first so that measurements of light absorption at this second wavelength are relatively insensitive to the concentration of the analyte and yet the second wavelength is sufficiently close to the first wavelength to minimize interference from scattering effects and the like.

Abstract: A first light emitting element directs light through a first region of tissue, a second light emitting element directs light through a second region of tissue that is spatially distinct from the first region of tissue, and a photodetector detects light traveling through the first and second regions. First and second oxygen saturation values are calculated from the amount of light detected from the first and second regions of tissue, respectively. A difference calculating unit calculates a difference value which represents how much the first oxygen saturation value differs from the second oxygen saturation value, and a comparator compares the difference value to a threshold value. A threshold indicating signal is provided when the difference value has a selected mathematical relationship (e.g., less than or equal) to the threshold value.

Abstract: The degree of hemoglobin oxygenation in the blood vessels of the retina is etermined under conditions of dark-adaptation and light-adaptation by directing a beam of near-infrared light having a range of wavelengths from 700 to 100 nanometers at a blood vessel in the retina, measuring the intensity of the backscattered light from the blood vessel in the range from 700 to 800 nanometers at regularly spaced intervals of wavelength, such as 2 nanometers, and determining the degree of hemoglobin oxygenation by reference to a correlation between hemoglobin oxygen and light absorbance in the near-infrared spectral range.

Abstract: An improved noninvasive, electrooptical sensor probe is suitable for removable adhesive attachment to the skin of a patient to measure light extinction during transillumination of the blood-perfused tissue beneath the skin. The probe has a flexible generally U-shaped, web-like support structure having spaced, opposed upper and lower inner surfaces. A light source such as an LED is mounted in the support structure and positioned to emit light from one of the inner surfaces. A photosensor is also mounted in the support structure and positioned on the other of the inner surfaces to detect light emitted by the light source. A U-shaped alignment member is disposed in the support structure and extends substantially from the light source to the photosensor to hold the probe into the desired shape for use and aid in aligning the LED and photosensor.

Abstract: A sensor for use in medical patient examination and monitoring by spectrophotometric apparatus, including a main body having a soft, resilient outer cover on at least one side for conformably contacting a selected area on the patient, in particular the forehead, also having and an electro-optical light source and a plurality of electro-optical light detectors spaced from the source and from one another, and exposed to the selected site on the patient by light-transmissive passages extending through the resilient cover, in which the resilient cover is formed of a thin, softly compressible member of light-absorbing and moisture-transmissible material, preferably of resilient cellular polymeric foam.

Abstract: An improved apparatus and method for non-invasive monitoring of blood oxygen saturation and pulse is made by modifying a conventional prior art pulse oximeter probe for use inside an ear canal or other body cavity. This placement is particularly useful for unobtrusively monitoring the blood oxygen saturation and pulse of pilots flying high performance military aircraft. When monitored blood oxygen saturation or pulse levels fall to a level indicating imminent unconsciousness, control of the aircraft can be removed from the pilot and the aircraft unloaded to reduce G-loading. The apparatus is made by removing the light emitting diode (LED) and light sensor from a commercially available pulse oximeter probe, or oxisensor, and cementing them on opposite sides of a conventional ear plug. The light emitted from the LED travels a reflective path through the vascular tissue surrounding the ear canal to be received by the light sensor on the other side of the canal.

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.

Abstract: A noninvasive oximeter sensor for controlling and optimizing the minimum detection depth in the tissue of a patient is disclosed. In general, a minimum detection depth of 0.35 mm in the skin is considered optimum. The reflectance oximeter sensor component configuration of the present invention achieves the minimum detection depth. The present invention offers a more accurate indication of blood oxygen saturation in a patient's arterial blood than was available from previous reflectance oximeter sensors.

Abstract: An oximeter probe is introduced through the vaginal canal and applied to the scalp or other readily accessible part of the fetus while still in utero. The fetal oxygenation is monitored during the entire labor and delivery period to obtain instantaneous indications of any peripartum fetal distress. The probe comprises a clamping device which can be easily manipulated within the narrow confines of the partially dilated cervix.

Abstract: A method and apparatus for non-invasively measuring blood constituent concentration and particularly the oxygen saturation of arterial blood. The apparatus includes at least one light source directed to a tissue area of a patient, such as a finger or earlobe. A photodetector receives emitted light passing through the sample, and a receiver circuit analyzes the data and produces an output which is proportional to the oxygen content of blood. The light source is modulated onto a preselected carrier frequency and the receiver circuit is tuned to the carrier frequency so that undesired signals such as ambient light can be filtered out leaving only the signals created by the emitted light passing through the tissue at the light source frequency. The oxygen content is then calculated using the patient's known red cell count, thereby correcting the final saturation value for patient anemia.

Abstract: An improved pulse oximeter for the measurement of oxygen saturation in the blood, which is faster and more accurate than conventional pulse oximeter. Improved speed and accuracy is attained by elimination of normalization and feedback circuitry and the use of analog to digital converting devices having a wide dynamic range along with a sophisticated computer analysis. The instant invention eliminates inaccurcies resulting from channel matching errors, and detects and eliminates aberrant input data.

Abstract: A sensor for non-invasive measurement of oxygen saturation using the reflection method comprises a red transmitter (55), an infrared transmitter (58) and a receiver (57). The distances between the transmitters and the receiver are selected such that the length of the light path (60, 61) between the red transmitter (55) and the receiver (57) is substantially equal to the length of the light path (62, 63) between the infrared transmitter (58) and the receiver (57). The sensor comprises a further red transmitter (56) which is used for another application at the human body or another tissue characteristics where the depth of penetration at the various wavelengths is different from the shown example. Together with an appropriate oximeter, manual or automatic adaptation is possible. Further signal improvement may be obtained by autocorrelating the received signal, detecting its frequency and cross-correlating it with a pattern function of the same frequency.

Abstract: A system for invasive measuring of blood gas parameters, such as pH, pO.sub.2 or pCO.sub.

Abstract: In a liver function testing apparatus, light sources (11, 12) expose vital tissue (15) to first light of a wavelength absorbed by the specific dye dosed into blood of the vital tissue to be taken in and removed by the liver and second light of a wavelength not absorbed by the dye. Optical pulses passing through the vital tissue are received by a light receiving element (13) and first and second outputs from element (13) are sampled by an A-D converter (30) to produce respective digital signals. Pulsation components of the outputs of the receiving light are detected by high-pass filters (51, 52) and amplifiers (53, 54). A coefficient of a linear regression expression between intensity values of the pulsation components and an average value using the sampled first and second outputs of the received light are determined for performing a biocalibration.

Abstract: A sensor and a method for using the sensor to determine the concentration or partial pressure of oxygen in a fluid media is provided. The sensor includes a light modifying medium containing a luminescent dye which is accessible to oxygen. The luminescent dye contains a hexanuclear core of molybdenum, tungsten or mixtures thereof having 14 coordination sites, wherein each site is occupied by a ligand. The sensor also includes an apparatus capable of transmitting and collecting light to and from the light modifying medium.

Abstract: A system for insertion of a fiber optic diagnostic sensor into the human body. The sensor is of the type which functions by emission of light into the body and reception of light reflected from the body. In particular, the system is intended for use with fiber optic reflectance oximeters. The fiber optic sensor is inserted into an introducer catheter, and coupled to monitoring equipment and activated as the sensor is advanced through the introducer catheter. By appropriately filtering or otherwise processing the signal indicative of reflected light received by the sensor, its position relative to the end of the introducer catheter can be determined. This allows for accurate insertion of the fiber optic sensor, regardless of the length of the introducer catheter and regardless of the length and/or number of fittings or manifolds through which the fiber optic sensor must pass.

Abstract: A system for non-invasively determining the oxygenation state of tissue located beneath the surface of the skin, such as muscle tissue, of an exercising person or other subject is disclosed. In a preferred embodiment, a user-wearable detector array and related circuitry which use near-infrared radiation to collect oxygenation data are provided. The apparatus also includes displays for displaying information regarding the oxygenation state in several ways. In one embodiment a user wearable wristband indicator connected to the detector array which is located at another location, such as on the leg, and provides information directly to the user. In another embodiment, a telemetry device allows remote monitoring of a subject during an activity, the oxygenation information being displayed to a coach or other observer. A separate, user-wearable battery pack, which is preferably designed to provide power for the duration of the activity being monitored, is also provided.

Abstract: A method and apparatus for increasing the blood flow in a patient's tissue by warming the tissue with heat generated by a semiconductor device mounted in a sensor. The amount of heat generated is controlled by varying either the magnitude or the duty cycle of the current that flows through the semiconductor device, with the amount of heat required determined by either the temperature of the sensor's contact surface or the operating performance of the apparatus.

Abstract: A light beam having a first wavelength (.lambda..sub.1) is applied to the blood from a first light radiation section, while a light beam having a second wavelength (.lambda..sub.2) is applied from second and third light radiation sections different in positions from the first radiation section and from each other to the blood and the respective reflected-light intensity (I.sub.1, I.sub.2, I.sub.3) is detected. A first correction value (X) for correcting the reflected-light intensity ratio (I.sub.2 /I.sub.3) is calculated by a first correction value operation section (40) and a second correction value (C.sub.1) is calculated by a second correction value operation section (42) by use of this first correction value and the reflected-light intensity (I.sub.3). The reflected-light intensity ratio (I.sub.1 /I.sub.2) is corrected by use of this second correction value and an oxygen saturation in the blood is operated based on correlation function by use of the corrected reflected-light intensity ratio (R.sub.s).

Abstract: An apparatus for measuring biopermeability is disclosed. The apparatus includes a frame, a light source, a light-receiving element, a pre-amplifier, an off-set adjustment amplifier and a DC volt meter. The light source and light-receiving element are secured to the frame such that they face each other while keeping a gap therebetween such that an organism under measurement can be received in the gap without being urged. The pre-amplifier is connected to the light-receiving element and has a gain switching function. The summing amplifier is connected for zero adjustment and gain adjustment to the output side of the pre-amplifier and has an output terminal from which a DC data representing biopermeability is provided. Between the output terminal and ground the DC volt meter is connected.

Abstract: A method and apparatus for measuring oxidative metabolism in an internal organ or tissue of interest wherein a percutaneous intravascular approach is utilized to bring a light-transmitting and receiving scope into contact with the site to be assessed. The tip of the scope is adapted so that the light-transmitting optical fiber(s) and light-receiving optical fiber(s) are in divergent relationship so as to increase the photon pathlength through the tissue of interest to provide optical information from a substantial volume of tissue relative thereto.

Abstract: A sensor for measuring the oxygen saturation of blood flow within the skull is described. In a first embodiment the sensor comprises a photodetector and a pair of light emitting diodes surface mounted near the end of a length of flexible printed wiring. The sensor is hermetically sealed by a coating of rubber or polymeric material which has an optical window over the photodetector and light emitting diodes. The sensor is inserted through a burr hole drilled in the skull and slides between the skull and the dura of the brain. The light emitting diodes are pulsed to illuminate blood within the dura and brain with light, and light reflected by the blood is received by the photodetector and converted to electrical signals. The signals are processed by a pulse oximeter to provide an indication of blood saturation. In a second embodiment the photodetector and light emitting diodes are mounted at the end of a core of compressible foam extending from the end of a hollow bone screw.

Abstract: A non-invasive retinal scanning system which monitors internal blood loss. A portion of the ocular fundus is illuminated, in an annular fashion, with two wavelengths of light, one of which serves as a reference. Scanning the fundus circumferentially enables retinal venous blood to be detected, which corresponds to desaturated hemoglobin. The intensity of light reflected from the retinal vein is detected and converted to an electronic signal proportional to the value of oxygen saturation of venous hemoglobin, which becomes the value of interest. Thus, a decline in venous oxygen saturation over time correlates linearly with progressive internal bleeding.

Abstract: An apparatus and method are disclosed for determining a level of a constituent such as glucose in a body fluid such as blood. The apparatus and method utilize a light generator for generating a testing light of known intensity with the testing light including a wavelength absorbable by the constituent being measured. The light generator also generates a reference light of known intensity having a wavelength not absorbable by the constituent being measured. The testing light and reference light are directed toward a fluid containing an unknown concentration of a constituent. A light detector is provided for measuring the intensity of the testing light and reference light being spectrally modified by the fluid. A light path distance measurer is provided for measuring a distance of a light path traveled by the testing light and reference light.

Abstract: An improved blood oxygen sensor apparatus having a special leakage compensation circuit that allows proper initialization of the oxygen sensor regardless or the value of leakage resistance which typically might be present in parallel with the oxygen sensor. During an initialization mode, in which a capacitor arranged in parallel with oxygen sensor is charged by a small initialization current, the leakage compensation circuit monitors the capacitor voltage and controllably increases the current if it is determined that the capacitor is charging at an insufficient rate, due to unspecified leakage resistance. This enables the oxygen sensor to be properly initialized such that it can thereafter accurately measure blood oxygen levels.

Abstract: A method is used for processing signals, particularly for oximetric measurements on living human tissue. Spurious signals are suppressed with respect to information signals. The spurious signals have a frequency lying in a first frequency range, and the information signals have a frequency lying in a second frequency range being different from said first frequency range. The signals are conducted over a filter having essentially a blocking characteristic in said first frequency range and having essentially a transmission characteristic in said second frequency range. An output signal of the filter is further processed.In order to eliminate distorting effects from the filter on the information signal, a first function is determined representing the deviation of the frequency response of the filter in said frequency range from an ideal transmission characteristic. A second function inverted with respect to said first function is generated.

Abstract: A noninvasive system and method for monitoring arterial oxygen saturation levels which may also be used to continuously and noninvasively monitor blood pressure, including generating a continuous blood pressure waveform. The apparatus of the described embodiment includes a red LED and an infrared LED which are positioned to direct their respective light beams into, or reflected by a patient's body part. A phototransducer device is positioned to receive the light beams which are transmitted through the body part. A pressure cuff surrounds the body part and the LEDs. During calibration periods, pressure is applied to the body part and the systolic and mean blood pressures are determined and the arterial oxygen saturation level in the body part is determined.

Abstract: An oximeter system for measuring blood oxygen saturation using a noninvasive optical technique is disclosed. A patient's arterial blood is illuminated with light at two different wavelengths and the intensity of the light which is transmitted through or reflected by said arterial blood is correlated with the blood oxygen saturation of the tissue. The system provides a manner in which filtering artifacts are avoided in the oximeter signal using a high resolution analog-to-digital converter of 14 bits or more, such that, it is unnecessary to separate the DC and pulsatile components of the oximeter signal prior to processing within the microprocessor.

Abstract: A bandage for attaching a sensor to a part of the human body while protecting the sensor against contamination and permitting its reuse in which the sensor is located within a flexible transparent sleeve which is fastened to the adhesive inner surface of the bandage, the parts of the bandage inner adhesive surface outside of the sleeve thereafter being fastened to the body. In the preferred embodiment the probe is an oximeter probe with a light emitter and a light detector. Apertures are provided in the bandage to view the positioning of the oximeter components.