Abstract: A medical diagnostic apparatus including a catheter and a probe assembly coupled to the catheter and a method involving the use of a catheter and a probe assembly coupled to the catheter. The probe assembly is capable of detecting a chemical analyte. The probe assembly includes a detection probe located within the catheter. The detection probe can be fixedly attached to the catheter or slideable within the catheter.

Abstract: An oximeter sensor can be used with multiple oximeter systems. The oximeter sensor includes a first light-emitting diode, a second light-emitting diode and a photodetector. Electrical connections to the anode and the cathode of each light-emitting diode and electrical connections to the terminals of the photodetector are provided on a connector. An interconnector is interposed between the connector of the oximeter sensor and a connector in communication with an oximeter system. The interconnector has interconnection wiring selected to electrically connect the sensor connector and the system connector in a manner to configure the light-emitting diodes in a configuration compatible with the oximeter system. In particular, a first interconnector configures the light-emitting diodes in a common anode arrangement. A second interconnector configures the light-emitting diodes in a back-to-back (anode to cathode, cathode to anode) configuration.

Abstract: Systems and methods are provided for noninvasively measuring the levels of urea, blood osmolarity (or Na+), plasma free hemoglobin and tissue water content in a patient's blood or tissue. Light of selected wavelengths is passed through blood or body tissue and the transmitted or reflected light is detected and the detected signals can be electronically compared and manipulated to provide the non-invasive, continuous and quantitative display of a patient's blood urea, blood osmolarity (or Na+), plasma free hemoglobin and tissue water content.

Abstract: An ophthalmic lens comprising a receptor moiety can be used to determine the amount of an analyte in an ocular fluid. The receptor moiety can bind either a specific analyte or a detectably labeled competitor moiety. The amount of detectably labeled competitor moiety which is displaced from the receptor moiety by the analyte is measured and provides a means of determining analyte concentration in an ocular fluid, such as tears, aqueous humor, or interstitial fluid. The concentration of the analyte in the ocular fluid, in turn, indicates the concentration of the analyte in a fluid or tissue sample of the body, such as blood or intracellular fluid.

Abstract: A system for determining a biologic constituent including hematocrit transcutaneously, noninvasively and continuously. A finger clip assembly includes including at least a pair of emitters and a photodiode in appropriate alignment to enable operation in either a transmissive mode or a reflectance mode. At least one predetermined wavelength of light is passed onto or through body tissues such as a finger, earlobe, or scalp, etc. and attenuation of light at that wavelength is detected. Likewise, the change in blood flow is determined by various techniques including optical, pressure, piezo and strain gage methods. Mathematical manipulation of the detected values compensates for the effects of body tissue and fluid and determines the hematocrit value. If an additional wavelength of light is used which attenuates light substantially differently by oxyhemoglobin and reduced hemoglobin, then the blood oxygen saturation value, independent of hematocrit may be determined.

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: An in vivo imaging device having an illumination system that creates a virtual source within a tissue region of a subject in a non-invasive manner. The illumination system transforms a maximum amount of illumination energy from a light source into a high contrast illumination pattern. The illumination pattern is projected onto the object plane in a manner that maximizes the depth to which clear images of sub-surface features can be obtained. The high intensity portion of the illumination pattern is directed onto the object plane outside the field of view of an image capturing device that detects the image. In this configuration, scattered light from within the tissue region interacts with the object being imaged. This illumination technique provides for a high contrast image of sub-surface phenomena such as vein structure, blood flow within veins, gland structure, etc.

Abstract: A signal processing method, preferably for extracting a fundamental period from a noisy, low-frequency signal, is disclosed. The signal processing method generally comprises calculating a numerical transform for a number of selected periods by multiplying signal data by discrete points of a sine and a cosine wave of varying period and summing the results. The period of the sine and cosine waves are preferably selected to have a period substantially equivalent to the period of interest when performing the transform.

Abstract: A method for determining physiological characteristics comprising the steps of (a) acquiring a first blood oxygen signal from a subject, the blood oxygen signal having an undesirable artifact signal component; (b) acquiring an additional physiological signal having a heart rate component using an acquisition technique that is different and independent from the first acquiring step; (c) processing the first blood oxygen signal and the physiological signal to provide a first waveform having a reduced level of the artifact signal component therein; (d) processing the first waveform and the physiological signal to provide a reference waveform; and (e) processing the reference waveform and the physiological signal to provide a second blood oxygen saturation signal corresponding to the blood oxygen saturation level of said subject.

Abstract: A switching device is interposed between a conventional physiological information monitor and a plurality of conventional sensors for a particular physiological function. The sensors are located on different parts of the body. Each of the plurality of sensors may be selected through the switching device to give a continuous indication of a particular physiological function in a localized area of the body. The device prevents the loss of information due to interrupted blood flow in a particular part of the body or the failure of a sensor.

Abstract: A method and device for measurement of a level of at least one blood constituent. The device includes a light source and a light detector proximate the surface of an organ. The device also includes a pair of adjustable gain amplifiers and a processor/controller connected within a processing unit. The processing unit operates to separate an AC signal component from a DC signal component. The light source includes at least one light emitting unit. Preferably, the light source alternatingly emits light at two different wavelength ranges and normalizes the AC and DC output signals corresponding with the intensity of the light reflected from the organ and calculates a ratio of the normalized signals for each wavelength range. The device may determine the level of the blood constituent and may also use this level for monitoring and/or to activate an alarm when the level falls outside a predetermined range.

Abstract: In a system for performing imaging measurement of a test object by mounting many optical fibers to the test object, incident positions of the test object on which to illuminate light, detection positions of the test object from which to detect light and measurement positions which are determined from a positional relationship between the incident positions and the detection positions are displayed as graphic elements on a display unit. A state of detection signal level or a change in the state is displayed as a change in color or in pattern of the graphic element. Further, incident optical fibers for illuminating light to the test object and detection optical fibers for detecting light from the test object are mounted to the test object, and light emitting elements are mounted to probes to be mounted to the test object and interlocked with the change of the graphic elements.

Abstract: A positioner, such as an elastic sock, is fitted with an optical probe, preferably designed for pulse oximetry. The sock preferably substantially forms to the shape of a wearer's foot or hand. In addition, the sock preferably comprises at least one positioning portion. According to one embodiment, the positioning portion is configured to receive at least a wearer's great toe, thumb, or finger, such that the sock maintains substantially opposing alignment of an emitter and a detector. Alternatively, the positioner may comprise a toecap, a glove, or a mitten. The positioner may also advantageously be fitted with a timer circuit, preferably providing an alarm at predetermined intervals.

Abstract: A red light and an infrared light which are emitted from a light emitting portion 2 are transmitted through a fingertip 4 of a subject and are converted into electric signals by a light receiving portion 3. The respective signals are separated and amplified and are then sent to a CPU 8. In the CPU 8, the input signals are divided into D.C. components DC1 and DC2 and A.C. components AC1 and AC2, changes &Dgr;A1=(AC/DC) 1 and &Dgr;A2=(AC/DC)2 in an absorbance are calculated, high frequency components thereof are extracted, a mutual ratio &PSgr; is calculated, and a noise removing waveform is calculated based thereon. Based on the noise removing waveform, a pulse wave is detected, a pulse rate is calculated, a display wave form is calculated and an oxygen saturation is calculated. These are displayed through a display unit 11.

Abstract: A respiration monitoring system monitors the state of disorder of the respiratory system of a sleeping patient based on the detection of respiratory body movement without the need of putting sensors directly on the patient's body. The system includes weight sensors that produce weight signals attributable to the patient's respiratory body movement. From weight signals having a frequency band of respiration, a respiratory body movement signal is produced, and the fall of blood oxygen saturation which occurs at obstructive apnea of the sleeping patient is determined based on the variation pattern of the amplitude of respiratory body movement signal. The occurrence and frequency of the fall of blood oxygen saturation are displayed on a display unit.

Abstract: Ultra-small optical probes comprising a single-mode optical fiber and a lens which has substantially the same diameter as the optical fiber. The optical fiber and lens are positioned in a probe housing which is in the form of an insertional medical device such as a guidewire. Connector elements are provided to facilitate the attachment of the probe to an optical system and the quick disconnection of the probe from the optical system. The probe is used to obtain optical measurements in situ in the body of an organism and can be used to guide interventional procedures by a surgeon.

Abstract: The present invention provides a frequency domain near infrared oximeter (fdNIRS) instrument and associated method of determining the oxygenation level of tissue. The tissue is irradiated by a near infrared light source whereby the incident light passing through the tissue is detected by a light detector. Specifically, light signals of a single frequency at at least three separate wavelengths are provided from the near infrared light source. The near infrared light signals are collected with the light detector and, the phase differences between the collected near infrared light signals and a reference near infrared light signal are determined. The fdNIRS oximeter utilizes frequency domain technology to monitor phase shifts relative to a reference signal to derive SO2 through photon transport and Beer-Lambert equations.

Abstract: A method of improving the accuracy and reproducibility of non-invasive measurements of a concentration of a constituent of interest carried in a body part has been developed. The method relies on elevating the body part during the measurement cycle so that the body part is maintained above the heart during the measurement cycle. Measurements of the constituent during an arterial pulse leads to improved intra-run and run-to-tun determinations.