Abstract: There is described a device for the non-invasive measurement of one or more analytes in blood in a patient's body part which comprises a light transmitter comprising a plurality of transmitting fibres positioned to transmit light to the body part and a light detector comprising a plurality of light detector fibres position to detect light transmitted through or reflected from the body part. The device especially utilises the non-pulsatile element of a patient's blood. There is also described a method of measuring blood glucose levels and a device programmed so as to calculate one or more of the haemoglobin index, the oxygen index and the blood oxygen saturation.

Abstract: The present invention provides a method for monitoring degradation of Hb-based blood substitutes, in a sample. This method involves determining a concentration of met-Hb within the sample, by applying a calibration algorithm for met-Hb to an absorbance obtained from the sample at one or more than one wavelengths, and using the concentration of met-Hb, as a measurement of degradation of the Hb-based blood substitutes. Using this assay, a concentration of met-Hb that is equal to or greater than 3% may be used as an indicator of degradation of Hb. Alternatively, by obtaining samples over a period of time, the concentration of met-Hb and the concentration of Hb-based blood substitute may be determined in each of these samples, and an increase in the concentration of met-Hb over the period of time is an indicator of degradation of Hb.

Abstract: The invention relates to the calibration of a pulse oximeter intended for non-invasively determining the amount of at least two light-absorbing substances in the blood of a subject. In order to bring about a solution by means of which the effects caused by the tissue of the subject can be taken into account in connection with the calibration of a pulse oximeter, initial characterization measurements are carried out for a pulse oximeter calibrated under nominal conditions. Based on the characterization measurements, nominal characteristics are established describing the conditions under which nominal calibration has been defined, and reference data indicating the nominal characteristics are stored. In-vivo measurements are then performed on living tissue and based on the in-vivo measurements and the reference data stored, tissue-induced changes in the nominal characteristics are determined.

Abstract: The invention relates to an apparatus for noninvasive determination of the oxygen turnover and data derived therefrom with an optical sensor (S) to be placed on the tissue with one or more light sources (W, L) which send light through the optical fibers to the sensor (S), one or more detectors (DD, DR) which receive light backscattered by the tissue through optical fibers, and an evaluation unit.

Abstract: The present invention generally relates to an apparatus and method for obtaining absolute values of concentrations of chromophores of a medium and/or absolute values of their ratios. More particularly, the present invention relates to non-invasive optical systems and methods for determining absolute values of oxygenated and/or deoxygenated hemoglobins and their ratios in a physiological medium. The optical system typically includes (1) a body, (2) a source module supported by the body, optically coupling with the medium, and irradiating into the medium multiple sets of electromagnetic waves with different wave characteristics, (3) a detector module supported by the body, optically coupling with the medium, and detecting such electromagnetic waves, and (4) a processing module operatively coupling with the detector module, and determining the absolute values of the concentrations and the ratios thereof from multiple wave equations applied to the source and detector modules.

Abstract: An injection device for use with tissue of a mammalian body comprising a first tubular member and a second tubular member slidably disposed in the first tubular member. The first and second tubular members have respective proximal and distal extremities. The distal extremity of the second tubular member is provided with a needle that is extendable from the distal extremity of the first tubular member. The proximal extremity of the second tubular member is lockable relative to the proximal extremity of the first tubular member. The second tubular member has a column strength when locked within the first tubular member for limiting retraction of the second tubular member relative to the first tubular member during puncture of the tissue by the needle.

Abstract: There is provided a method and a system for determining the concentration of chromophores and reconstructing images in turbid media, such as animal tissues, using a continuous wave optical approach. In particular the approach is based on measurements of attenuation signals and the calculation of concentrations of chromophores using a predetermined scatter law. The system comprises a continuous wave photon migration model calculator coupled to an optical source and detector for estimating concentrations of chromophores and scatter parameters used in image reconstruction.

Abstract: A method of determining the autoregulatory status of a subject by obtaining a measurement of a selected parameter of the retinal blood vessels in a non-stimulated subject, administering to the subject a preselected stimulus, obtaining a measurement of the selected parameter of the retinal blood vessels of the subject in response to the administration of the selected stimulus, and determining the ratio of the measurement for the selected parameter in the non-stimulated retinal blood vessels to the measurement of the selected parameter for the retinal blood vessels following the administration of its selected stimulus whereby the ratio provides an indicator of the autoregulatory function or status of the subject.

Abstract: The present invention relates to a method for non-invasive local quantification of angiogenesis or destruction of existing blood vessels in living tissue, the use of the said method for local measurements of hemoglobin concentration and blood perfusion at the same location on the subject and an apparatus for carrying out the method according to the invention. The apparatus comprises a xenon flash unit, an optical filter and a Y-shaped optical fiber-bundle, one branch of the fiber-bundle being coupled to the flash unit and the other branch of the fiber-bundle being coupled to a detection unit and the merged part of the fiber-bundle being adapted to couple the apparatus to the tissue to be tested.

Abstract: The present invention relates to a method for detecting blood characteristics including hemoglobin in a fluid medium using both transmission and reflection of a light beam which forms a quotient.

Abstract: The present invention generally relates to an apparatus and method for obtaining absolute values of concentrations of chromophores of a medium and/or absolute values of their ratios. More particularly, the present invention relates to non-invasive optical systems and methods for determining absolute values of oxygenated and/or deoxygenated hemoglobins and their ratios in a physiological medium. The optical system typically includes (1) a body, (2) a source module supported by the body, optically coupling with the medium, and irradiating into the medium multiple sets of electromagnetic waves with different wave characteristics, (3) a detector module supported by the body, optically coupling with the medium, and detecting such electromagnetic waves, and (4) a processing module operatively coupling with the detector module, and determining the absolute values of the concentrations and the ratios thereof from multiple wave equations applied to the source and detector modules.

Abstract: A spectrophotometric method and apparatus for determining the degree of oxygen saturation of the hemoglobin in the blood within a body part utilizes differences in light absorption based on differences in extinction coefficients at different wavelengths. Oxygen saturation is determined by utilizing absorption at three or more wavelengths of radiation preferably in the near red and infrared region (NIR) of the spectrum, specifically tailored to two or more components to be detected by the radiation. The first (reference) wavelength is preferably chosen to be at an isosbestic point for the two components, commonly the oxygenated and deoxygenated forms of hemoglobin. The absorption at the isosbestic point is subtracted from the absorption at the other wavelengths. Using these differences in absorption, the amount of each of the components encountered by the light may be determined without determination of pathlength, which would be required to determine the concentration.

Abstract: The present invention generally relates to apparatus and methods for obtaining absolute values of concentrations of chromophores of a medium and/or absolute values of their ratios. In particular, the present invention relates to continuous wave spectroscopic optical systems and methods for determining the absolute values of deoxygenated and/or oxygenated hemoglobins and their ratios in a physiological medium. The optical system typically includes (1) a source module optically coupling with the medium and irradiating into the medium multiple sets of electromagnetic waves with different wave characteristics, (2) a detector module optically coupling with the medium and detecting electromagnetic waves, and (3) a processing module operatively coupling with the detector module, and determining the absolute values of the concentrations and the ratios thereof from multiple wave equations applied to the source and detector modules.

Abstract: A system for assessing organ function couples light emitters into an optical fiber delivery assembly of which the tip extends to or into an internal organ and illuminates tissue; the device senses temperature at the tip, and a collection fiber collects light scattered, reflected or emitted by the surrounding tissue. Control and processing modules drive the laser diodes and process return spectral signals, e.g., to assess metabolic activity and detect onset of shock. A prototype uses four laser diodes with peaks at 735, 760, 805 and 890 nm, with a front end splitter providing a reference beam to a photo detector for normalizing detection output and correcting the signal samples. The device may include a plurality of laser diodes and may select subsets of the sources to tailor spectral illumination to different target enzymes, metabolites or other compounds.

Abstract: A method and apparatus for noninvasively monitoring hemoglobin concentration and oxygen saturation, wherein the method includes selecting at least two wavelengths from a region of wavelengths in which an extinction coefficient for water is smaller that for hemoglobin, the at least two wavelengths including at least two isobestic wavelengths; sequentially radiating incident light beams having the selected wavelengths onto a predetermined site of a body which includes a blood vessel; receiving, at another site of the body, light beams sequentially transmitted through the predetermined site and converting the received light beams into electrical signals; calculating the light attenuation variation caused by pulses of blood for the respective wavelengths from the electrical signals; obtaining at least one ratio of the light attenuation variation between the selected wavelengths; and calculating the hemoglobin concentration CHb in blood using the calculated at least one ratio of the light attenuation variation bet

Abstract: An apparatus for measuring an oxygen saturation of a living subject, including a light source which emits, toward a tissue of the subject, a first light having a first wavelength whose absorption coefficient with respect to hemoglobin changes depending upon oxygen saturation, and a second light having a second wavelength whose absorption coefficient with respect to hemoglobin does not change depending upon oxygen saturation, a light sensor which detects a secondary light resulting from the first light, and a secondary light resulting from the second light, and produces a first light signal representing the detected secondary light of the first light, and a second light signal representing the detected secondary light of the second light, and an oxygen-saturation determining device for determining the oxygen saturation of the subject, based on a ratio of a magnitude of one of the first and second light signals to a magnitude of the other of the first and second light signals, according to a predetermined linea

Abstract: One preferred embodiment utilizes differential measurement of radiation that migrated in two migration paths between two source (100) detector (110) pairs placed on the head in a manner that each path is localized in a portion of one hemisphere. The present invention also provides in various embodiments of spectrophotometer systems for in vivo examination of a tissue of a human by measuring changes in electromagnetic radiation scattered and absorbed in a migration path in the tissue.

Abstract: A method for operating a spectrophotometric instrument of the type for measuring the oxygenation state of hemoglobin in tissue. The method includes the use of stored hemoglobin concentration relationship data characterizing the relationship between second derivative absorbance values at a hemoglobin-absorbing wavelength and hemoglobin concentration in a tissue as a function of hemoglobin oxygenation state. Data representative of a second derivative absorbance value of tissue being analyzed is received. The hemoglobin oxygenation state of the tissue is determined as a function of the second derivative absorbance value. The hemoglobin concentration in the tissue is then determined as a function of the hemoglobin concentration relationship data, the second derivative absorbance value and the hemoglobin oxygenation state. The accuracy of the hemoglobin oxygenation state can be determined as a function of the hemoglobin concentration value.

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: Constituents such as oxy- and deoxy-hemoglobin are monitored non-invasively in an animal organ such as a brain with a spectrometric instrument by passing radiation through the organ. Concentrations are computed from the spectral intensities and from a statistical correlation model. To predetermine the correlation model, the procedures are effected for a plurality of organs of a same type with each organ having established concentrations of the selected constituents, and the correlation model is statistically determined from the concentrations and corresponding intensities. For more accuracy computations are normalized to path length which may be determined by utilizing several discrete wavelengths with RF modulations.

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.

Abstract: A system for assessing organ function has a plurality of light emitters of distinct spectral characteristics are coupled into a percutaneous fiber delivery assembly with a tip extending to or into an internal organ to illuminate organ tissue. The assembly includes a delivery optical fiber, and a collection fiber that collects and returns light scattered, reflected or emitted by the surrounding tissue to a detector at the proximal end. The device also senses temperature at the tip. Control and processing modules drive the laser diodes and process the return signals. The instrument may assess general metabolic activity by detecting light absorption of a linked substance, for example at a peak attributed to deoxygenated hemoglobin and/or at one or more peaks attributed to oxygenated hemoglobin. Preferably, change of a parameter such as pulse oxygen saturation together with one or more other parameters such as temperature are detected to provide an indication of organ function, e.g., the onset of shock.

Abstract: An optical system for in vivo, non-invasive imaging of tissue change includes an optical module with an array of input ports and detection ports located in a selected geometrical pattern to provide a multiplicity of arrayed single source, single detector pairs engaged directly with the subject; a spectrophotometer including a light source constructed to introduce electromagnetic radiation of visible or infra-red wavelength into the examined tissue successively at the input ports, the wavelength being sensitive to a constituent of the imaged tissue; a detector constructed to detect, at the detection ports, radiation of the selected wavelength that has migrated in the tissue from respective input ports; and a processor receiving signals of the detected radiation from the detector, and constructed and arranged to create a defined spatial image of the tissue by effectively producing from signals from the multiplicity of arrayed single source, single detector pairs, a succession of data sets representing, from a s

Abstract: Noninvasive, in-vivo, methods and system for determining a person's relative individual percentages of a plurality of hemoglobin species and for determining a person's total hemoglobin concentration, as well as, the concentration of the hemoglobin species which contribute to this total concentration, i.e., oxy-, deoxy-, carboxy-, met- and suf- hemoglobin are described. In a first embodiment, analyte wavelengths are selected in the visible region from 510 nm to 620 nm, with separate analyte wavelengths for each hemoglobin species to determine relative individual percentages. The measurements are then combined in a series of simultaneous equations which are then solved for the concentration of each species and the total concentration of hemoglobin.

Abstract: A system for determining the hematocrit transcutaneously and noninvasively. Disclosed are a finger clip assembly and an earlobe clip assembly, each 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 two, and preferably three, predetermined wavelengths of light are passed onto or through body tissues such as the finger, earlobe, or scalp, etc. and the extinction of each wavelength is detected. Mathematical manipulation of the detected values compensates for the effects of body tissue and fluid and determines the hematocrit value. If a fourth wavelength of light is used which is extinguished substantially differently by oxyhemoglobin and reduced hemoglobin and which is not substantially extinguished by plasma, then the blood oxygen saturation value, independent of hematocrit, may be determined.

Abstract: Blood perfusion in tissue is imaged using a beam from a monochromatic laser light source that is scanned over the tissue surface in a predetermined pattern at a substantially constant speed. Light scattered from the tissue surface is collected. The position of the beam can be determined and recorded at any point of the scan, and the beam can be halted at a predetermined position or positions during the scan. Two or more photodetectors are positioned to collect light diffusely scattered from the tissue surface such that specularly reflected light is detected by either no detector or by only one detector at a given time. Electrical signals from the photodetectors are processed, and saturation of a photodetector is registered. The saturated photodetector is eliminated from the signal processing to ensure that only unsaturated photodetector signals are processed. The blood perfusion measurements are recorded and displayed.

Abstract: The invention relates to a procedure for determining the relative concentration or composition of different kinds of haemoglobin, such as oxyhaemoglobin, deoxyhaemoglobin and dyshaemoglobins, and/or dye components contained in blood in a non-invasive manner using the light absorption caused by different haemoglobin varieties and/or dye components, in which procedure light signals are transmitted at at least two predetermined wavelengths to a tissue comprised in the patient's blood circulation, the light signal transmitted through the target under measurement and/or reflected from it is received and the proportion of the intensity of the pulsating light signal received at each wavelength is determined in relation to the total intensity of the light transmitted through the tissue or reflected from the tissue.

Abstract: A non-invasive blood component analyzer using spectrophotometry, with systole/diastole corrections for tissue absorbance, and with built-in monitoring of light path length to allow its accurate use in subjects with widely varying finger size and/or varying pulse amplitude. Blood components that are able to be analyzed include oxy-hemoglobin, total hemoglobin, bilirubin, glucose, hormone levels and a variety of drugs.

Abstract: Disclosed is an improvement to the method of determining the concentration of a hemoglobin adduct in a blood sample by the steps of assaying the blood sample for the total amount of hemoglobin, assaying the blood sample for the hemoglobin adduct, and dividing the hemoglobin adduct concentration by the total hemoglobin concentration. The improvement involves normalizing the measurement of the hemoglobin adduct to the total amount of hemoglobin in the blood sample.

Abstract: An optical system for in vivo, non-invasive imaging of tissue change including an optical module, a spectrophotometer, and a processor. The optical module includes an array of input ports and detection ports located in a selected geometrical pattern to provide a multiplicity of arrayed source-detector pairs engaged directly with the subject. The spectrophotometer includes at least one light source constructed to introduce electromagnetic radiation of visible or infra-red wavelength into the examined tissue successively at the input ports, wherein the wavelength is sensitive to a constituent of the imaged tissue, and at least one detector constructed to detect, at the detection ports, radiation of the selected wavelength that has migrated in the tissue from respective input ports.

Abstract: In accordance with the present invention, a transmittance pulse oximeter sensor having an emitter that is offset from the detector. Offsetting the emitter and detector allows more light to pass through a thin tissue pulsating arterial bed than does a vertically aligned design. The offset between the emitter and the detector increases the effective arterial blood component without increasing artifact. Thus, the arterial blood component strength relative to the artifact strength is increased resulting in an improved signal and an improved pulse oximetry reading. The offset pulse oximetry sensor is especially important in veterinary pulse oximeter applications where it is necessary to monitor small animals whose optimal pulse oximetry location is a thin tissue tongue. The offset pulse oximetry sensor is additionally important in the realm of human medicine where often the optimal position for a pulse oximeter sensor is a thin tissue ear or an infant's thin tissue finger or toe.

Abstract: One preferred embodiment utilizes differential measurement of radiation that migrated in two migration paths between two source (100) detector (110) pairs placed on the head in a manner that each path is localized in a portion of one hemisphere. The present invention also provides in various embodiments of spectrophotometer systems for in vivo examination of a tissue of a human by measuring changes in electromagnetic radiation scattered and absorbed in a migration path in the tissue. Generally, the spectrophotometer systems comprise a light source for introducing the radiation into the tissue, a detector for detecting radiation that has migrated in the tissue, processing means for processing signals of the detected radiation to create processed data, and evaluation means for determining physiological or pathophysiological changes in the tissue of interest.

Abstract: A retractor for placement proximate an incision for holding back the edges of the incision, the retractor comprising a pair of substantially elongate retractor portions having outer substantially irregular edges formed along substantially the entire length thereof for engaging and holding back the opposing edges of an incision, and an expansion assembly coupled to the retractor portions for moving the retractor portions between a collapsed position and an expanded position.