Abstract: An automatic skin perfusion measuring device automatically analyzes perfusion measurements to identify motion artifact and SPP values. Motion artifact is ignored. Perfusion measurements are designated as SPP values if various criteria are met. SPP value criteria pertain to factors including cuff pressure, perfusion, perfusion change percentages relative to previous and subsequent perfusion measurements, and whether perfusion measurements are increasing or decreasing relative to previous and subsequent perfusion measurements.

Abstract: The invention provides a device for contacting a surface of a patient's body to determine a physiologic parameter in a measurement region of a tissue of the patient. The device typically comprises a sensor responsive to the physiologic parameter and a probe housing the sensor. The probe is constructed to allow the sensor to be secured at a sensing site adjacent to the measurement region, without disturbing the blood flow within the measurement region of the tissue. The device may also include a means for reducing interference in the sensing area. Preferably, the device further comprises an indicating means operably connected to the sensor for indicating an analyte quantity and/or concentration associated with the physiologic parameter.

Abstract: There is a need for a non-invasive method of calibrating medical devices at the point of care, where the calibration is performed without the removal of blood or bodily fluids. The invention is directed to an approach for calibrating a first non-invasive sensor in which the tissue being measured is modulated in some way so as to after the value of the parameter being measured by the first optical sensor. A second sensor detects another parameter that also changes with the modulation. The second sensor is absolutely calibrated. Where there is a known relationship between the first and second parameters, a calibration may be derived for the first sensor. Such a technique is applicable to calibrating non-invasive sensors for monitoring a wide variety of physiologic parameters including, inter alia, glucose, blood gases, blood electrolytes and blood pH.

Abstract: There is a need for a technique to compensate for, or eliminate, motion-induced artifacts in patient-attached critical care monitoring instruments. Also, a need exists to extend the accurate operational range of patient-attached pulse oximeters in environments when the patient's blood oxygen saturation is well below the normal physiologic range, or where there is low blood flow. Accordingly, the invention is directed to improving pulse-oximetry by incorporating additional signals to aid in the triggering of the pulse-oximeter or in analyzing the data received by the pulse oximeter. These approaches include measuring a pulsatile characteristic of the patient at a position close to, or at the pulse-oximetry measurement site, or using pulsatile characteristics that result from contraction of the patient's heart.

Abstract: There is a need for a technique to compensate for, or eliminate, motion-induced artifacts in patient-attached critical care monitoring instruments. Consequently, the invention is directed to improving pulse-oximetry by incorporating additional signals to aid in the triggering of the pulse-oximeter or in analyzing the data received by the pulse oximeter. This includes detecting when the patient moves and analyzing the pulse-oximetry data in light of the detected movement.

Abstract: There is a need for a technique to compensate for, or eliminate, motion-induced artifacts in patient-attached critical care monitoring instruments. Also, a need exists to extend the accurate operational range of patient-attached pulse oximeters in environments when the patient's blood oxygen saturation is well below the normal physiologic range, or where there is low blood flow. Accordingly, the invention is directed to improving pulse-oximetry by incorporating additional signals to aid in the triggering of the pulse-oximeter or in analyzing the data received by the pulse oximeter. These approaches include measuring a pulsatile characteristic of the patient at a position close to, or at the pulse-oximetry measurement site, or using pulsatile characteristics that result from contraction of the patient's heart.

Abstract: The invention relates to a cartridge for packaging an analyte-containing fluid calibrant. The cartridge is formed from a container having an opening sealed by a sealing member. A septum divides the container into a calibrant compartment and an outer compartment. A probe is provided comprising an analyte-detecting portion and a connecting portion that allows for operative connection to a device for quantitating or determining the concentration of the analyte. The probe may extend sealingly through the septum such that the analyte-detecting portion is located in the calibrant compartment and the connecting portion is located in the outer compartment. The construction of the cartridge provides ease and reduces the likelihood of error in calibrating the probe. The invention also relates to a method of manufacturing the cartridge and a method for calibrating a device for analyte concentration determination and quantitation using the inventive cartridge.

Abstract: There is a need within the medical community for non-invasive instruments to measure critical physiologic parameters at the point of care. Such a technique may be applicable to a wide variety of commonly monitored physiologic parameters during critical care patient management. The invention is directed to a method of measuring the pH of a patient's tissue. The method includes measuring the optical signal from a specie whose fluorescence is pH sensitive, such as nicotinamide adenine dinucleotide (NADH) and also measuring the optical signal from a second biological marker, such as FAD, the fluorescence from the second marker being substantially insensitive to pH. The method includes determining the patient's pH by using the first and second optical signals.

Abstract: Generally, the present invention relates to a method for non-invasive optical measurements at at physiologic sites that may reduce or minimize the effects of skin chemistries that optically interfere with the desired optical measurement. An embodiment of the invention is directed to a method of making an optically-based, non-invasive optical measurement of a first physiologic parameter of a patient. The method comprises probing the tissue of a first epithelial site with a first probe light propagating from the optical sensor and detecting a first signal light received from the first assay site with the optical sensor. The method also comprises measuring a value of a second parameter of the patient and determining the level of the first physiologic parameter within the tissue of the first assay site based on the detected first signal light and on the measured second parameter of the patient.

Abstract: There is a need for a non-invasive method of calibrating medical devices at the point of care, where the calibration is performed without the removal of blood or bodily fluids. The invention is directed to an approach for calibrating a first non-invasive sensor in which the tissue being measured is modulated in some way so as to after the value of the parameter being measured by the first optical sensor. A second sensor detects another parameter that also changes with the modulation. The second sensor is absolutely calibrated. Where there is a known relationship between the first and second parameters, a calibration may be derived for the first sensor. Such a technique is applicable to calibrating non-invasive sensors for monitoring a wide variety of physiologic parameters including, inter alia, glucose, blood gases, blood electrolytes and blood pH.

Abstract: A method for making a optical sensor for measuring the pH of a fluid includes the steps of applying a solution containing (a) a cellulose acrylamide, (b) an acrylamide, and (c) a copolymerizable monomeric fluorescent indicator species to the distal end of an optical fiber and polymerizing the solution to form a pH sensor means.

Abstract: An optical method for obtaining hematocrit values of blood uses the light transmittance properties of blood as a means of acquiring information about the blood sample. An algorithm is used to calculate the hematocrit value based on the absorbance spectra obtained at wavelengths of approximately 500 nm and 800 nm. These absorbance wavelengths are selected for their insensitivity to the oxygen saturation level of hemoglobin. Additionally, the algorithm has demonstrated insensitivity to plasma and other blood constituent scattering effects.

Abstract: Infrared radiation emitted from tissue surface of body cavity is measured by an infrared sensor located within a probe which generates a signal voltage dependent on the difference in temperature between the tissue and the infrared sensor. An additional ambient sensor measures the ambient temperature of the infrared sensor. The signals of the two sensors are added. To calibrate and eliminate errors, the housing of the device is provided with a chamber shaped to receive the probe and containing a target viewed by the infrared sensor. An error signal is thus generated which is added to the signals of the two sensors when they view the body tissue. A disposable, sanitary cover for the probe is made of a truncated polyethylene member of substantially uniform thickness closed by an end window. A filter in the probe suppresses absorption bands of polyethylene to eliminate errors due to minor variations in cover thickness.