Abstract: The invention comprises a method and apparatus for processing signals reflecting a physiological characteristic by performing an error minimizing mathematical combination between signals from at least two independent sensors. For example, the intensity of light is detected following tissue absorption at two wavelengths and the signals are corrected. Preferably, corrected intensity signals are derived by orthogonal regression. In one embodiment, the method and apparatus are used to determine arterial oxygen saturation.

Abstract: An apparatus for analyzing the composition of bodily fluid. The apparatus comprises a fluid handling network including a patient end configured to maintain fluid communication with a bodily fluid in a patient. The apparatus further comprises a pump unit in operative engagement with the fluid handling network. The pump unit has an infusion mode in which the pump unit is operable to deliver infusion fluid to the patient through the patient end, and a sample draw mode in which the pump unit is operable to draw a sample of the bodily fluid from the patient through the patient end. The apparatus further comprises a spectroscopic analyzer configured to obtain spectra from at least a portion of the sample, and a processor in communication with or incorporated into the spectroscopic analyzer.

Abstract: The invention comprises a gastric device having an outer region and a gas producing material. The gastric device hydrates within a patient's stomach and the gas producing material expands the device to a greater volume. Accordingly, the volume of the hydrated, expanded gastric devices occupy space in the stomach cavity and reduce the amount of food the patient will ingest before reaching the feeling of fullness. Preferably, the gastric device is made from food grade materials. The gastric device is configured to expand to a desired volume and then degrade after a residence time, allowing the device to be passed by the patient's normal digestive process.

Abstract: The invention comprises a method and apparatus for processing signals reflecting a physiological characteristic by detecting the intensity of light following tissue absorption at two wavelengths and subtracting the best estimate of the desired signal from the difference between the signals. Corrected first and second intensity signals are determined by applying a residual derived from a combination of the first and second intensity signals as multiplied by a residual factor and subtracted from a difference between the first and second intensity signals to the first and second intensity signals. In one embodiment, the method and apparatus are used to determine arterial oxygen saturation.

Abstract: The invention comprises a gastric device having a pouch formed from a degradable film. Preferably, the pouch contains a gas producing material. The gastric device hydrates within a patient's stomach and the gas producing material expands the device to a greater volume. Accordingly, the volume of the hydrated, expanded gastric devices occupy space in the stomach cavity and reduce the amount of food the patient will ingest before reaching the feeling of fullness. Preferably, the gastric device is made from food grade materials. The gastric device is configured to expand to a desired volume and then degrade after a residence time, allowing the device to be passed by the patient's normal digestive process.

Abstract: In certain embodiments, a method samples a body fluid of a patient. The method includes providing a fluid handling system having one or more fluid passageways. The method further includes infusing an infusion fluid by way of a fluid handling system into a patient through one or more fluid passageways. The method further includes obtaining a sample of body fluid by way of a fluid handling system from a patient through one or more fluid passageways. The obtained sample is no more than 5 milliliters in volume. The method further includes analyzing at least an analyzed portion of the obtained sample by way of an analyte detection system operatively associated with the fluid handling system to determine a concentration of at least one analyte.

Abstract: In certain embodiments, a method of maintaining health of a patient uses an analyte detection system. The analyte detection system is coupled to the patient such that a bodily fluid of the patient is accessible to the analyte detection system. The method includes automatically initiating and conducting a measurement of an analyte in the bodily fluid using the analyte detection system. The method further includes determining a treatment dose for the patient based on the measurement using the analyte detection system.

Abstract: An apparatus is presented for estimating the concentration of an analyte using a combined enzyme-spectroscopic method. Examples are provided for the detection of glucose and lactate. A sample of biological fluid is mixed or contacted with an enzyme specific to the analyte of interest, and the reacting fluid is probed with an optical system at wavelengths that includes at least one wavelength that is sensitive to the analyte concentration and at least one wavelength that is not sensitive to the analyte concentration. The optical system measures properties, such as optical density, and relates the measurements to concentration through a calibration of the system. A method is also provided for analyzing the data obtained from optical measurements of reactions of enzymes with biological fluids. These technologies may be applied to continuous or periodic patient sampling systems or to test strip type devices.

Abstract: A method and apparatus are described that permit an analyte concentration to be estimated from a measurement in the presence of compounds that interfere with the measurement. The method reduces the error in the analyte concentration in the presence of interferents. The method includes the use of a set of measurements obtained for a large population having a range of known analyte and interfering compound concentrations. From a sample measurement, which may or may not be one of the population, likely present interferents are identified, and a calibration vector is calculated.

Abstract: An apparatus for analyzing the composition of bodily fluid. The apparatus comprises a fluid handling network including a patient end configured to maintain fluid communication with a bodily fluid in a patient and at least one pump intermittently operable to draw a sample of bodily fluid from the patient. The apparatus further comprises a fluid analyzer positioned to analyze at least a portion of the sample and measure the presence of two or more analytes. Also disclosed is a method for analyzing the composition of a bodily fluid in a patient. The method comprises drawing a sample of the bodily fluid of the patient through a fluid handling network configured to maintain fluid communication with a bodily fluid in a patient. The method further comprises analyzing the at least a portion of the sample in a fluid analyzer to estimate the concentration of two or more analytes in the sample.

Abstract: A fluid sampling and analysis system. The system comprises a fluid handling network including a patient end configured to maintain fluid communication with a bodily fluid of a patient; a sample analysis chamber accessible by the fluid handling network; and a pump unit in operative engagement with the fluid handling network. The pump unit has an infusion mode in which the pump unit is operable to deliver infusion fluid to the patient through the patient end; a sample draw mode in which the pump unit is operable to draw a sample of bodily fluid from the patient through the patient end, and provide a portion of the sample to the sample analysis chamber; and an optical calibration mode in which the pump unit is operable to supply calibration fluid to the sample analysis chamber.

Abstract: In certain embodiments, a method samples a body fluid of a patient. The method includes providing a fluid handling system having one or more fluid passageways. The method further includes infusing an infusion fluid by way of a fluid handling system into a patient through one or more fluid passageways. The method further includes obtaining a sample of body fluid by way of a fluid handling system from a patient through one or more fluid passageways. The obtained sample is no more than 400 microliters in volume. The method further includes analyzing at least an analyzed portion of the obtained sample by way of an analyte detection system operatively associated with the fluid handling system to determine a concentration of at least one analyte.

Abstract: An apparatus for analyzing the composition of bodily fluid. The apparatus comprises a fluid handling network including a patient end configured to maintain fluid communication with a bodily fluid in a patient; and a pump unit in operative engagement with the fluid handling network. The pump unit has an infusion mode in which the pump unit is operable to deliver infusion fluid to the patient through the patient end, and a sample draw mode in which the pump unit is operable to draw a sample of the bodily fluid from the patient through the patient end. The apparatus further comprises a spectroscopic analyzer positioned to analyze at least a portion of the sample; a processor in communication with or incorporated into the spectroscopic analyzer; and stored program instructions executable by the processor to obtain measurements of two or more properties of the sample.

Abstract: A method determines an analyte concentration in a sample including the analyte and a substance. The method includes providing an absorption spectrum of the sample. The absorption spectrum has an absorption baseline. The method further includes shifting the absorption spectrum so that the absorption baseline approximately equals a selected absorption value in a selected absorption wavelength range. The method further includes subtracting a substance contribution from the absorption spectrum. Thus, the method provides a corrected absorption spectrum substantially free of a contribution from the substance.

Abstract: A system and method are provided for determining a concentration of an analyte in a material sample. The method includes providing a sample element with a sample chamber at least partially defined by at least one window formed from a material having greater than about 1% wavelength-domain variation in absorbtivity of electromagnetic radiation incident thereon. The method further includes employing the sample element with an analyte detection system which determines the concentration of the analyte with clinically acceptable accuracy.

Abstract: A method determines an analyte concentration in a sample. The sample includes the analyte and a substance. The method includes providing absorption data of the sample. The method further includes providing reference absorption data of the substance. The method further includes calculating a substance contribution of the absorption data. The method further includes subtracting the substance contribution from the absorption data, thereby providing corrected absorption data substantially free of a contribution from the substance.

Abstract: An analyte detection system is configured to measure concentrations of at least first and second analytes in a single material sample supported by a sample element. The measurement of a second analyte can be conditioned on a quantitative or qualitative result of the first measurement. In one embodiment, the first analyte is glucose and the second analyte is a ketone. According to such an embodiment the ketone is measured if the result of the glucose measurement exceeds a previously-specified value or falls outside of a previously-specified range.