Abstract: Embodiments of the present invention relate to a system and method for practicing spectrophotometry using light emitting nanostructures. Specifically, embodiments of the present invention include a physiologic sensor comprising a sensor body configured for placement adjacent pulsatile tissue of a patient, a first light emitting nanostructure device configured to emit light at a first wavelength through the pulsatile tissue, a second light emitting nanostructure device configured to emit light at a second wavelength through the pulsatile tissue, and a light detector configured to detect the light at the first wavelength and the light at the second wavelength after dispersion through the pulsatile tissue.

Abstract: An apparatus for intermittent measurement of blood parameters using spectrophotometry is provided. In exemplary embodiments, blood is temporarily withdrawn from the patient and passed through a cuvette, allowing spectrophotometric analysis. This blood may then immediately returned to the patient in a sterile fashion. The technique allows for real-time analysis of blood at the bedside without delays in transportation and laboratory analysis. In exemplary embodiments, there is no blood loss, so measurements can be repeated frequently with no detriment to the patient. In exemplary embodiments, the spectrophotometer is detachable from the cuvette and does not come in contact with blood, such that it can be used for multiple patients with minimal cost. The apparatus may be used to measure the oxygen saturation of blood and hemoglobin concentration, although it could be easily adapted to measure these and many other parameters simultaneously.

Abstract: A system and method for detecting vascular contamination by surgical anesthetic using non-invasive IR spectrophotometry. One embodiment is a method for operating an instrument such as an enhanced pulse oximeter to monitor a patient receiving local anesthetic marked with dye that absorbs infrared light. Light is applied to and detected from tissue of the patient. A signal representative of the detected light is processed to derive patient oxygenation information. The detected light is also processed to derive information representative of the presence of the dye-marked anesthetic. The oxygenation information and the information representative of the presence of anesthetic are displayed. The oxygenation monitoring and display and the anesthetic monitoring and display can occur separately or concurrently. Fluorescing dyes and fluorescence detection approaches are used for anesthetic detection in some embodiments.

Abstract: Devices and methods for measuring body fluid-related metric using spectrophotometry that may be used to facilitate diagnosis and therapeutic interventions aimed at restoring body fluid balance. In one embodiment, the present invention provides a device for measuring a body-tissue water content metric as a fraction of the fat-free tissue content of a patient using optical spectrophotometry. The device includes a probe housing configured to be placed near a tissue location which is being monitored; light emission optics connected to the housing and configured to direct radiation at the tissue location; light detection optics connected to the housing and configured to receive radiation from the tissue location; and a processing device configured to process radiation from the light emission optics and the light detection optics to compute the metric where the metric includes a ratio of the water content of a portion of patient's tissue in relation to the lean or fat-free content of a portion of patient's 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: A sensor for pulse oximetry or other applications utilizing spectrophotometry may be adapted to reduce motion artifacts by fixing the optical distance between an emitter and detector. A flexible sensor is provided with a stiffening member to hold the emitter and detector of the sensor in a relatively fixed position when applied to a patient. Further, an annular or partially annular sensor is adapted to hold an emitter and detector of the sensor in a relatively fixed position when applied to a patient. A clip-style sensor is provided with a spacer that controls the distance between the emitter and detector.

Abstract: The present disclosure relates to a method for estimating blood constituent concentration of a user under low perfusion conditions using a spectrophotometry-based monitoring device; the method comprising: measuring a plurality of photoplethysmographic (PPG) signals; measuring a cardio-synchronous (CV) signal; detecting an instantaneous heart rate and determining a heart rate variability from the CV signal; selecting reliable projected PPG signals; estimating a value of said blood constituent concentration from the magnitude of said reliable projected PPG signals. The disclosed method requires diminished computational load compared to conventional methods based on frequency domain approach as FFT or DCT. The disclosure also pertains to a monitoring device for estimating blood constituent concentration in tissue under low perfusion of a user.

Abstract: Methods and apparatus using the principles of time-resolved spectroscopy are disclosed. The present invention employs incident light pulses of sufficiently short duration to permit the rate of the rise and decay of such pulses to be measured. Consequently, the rate of decay, u, permits a determination of the concentration of an absorptive pigment, such as hemoglobin. The present invention also allows the precise path length the photons travel to be determined. Using this path length information and by measuring changes in optical density using known continuous light (CW) spectrophotometry systems, the methods and apparatus disclosed allow changes in the concentration of an absorptive pigment to be correctly be measured. From these data, the oxygenation state of a tissue region, such as the brain, can be accurately determined in real time.

Abstract: Methods and apparatus using the principles of time-resolved spectroscopy are disclosed. The present invention employs incident light pulses of sufficiently short duration to permit the rate of the rise and decay of such pulses to be measured. Consequently, the rate of decay, u, permits a determination of the concentration of an absorptive pigment, such as hemoglobin. The present invention also allows the precise path length the photons travel to be determined. Using this path length information and by measuring changes in optical density using known continuous light (CW) spectrophotometry systems, the methods and apparatus disclosed allow changes in the concentration of an absorptive pigment to be correctly be measured. From these data, the oxygenation state of a tissue region, such as the brain, can be accurately determined in real time.

Abstract: The method and the device according to the invention are used for the non-invasive measurement of concentrations of blood components. At least one light source generates light using spectrophotometry and the light is guided to at least one photodetector through a tissue present at the location of application and supplied with pulsating blood. At least the measuring signal of the photodetector is guided to an evaluation unit. The light signals of a first, second, third to (n+1)st wavelength are generated at subsequent pairwise times T1 and T2, T3 and T4 and T5 and T6 to Tn and Tn+1. The evaluation unit takes into consideration the received signals of the photodetector for all wavelengths according to a defined arithmetic pattern and determines a concentration of the blood component. The inventive device comprises at least three light sources that generate light of different wavelength in relation to each other.

Abstract: A device and a method for measuring body fluid-related metrics using spectrophotometry to facilitate therapeutic interventions aimed at restoring body fluid balance. The specific body fluid-related metrics include the absolute volume fraction of water in the extravascular and intravascular tissue compartments, as well as the shifts of water between these two compartments. The absolute volume fraction of water is determined using algorithms where received radiation measured at two or more wavelengths are combined to form either a single ratio, a sum of ratios or ratio of ratios of the form log[R(?1)/R(?2)] in which the received radiation in the numerator depends primarily on the absorbance of water and the received radiation in the denominator depends primarily on the absorbance of water and the sum of the absorbances of non-heme proteins, lipids and water in tissue.