Abstract: An embodiment of is cooling pack 110 having at least two components that cause an endothermic reaction when mixed together. At least one of the at least two components being in liquid form 410 and contained in, or separated from, the other at least one component 430 by a frangible membrane 150. The at least two components (410, 430) contained within a vacuum sealed common envelope 120. Other embodiments are described and shown.

Abstract: An embodiment of a light homogenizing apparatus having one or more emitters (110, 120) incident on a light mixing element. The emitters including at least one laser light source. The light mixing element comprising a diffuser (130) followed by an internally reflective light guide (160). This apparatus substantially homogenizes light from all emitters (110, 120) before light exits the internally reflective light guide (160) where it could then be incident on living tissue for use in photoplethysmographic measurement. Other embodiments are described and shown.

Abstract: A method and apparatus for photoplethysmographic measurements from non-human species is disclosed. The extinction of light by hemoglobin, as a function of wavelength, varies as a function of the species of the subject being monitored. The calibration of a photoplethysmographic device should therefore also vary dependant upon the species of the subject. The photoplethysmographic device of this invention includes calibrations specifically designed to provide accurate readings on non-human subjects.

Abstract: A photoplethysmographic measurement system includes an electrical lockout to effectively prevent users, such as patients and medical personnel, from being exposed to high levels of light energy illuminating from light emitters (18) housed within a main instrument (10) when a probe (12) becomes detached from the system during use. The probe (12) is provided with a resistor having a range of resistor values. In use, the electrical lockout frequently or continuously interrogates the probe connection and determines whether the detected value of the resistor falls within predetermined allowable levels. If the probe (12) inadvertently becomes disconnected from the main instrument, the value of the resistor will fall outside of the predetermined allowable levels indicative of an incompatible probe, an improper coupling of the probe, or a complete detachment of the probe. In this case, lockout switch (44) is employed to inhibit activation of the light emitters (18).

Abstract: The present invention is directed to a method and system for use in assessing collateral blood flow to a tissue region of interest (ROI). The method includes the steps of obtaining a first pulsatility measurement and a second pulsatility measurement, wherein one of the pulsatility measurements is obtained with a plurality of arteries supplying blood to the tissue ROI and the other pulsatility measurement is obtained with at least a selected one of such arteries substantially occluded. The method further provides for use of the first and second pulsatility measurements to generate a collateral flow value useful to medical personnel as an objective measure in assessing collateral blood flow to a tissue ROI. The method may further include the step of obtaining a check pulsatility measurement after obtaining a first pulsatility measurement and prior to obtaining a second pulsatility measurement, wherein all of the plurality of the arteries are substantially occluded.

Abstract: The present invention is directed to a method and system for use in assessing collateral blood flow to a tissue region of interest (ROI). The method includes the steps of obtaining a first pulsatility measurement and a second pulsatility measurement, wherein one of the pulsatility measurements is obtained with a plurality of arteries supplying blood to the tissue ROI and the other pulsatility measurement is obtained with at least a selected one of such arteries substantially occluded. The method further provides for use of the first and second pulsatility measurements to generate a collateral flow value useful to medical personnel as an objective measure in assessing collateral blood flow to a tissue ROI. The method may further include the step of obtaining a check pulsatility measurement after obtaining a first pulsatility measurement and prior to obtaining a second pulsatility measurement, wherein all of the plurality of the arteries are substantially occluded.

Abstract: A system is provided for improving photoplethysmographic analyte measurements by de-emphasizing motion-contaminated data and/or emphasizing motion-free data. The system 100 is used in a measurement instrument which includes at least illumination source 104 for transmitting at least two light signals at two center wavelengths through a patient's appendage 106 and a sensor 108 for converting the light signals transmitted through the appendage into electrical output signals. The system 100 includes a first buffer 116 configured to temporarily store at least one pulse cycle of output signals received from the sensor 108. A motion estimator 122 quantifies an amount of motion associated with the output signals stored in the first buffer 116 by performing a principal component analysis on differential absorption values derived from the output signals. Based on the amount of motion estimated, a weight application module 118 is configured to associate a weight with the output signals in the first buffer.

Abstract: A medical monitoring instrument such as a pulse oximeter uses vertical cavity surface emitting laser diodes (VCSELs) to produce at least two high intensity, essentially monochromatic light beams. The VCSELs are located either in: (1) the probe itself, (2) the connector to the probe, or (3) the monitor box connected with an optical fiber to the probe.

Abstract: An improved method and apparatus for the photoplethysmographic monitoring of blood analyte parameters, specifically oxyhemoglobin, deoxyhemoglobin (reduced hemoglobin), carboxyhemoglobin and, in addition, in a four emitter apparatus, methemoglobin, uses a plurality of beams of light having different spectral contents to trans-illuminate the tissue of a patient. The apparatus and method require the application of an emitter set comprised of four emitters. The emitters may be LED's or laser diodes. In the three analyte system the center wavelength of the emitters must fall within three specific bands. In the four emitter system (capable of measuring methemoglobin) the center wavelength of the emitters in the emitter set must fall within four predetermined bands and the emitters having the two lowest center wavelengths must be at least 5 nanometers apart.

Abstract: A two-stage statistical calibration and measurement method and system is disclosed for performing photoplethysmographic measurement of blood analyte concentrations. Concentrations in a tissue sample of MetHb, O.sub.2 Hb, RHb and COHb are estimated by first estimating a concentration of MetHb (in a first stage) and subsequently, if the concentration of MetHb is within a predetermined range, then the estimated concentration of MetHb is assumed to be accurate and this estimated concentration of MetHb is utilized as a "known value" in determining the concentrations of the remaining analytes O.sub.2 Hb, RHb and COHb (in a second stage). That is, by eliminating one "unknown" from the system of equations, these remaining analytes can be calculated with increased accuracy. Each stage is performed using data obtained by transmitting light through the tissue sample (typically a finger or earlobe). The transmitted light is generated by four discrete light emitters, each emitter having a distinct spectral content.

Abstract: A photoplethysmographic measurement device that utilizes wavelength division multiplexing is provided. Signals from multiple light emitters are combined into a single multiplexed light signal in a test unit before being delivered to a physically separated probe head attached to a test subject. The probe then causes the single multiplexed signal to be transmitted through a tissue under test on the test subject, after which it is processed to determine a blood analyte level of the test subject. By combining the light signals into a single multiplexed signal before delivering the signals to the probe, a single light guide, such as a single optical fiber, can be used to deliver the signals to the probe, thereby reducing system implementation cost and increasing the flexibility of the probe cable. In addition, the invention allows the signals from the light emitters to be directed into the test subject from a single point source, which can significantly increase measurement accuracy.

Abstract: The integrated multimode optical coupling apparatus comprises an N-to-M optical coupling arrangement that is simple to manufacture, minimizes optical losses and is significantly less expensive than the prior art arrangements of coupling optical signals. The preferred embodiment of the apparatus of the present invention comprises a substrate into which is formed a plurality of optical channels, each of which is joined at one end into a single output optical channel. This integrated optical coupler is formed by diffusing silver ions or other equivalent ions into the glass substrate in these defined areas to form channels of high optical refractive index in the body of the substrate. At one end of each of the optical channels that are formed in the substrate, the plurality of the optical channels are joined together in a volumetric region of the substrate wherein the individual channels merge into one unified common structure.

Abstract: An improved method and apparatus for the monitoring perfusion of the tissue of a patient by arterial blood is provided. An optical path length change is calculated for a number of digitized samples of a received light intensity signal generated by a photo detector that receives light directed into a patient's tissue by one or more light emitting diodes or laser diodes. The optical path length changes are summed over a predetermined time such as one half cardiac cycle or other set interval to generate a perfusion index. An average perfusion index value may also be generated. In calculating the perfusion index spectral content compensation may be employed to compensate for the variety of center wavelengths associated with the spectral contents of various emitters.

Abstract: The improved pulse oximeter preprocesses the sets of red and infrared signals received from the probe. The set of pairs of processed red and infrared data points are fitted to a linear equation to compute the slope of the best fit line through these data points and account for noise in both of these sets of data points. A measure of the linearity of the input data points, if less than a predetermined threshold, indicates that a distorted signal has been received from the probe. The computed slope of the best fit line is converted to a RRatio which is used in a empirical calibration formula to compute the average SpO.sub.2 value.

Abstract: The nasal septum probe of the present invention mounts the optical devices of a photoplethysmographic probe in a housing that clips onto the patient's nasal septum. The septum provides an arterial bed for monitoring purposes and this locus is not subject to significant patient motion or peripheral shutdown of arteriolar blood flow. Furthermore, one embodiment of the invention shows a combination of the photoplethysmographic apparatus with a nasal cannula to provide dual purpose apparatus to minimize the sensor and cable proliferation.

Abstract: This arterial blood monitoring system takes advantage of the basic statistical property that arterial blood contains a plurality of dominant absorbers, whose measured light absorption spectra appear as a constant over a short interval of time. By measuring the transmitted light as it varies with arterial pulsation at selected wavelengths of light, over a common light path, the relative amount of these dominant absorbers in the arterial blood can noninvasively be determined. To ensure the common light path, a sandwich construction light detector is used.