Critikon, Inc

Optiscan Biomedical Corporation

Square One Technology, Inc.

Optiscan Limited

Roger O Herrera

James Roswell Braig

Daniel S Goldberger

Mark L Yelderman

Bernhard B Sterling

Peter Rule

Philip C Hartstein

Kenneth G Witte

Julian M Cortella

Mark D Agostino

Heidi M Smith

A device and method are provided for use with a noninvasive optical measurement system, such as a thermal gradient spectrometer, for improved determination of analyte concentrations within living tissue. In one embodiment, a wearable window is secured to a patient's forearm thereby isolating a measurement site on the patient's skin for determination of blood glucose levels. The wearable window effectively replaces a window of the spectrometer, and thus forms an interface between the patient's skin and a thermal mass window of the spectrometer. When the spectrometer must be temporarily removed from the patient's skin, such as to allow the patient mobility, the wearable window is left secured to the forearm so as to maintain a consistent measurement site on the skin. When the spectrometer is later reattached to the patient, the wearable window will again form an interface between the spectrometer and the same location of skin as before.

Device for capturing thermal spectra from tissue

A disposable anti-fog airway adapter for use with a mainstream respiratory gas analyzer which provides a measurement of a patient's inhaled and exhaled gases. The airway adapter includes windows that are constructed of a thin, low heat capacity plastic that rapidly equilibrates to the temperature of the warm moist gases in the patient breathing circuit. In addition, the inside of the windows is also coated with an anti-fog surfactant either by laminating an anti-fog film with the window plastic prior to attaching the window to the airway adapter body or by first attaching the window to the airway adapter body and then applying the surfactant to the airway adapter after the window film is bonded in place so that the surfactant coats the entire inside of the adapter. The surfactant functions to increase the critical wetting tension of the surface it covers so that water on the window spreads into a uniform thin layer which does not absorb very much infrared energy and thus does not significantly reduce the signal strength. 'Instant on' operation is accomplished because no heater and the like is necessary to warm up the windows to maintain them at an elevated temperature to prevent fogging. Numerous techniques are also provided for adhering the windows to the airway adapter body so that a substantially airtight seal may be obtained.

Disposable anti-fog airway adapter

A method and apparatus for monitoring glucose, ethyl alcohol and other blood constituents in a noninvasive manner. The measurements are made by monitoring infrared absorption of the desired blood constituent in the long infrared wavelength range where the blood constituent has a strong and distinguishable absorption spectrum. The long wavelength infrared energy emitted by the person as heat is monitored and the infrared absorption of particular constituents in the blood (such as glucose or blood alcohol) is measured at characteristic infrared absorption wavelengths for those constituents. The measurements are preferably synchronized with systole and diastole of the cardiac cycle so that the signal contribution caused by veins and tissues (which do not pulse) may be cancelled when a ratio of the detected signals is taken. The concentration of the blood constituents are then determined in accordance with a polynomial equation.

Self-emission noninvasive infrared spectrophotometer

An anesthetic agent analyzer having six or more independent analytical channels, where each channel comprises a first thermopile which receives incident infrared radiation and a second thermopile behind the first thermopile which is blocked from the incident infrared radiation and thus serves as a reference for detecting ambient temperature variations. The first and second thermopiles are connected in a 'parallel opposed' fashion so that the effects of ambient temperature variations automatically cancel and the detectors may be readily configured in a detector package. The anesthetic agent analyzer of the invention is designed for use with a wideband infrared radiation source so that anesthetic agents having characteristic absorption bands in the far infrared wavelength range (6-15 microns) may be more readily detected and discriminated. When implemented in a mainstream configuration, a disposable airway adapter with windows formed of polypropylene or some other suitable window material which minimally attenuates the infrared energy at the wavelengths of interest is also used. The concentrations of the discriminated anesthetic agent gases are then calculated using a second order polynomial equation having cross product terms. By connecting the first and second thermopiles in a back to back configuration, the detector device of the invention permits twice as many independent analytical channels to be provided in the same substrate area, with the resultant reduction in ambient temperature gradients.

Shutterless mainstream discriminating anesthetic agent analyzer

An infrared source which provides a miniature, highly stable and efficient source of infrared energy for use with infrared detectors and the like. The infrared source of the invention incorporates a platinum resistance temperature detector (RTD) which is integrated with the heater element to provide a means of electronic servo control of the heater temperature. The heater element and the RTD are tightly coupled thermally to provide accurate, continuous tracking and control of the heater temperature. The infrared source design provides excellent infrared energy output with less than one watt input power to the heater.

Regulated infrared source

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Oakland, CA, United States of America

Roger O Herrera