Abstract:
A quick registering thermometer (34) utilizing a sensor (50) that has electrical resistance varying with temperature and that is located at the tip (37) of a probe (36), the sensor (50) having a relatively small thermal mass and a short thermal time constant. Within seconds of contact with the patient, the circuitry (40) communicating with the sensor (50) determines the rate of change in resistance of the sensor (50) and, in turn, the temperature that the sensor (50) would reach if allowed the length of time it would need to reach equilibrium with the contact surface of the patient. Based on the equilibrium temperature determined for the surface of the patient, the circuitry (40) calculates and registers the core body temperature.
Abstract:
This invention is a method and apparatus for monitoring glucose, ethyl alcohol, and other blood constituents in a noninvasive manner. Long wavelength infrared energy emitted by the person as heat is monitored and the infrared absorption of particular constituents in the blood is measured (114) at characteristic infrared absorption wavelengths (110) for those constituents. The measurements are preferably synchronized (124) with systole and diastole of the cardiac cycle so that the signal contribution caused by veins and tissues may be cancelled when a ratio of the detected signals is taken. If no synchronization is provided, the spectrophotometer may measure the arterial, venous, and tissue constituent concentrations simultaneously. The internal "blackbody" energy level of an infrared emissions source such as a vascularized appendage is measured (300) and used to compensate temperature dependent effects in the concentration calculation. The internal energy level ratio is ratioed to the actual measured energy.
Abstract:
This invention is a scheme for monitoring a solute in a biological system comprising the steps of delivering light into a biological system (12) containing a solute, the light having a wavelength selected to be in a range wherein the solute is substantially non-absorbing; detecting at least first and second portions of the delivered light (16, 18, 20), the first portion having traveled through the biological system along one or more paths characterized by a first average path length, and the second portion having traveled through the biological system along one or more paths characterized by a second average path length that is greater than the first average path length; and comparing the first and second portions of the delivered light to monitor concentration of the solute in the biological system. Also described are schemes for monitoring low molecular weight polyhydroxy solutes, generally sugars (mannitol, fructose, sucrose, glucose, sorbitol), alcohols (methanol, ethanol, propanediol), and electrolytes (sodium, potassium, magnesium, calcium, and chloride ions).
Abstract:
A device for the non-invasive measurement of the concentration of a specific analyte, particularly glucose, in arterial blood flowing in a patient's body part (10), which device comprises a first portion having a surface profile adapted to be held against the selected body part, a source (11) of near infrared radiation mounted in a second portion associated with said first portion such that near infrared radiation is transmitted through or reflected from said body part, a third portion containing a detector (15) and filters (14) to receive radiation transmitted through or reflected from said body part, to select signals generated by the pulsatile component of the absorption spectrum and to provide a ratio representative of the desired concentration. A method for the determination of glucose concentration in arterial blood is also disclosed.
Abstract:
An apparatus for the determination and continuous monitoring of bladder epithelial oxygen (pb02) which comprises, in combination, an introductory catheter (1) with an inflatable placement cuff (4) and an oxygen sensor, wherein the sensor is completely accommodated within the catheter (1) when not in use and, when the apparatus is placed within a patient's bladder, the sensor is adapted to be deployed so that the distal end (7) of the sensor passes through an open port (3) in the distal wall of the catheter (1) and extends beyond the tip (2) of the catheter (1) to rest against the wall of the bladder; and a method for the continuous monitoring of pb02 using such apparatus.
Abstract:
A method for detecting epithelial cancer includes generating a real-time video image of the locus of potential cancerous sites on the epithelium. The real-time video image is displayed on a television monitor screen. The real-time video image on the monitor is examined to locate suspected cancerous sites and the results of such examination are recorded.
Abstract:
A procedure for verifying the accuracy of a non-invasive blood glucose measurement instrument (10) utilizes in vitro or invasive measurement instruments (100), the accuracy of which is independently verifiable. Several glucose readings are taken with each instrument at approximately the same times. The measurement data from the in vitro instrument (100) is transferred to the non-invasive instrument (10) where it is compared to the data regarding the non-invasive measurements. If the difference between the measurements of the respective instruments is within a preset range, the non-invasive instrument is permitted to be used for an additional period of time. However, if the difference is beyond an acceptable limit, then the non-invasive instrument is prevented from taking any additional measurements and must be serviced or repaired.
Abstract:
This invention is a method and apparatus (2) for obtaining and displaying in real time an image of an object (10) obtained by one modality such that the image corresponds to a line of view established by another modality. The method comprises steps of obtaining a follow image library (14) of the object via a first imaging modality; providing a lead image library (12) obtained via the second imaging modality; referencing the lead image libray to the follow image library; obtaining a lead image of the object in real time via the second imaging modality along a lead view; comparing the real time lead image to lead images in the lead image library via digital image analysis to identify a follow image line of view corresponding to the real time lead view; transforming the identified follow image to correspond to the scale, rotation, and position of the lead image; and displaying the transformed follow image.
Abstract:
The present invention provides a medical sensor for detecting a blood characteristic. The sensor includes a transducer for producing an analog signal related to the blood characteristic. The analog signal is converted into a transmission signal which is in amplitude-independent form for transmission to a remote analyzer. In one embodiment, a current-to-frequency converter converts a signal from a pulse oximeter sensor into a frequency signal which can be transmitted over a transmission line to a remote pulse oximeter.
Abstract:
The present invention provides an encoding mechanism for a medical sensor which uses a modulated signal to provide the coded data to a remote analyser. The modulated signal could be, for instance, a pulse width modulated signal or a frequency modulated signal. This signal is amplitude independent and thus provides a significant amount of noise immunity.