Abstract: A cuff for measuring volume and change in volume of a body appendage includes a hollow, rigid tube having an inner surface; and a bladder having an inner surface and an outer surface, the ends of the bladder being sealed to the ends of the tube to create an enclosed internal volume between the inner surface of the bladder and the inner surface of the tube and an external volume defined by the outer surface of the bladder and surrounded by the internal volume, the bladder having a normal, relaxed state, in which the internal volume is filled with a fluid and a retracted state in which the fluid is evacuated from the internal volume. Two stiffener ribs placed on the inner surface of the bladder, parallel to each other and to the lengthwise axis of the tube at diametrically opposite positions. A plurality of emitters and detectors arranged in a linear array are embedded in one of the ribs, so as to emit and detect light through the bladder.

Abstract: An earplug composed of an injected molded resilient polymeric material for insertion into an ear canal by a fingertip of a user, including an elongated member having a nose portion formed as a curved front end. An open cup shaped rearward extending flange located at the end of the elongated member opposite to the nose portion and with the open cup shaped rearward extending flange configured to receive the fingertip of the user. The elongated member including at least one flange element located intermediate the nose portion and the open cup shape flange. The nose portion and the flange element having a generally curved shape to extend into and conform to the wall of the ear canal.

Abstract: A technique of increasing the corona inception voltage (CIV), and thereby increasing the operating voltage, of film/foil capacitors is described. Intentional venting of the capacitor encapsulation improves the corona inception voltage by allowing internal voids to equilibrate with the ambient environment.

Abstract: An optical sensor includes photoemitter and photodetector elements at multiple spacings (d1, d2) for the purpose of measuring the bulk absorptivity (?) of an area immediately surrounding and including a hemodialysis access site, and the absorptivity (?o) of the tissue itself. At least one photoemitter element and at least one photodetector element are provided, the total number of photoemitter and photodetector elements being at least three. The photoemitter and photodetector elements are collinear and alternatingly arranged, thereby allowing the direct transcutaneous determination of vascular access blood flow.

Abstract: An external focused ultrasonic beam, non-destructive, open-air, inspection method of sheet metal spot and seam weldments using a probe in combination with motion measurement of the probe over the weldments during inspection without immersion of the material. Reflected ultrasonic waves are received and signals produced and processed or displayed as A-scan, B-scan and C-scan images that are easily recognized. An A-Scan is based on the time-of-flight difference between the outer surface, the weldment and inner and opposite surfaces of the component. B-scan and C-scan indicate the degree of weld fusion and provide data relative to fused thickness and defects sheet metal or welds. A special purpose scanner that enables ultrasonic examination welds. Scanner is pencil like ultrasonic probe with bearing face and position sensing device disposed adjacent a weld position. Scanner collects data for method to determine various characteristics of welded items.

Abstract: An optical sensor includes photoemitter and photodetector elements at multiple spacings (d1, d2) for the purpose of measuring the bulk absorptivity (?) of an area immediately surrounding and including a hemodialysis access site, and the absorptivity (?o) of the tissue itself. At least one photoemitter element and at least one photodetector element are provided, the total number of photoemitter and photodetector elements being at least three. The photoemitter and photodetector elements are collinear and alternatingly arranged, thereby allowing the direct transcutaneous determination of vascular access blood flow.

Abstract: A system for determining a biologic constituent including hematocrit transcutaneously, noninvasively and continuously. A finger clip assembly includes including at least a pair of emitters and a photodiode in appropriate alignment to enable operation in either a transmissive mode or a reflectance mode. At least one predetermined wavelength of light is passed onto or through body tissues such as a finger, earlobe, or scalp, etc. and attenuation of light at that wavelength is detected. Likewise, the change in blood flow is determined by various techniques including optical, pressure, piezo and strain gage methods. Mathematical manipulation of the detected values compensates for the effects of body tissue and fluid and determines the hematocrit value. If an additional wavelength of light is used which attenuates light substantially differently by oxyhemoglobin and reduced hemoglobin, then the blood oxygen saturation value, independent of hematocrit may be determined.

Abstract: An apparatus and method for reproducibly interfacing a living tissue sample to the measurement probe of a spectrometer instrument in-situ minimizes spectral interference related to sampling variations. A minimal contact subject interface includes supports replaceably mounted on a base. An optical coupling means, such as a fiber optic probe, contacts the measurement site through a probe aperture in the base. During use, a subject rests an extremity on the support elements, so that the extremity is reproducibly positioned and supported in relation to the optical coupling means. The supports have a small contact area, minimizing contact with the skin at the measurement site. The interface module is adjustable to fit any subject. By reproducibly positioning and supporting the body appendage using minimal contact supports, spectral interference due to variations in placement, applied pressure, and temperature transients secondary to contact with the interface module are greatly minimized.

Abstract: An optical sensor includes a sensing pair of complementary emitter and detector elements for measuring the bulk absorptivity (&agr;) of an area parallel to and including a hemodialysis access site, and a normalizing pair of complementary emitter and detector elements for measuring the absorptivity (&agr;o) of the tissue itself perpendicular to the access site. The pairs of emitter and detector elements define two lines at right angles to each other, and one of the pairs lies to one side of the line defined by the other of the pairs, such that the two pairs of emitter and detector elements form a “T” shape. Indicator dilution techniques are used to measure vascular access flow rates during routine hemodialysis, using the sensor.

Abstract: Indicator dilution techniques are used to measure vascular access flow rates during routine hemodialysis. A bolus injection port is used to infuse a specific volume (Vi) of an indicator diluent, such as saline or dye, into the patient cardiovascular circuit by one of the following: 1. Needle injection of a known volume (bolus) of indicator diluent directly into the access site in the presence or absence of the hemodialysis circuit. 2. Infusion of an indicator diluent into the arterial, venous line upstream of the venous needle. 3. Turning the ultrafiltration of the dialysis delivery system from OFF to ON and OFF again over a predetermined time period. 4. In a hemodialysis circuit, turning on the hemodialysis pump and using the priming saline volume as a single saline bolus. A transdermal sensor is used to measure the percent change in a blood parameter.

Abstract: A cuvette having a pedestal for transmitting light through a relatively thin layer of blood. While the pedestal enables the use of a small path length it also permits the use of a high volume and/or high flow rate conduit. The pedestal further enables methods of determining various blood parameters in which the path length, d, is fixed; i.e., there are little or no pulsatile variations. Hence, the flow-through cuvette accommodates a large range of blood flow rates without any reduction in accuracy of the hematocrit measurement. The pedestal, because of its elliptical shape, does not damage or hemolyze the individual red blood cells as they pass through. A quantitative method for determining changes in blood volume in view of the path length is provided along with a method for measuring a patient's cardiac output and oxygen consumption rate. Cardiac output is obtained by injecting a saline arterial bolus and a saline venous bolus into a patient and measuring the change in hematocrit caused by each bolus.

Abstract: An optical sensor includes photoemitter and photodetector elements at multiple spacings (d1, d2) for the purpose of measuring the bulk absorptivity (&agr;) of an area immediately surrounding and including a hemodialysis access site, and the absorptivity (&agr;o) of the tissue itself. At least one photoemitter element and at least one photodetector element are provided, the total number of photoemitter and photodetector elements being at least three. The photoemitter and photodetector elements are collinear and alternatingly arranged, thereby allowing the direct transcutaneous determination of vascular access blood flow.

Abstract: Systems and methods are provided for noninvasively measuring the levels of urea, blood osmolarity (or Na+), plasma free hemoglobin and tissue water content in a patient's blood or tissue. Light of selected wavelengths is passed through blood or body tissue and the transmitted or reflected light is detected and the detected signals can be electronically compared and manipulated to provide the non-invasive, continuous and quantitative display of a patient's blood urea, blood osmolarity (or Na+), plasma free hemoglobin and tissue water content.

Abstract: A system determines heamtocrit transcutaneously and noninvasively. Disclosed are a finger clip assembly and an earlobe clip assembly, each including at least a pair of emitters and a photodiode in appropriate alignment to enable operation in either a transmissive mode or a reflectance mode. At least two, and preferably three, predetermined wavelengths of light are assed onto or through body tissues such as the finger, earlobe, or scalp, etc. and the extinction of each wavelength is detected. Mathematical manipulation of the detected values compensates for the effects of body tissue and fluid and determines the hematocrit value. If a fourth wavelength of light is used which is extinguished substantially differently by oxyhemoglobin and reduced hemoglobin and which is not substantially extinguished by plasmas, then the blood oxygen saturation value, independent of hematocrit, maybe determined. It is also disclosed how to detect and analyze multiple wavelengths using a logarithmic DC analysis technique.

Abstract: A system for determining a biologic constituent including hematocrit transcutaneously, noninvasively and continuously. A finger clip assembly includes including at least a pair of emitters and a photodiode in appropriate alignment to enable operation in either a transmissive mode or a reflectance mode. At least one predetermined wavelength of light is passed onto or through body tissues such as a finger, earlobe, or scalp, etc. and attenuation of light at that wavelength is detected. Likewise, the change in blood flow is determined by various techniques including optical, pressure, piezo and strain gage methods. Mathematical manipulation of the detected values compensates for the effects of body tissue and fluid and determines the hematocrit value. If an additional wavelength of light is used which attenuates light substantially differently by oxyhemoglobin and reduced hemoglobin, then the blood oxygen saturation value, independent of hematocrit may be determined.

Abstract: A non-invasive system for characterizing and classifying the state and structure of a tissue sample operates on a near infrared absorbance spectrum of in vivo tissue. A method that uses near-infrared spectral measurements to characterize and classify the state and structure of tissue sampled based on absorbance features related to fat in adipose tissue is provided. Also provided is a method of estimating skin fold thickness. The approach provides information about sources of tissue variability and is therefore useful for establishing the general category of the tissue structure. Categorization of subjects on the basis of the determination is suitable for further spectral analysis and the measurement of biological and chemical compounds, such as blood analytes. The invention further provides a method of estimating percent body fat based on a skin fold thickness estimate.

Abstract: A method and device is provided for determining aortic valve abnormalities. The method first includes the step of providing a sphygmomanometer device for inducing a pressure on a body part of a patient. A data stream receiver is provided for receiving a stream of data relating to the pressure response of the pulsed fluid flowing through the cardiovascular system of the patient. A data processor is provided for processing the data to create a series of time dependant pulse wave forms. The data can be converted by Fast Fourier Transformation (FFT) to obtain Power Spectrum (PS) which comprises a frequency dependant array of pulse signals. Both of the time dependant and frequency dependant (Power Spectrum) data can be displayed and analyzed to help determine the condition of the aortic valve and the percentage of regurgitation of the patient.