Abstract: A sensor clip assembly for an optical blood monitoring system includes a circuit board with a microprocessor that is programmed with a ratiometric model to calculate hematocrit and/or oxygen saturation levels of a patient.

Abstract: An optical blood monitoring system and corresponding method avoid the need to obtain a precise intensity value of the light impinging upon the measured blood layer during the analysis. The system is operated to determine at least two optical measurements through blood layers of different thickness but otherwise substantially identical systems. Due to the equivalence of the systems, the two measurements can be compared so that the bulk extinction coefficient of the blood can be calculated based only on the known blood layer thicknesses and the two measurements. Reliable measurements of various blood parameters can thereby be determined without certain calibration steps.

Abstract: An optical blood monitoring system for blocking unwanted light from reaching sensors in a sensor clip assembly fastened to a blood chamber connected in an extracorporeal blood treatment system. The blood chamber has an internal flow cavity for communicating the extracorporeal blood flow and viewing windows to enable the sensor clip assembly to illuminate the blood with light as the blood flows through the blood chamber in order to monitor characteristics of the blood. The sensor clip assembly includes opposing heads with LED emitters and photodetectors. In one embodiment, lenses in the heads are surrounded by shrouds extending from the lenses so that when the sensor clip assembly is fastened to the blood chamber the shrouds block unwanted light from reaching the photodetectors.

Abstract: An optical blood monitoring system for blocking unwanted light from reaching sensors in a sensor clip assembly fastened to a blood chamber connected in an extracorporeal blood treatment system. The sensor clip assembly includes opposing heads with LED emitters and photodetectors. In one embodiment, lenses in the heads are surrounded by shrouds extending from the lenses so that when the sensor clip assembly is fastened to the blood chamber the shrouds block unwanted light from reaching the photodetectors. Either alternatively or as a complement to the shrouds, the blood chamber includes an opaque portion or a portion colored to attenuate particular wavelengths of light to further enhance the overall ability of the blood chamber and sensor clip assembly to block unwanted light from reaching the photodetectors.

Abstract: An optical blood monitoring system includes a sensor clip assembly and a blood chamber. The blood chamber has an internal flow cavity for extracorporeal blood flow and viewing lenses to enable the sensor clip assembly to monitor the blood when it is mounted on the blood chamber. The sensor clip assembly includes an annular shroud surrounding the LED emitters and another annular shroud surrounding the photodetectors, both for the purpose of blocking ambient light and limiting light piping. The blood chamber includes separate, distinct shroud mating surfaces to engage the shrouds on the sensor clip assembly.

Abstract: A low flow blood chamber for optically monitoring blood flowing through extracorporeal tubing has a flat elongated blood flow cavity but preserves the circular viewing area of conventional blood chambers. The blood chamber provides consistent, mixed flow through the blood cavity even at low blood flow rates, e.g. 10 to 500 ml/min., while maintaining certain dimensional characteristics of conventional blood chambers.

Abstract: An extracorporeal blood chamber for an optical blood monitoring system has a mixing area and viewing area that are offset from the axis of the blood flow path into and out of the blood chamber. A flow guide structure redirects an entirety of the flow of blood in a direction substantially orthogonal to the axis and into the viewing area.

Abstract: An optical blood monitoring system for blocking unwanted light from reaching sensors in a sensor clip assembly fastened to a blood chamber connected in an extracorporeal blood treatment system. The sensor clip assembly includes opposing heads with LED emitters and photodetectors. In one embodiment, lenses in the heads are surrounded by shrouds extending from the lenses so that when the sensor clip assembly is fastened to the blood chamber the shrouds block unwanted light from reaching the photodctectors. Either alternatively or as a complement to the shrouds, the blood chamber includes an opaque portion or a portion colored to attenuate particular wavelengths of light to further enhance the overall ability of the blood chamber and sensor clip assembly to block unwanted light from reaching the photodetectors.

Abstract: An optical blood monitoring system includes a sensor clip assembly and a blood chamber. The blood chamber has an internal flow cavity for extracorporeal blood flow and viewing lenses to enable the sensor clip assembly to monitor the blood when it is mounted on the blood chamber. The sensor clip assembly includes an annular shroud surrounding the LED emitters and another annular shroud surrounding the photodetectors, both for the purpose of blocking ambient light and limiting light piping. The blood chamber includes separate, distinct shroud mating surfaces to engage the shrouds on the sensor clip assembly.

Abstract: Systems and sensor clip assemblies for optically monitoring blood flowing through a blood chamber are provided. A sensor clip assembly includes emitters and photodetectors positioned on opposing arms, a signal conditioning circuit for conditioning raw analog signals generated by the photodetectors while the sensor clip assembly is fastened to a blood chamber, and an analog-to-digital converter for converting the conditioned analog signals to raw digital data. The sensor clip assembly may output the raw digital data to an external device and receive synchronized control signals from the external device, or the sensor clip assembly may include a microcontroller for performing calculations on the raw digital data and providing synchronized control signals internally. Parameters of blood flowing through the blood chamber such as hematocrit, oxygen saturation, and change in blood volume may be calculated from the raw digital data derived from the raw analog signals generated by the photodetectors.

Abstract: A sensor clip assembly for an optical blood monitoring system includes a circuit board with a microprocessor that is programmed with a ratiometric model to calculate hematocrit and/or oxygen saturation levels of a patient.

Abstract: An extracorporeal blood chamber for an optical blood monitoring system has a mixing area and viewing area that are offset from the axis of the blood flow path into and out of the blood chamber. The off-axis design provides more leverage for threading the blood chamber onto a dialysis filter. It also eliminates the need for turbulence posts.

Abstract: An extracorporeal blood chamber for an optical blood monitoring system includes an opaque chamber body in order to prevent inaccuracies when measuring oxygen saturation levels due to light ducting, which can occur at low oxygen saturation levels and low hematocrit levels. In one embodiment, the blood chamber need not include a moat as is present in conventional blood chambers.

Abstract: A low flow blood chamber for optically monitoring blood flowing through extracorporeal tubing has a flat elongated blood flow cavity but preserves the circular viewing area of conventional blood chambers. The blood chamber provides consistent, mixed flow through the blood cavity even at low blood flow rates, e.g. 10 to 500 ml/min., while maintaining certain dimensional characteristics of conventional blood chambers.

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: 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: 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.