Abstract: A method of performing closed-loop dialysis treatment during hemodialysis is provided. The method involves determining an initial ultrafiltration rate and setting an ultrafiltration pump of a dialysis system to the determined ultrafiltration rate. A series of measurements and calculations are made to ensure that a rate of change of blood volume during treatment follows a specified profile. A threshold may be used to keep the rate of change of blood volume tracking the profile. Patient fluid dynamics may be measured in real-time and used to determine the ultrafiltration pump rate.

Abstract: A measurement system for measuring blood characteristics includes a controller, an emitter, a sensor, a reference photo sensor, and a mask. The emitter emits light at a plurality of wavelengths from a first side of a blood flow channel to a second side of the blood flow channel. The sensor is provided on the second side of the blood flow channel. The reference photo sensor is provided on the first side of the blood flow channel. The mask is provided on the first side blocking reflected light other than from the light from the emitter to enter the reference photo sensor. The controller compensates measurements from the sensor based upon measurements from the reference photo sensor.

Abstract: A method of performing closed-loop dialysis treatment during hemodialysis is provided. The method involves determining an initial ultrafiltration rate and setting an ultrafiltration pump of a dialysis system to the determined ultrafiltration rate. A series of measurements and calculations are made to ensure that a rate of change of blood volume during treatment follows a specified profile. A threshold may be used to keep the rate of change of blood volume tracking the profile. Patient fluid dynamics may be measured in real-time and used to determine the ultrafiltration pump rate.

Abstract: An embodiment of the disclosure provides a system for determining information on one or more constituents in a medium. The system includes N light emitters L1 . . . LN, wherein each light emitter Lx provides an amplitude modulated (AM) light at modulation frequency fx into a flow path of the medium from one side of a containment vessel for the medium. The system further includes a photodetector, for receiving the AM light from each light emitter after it passes through the flow path of the medium, and converting the AM light to an electrical signal characterized by a summation of frequency components from each modulation frequency fx. The system further includes one or more measuring circuits providing information about a concentration of one or more constituents in the medium determined from log ratios of a pair of amplitudes of fy and fz frequency components in the electrical signal.

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: An embodiment of the disclosure provides a method for measuring change in blood volume using a transcutaneous measurement system applied to a patient's skin. The method involves placing a sensor in contact with the skin of a patient, where the sensor includes a light emitter and a photodetector. An intensity of light emanating from the light emitter is set and an initial intensity of light received at the photodetector is determined, where the light received at the photodetector has traveled through the patient's tissue. A later determination is then made of the intensity of the light received at the photodetector. A change in the blood volume is determined based on the intensity of the light emanating from the light emitter, the initial intensity of light received at the photodetector and the final intensity of light received at the photodetector.

Abstract: Embodiments of the disclosure provide a method and system for providing a diagnostic vascular window that may be used in real time to monitor a patient's fluid conditions in a variety of settings. The diagnostic vascular window may, for example, be used pre-surgery, during surgery, and post-surgery to determine whether a correct type and dose of diuretic drugs are being used for the patient. The diagnostic vascular window utilizes low flow accesses to view blood/fluids leaving and entering the patient's body. In addition, the same amount of fluids leaving the body enters the body, so there are no fluid losses or gains within the diagnostic vascular window. The low flow accesses in conjunction with a monitoring system allows for real-time measurements of blood parameters without fluid loss.

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: 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: 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: An embodiment of the disclosure provides a system for determining information on one or more constituents in a medium. The system includes N light emitters L1 . . . LN, wherein each light emitter Lr provides an amplitude modulated (AM) light at modulation frequency fr into a flow path of the medium from one side of a containment vessel for the medium. The system further includes a photodetector, for receiving the AM light from each light emitter after it passes through the flow path of the medium, and converting the AM light to an electrical signal characterized by a summation of frequency components from each modulation frequency fr. The system further includes one or more measuring circuits providing information about a concentration of one or more constituents in the medium determined from log ratios of a pair of amplitudes of fy and fz frequency components in the electrical signal.

Abstract: A measurement system for measuring blood characteristics includes a controller, an emitter, a sensor, a reference photo sensor, and a mask. The emitter emits light at a plurality of wavelengths from a first side of a blood flow channel to a second side of the blood flow channel. The sensor is provided on the second side of the blood flow channel. The reference photo sensor is provided on the first side of the blood flow channel. The mask is provided on the first side blocking reflected light other than from the light from the emitter to enter the reference photo sensor. The controller compensates measurements from the sensor based upon measurements from the reference photo sensor.

Abstract: An embodiment of the disclosure provides a method for measuring change in blood volume using a transcutaneous measurement system applied to a patient's skin. The method involves placing a sensor in contact with the skin of a patient, where the sensor includes a light emitter and a photodetector. An intensity of light emanating from the light emitter is set and an initial intensity of light received at the photodetector is determined, where the light received at the photodetector has traveled through the patient's tissue. A later determination is then made of the intensity of the light received at the photodetector. A change in the blood volume is determined based on the intensity of the light emanating from the light emitter, the initial intensity of light received at the photodetector and the final intensity of light received at the photodetector.

Abstract: A hemodialysis patient data acquisition and management system resides on a host computer which receives information from one or more non-invasive, optical blood monitors associated with a hemodialysis system. When a patient is undergoing hemodialysis treatment, a sensor assembly monitors the patient's blood flowing through the hemodialysis system and a controller for the blood monitor generates data which includes at least an identification code for the patient undergoing the treatment on the respective system, and non-invasively determined blood data taken at the onset of the scheduled treatment, such as initial Hgb, HCT, and SAT values. A host computer communicates with the one or more optical blood monitors, preferably via a wireless network, and the patient's session commencement data is downloaded to the host computer.

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 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 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.