Abstract: Systems and methods are provided for assessing patient blood flow using video image processing. According to one aspect, a method of analyzing at least one blood flow characteristic of a patient includes capturing a video including a plurality of frames of an arterio-venous (AV) fistula on the patient; amplifying motion in the video to produce a motion-amplified video; determining a difference in intensity between consecutive frames in the motion-amplified video to produce a time-function of an amplitude of the optic flow representing movement in an area of interest on the patient; and determining the at least one blood flow characteristic of the patient based on the time-function.

Abstract: Systems and methods are provided for assessing patient blood flow using video image processing. According to one aspect, a method of analyzing at least one blood flow characteristic of a patient includes capturing a video including a plurality of frames of an arterio-venous (AV) fistula on the patient; amplifying motion in the video to produce a motion-amplified video; determining a difference in intensity between consecutive frames in the motion-amplified video to produce a time-function of an amplitude of the optic flow representing movement in an area of interest on the patient; and determining the at least one blood flow characteristic of the patient based on the time-function.

Abstract: A method of detecting an indication of a potential intradialytic morbid event (IME) by monitoring a patient's condition during excess fluid removal by ultrafiltration during a hemodialysis treatment includes determining the patient's relative blood volume (RBV), and removing a portion of the volume of excess fluid from blood of the patient at an initial ultrafiltration rate while periodically monitoring a second derivative over time of the relative blood volume (SDRBV). The method then includes continuing to remove excess fluid from blood of the patient at the same ultrafilration rate, or, optionally, incrementally increasing the ultrafiltration rate. The method further includes triggering an alarm for an IME for the patient if the SDRBV is in a range of between a low SDRBV alarm level and a high SDRBV alarm level, and, alternatively or additionally monitoring the patient's normalized blood pressure ratio, and taking a remedial action if the alarm is triggered.

Abstract: In an embodiment, the invention relates to methods, apparatus, computer programs and computer program products for estimating a dry weight of a dialysis patient comprising the steps of determining a first fluid status of the patient between treatment sessions in a first stage, determining a second fluid status of the patient during treatment sessions in a second stage and estimating the dry weight based on the second fluid status.

Abstract: In an embodiment, the invention relates to methods, apparatus, computer programs and computer program products for estimating a dry weight of a dialysis patient comprising the steps of determining a first fluid status of the patient between treatment sessions in a first stage, determining a second fluid status of the patient during treatment sessions in a second stage and estimating the dry weight based on the second fluid status.

Abstract: Systems and methods are provided for assessing patient blood flow using video image processing. According to one aspect, a method of analyzing at least one blood flow characteristic of a patient includes capturing a video including a plurality of frames of an arterio-venous (AV) fistula on the patient; amplifying motion in the video to produce a motion-amplified video; determining a difference in intensity between consecutive frames in the motion-amplified video to produce a time-function of an amplitude of the optic flow representing movement in an area of interest on the patient; and determining the at least one blood flow characteristic of the patient based on the time-function.

Abstract: Apparatus is disclosed for measuring the circumference of a limb of an individual, e.g., the individual's arm and/or calf. The apparatus uses one or more magnetic strips which surround the limb and contain magnetic coding of length information. Tension is applied to the magnetic strip by a tensioning assembly, which can be a pressure cuff or a stepping motor, and a magnetic read head reads the magnetic coding of length information from the strip. When used in a bioimpedance analysis procedure, the length information can be used to convert measured voltage differences into normalized bioimpedance values, e.g., resistivity values.

Abstract: A method of detecting an indication of a potential intradialytic morbid event (IME) by monitoring a patient's condition during excess fluid removalby ultrafiltration during a hemodialysis treatment includes determining the patient's relative blood volume (RBV), and removing a portion of the volume of excess fluid from blood of the patient at an initial ultrafiltration rate while periodically monitoring a second derivative over time of the relative blood volume (SDRBV). The method then includes continuing to remove excess fluid from blood of the patient at the same ultrafilration rate, or, optionally, incrementally increasing the ultrafiltration rate. The method further includes triggering an alarm for an IME for the patient if the SDRBV is in a range of between a low SDRBV alarm level and a high SDRBV alarm level, and, alternatively or additionally monitoring the patient's normalized blood pressure ratio, and taking a remedial action if the alarm is triggered.

Abstract: A peritoneal dialysis (PD) system for infusing a volume of PD solution into a patient's peritoneal cavity in order to perform peritoneal dialysis on the patient includes a peritoneal cavity monitor (PCM) that measures this volume of fluid in the patient's peritoneal cavity by segmental bioimpedance spectroscopy (SBIS), to thereby determine an ultrafiltration volume of fluid in the patient's peritoneal cavity, and a switch, controlled by the PCM, for filling the patient's peritoneal cavity and draining the patient's peritoneal cavity when the ultrafiltration volume is unchanged over time, significantly decreased, or decreasing at a significant rate.

Abstract: In an embodiment, the invention relates to methods, apparatus, computer programs and computer program products for estimating a dry weight of a dialysis patient comprising the steps of determining a first fluid status of the patient between treatment sessions in a first stage, determining a second fluid status of the patient during treatment sessions in a second stage and estimating the dry weight based on the second fluid status.

Abstract: Methods and apparatus for predicting/estimating the dry weight of an individual, e.g., a patient undergoing dialysis treatment, are provided. The techniques employ a bioimpedance measurement (303) on the individual's calf (101) to obtain information regarding the extracellular fluid volume of the calf. Using a measurement of the calf's circumference (309), a resistivity value is calculated, normalized by the individual's body mass index (BMI), and then offset by a reference value to obtain a new variable, ?nRho, which is shown, by comparison with a “gold standard” (FIGS. 5-9), to be highly effective in predicting/estimating dry weight (FIGS. 10-13 and 15-16). The techniques are easy to use and provide accurate dry weight predictions/estimations without substantially adding to the complexity or cost of dialysis procedures. The techniques can also be used for individuals who are not renal patients, e.g.

Abstract: Methods and apparatus for providing bioimpedance analysis are provided. In certain aspects, equivalent circuit frequency response models are provided which lead to improved correlations with MRI data. The frequency response models take account of body composition, including the fat component of a body segment. Data obtained by performing bioimpedance spectroscopy (BIS) and MRI on the calves of subjects illustrates the improved correlations achieved compared to single frequency analyses at 50 kilohertz and analyses performed using the conventional Cole-Cole model.

Abstract: Methods and apparatus for providing bioimpedance analysis are provided. In certain aspects, equivalent circuit frequency response models are provided which lead to improved correlations with MRI data. The frequency response models take account of body composition, including the fat component of a body segment. Data obtained by performing bioimpedance spectroscopy (BIS) and MRI on the calves of subjects illustrates the improved correlations achieved compared to single frequency analyses at 50 kilohertz and analyses performed using the conventional Cole-Cole model.

Abstract: Methods and apparatus for providing bioimpedance analysis are provided. In certain aspects, equivalent circuit frequency response models are provided which lead to improved correlations with MRI data. The frequency response models take account of body composition, including the fat component of a body segment. Data obtained by performing bioimpedance spectroscopy (BIS) and MRI on the calves of subjects illustrates the improved correlations achieved compared to single frequency analyses at 50 kilohertz and analyses performed using the conventional Cole-Cole model.

Abstract: A method and device for continuously calculating the circumference of a body segment is based on the continuous measurement of the extracellular resistance of the body segment. Also disclosed is a method and device for determining the dry weight of a dialysis patient wherein the time at which the dry weight of the patient has been achieved is identified as the time at which the patient's normalized resistivity as a function of time (?N(t)) is greater than or equal to a minimum level of normalized resistivity in healthy subjects (?N,H).

Abstract: A system for performing electrical impedance tomography. The system includes a first set of electrodes positioned in a first plane and a second set of electrodes positioned in a second plane. The system also includes a third set of electrodes positioned in a third plane between the first and second planes. The third set of electrodes is rotatable around an axis intersecting the third plane. Furthermore, the third set of electrodes may be moveable in an axial direction between the first and second planes to various other planes, e.g., a fourth plane, a fifth plane, etc. The processor is further configured to process the voltage measurements taken by the voltage measurement device so as to generate a current density distribution in the various other planes. In addition, the processor is further configured to generate a three-dimensional image corresponding to the current density distribution between the first and second planes.

Abstract: Methods and apparatus for determining peritoneal cavity fluid volume include four groups of two electrodes applied to a subject's skin. Measuring electrodes (MLL, MRL) are applied to the subject's loins, measuring electrodes (MLB, MRB) are applied to the subject's buttocks, and upper and lower current-providing electrodes (IRU, ILU, IRL, ILL) are applied to the subject's left and right sides distal from the measuring electrodes (MLL, MRL, MLB, MRB). The resistance between left measuring electrodes (MLL, MLB) is measured and the resistance between right measuring electrodes (MRL, MRB) is measured while current is applied between the upper and lower current-providing electrodes. By averaging resistance values, in combination with a calibration procedure, measurements of peritoneal cavity fluid volume are obtained. The measurement techniques can be used in continuous flow peritoneal dialysis to control or adjust dialysis parameters based on peritoneal cavity fluid.

Abstract: The present invention includes a method of determining the dry body weight of a patient undergoing dialysis by means of segmental bioimpedance analysis. In preferred embodiments, dry body weight is determined by comparison to the bioimpedance values of normal subjects or by monitoring changes in bioimpedance during dialysis. One embodiment of the present invention is a device for determining dry body weight during dialysis.

Abstract: Methods and apparatus for providing bioimpedance analysis are provided. In certain aspects, equivalent circuit frequency response models are provided which lead to improved correlations with MRI data. The frequency response models take account of body composition, including the fat component of a body segment. Data obtained by performing bioimpedance spectroscopy (BIS) and MRI on the calves of subjects illustrates the improved correlations achieved compared to single frequency analyses at 50 kilohertz and analyses performed using the conventional Cole-Cole model.

Abstract: A method and device for continuously calculating the circumference of a body segment is based on the continuous measurement of the extracellular resistance of the body segment. Also disclosed is a method and device for determining the dry weight of a dialysis patient wherein the time at which the dry weight of the patient has been achieved is identified as the time at which the patient's normalized resistivity as a function of time (?N(t)) is greater than or equal to a minimum level of normalized resistivity in healthy subjects (?N,H).