Neck-Worn Monitoring Sensor for - A Study for Monitoring Subjects With Fluid-Management Issues During Dialysis
Condition: Heart Failure; Kidney Disease
MeSH terms: Kidney Diseases; Heart Failure
Study type: Observational

Summary: 
      The study has two objectives based on the intended-use measurements and populations described
      above. The first objective is to show that relative changes in impedance as measured by the
      test device (ΔSFI) are strongly correlated with the amount of fluid removed during dialysis
      (ΔF) for subjects with ESRD and possibly Heart Failure.

      The second objective is to demonstrate correlation between ΔSFI and relative changes in
      impedance (ΔZ) as measured by the reference device.
    

Detailed description: 
      The investigators propose a study for validating the test device's measurement of a parameter
      called 'sternal fluid index' (SFI) in patients with diagnosed medical conditions related to
      fluid management, e.g. end-stage renal disease (ESRD), that are undergoing dialysis. The
      reference device for the study measures the averaged amplitude of a thoracic bio-impedance
      signal (Z) and a parameter called 'thoracic fluid content' (TFC), which is equal to 1000/Z.
      The test device measures SFI from a localized region near the sternum, whereas the reference
      device measures Z and TFC from the entire thoracic cavity. This means Z (or TFC) and SFI, if
      measured at approximately the same time, will likely correlate but have different absolute
      values. Thus, the statistical analysis will investigate the ability of SFI to track fluids,
      as well as the agreement between fluid-dependent trends displayed by SFI and Z (or TFC), as
      described below.

      During the study the investigators will collect multiple samples, each containing a value of
      SFI from the test device, and values of TFC and Z from the reference device. The
      investigators will enroll approximately 20-50 subjects, with the goal of at least 20 subjects
      completing the study. The statistical analysis will include data from all subjects that
      complete the study. All subjects will undergo dialysis in a clinic. Approximately half to a
      third will have both ESRD and Heart Failure (HF). The investigators will measure a sample
      from each subject every 15 minutes during a standard dialysis session, which typically lasts
      about 3 to 4 hours. Levels of extracted fluids, determined by the dialysis machine, will be
      recorded at the time each sample is measured.

      The statistical model compares time-dependent changes in SFI and Z values collected during
      dialysis. It is designed is to demonstrate: 1) that the test device is effective in
      characterizing fluid levels when used as intended; and 2) that the test and reference
      devices' measurements of trends in fluids are substantially equivalent, since they sense
      different physiological regions which are expected to yield different values of impedance.
    

Observational model: Cohort
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        Subjects will be volunteers, solicited using accepted recruitment methods, such as through
        clinicians associated with dialysis centers. Subjects will have a clinical diagnosis of
        Kidney Failure and will be currently undergoing Hemodialysis with possible related
        co-morbidity of Heart Failure.
      
Keywords: Hemodialysis; Heart failure; Impedance; Fluids