Measuring Thoracic Impedance in Hemodialysis Patients With the u-Cor Monitoring System

The µ-Cor System is intended to record, store, transmit, and display the following physiological data to medical professionals: thoracic impedance, ECG, heart rate, respiration rate, activity and posture. The µ-Cor System is indicated for patients who are 21 years of age or older who: * have fluid-management problems, * are taking diuretic medication, * are living with heart failure, * are living with end-stage renal disease, * are recovering from a coronary artery disease-related event, and/or * are suffering from recurrent dehydration. Objectives: * This clinical trial is intended to provide evidence of substantial equivalence between the µ-Cor System and the ZOE System in the ability to measure thoracic impedance, by comparing the correlation between µ Cor measurement and ultrafiltration volume (UFV) as compared with the correlation between ZOE measurement and UFV. The actual UFV changes will be used to arbitrate any differences. * The ability of the µ-Cor System to measure thoracic impedance will be demonstrated at 2 body locations: side location (below left axilla, Study Arm 1), and front location (upper left pectoral area, Study Arm 2). Subject population: Forty patients undergoing hemodialysis (n = 40) in 2 study arms with at least 50% enrollment of patients diagnosed with congestive heart failure (CHF) in each arm: * Study Arm 1: 20 patients undergoing hemodialysis, with at least 10 of these patients having CHF, will have the µ-Cor device placed on the side location * Study Arm 2: 20 patients undergoing hemodialysis, with at least 10 of these patients having CHF, will have the µ-Cor device placed on the front location Patients will wear the µ-Cor device and will be connected to the ZOE monitor during one hemodialysis session in the clinic. Patients will be randomly allocated to Study Arm 1 or Study Arm 2, with randomization stratified by CHF status (CHF or non-CHF). During the hemodialysis session, the patient will wear 1 µ-Cor device and will be connected simultaneously to 1 ZOE monitor (via 2 ZOE electrodes) for comparative measurements and UFV correlation, from at least 15 minutes before the start of dialysis to at least 15 minutes after the end of the dialysis session. The µ-Cor will record measurements during the dialysis session, including at least the 15 minutes before and 15 minutes after the session. ZOE (Z0) values will be measured every 6 minutes (± 1 minute) during the dialysis session. ZOE (Z0) values also will be measured every 3 minutes (± 1 minute) before and after the session, for a minimum of 5 measurements. The UFV during the course of hemodialysis will be measured by automated readings provided by the dialysis machine every 6 minutes (± 1 minute). 10. Any IV infusions administered, oral fluid or solid intake, and urine output during the course of hemodialysis will be recorded. Weight, blood pressure, and heart rate will be recorded before and after the dialysis session.The patient's involvement in the study ends after the completion of all procedures planned for the hemodialysis session.