REDIEM - Renal Extremity Device to measure Impedance, Edema and Movement

Kidney or renal disease, leading to chronic kidney disease (CKD) and eventual end-stage renal disease (ESRD) is on the rise in the U.S., affecting 37 million people, or 15% of adults. Kidneys regulate the body’s water and electrolyte balance and remove wastes and excess fluids to maintain homeostasis.

Patients afflicted with CKD and ESRD suffer from excess fluid retention and leg edema or swelling. Many of these patients also develop uncontrolled leg movement, known as restless leg syndrome (RLS). In dialysis, the standard therapy, a machine effectively functions as a kidney substitute, removing excess water and wastes. Despite the efficacy of dialysis, physicians are unable to determine a patient’s baseline water content, or what is termed “dry weight” vs. water excess, making it unclear how to optimally time recurrent dialysis.

The team constructed a wearable lower leg band measurement device containing a single, four-electrode impedance-edema circuit and an accelerometer. A constant voltage and current is applied to the circuit to determine corresponding resistance values. With this impedance value, edema can be extrapolated using a simple mathematical model. The accelerometer detects movements associated with the motion of RLS. The device communicates data to a connected iOS app. This app displays the impedance, edema and RLS detection data for patients and physicians to view.