The present disclosure introduces systems and methods to measure fluid in a body segment. In one embodiment, a computer system used to measure fluid in a body segment is described. A current generation module may be used to emit an electrical through at least one body segment. The electrical current may be used to measure fluid-volume content of the at least one body segment. An electrode module having a plurality of electrodes may be attached to the current generation module. A signal-processing module may be used to measure changes in the electrical current through at least one body segment. Further, an impedance module may be used to calculate fluid-volume change in at least one body segment and determine the flow of fluid through the at least one body segment. Other embodiments also are described.