Systems and methods for sensing lung fluid and functionality

An apparatus for monitoring for accumulation of lung fluid comprises a feeding tube having first electrode(s) positioned thereon for electrical contact with tissue of an esophagus of a target patient including a lower esophageal sphincter (LES) and/or tissue in proximity to the LES, second electrode(s) sized and shaped for contacting skin of the target patient, and a non-transitory memory having stored thereon code instructions for applying alternating current(s) to pair(s) of first and second electrodes, measuring a voltage over the pair(s), and computing an estimate of a change of lung fluid relative to a baseline in lung(s) of the target patient according to the applied alternating current and measured voltage, wherein the applying, the measuring, and the computing the estimate of the change in lung fluid are iteratively executed for monitoring the target patient for accumulation of lung fluid while the feeding tube is in use.