Exploring Lung Fluid Dynamics in Haemodialysis With Remote Dielectric Sensing

Pulmonary congestion is a common complication in haemodialysis patients, significantly contributing to cardiac events and mortality. Traditional methods for assessing fluid status lack sensitivity and specificity, necessitating the development of more reliable techniques. Remote dielectric sensing (ReDS) offers rapid, non-invasive, and quantitative lung fluid measurements, potentially aiding fluid management in this population.

In this prospective cross-sectional study, patients on chronic maintenance haemodialysis were invited to participate between March and June 2022. ReDS measurements were performed immediately before and after haemodialysis to assess pulmonary congestion, defined as ReDS values exceeding 35%. Ultrafiltration volumes, intradialytic hypotension, and associated risk factors were analysed.

Among 58 analysed haemodialysis patients (mean age 76 years; 43% male), 48% exhibited pulmonary congestion pre-haemodialysis (mean ReDS: 37%), with 33% remaining congested post-haemodialysis despite a 4% average reduction. Ultrafiltration volumes averaged 1.4 L and showed a weak correlation with ReDS changes (Pearson's r = 0.309, p = 0.018). Intradialytic hypotension occurred in 21% of patients and was associated with hypoalbuminaemia (75% vs. 46%; p = 0.070), and was less common in hypertensive individuals (50% vs. 78%; p = 0.072). ReDS measurements did not predict intradialytic hypotension.

ReDS is a valuable tool for assessing pulmonary congestion in haemodialysis patients, detecting fluid overload both before and after sessions. Pulmonary congestion often persists despite achieving dry weight, highlighting the need for precise fluid management. While ReDS shows promise for clinical use, further longitudinal studies are essential to validate its prognostic value and refine its application in haemodialysis care.