The Venous Excess Ultrasound Grading System in the Management of Hospitalized Patients with Hyponatremia: A Diagnostic Study

Introduction: Hyponatremia is the most common electrolyte disorder in hospitalized patients and requires accurate assessment of volume status to guide appropriate management. The venous excess ultrasound grading system (VExUS) is a point‑of‑care ultrasound tool used to assess venous congestion through Doppler evaluation of abdominal venous flow patterns. Its role in the context of hypoosmolar hyponatremia remains to be defined. Methods: In this proof‑of‑concept, prospective, observational study, hospitalized adult patients with hypoosmolar hyponatremia (plasma sodium ≤130 mEq/L) were included. Within 24 hours of enrolment, all patients underwent VExUS assessment evaluating the inferior vena cava diameter and Doppler waveforms in at least one venous territory (hepatic, portal, or renal veins). Treating physicians were blinded to ultrasound findings. Serum sodium was measured at baseline and at 24, 48, and 96 hours. VExUS evaluation of volume status was compared to final diagnosis and other surrogates of volume. Results: A total of 26 patients were included. VExUS identified venous congestion in 4 patients (15.4%). VExUS discrepancies between clinical and ultrasound‑based volume assessment were observed in 2 cases (7.7%). These discrepancies were not associated with significant differences in sodium level trends (0h: p=0.409; 24h: p=0.884; 48h: p=0.598; 96h: p=0.351), nor with changes in treatment. However, VExUS eliminated discrepancies between final diagnosis and presumptive diagnosis at study inclusion. Conclusion: In this study, VExUS proved useful in detecting venous congestion not evident on clinical examination, improving diagnostic accuracy.