Abstract: FR-PO0610
Integrating Left Ventricular Outflow Tract Velocity Time via Point-of-Care Ultrasonography (POCUS) for Volume Assessment and Tailored Management of Hyponatremia: A Case Series
Session Information
- Fluid, Electrolyte, and Acid-Base Disorders: Clinical - 2
November 07, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Fluid, Electrolytes, and Acid-Base Disorders
- 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical
Author
- Lim, Annabelle Sy, St Luke's Medical center, Philippines, Metro Manila, Philippines
Introduction
Hyponatremia is a prevalent electrolyte disturbance that requires accurate volume status assessment for appropriate management. Traditional clinical signs and laboratory markers often provide conflicting or ambiguous information. Point-of-care ultrasound (POCUS), particularly using left ventricular outflow tract velocity-time integral (LVOT VTI), offers a noninvasive, reproducible surrogate for cardiac output (CO). VTI <16 cm suggests hypovolemia; >18 cm is considered normal. We report four cases where VTI-guided evaluation aided in the diagnosis and treatment of hyponatremia.
Case Description
Case 1: A 70-year-old man with malignancy and encephalitis developed new-onset hyponatremia(Na 131)despite hydration. VTI was high (25.48 cm,CO 4.3 L/min), indicating euvolemia. IV fluid was stopped, and tolvaptan was initiated, normalizing sodium to 137.
Case 2: A 30-year-old HIV-positive male on cotrimoxazole presented with Na 125. Initial VTI was <13.43 cm. Patient was hydrated with saline at 1.2cc/kg/hr then to 3cc/kg/hr when repeat VTI and Na was still low (14cmand 126). VTI guided fluid escalation ensued. Sodium normalized with increased VTI and CO.
Case 3: An 80-year-old woman on diuretics had a Na of 126 and appeared volume-depleted. But VTI ranged from 20–32 cm. Tolvaptan was started and up titrated. Sodium improved to 136.
Case 4: A 55-year-old woman with Guillain-Barré syndrome presented with Na 120. Initial sodium rose with fluids but later dropped to 116. VTI was high(23.69 cm,CO 5.37 L/min),indicating euvolemia. Fluids were discontinued, and tolvaptan was started, resulting in stable sodium recovery.
Discussion
In all four cases, clinical exam and standard labs were inadequate to confirm true volume status. POCUS-derived VTI enabled precise assessment, revealing cases of euvolemia that might have been misclassified. This real-time, noninvasive method guided effective management decisions leading to improved and sustained correction of hyponatremia. LVOT VTI should be considered a valuable bedside tool to supplement clinical judgment, particularly in patients with confounding signs, unreliable intake/output monitoring, or ongoing gastrointestinal and diuretic losses.