The following is a summary of “Point-of-care ultrasound is a useful adjunct tool to a clinician’s assessment in the evaluation of severe hyponatraemia,” published in the January 2024 issue of Endocrinology by Rahman, et al.

Hyponatremia, characterized by low serum sodium levels, is the most prevalent electrolyte disorder among inpatients, primarily stemming from water homeostasis disturbances. Accurately assessing intravascular fluid status is crucial but often complex due to multimorbidity, polypharmacy, and diuretic use. For a study, researchers sought to evaluate the utility of point-of-care ultrasound (POCUS) as an adjunct tool to standard practice for fluid assessment in patients with severe hyponatremia.

Patients presenting with severe hyponatremia (Serum Sodium [Na] < 120 mmol/L; Normal range: 135−145 mol/L) and managed with standard care were included. Biochemical workup for hyponatremia and POCUS examination were conducted. Both clinicians and POCUS independently categorized fluid status as hypovolemia, hypervolemia, or euvolemia. The final fluid status diagnosis at discharge was determined retrospectively. The clinician’s standard and POCUS fluid assessments were compared to the final discharge diagnosis.

About 19 patients were included. Median Na on admission was 113 mmol/L (109-116), improving to 129 ± 3 mmol/L on discharge. POCUS demonstrated higher agreement with the final diagnosis (84%; n = 16/19) than the clinician assessment (63%; n = 12/19). Although not statistically significant, POCUS trended towards higher accuracy in fluid status assessment than in clinician assessment (84% vs. 63%, P = 0.1611). Biochemical markers were unreliable in 58% (n = 11/19), possibly due to renal failure, polypharmacy, or diuretic use. Inappropriate emergency fluid management occurred in 37% (n = 7/19) of cases based on initial clinician assessment. Thirst symptoms correlated with hypovolemia in 80% (4/5) of cases.

Given the limitations of subjective clinical and biochemical assessments of fluid status in patients with severe hyponatremia, POCUS emerges as a rapid and objective diagnostic tool. It can facilitate accurate emergency fluid management by providing reliable fluid status assessment, mainly when comorbidities and medication use compromise conventional methods.

Reference: onlinelibrary.wiley.com/doi/10.1111/cen.15024