Rapid bolus versus 3-h continuous infusion of 3% hypertonic saline for acute symptomatic hyponatremia

Hyponatremia is a common electrolyte disorder in emergency care that requires careful clinical management. Sodium correction, safety, 30-day hyponatremia-related hospital readmission, and mortality were compared between a 20-min rapid intermittent bolus (RIB) and a 3-h slow continuous infusion (SCI) of 3% hypertonic saline in adults with acute symptomatic hyponatremia.

This prospective cohort study included 58 adults presenting to the emergency department with acute symptomatic hyponatremia patients were assigned to RIB (20 min; n = 29) or SCI (3 h; n = 29) using a study-specific allocation list. Sodium kinetics through 24 h, safety, and 30-day outcomes were assessed using ANCOVA, repeated-measures ANOVA, multivariable regression, and ROC analysis.

Twenty-four-hour sodium correction was comparable between groups. One overcorrection occurred with SCI; no osmotic demyelination syndrome occurred. Thirty-day hyponatremia-related hospital readmission was 13.8% with RIB and 41.4% with SCI (p = 0.019); In an exploratory adjusted analysis, SCI was associated with higher adjusted odds (aOR) of readmission (aOR:7.04; 95% confidence interval [CI], 1.56-31.80; p = 0.011). Higher baseline Glasgow Coma Scale score was associated with lower 30-day-all-cause mortality (aOR, 0.39; 95% CI, 0.17-0.88; p = 0.025). A baseline sodium cutoff of ≤115.5 mmol/L showed exploratory discrimination for second dose requirement with an area under the curve of 0.754.

Both RIB and SCI protocols demonstrated similar short-term sodium correction, with few observed adverse events. The difference in 30-day hyponatremia-related hospital readmission and exploratory associations involving baseline neurological status and serum sodium require confirmation in larger studies.