(1312) Impact of Treatment Modalities on ICU Length of Stay for Patients Admitted With Severe Hyponatremia

Introduction: Severe hyponatremia ( < 125 mmol/L) often requires intensive care unit (ICU) admission. Consensus guidelines recommend correction by no more than 10 mmol/day to mitigate risk of osmotic demyelination syndrome (ODS), though treatment approach is highly variable. The purpose of this study is to evaluate if treatment selection for the management of severe hyponatremia warranting ICU admission is associated with ICU length of stay.

Methods: This single-center, retrospective study included patients 18 years of age or older admitted to the medical intensive care unit (MICU) between September 1, 2013, and December 31, 2022 with a glucose-corrected serum sodium < 125 mmol/L and received pharmacologic treatment for hyponatremia. The primary endpoint was a multivariable Poisson regression analysis assessing ICU length of stay. Primary explanatory variables were treatment modalities (3% NaCl, isotonic fluids, diuretics, etc), etiology, nephrology consultation and pretreatment serum sodium. Secondary endpoints included hospital length of stay, time to sodium normalization, rate of sodium rise, the incidence of overcorrection, incidence of ODS, ICU mortality, and temporal prescribing trends.

Results: Eight-two patients were included in the final analysis. The median baseline glucose-corrected serum sodium was 116.3 mmol/dL (IQR 112.9, 120.5). The median ICU length of stay was 3 days. Two variables were associated with an increased length of ICU stay: nephrology consultation for management of hyponatremia (IRR 1.22, 95% CI 1.01-1.46) and proactive re-lowering therapy (IRR 1.38, 95% CI 1.11-1.71), defined as pharmacologic treatment administered to prevent the occurrence of overcorrection. The median time to sodium correction was 63.9 hours. Overcorrection occurred in 37 (45.1%) patients and was treated with rescue re-lowering therapy in 25 patients (30.5%). During the study period, a temporal trend toward increased frequency and proportion of 3% sodium chloride and desmopressin was noted. Concurrently, a trend toward increased length of ICU stay was noted. No patients developed ODS.

Conclusions: Proactive re-lowering therapy and nephrology consultation were associated with an increased ICU length of stay for patients admitted to a medical intensive care unit with severe hyponatremia.