Rapid Rehydration in the Treatment of Severe Hypernatremia

Hypernatremia (high serum sodium) indicates a deficit in total body water. Hypernatremia is common in hospitalized patients and is associated with high mortality rates, directly associated with hypernatremia severity (30-70% for severe hypernatremia). The traditional approach is to correct hypernatremia slowly, not exceeding 0.5 mEq/L/hour or 10 mEq/L/day, using hypotonic intravenous fluids, to avoid hypothetical cerebral edema and related neurological complications. This treatment strategy is not supported by empirical clinical data in adults, and there are no convincing reports of neurological harm in rapidly corrected patients. Several retrospective studies have shown rapidly corrected patients had significantly lower mortality rates, without neurological complications. Whether current recommendations reflect the optimal balance between patient safety and potential harm is unknown.

This study is a feasibility RCT of 80 patients with severe hypernatremia (serum sodium ≥155 mEq/L) comparing rapid hydration to standard-of-care therapy, leading to a large, multicenter RCT powered to detect lower 30-day mortality in the rapid hydration arm. The personalized, weight-based intravenous rapid hydration protocol targets a correction rate of 18 mEq/L/day until hypernatremia is resolved (serum sodium lower than 145 mEq/L). Treatment fidelity will be assessed twice daily, with real-time interventions for any deviations from protocol. Safety monitoring will include twice daily assessments of patients' level of consciousness and presence of delirium using the Glasgow coma scale and the brief confusion assessment method (bCAM), respectively, neurological function status assessments using the modified Rankin score, brain imaging to exclude brain edema and daily chart reviews for pre-specified neurological, cardiopulmonary or other complications. This study aims to demonstrate the feasibility of patient identification, consenting, randomization, effective implementation of rapid hydration in the intervention arm (primary endpoint), adverse event monitoring and 30-day survival ascertainment in both study arms. This study will also collect preliminary safety and efficacy data informing the design of the subsequent RCT, including any neurological or cardiopulmonary adverse events, 30-day survival and length of hospitalization.

This is first pilot RCT to prospectively compare treatment strategies for adults with hypernatremia, a prevalent but understudied condition. The results of this study and the subsequent RCT will be novel and will influence clinical practice, potentially improving survival and shortening hospitalizations.