Safety and Efficacy of Intravenous Hypotonic 0.225% Sodium Chloride Infusion for the Treatment of Hypernatremia in Critically Ill Patients

Background: The purpose of this study was to evaluate the safety and efficacy of central venous administration of a hypotonic 0.225% sodium chloride (one-quarter normal saline [¼ NS]) infusion for critically ill patients with hypernatremia. Methods: Critically ill, adult patients with traumatic injuries and hypernatremia (serum sodium [Na] >150 mEq/L) who were given ¼ NS were retrospectively studied. Serum sodium, fluid balance, free water intake, sodium intake, and plasma free hemoglobin concentration (fHgb) were assessed. Results: Twenty patients (age, 50 ± 18 years; Injury Severity Score, 29 ± 12) were evaluated. The ¼ NS infusion was given at 1.5 ± 1.0 L/d for 4.6 ± 1.6 days. Serum sodium concentration decreased from 156 ± 4 to 143 ± 6 mEq/L (P < .001) over 3–7 days. Total sodium intake was decreased from 210 ± 153 to 156 ± 112 mEq/d (P < .05). Daily net fluid balance was not significantly increased. Plasma fHgb increased from 4.9 ± 5.4 mg/dL preinfusion to 8.9 ± 7.4 mg/dL after 2.6 ± 1.3 days of continuous intravenous (IV) ¼ NS in 10 patients (P = .055). An additional 10 patients had a plasma fHgb of 10.2 ± 9.0 mg/dL during the infusion. Hematocrit and hemoglobin decreased (26% ± 3% to 24% ± 2%, P < .001 and 9.1 ± 1.1 to 8.2 ± 0.8 g/dL, P < .001, respectively). Conclusions: Although IV ¼ NS was effective for decreasing serum sodium concentration, evidence for minor hemolysis warrants further research to establish its safety before its routine use can be recommended.