Effect of Change in Sodium after Slow Low-Efficiency Dialysis in Critically Ill Patients with Acute Kidney Injury.

Introduction: The effect of sodium (Na) correction by slow low-efficiency dialysis (SLED) in dysnatremic (135 mEq/L <Na >145 mEq/L) critically ill patients is unclear.

Methods: Prospective observational study enrolled dysnatremic critically ill adult patients with acute kidney injury undergoing the first SLED as cases and normonatremic patients as controls. Baseline and SLED-related parameters and 30-day mortality were noted.

Results: 100 dysnatremic and 51 normonatremic patients were included, with a median age of 31 (25-52) years and median admission SOFA scores of 10 (9-12). Patients with dysnatremia at study inclusion had a mortality of 53%, with the highest mortality in severe hypernatremia (Na >160 mEq/L) (75%), followed by those with severe hyponatremia (Na <120 mEq/L) (68.6%). SLED-associated natremia change >10 mEq/L was significantly associated with mortality, in patients with mild dysnatremia and normonatremia (Na: 130-150) (p < 0.001), and not in those with moderate to severe dysnatremia (Na <130 and Na >150) (p = 0.72). Upon multivariate logistic regression analysis, a model with pre-SLED pH, dialyzate-pre-SLED Na difference, and duration of SLED significantly predicted SLED-associated natremia change (R2 0.18, p = 0.001).

Conclusions: SLED can be safely and effectively performed in critically ill adults with dysnatremia requiring renal replacement therapy with mortality comparable to normonatremic controls.