ICU acquired hypernatremia treated by enteral free water – A retrospective cohort study

ICU acquired hypernatremia (IAH) is associated with increased morbidity and mortality, however treatment remains controversial. This study aims to determine the effect of enteral free water suppletion in patients with IAH. Retrospective single center study in a tertiary ICU. Inclusion criteria: patients with IAH and treatment with enteral free water. Exclusion criteria: patients with renal replacement therapy, diabetic ketoacidosis or hyperosmolar hyperglycaemic state. Primary outcome: change in plasma sodium (in mmol/l) after 5 days treatment. Responders were defined as patients with a decrease in sodium level of 5 mmol/l or more. In total 382 consecutive patients were included. The median sodium level at the start of water therapy was 149 mmol/l (IQR 147–150). The median volume of enteral water was 4423 ml (IQR 3349–5379 ml) after 5 days and mean sodium decrease was 1.87 mmol/l (SD 4.84). There was no significant correlation between the volume of enteral water and sodium decrease (r2 = 0.01). Treatment with enteral free water did not result in a clinically relevant decrease in serum sodium level in patients with IAH. In addition, the volume of enteral free water and the use of diuretics was unrelated with sodium change over 5 days. •Enteral free water treatment did not result in a clinically relevant decrease in serum sodium level•Furosemide use was not associated to a more or less extensive decrease in sodium level•Sodium balance in critically ill patients is probably more complex than just water deficit