Sodium

Abstract

Sodium is a major extracellular cation. It is a significant determinant of the osmolality of the plasma. Human cells are bathed in salty water, so the osmolality must be regulated. The primary cause of dysnatraemias (abnormal sodium concentrations), hyper- and hypo-, is caused by the imbalance of electrolyte-free fluid intake and loss.¹ Clinicians must look at correcting the fluid abnormality instead of focusing on serum sodium. Dysnatraemias are a significant cause of morbidity in intensive care unit (ICU) patients, with an incidence of up to 27% in ICU patients compared to 0.2% in general ward patients.^2,3