Fluid and electrolyte balance in children

Fluid administration to children is a ubiquitous part of the medical management of hospitalized children. In this review we examine the rationale for the use of various fluids including oral rehydration therapy. The basic physiology relating to distribution of infused fluids is discussed with regards to serum osmolality and tonicity. This review should guide safe prescription of appropriate volumes, rates of infusion and types of fluids. The potential complications of fluid therapy are discussed, in particular hyponatraemic encephalopathy. Children at particular risk of developing hyponatraemic encephalopathy are identified; the importance of frequent assessment and evaluation is highlighted and rational treatment of this medical emergency is reviewed. The use of a dehydration correction calculation is examined in the context of diabetic ketoacidosis. Finally the initial management of commonly occurring electrolyte disorders is examined.