Intravenous fluids in children and young people

Abstract

The enteral absorption of fluids, electrolytes, and nutrition is preferable to the intravenous route, but gastrointestinal pathology or fasting for surgery may limit or preclude it. We are concerned here with patients for whom enteral intake is negligible and for whom we need not yet worry about nutrition. In the premature neonate, intravenous nutrition should not be delayed as reserves are low. See NICE guidance NG29 entitled Intravenous fluid therapy in children and young people in hospital, as updated in June 2020. Hypotonic maintenance fluids, excessive volumes and failure to monitor and respond to electrolyte levels can lead to fluid overload, acute symptomatic hyponatraemic encephalopathy and death caused by too much water crossing the phospholipid cell membrane. However, more frequently, the fluid overload, compounded by the response to stress, leads to peripheral oedema involving the semi-permeable membrane of the capillary wall when the colligative solute is low albumin. We must not merge these phenomena or their mechanisms. This article aims to help the reader: (i) revise some basic science; (ii) use the terms tonicity and osmolarity safely; (iii) prescribe and monitor fluids; and (iv) manage common electrolyte derangements.