Notes on intravenous fluids for paediatric surgeons

The enteral route for absorbing fluids, electrolytes and nutrition is preferable to the intravenous route, but gastrointestinal pathology or fasting for surgery may 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. If you are prescribing or monitoring intravenous fluids for children, you should read NICE guidance NG29 entitled Intravenous fluid therapy in children and young people in hospital, as updated in June 2020. Inappropriate maintenance fluids, excessive volumes and failure to monitor and respond to electrolyte levels can lead to acute symptomatic hyponatraemic encephalopathy and death. This article aims to help the reader: (i) revise and challenge their understanding of osmosis; (ii) use the terms tonicity and osmolarity safely; (iii) prescribe and monitor fluids; and (iv) manage common electrolyte derangements. In addressing the first aim, the article invites the reader to pause, spend some time thinking, and only later return to the text. This exercise could prove most valuable.