ABSTRACT
Infants are born into a low-humidity, gaseous environment from the liquid intrauterine world. Term and preterm neonates have different fluid requirements and electrolyte changes to older children and adults especially at this time of rapid postnatal transition. Renal blood supply arises from the aorta between T12 and L2, a relationship that remains constant between 24 and 44 weeks gestation. Renal blood flow and glomerular filtration rate (GFR) in utero increase gradually with gestational age. Insensible water loss is the continuous invisible loss of water by evaporation that occurs from the skin and lung surface. Intestinal absorption of sodium in the very preterm infant is low and improves progressively with increasing gestational age. Treatments used in premature infants with non-oliguric hyperkalemia aim to decrease the arrhythmogenicity of hyperkalemia, redistribute potassium into the intracellular space, or remove potassium from the body. Infants receiving intravenous fluids should be provided with calcium gluconate as maintenance.
