Alfie was born following spontaneous labour at 29 weeks gestation. At a 20-week routine ultrasound scan he was noted to be small. Over the last few weeks there have been concerns about poor fetal growth. His mother was admitted 2 days earlier with pre-labour rupture of the membranes, and received antenatal Betamethasone. His birthweight was 850 g and he has been ventilated from birth. He was commenced on i.v. 10% dextrose, but this was replaced with a parenteral amino acid solution along with intravenous lipid (referred to as “TPN”), at 09.00 h this morning. He has an Umbilical Arterial Catheter (UAC) and a peripheral i.v. cannula. Blood glucose is 11 mmol/litre, sodium is 140 mmol/litre, blood gas is normal, FiO2 is 35% and systolic blood pressure is 45 mmHg.