NeoCirc-001 - The primary objective is to answer some important questions required for the design of a subsequent placebo-controlled trial (NeoCirc-003), which will evaluate the effectiveness of a new neonatal formulation of dobutamine to treat haemodynamic insufficiency in the first 72 hours after birth in babies born at less than 33 weeks' gestation. Observational data will be collected from this population with a view to determining the degree to which diagnostic measures influence treatment decisions. The primary outcome is death or worst cranial ultrasound (CUS) appearance at or before 36 weeks' gestation.