The current definitions of neonatal shock/circulatory failure are outdated and inaccurate. This makes the development of evidence based protocols for its treatment very difficult. Furthermore these definitions often rely on invasive methods of monitoring in patients such as an arterial line. Since the advent of functional echocardiography in neonatology there has been increased interest in non-invasive measurements of neonatal circulatory failure. However research in this field has been confined to premature infants.