Study on the Geometric Parameters and Hemodynamic Reference Range of Neonatal Heart.

Perform bedside echocardiography on neonates (term and preterm infants) who were admitted to our neonatal department within 24 hours of birth, and establish a geometric reference range of neonatal cardiac ultrasound and explore the hemodynamic changes of early newborns. Bedside echocardiography were performed to measure the diameter of each heart cavity and large vessels, velocity of each valve and aorta, wall thickness, left ventricular systolic function, right heart Tei index, Tricuspid Annular Plane Systolic Excursion(TPASE) of term and preterm infants respectively on 0 day, 3d, 7d of life and postmenstrual age of 30 weeks, 32 weeks, 34 weeks and 36 weeks.