Table 2 Inclusion and exclusion criteria for WP-I

1. Born at < 32 weeks gestational age.

2. The echo scans are indicated as per the recommended neonatal practice [19]:

 i. Preterm infants who require mechanical ventilation or non-invasive respiratory support (CPAP ≥ 4 cm H₂O, high flow ≥ 4 L/min)

 ii. Detection of a cardiac murmur in the first 3 days after birth

 iii. Assessment of patent ductus arteriosus (PDA)

 iv. Preterm infants have central line in-situ, so echo is needed to assess line position

1. Preterm infants with major congenital anomalies, such as pulmonary hypoplasia or congenital heart disease (except PFO or PDA)

2. Preterm infants with a poor prospect of survival

3. Preterm infants whose parents do not consent

4. Preterm infants who are still in need of blood pressure supporting medications, such as, (inotropes) when the study echo scans are due

5. Preterm infants need inhaled nitric oxide gas when the study echo scans are due