13. PEDIATRIC & SPECIAL-POPULATION NOTES

1. EPSS: validated in adults only. Do not apply to children.

2. ONSD: pediatric and ethnic cutoffs differ.

3. IVC collapsibility: only moderate ability to predict fluid responsiveness in children.

4. Umbilical catheters confound IVC assessment.

5. Neonatal cardiovascular transition is rapid and dynamic.

6. Suspected congenital or structural heart disease: pediatric cardiology.

7. TCD: adult norms are not applicable to children without pediatric reference data.

8. HCM: rare in children; differentiate from physiological LVH, storage diseases, and Noonan syndrome.

9. Obstetric/gynaecologic POCUS: transvaginal scanning is preferred for early pregnancy and placental localization when available and safe; POCUS has limited sensitivity for small intrauterine lesions.