Inclusion Criteria:  Infants who are born at ≤ 32 weeks Gestational Age, Admitted to the neonatal intensive care at Mount Sinai Hospital Receiving invasive mechanical ventilation.  Exclusion Criteria:  Infants who are born at >32 weeks Gestational Age, On non-invasive mechanical ventilation Infants having congenital or chromosomal abnormalities, Infants intubated for < 12 hours Infants who have neurological insult, pneumothorax, or under muscle relaxant. If parents declined the consent.