Inclusion Criteria:  Infants born at 34 weeks completed gestation and above requiring mechanical ventilation and admitted to King's NICU Any gender, ethnicity or other comorbidities  Exclusion Criteria:  Preterm infants less than 34 weeks gestation Infants with cyanotic congenital heart disease Infants undergoing planned procedures or surgery during the monitoring period Infants on high frequency oscillatory ventilation (HFOV)