Final answer:
The infant should be suspected to having moderate BPD according to the diagnostic criteria outlined by the National Institutes of Health.
Step-by-step explanation:
Respiratory distress syndrome (RDS) is a disorder that primarily occurs in premature infants. It results from insufficient production of pulmonary surfactant, which prevents the lungs from properly inflating at birth. Infants with RDS may require supplemental oxygen to maintain adequate oxygen levels in their blood.
Based on the information given, the infant in question was born at 30 weeks gestation and is now 36 weeks postmenstrual age (PMA), and is still receiving oxygen by nasal cannula at 0.5L/min and an FIO2 of 26%. According to the diagnostic criteria outlined by the National Institutes of Health, an infant who requires supplemental oxygen at 36 weeks, PMA would be classified as having moderate BPD (Bronchopulmonary Dysplasia).