A 2-hour-old male neonate born to a 28-year-old primigravida at 38 weeks gestation presents with respiratory distress. The mother had meconium-stained amniotic fluid (MSAF) noted during labour. The infant was vigorous at birth with Apgar scores 8/9, and routine suctioning of the oropharynx and nasopharynx was performed. Now the baby has tachypnea (RR 68/min), grunting, intercostal and subcostal retractions, and mild cyanosis on room air. Chest X-ray shows patchy infiltrates with areas of hyperinflation and atelectasis. What is the most appropriate immediate management?