Caffeine as an Adjuvant Therapy for Late Preterm Infants With Respiratory Distress

late preterm infants will be randomized in a blinded manner to receive either caffeine in loading dose 20 mg/kg (equivalent for 10 mg/kg caffeine base) and maintenance dose 10 mg/kg/day (equivalent for 5 mg/kg caffeine base) in Caffeine treatment group, or equivalent volume of saline in the placebo group. Caffeine will be continued until infants get off all forms of respiratory support. Preparation of caffeine and placebo will be performed by a designated pharmacist who is not part of the study. Parents and investigators will be remained blinded to the administered medications throughout the study period.