Patients will receive nebulized azithromycin (Xithrone, Amoun, Egypt) that will be initiated from day 7 of birth in a dose of 20 mg/kg/day in two divided doses for 3 weeks till the time of primary outcome assessment (at 28 days of age).

Patients will not receive the medication, instead will receive 3 ml of nebulized normal saline as placebo control.

nebulized azithromycin (Xithrone, Amoun, Egypt) that will be initiated from day 7 of birth in a dose of 20 mg/kg/day in two divided doses for 3 weeks till the time of primary outcome assessment (at 28 days of age). Azithromycin solution for nebulization will be prepared from intravenous vials containing 500 mg lyophilized powder. First, each lyophilized powder vial will be prepared with 5 ml normal saline according to the manufacturer's instruction. The reconstituted solution will be diluted with 28.5 ml normal saline to make a final concentration of 17.5 mg/ml according to clinical pharmacy recommendation. For nebulization of azithromycin, 0.6 ml of final drug prepared solution will be taken for every

1 kg body weight of patient, then made up to 3 ml of normal saline and will be administered by Aerogen Jet Nebulizer every 12 hours using 8 liter/min of medical air or by face mask if not mechanically ventilated. According to the manufacturer's declaration, prepared azithro

Developed BPD :Yes or No If patient fulfilled criteria of BPD ; patient is born at or less than 32 weeks gestational age and still need oxygen and or respiratory support at the 28 day or more postnatal age and/or 36 weeks postmenstrual age.

Lung ultrasound score The score is calculated by the following points at different lung zones using lung ultrasound 0: A lines

1. 3 or more nonconfluent B lines
2. confluent B lines
3. C profile or consolidation