Inclusion Criteria:  1. Extremely low gestational age newborn infants (GA < 28 weeks) - gestational age matching between maternal dates and/or early antenatal ultrasound 2. Singleton or multiple birth 3. Postnatal age between 7 and 10 days 4. Invasive mechanical ventilation still needed 5. Fraction of inspired oxygen (FiO2) of more than 0.30 and/or an oxygenation index of 8 or more for at least 6 hours 6. Stable cardiovascular condition 7. Informed consent form signed by parents or legal guardian  Exclusion Criteria:  1. Major congenital malformation (i.e., infants with genetic, metabolic or endocrine disorder diagnosed before enrolment) 2. High index of suspicion of infection before enrolment 3. Neurological conditions that might contraindicate extubation 4. Inotropic agents needed 5. Pneumothorax 6. Hemodynamically significant ductus arteriosus 7. Surgical intervention within the past 72 hours 8. Partecipation in another interventional clinical study that may interfere with the results of this trial 9. Known hypersensitivity to the drug or to one of the excipients