High Flow Nasal Oxygen Therapy in Pediatric Hypercapnic Respiratory Failure During Perioperative Stage

Inclusion Criteria: 1. Age ranges from 1 to 18 years 2. Hypercapnic respiratory failure: PaO2\<60mmHg and PaCO2 \>50 mmHg 3. Candidate for non-invasive respiratory support as a result of: 1. an intention to manage the patient with non-invasive (no endotracheal tube) respiratory support 2. an intention to extubate the patient being managed with intubated respiratory support to non-invasive support Exclusion Criteria: 1. Participation in a concurrent study that prohibits the use of HHFNC 2. Active air leak syndrome 3. Patients with abnormalities of the upper and lower airways; such as Pierre- Robin, Treacher-Collins, Goldenhar, choanal atresia or stenosis, 4. Patients with significant abdominal or respiratory malformations including tracheo-esophageal fistula, intestinal atresia, omphalocele, gastroschisis, and congenital diaphragmatic hernia 5. PaCO2\<50mmHg