comparison between Noninvasive Intermittent Positive Pressure Ventilation (NIPPV) and Noninvasive High Frequency Oscillation Ventilation (NHFOV) post-extubation in preterm neonates as regards the efficacy and their possible complications.

The global definition of preterm infant by the World Health Organization is any infant born before 37 weeks of gestation. Annually, an estimated 15 million (11.1%) preterm infants are born worldwide. Preterm birth is further classified as extremely preterm (<28 weeks), very preterm (28 to <32 weeks), and moderate (32 to <34 weeks) to late preterm (34 to <37 weeks).

Prematurity has been associated with several risk factors, such as history of previous preterm birth, pregnancy induced hypertension, premature rupture of fetal membranes, multiple pregnancy, bleeding during pregnancy, history of abortion, fetal malformation, inadequate antenatal care, polyhydramnios and previous caesarean section.

Preterm neonates are at greater risk of a range of short-term and long-term morbidities. Respiratory distress syndrome (RDS) is one of the most common causes of morbidity and mortality in preterm infants. RDS is characterized by a lack of lung surfactant. Insufficient surfactant production or secretion results in higher alveolar surface tension, leading to atelectasis and impaired gas exchange. Respiratory distress typically manifests in newborns as tachypnea, intercostal retractions, nasal flaring, grunting, and cyanosis.

Invasive mechanical ventilation (IMV) increases survival in preterm infants with severe RDS. However, prolonged intubation and mechanical ventilation of preterm infants increases the risk of life-threatening complications including, ventilator induced lung injury and airway inflammation leading to bronchopulmonary dysplasia, and nosocomial pneumonia, and also increases the risk of a poor neurodevelopmental outcome. Therefore, when caring for premature infants, clinicians should focus on weaning from IMV as expeditiously as possible to noninvasive respiratory support (NRS).

There are many strategies and criteria for weaning, including evaluation of ventilatory parameters, clinical/biochemical criteria, and predictive indices of extubation that can be followed by or combined with spontaneous breathing trials or gradual withdrawal from ventilatory support.

Noninvasive respiratory support modalities include continuous positive airway pressure (CPAP), high flow nasal cannula (HFNC), noninvasive intermittent positive pressure ventilation (NIPPV), bilevel CPAP (BiPAP) and noninvasive high frequency oscillation ventilation (NHFOV).

NIPPV is a time cycled, pressure limited mode of ventilation. Conventional ventilator is used to generate two levels of pressures, namely, Peak inspiratory pressure and positive end expiratory pressure. Additionally, a backup rate is provided typically using longer inspiratory time. The main drawback of neonatal NIPPV is the lack of synchronization, which is difficult to achieve and is often unavailable.

NHFOV is the application of a bias flow generating a continuous distending positive pressure with superimposed oscillations which have a constant frequency and an active expiratory phase. NHFOV combines the advantages of NCPAP and high-frequency ventilation, making it more effective at maintaining alveolar stability, eliminating CO2, and limiting barotrauma.

The study assumed that NHFOV is more efficacious than NIPPV as regard prevention of the need for re-intubation in preterm infants with gestational age between 32 and 36 weeks and 6 days after their 1st extubation.

Inclusion Criteria:

• Preterm neonates with gestational age between 32 and 36 weeks and on mechanical ventilation ready to be extubated.

When the case is ready for extubation , will receive at least one loading dose of caffeine citrate (20 mg/kg/dose) and daily maintenance dose of 5 mg/kg/dose.

Criteria for extubation:

• Blood gas analysis: PH > 7.25 and PaCO2 ≤ 60 mmHg.
• Airway pressure (Paw) of 7 to 8 cmH2O.
• Required fraction of inspired oxygen (FiO2) ≤ 30%.
• Sufficient spontaneous breathing by clinical evaluation.

Exclusion Criteria:

• Full term neonates.
• Preterm neonates who will not require intubation.
• Preterm neonates with one of the following criteria:

birth weight > 900 gms , major congenital anomalies, upper airway anomalies, neuromuscular diseases, surgical cases, intraventricular hemorrhage grade IV.

• Cases that require reintubation after more than 72 hours of extubation.