Nasal High Frequency Ventilation in Preterm Infants: A Pilot Study

Prolonged mechanical ventilation is frequently needed to treat respiratory insufficiency and apnea in very low birthweight (VLBW, <1500 g) preterm infants. Endotracheal intubation and mechanical ventilation carry many risks including potentially fatal air leaks and ventilator-associated pneumonias. Less-invasive methods of respiratory support are needed to minimize these risks while supporting the convalescing preterm infant. We propose to test the effectiveness of nasal high-frequency ventilation (NHFV) in stable neonates with mild respiratory acidosis who are dependent on nasal continuous positive airway pressure for respiratory support (CPAP). Nasal high frequency ventilation may be effective in decreasing rates of reintubation for apnea or respiratory insufficiency in VLBW infants. We will enroll 60 stable VLBW infants who are currently being treated with nasal CPAP and who have mild respiratory acidosis. Twenty patients will be assigned to each ventilator under investigation. Nasal high frequency ventilation will be applied at the same mean airway pressure as the patients' previous CPAP support. The amplitude on nasal high frequency ventilation will be adjusted to achieve adequate shaking of the chest wall. Blood gas measurements, transcutaneous continuous pCO2 monitoring, continuous pulse oximetry, and chest x-rays will be used to assess safety and efficacy. Study power has been calculated to detect a difference (drop or rise) in partial pressure of CO2 (pCO2) equal to two-thirds of the standard deviation of pCO2 change reported in another study (van der Hoeven et al., 1998), which is a clinically relevant difference.

Inclusion criteria

• birthweight less than 1500 g
• Age >7 days
• Free of severe intraventricular hemorrhage (Grade III-IV)
• requiring nasal continuous positive airway pressure with a stable compensated respiratory acidosis (pH 7.25 - 7.45, pCO2 > 43 mm Hg),
• medically stable.

Exclusion criteria

• major congenital anomalies