Nasal High Frequency Ventilation in Preterm Infants: A Pilot Study

The purpose of this study is to test whether application of high frequency ventilation through a nasal tube can lower blood carbon dioxide levels in stable preterm infants.

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.

Stable infants born at less than 1501 g who are at least 7 days old and undergoing nasal continuous positive airway pressure treatment.

use of the high frequency ventilation mode of the Infant Star ventilator via a single nasopharyngeal prong.

Capillary partial pressure of CO2 (pCO2) was measured before and after 2 hours of nasal high frequency ventilatiion in a group of subjects. Each served as his/her own control.

We used a transcutaneous CO2 monitor (TCOM) as a safety device throughout the study. We analyzed the change in TCOM readings recorded every 30 minutes (5 measurements) to determine safety

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