Nasal High Frequency Oscillatory Ventilation (NHFOV) Versus Nasal Continuous Positive Airway Pressure (NCPAP) Ventilation: a Pilot Trial

Extremely preterm infants frequently need to be placed back on invasive mechanical ventilation following initial attempts to remove them from this mode of respiratory support. Continued mechanical ventilation is thought to be the primary driver in the development of chronic lung disease and a major component in adverse developmental outcome of these infants. Infants fail their first trial of removal from ventilation because of apnea and respiratory failure. Animal studies and early clinical experience suggest that it is possible to effectively provide ventilation via high frequency nasal ventilation. In the animal models this mode of ventilation appears to provide for better lung development and less injury.

Nasal CPAP has been shown to improve the success rate of extubation from mechanical ventilation by preventing post extubation atelectasis with resultant improvements in gas exchange. However in many of the most premature infants, poorly developed control of respiratory drive is a major problem and despite treatment with caffeine, mechanical ventilation is needed. High frequency nasal ventilation may support ventilation enough during apneic periods to mitigate the need for traditional mechanical ventilation. Use of non-invasive modes may result in a decrease in the incidence and or severity of chronic lung problems and developmental disability of this group of infants.

Extremely premature infants (GA <28 weeks) less than 7 days old will be randomized to either NHFV or nCPAP following the first attempt at extubation and removal from mechanical ventilation. All infants will have received at least a loading dose of caffeine citrate (10 mg/kg of caffeine base equivalent prior to extubation. Initial nCPAP level will be determined by clinical staff but will be at least equal to the level of positive end expiratory pressure (PEEP) used during mechanical ventilation. A similar level of pressure will be used as initial mean airway pressure (MAP) in infants receiving HFNV.

The primary outcome will be need for reintubation during the first 7 days after extubation attempt due to preset criteria. Crossover to the other modality will not be allowed during this period. Infants may remain on HFNF beyond the 7 day primary endpoint if deemed necessary by the clinical staff. Weaning of HFNV to nCPAP will be allowed during the 7 day primary study period and reinstitution of HFNF will be allowed for those initially randomized to that mode of respiratory support.

The magnitude of the effect size cannot be determined as there are no studies to base a sample size calculation on. A pragmatic sample size of 20 infants was selected (10 in each arm) to allow estimation of any potential effect size. Further study(ies) will need to be performed to show conclusively efficacy (or lack) of NHFV to prevent post-extubation respiratory failure or its use in preventing chronic lung disease or improving developmental outcomes.