Forced Oscillometry in Infants With Bronchopulmonary Dysplasia

Pulmonary function testing has been the standard of care to diagnose and evaluate response to therapy in various respiratory diseases in adults and children. There are several equipment and techniques that are FDA approved for these purposes. However, there are currently no lung function tests that are practically feasible, clinically meaningful and widely used in infants.

The forced oscillation technique (FOT) is a non-invasive method that had been used to measure respiratory mechanics. FOT employs small amplitude pressure oscillations superimposed on the normal breathing and therefore has the advantage over conventional lung function techniques that it does not require the performance of respiratory maneuvers. To date, the use of this technique is FDA approved in adults and children but remains largely experimental in infants and newborns. THORASYS has recently developed a new respiratory function test device aimed specifically at newborn and infants (0 - 2 years age group) called tremoflo N-100 ("Neo"). This new device measures lung function in only a few minutes while the newborn or infant is sleeping normally. It uses an adapted version of the Airwave Oscillometry (AOS) to calculate the impedance of the lungs and quantify airway obstruction.

Diuretics and bronchodilators are two on the most commonly used medications to ameliorate the symptoms of BPD. The benefits of these therapies have not been shown to prevent the development of BPD in a randomized control trial (RCT). More recently, there have been some evidence from pharmacogenetic studies that the variability in bronchodilator responsiveness in patients with asthma, (and possibly BPD) may lie on the gene encoding the B2-adrenergic receptor (ADRB2) as well as within the associated G-protein receptor pathway, the nitric oxide biosynthetic pathway and other novel loci identified in recent genome-wide studies. This part of the study will be hypothesis generating to try to understand the variability in bronchodilator response in infants with BPD. Normative data will be established in term neonates.

Inclusion criteria

Preterm Cohort:

• Premature infants with BPD who are in room air based on the (per NICHD definition)
• Premature infants with BPD who are receiving low flow O2 support and able to maintain normal spO2 in Room air for brief period ( up to 3 minutes) Term Cohort without pulmonary disease
• Infants >36 weeks gestational age without pulmonary disease
• Infants < 4 weeks of age

Outpatient Cohort:

• Former preterm infants < 32 weeks at birth
• Those with BPD based on NIH 2001 definition
• Seen prior to 2 years of age

Exclusion criteria

• Infants with BPD requiring invasive or non-invasive positive pressure ventilation
• Infants with BPD who have associated genetic diagnosis or major congenital anomalies.