Design and implementation of a multicenter protocol to obtain impulse oscillometry data in preterm children.

Importance: Objective measures of lung function are critical for assessing respiratory outcomes of prematurity. Among extremely low gestational age neonates (ELGANs) (< 29 weeks gestational age), high rates of neurodevelopmental impairment may interfere with lung function testing. Impulse oscillometry (IOS) is a noninvasive test of respiratory system mechanics not requiring forced expiration. Objective: To describe a multicenter study design for respiratory follow-up testing in a cohort with a high rate of extreme prematurity. Methods: School-age children enrolled in two prior trials of ELGANs and term controls were assessed by IOS at five centers. Groups consisted of children with prematurity with a high incidence of bronchopulmonary dysplasia, children with prematurity with no or minimal lung disease, and healthy term children. A rigorous centralized review process reviewed IOS studies for technical acceptability. Approach to design and implementation, rates of feasibility and success, and characteristics of participants are described. Results: A total of 243 children were recruited, of whom 239 (98%) attempted oscillometry. There were high rates of technical acceptability across all three cohorts (85%-90% of attempted tests), and across all five centers (80%-94% of attempted tests). Respiratory and neuromotor clinical factors associated with testing failure included a higher number of days on ventilation during neonatal intensive care, a history of intraventricular hemorrhage grade 3 or 4, and gross motor functional impairment. Interpretation: We report high rates of feasibility and success of oscillometry in a large multicenter ELGAN population, in whom neurological and developmental comorbidities likely play a confounding role.