Abstract

Objectives: To determine whether abnormalities of lung volume and/or airway function were associated with wheeze at follow-up in infants born very prematurely and to identify risk factors for wheeze.

Design: Lung function data obtained at 1 year of age were collated from two cohorts of infants recruited into the UKOS and an RSV study, respectively.

Setting: Infant pulmonary function laboratory.

Patients: 111 infants (mean gestational age 26.3 (SD 1.6) weeks).

Interventions: Lung function measurements at 1 year of age corrected for gestational age at birth. Diary cards and respiratory questionnaires were completed to document wheeze.

Main outcome measures: Functional residual capacity (FRC_pleth and FRC_He), airways resistance (R_aw), FRC_He:FRC_pleth and tidal breathing parameters (T_PTEF:T_E).

Results: The 60 infants who wheezed at follow-up had significantly lower mean FRC_He, FRC_He:FRC_pleth and T_PTEF:T_E, but higher mean R_aw than the 51 without wheeze. Regression analysis demonstrated that gestational age, length at assessment, family history of atopy and a low FRC_He:FRC_pleth were significantly associated with wheeze.

Conclusions: Wheeze at follow-up in very prematurely born infants is associated with gas trapping, suggesting abnormalities of the small airways.