Lung function of preterm infants before and after viral infections

Our aim was to determine whether viral lower respiratory tract infections (LRTIs) adversely affect prematurely born infants' lung function at follow up. Seventy infants, median gestational age 34 (range, 24-35) weeks were prospectively followed; 32 had an RSV (n = 14) or another respiratory viral (n = 18) LRTI (viral LRTI group) and 38 had no LRTI (no LRTI group). Six of the viral LRTI and five of the no LRTI group had been hospitalised. Nasopharyngeal aspirates (NPAs) obtained whenever the infants had an LRTI. Lung function (functional residual capacity [FRCHe], compliance [Crs] and resistance [Rrs] of the respiratory system) was measured at 36 weeks postmenstrual age (PMA) and 1 year corrected. At 1 year, lung volume (FRCpleth) and airways resistance (Raw) were also assessed. There were no significant differences in the lung function of the two groups at 36 weeks PMA but at 1 year, the viral LRTI compared to the no LRTI group had a higher mean Raw (23 versus 17 cm H2O/l/s, p = 0.0068), the differences remained significant after adjustment. Conclusion: These results suggest viral LRTIs, regardless of whether hospitalisation is required, adversely affect prematurely born infants' airway resistance at follow up.