DOES THE DURATION OF OXYGEN DEPENDENCE AFTER BIRTH INFLUENCE SUBSEQUENT RESPIRATORY MORBIDITY

The relationship of respiratory morbidity at follow up to the developm ent and type of ''neonatal'' chronic lung disease has been assessed. T hree groups, each of ten infants matched for gestational age and gende r, were compared. Group A had Type I chronic lung disease and group B bronchopulmonary (BPD), the most severe form of neonatal chronic lung disease (Type II CLD); group C had developed neither Type I or Type II CLD. Group B compared to group A compared to group C required a signi ficantly longer duration of oxygen therapy on the neonatal unit. All t hree groups were prospectively followed; the occurrence of symptoms wa s documented in each of the first 3 years of life and lung function wa s measured using a plethysmographic technique at the end of year 1. In all 3 years a significantly greater proportion of groups A and B were symptomatic compared to group C, but there was no significant differe nce in the proportion so affected between groups A and B. Airway resis tance was higher in both groups A and B compared to C but only reached statistical significance on comparing groups A and C. We conclude oxy gen dependency beyond 1 month of age, irrespective of the development of BPD, significantly increases respiratory morbidity at follow up.