Editor—Dargaville et al 1 suggest that infants with severe bronchiolitis exhibit surfactant deficiencies. This has exciting implications for treatment in an illness in which active treatment is essentially supportive. However, the conclusions drawn from their pilot study are limited by the inclusion of unmatched controls.

Most controls were not premature (median gestational age 39 weeks) compared with the infants with bronchiolitis, who were (median gestational age 34 weeks, including one infant born at 24 weeks). At the time of study, the median age of control infants was 1.5 months, whereas the corrected median age of the bronchiolitic infants made them the equivalent of term babies. Weights were also correspondingly different.

Preterm neonates are more likely to have been ventilated before, and to have underlying lung disease, such as …