Objective To investigate the association between invasive mechanical ventilation (IMV) duration and long-term neurodevelopmental outcomes in preterm infants in an era of restricted IMV.

Design Retrospective cohort study.

Setting Single neonatal intensive care unit in Amsterdam.

Patients All ventilated patients with a gestational age between 24 and 30 weeks born between 2010 and 2015.

Main outcome measures Neurodevelopmental impairment (NDI) at 24 months corrected age (CA). Data on patient characteristics, respiratory management, neonatal morbidities, mortality and bronchopulmonary dysplasia were collected. The relationship between IMV duration and NDI was determined by multivariate logistic regression analysis.

Results During the study period, 368 admitted infants received IMV for a median duration of 2 days. Moderate and severe bronchopulmonary dysplasia was diagnosed in 33% of the infant. Multivariate regression analysis with adjustment for gestational age, small for gestational age and socioeconomic status showed a significant association between every day of IMV and NDI at 24 months CA (adjusted OR [aOR] 1.08, 95% CI 1.004 to 1.16, p=0.04). This association only reached borderline significance when also adjusting for severe neonatal morbidity (aOR 1.08, 95% CI 1.00 to 1.17, p=0.05).

Conclusion Even in an era of restricted IMV, every additional day of IMV in preterm infants is strongly associated with an increased risk of NDI at 24 months CA. Limiting IMV should be an important focus in the treatment of preterm infants.