Risk Factors and Outcomes Associated with Pneumothorax in Very Preterm Infants.

Background/objectives: Pneumothorax can be a major complication of neonatal lung diseases. We aim to delineate trends and describe the main outcomes related to pneumothorax in very preterm infants (VPI).

Methods: Preterm infants < 32 weeks of gestation admitted in two-level III neonatal intensive care units (1995-2019) were included. Risk factors and outcomes were assessed by logistic regression and adjusted for gestational age (GA).

Results: In total, 4271 VPI with a mean GA of 28.7 ± 2.3 weeks were evaluated. Pneumothorax was diagnosed in 174 patients (4.1%, 95% Confidence Interval (CI) 3.5-4.7) with its incidence inversely proportional to GA: 9.9% in 23-25 w and 2.1% in 30-31 w (p < 0.001), but stable over the years 1995-1999 (5.2%) and 2015-2019 (4.2%) (p = 0.309). Patients with pneumothorax exhibited higher rates of severe intraventricular hemorrhage (IVH) (Odds Ratio (OR) = 2.0 (95%CI 1.3-3.1), p = 0.003), bronchopulmonary dysplasia (OR = 2.7 (95%CI 1.7-4.4), p < 0.001), and death (OR = 8.5 (95%CI 6.2-11.6), p < 0.001). Independent risk factors for pneumothorax were GA, prolonged premature rupture of membranes, and intubation in the delivery room. The composite outcome of death or severe IVH was higher in patients with pneumothorax with an adjusted OR = 6.7 (95%CI 4.7-9.6), p < 0.001. Although VPI mortality has significantly decreased over the years (20.3% 1995-1999 and 11.7% 2015-2019, p < 0.001), we found no significant difference in pneumothorax-related deaths.

Conclusion: Pneumothorax remains a serious threat to VPI, leading to a higher incidence of morbidity, and mortality attributable to this complication has not decreased. Preventive strategies and early recognition are essential for improving disability-free survival in VPI.