Respiratory support and bronchopulmonary dysplasia in infants born at 22-26 weeks gestation in Sweden, 2004-2007 and 2014-2016.

Background: Our aim was to evaluate if increased survival and new ventilation strategies were accompanied by a changed incidence of bronchopulmonary dysplasia (BPD) in Sweden over a decade.
Methods: Data from two Swedish population-based studies of live-born infants with gestational age (GA) 22-26 weeks, born during 2004-2007 (n=702) and 2014-2016 (n=885), were compared for survival, any BPD, moderate BPD and severe BPD and the composite outcomes of any BPD or death and severe BPD or death at 36 weeks postmenstrual age (PMA). Ventilation strategies and interventions were analysed. Any BPD was defined as the use of supplemental oxygen or any respiratory support at 36 weeks PMA, moderate BPD as nasal cannula with <30% oxygen and severe BPD as ≥30% oxygen, continuous positive airway pressure (CPAP) or mechanical ventilation.
Results: Survival to 36 weeks PMA increased from 72% to 81% (p<0.001). Total days on mechanical ventilation increased from a median of 9 to 16 days (p<0.001). High-flow nasal cannula (HFNC) was introduced between the cohorts, and days of CPAP and HFNC increased from 44 to 50 days (p<0.001). Any BPD was unchanged at 65% versus 68%. Moderate BPD increased from 37% to 47% (p=0.003), while the incidence of severe BPD decreased from 28% to 23% (p<0.046). Severe BPD or death decreased from 48% to 37% (p<0.001), while any BPD or death remained unchanged at 74% versus 75%.
Conclusion: Even though an increased survival of infants born at 22-26 weeks GA was accompanied by an increased duration of invasive and non-invasive respiratory support, the incidence of any BPD remained unchanged, while severe BPD decreased in infants alive at 36 weeks PMA.
Competing Interests: Conflict of interest: L. Löfberg reports support for the present manuscript from Östergötland County Council, Linköping, Sweden. They also report support for attending meetings and/or travel from Crown Princess Victoria Children's Hospital, Linköping, Sweden. T. Abrahamsson has nothing to disclose. L.J. Björklund has nothing to disclose. L. Hellström Westas reports grants from the Swedish Research Council, participation on a data safety monitoring board with the BANON (Biomarkers And Neurological Outcomes in Neonates) Advisory Board (2018–2023), leadership roles with the Swedish National Board of Health and Welfare (Scientific Advisor in Neonatology), Queen Silvia Jubilee Foundation (Research Board), Foundation Acta Paediatrica (Board member), Swedish Paediatric Association (Chair 2020–2022) and John Lind Foundation (Board member), and stock with NeoEnergy Sweden AB (family company, owns 30%, technical and medical consulting). A. Farooqi has nothing to disclose. M. Domellöf has nothing to disclose. U. Ådén reports support for the present study from Region Stockholm and Karolinska Institutet, grants from Region Stockholm and Karolinska Institutet and the Childhood Foundation of the Swedish Order of Freemasons, and payment or honoraria for lectures, presentations, manuscript writing or educational events from Chiese Pharma (invited speaker at Nordic Neonatal Meeting 2021). C. Gadsbøll reports support for the present study and travel support from the Swedish Heart–Lung Foundation (20200808), Swedish Research Council (2020-01236), Swedish governmental funding of clinical research (ALF), and Region Skåne, Skåne University Hospital in Lund. K. Källén has nothing to disclose. D. Ley reports grants from ALF project grant, Lund University, and the Swedish Research Council. E. Normann has nothing to disclose. K. Sävman has nothing to disclose. A. Elfvin has nothing to disclose. S. Håkansson has nothing to disclose. M. Norman reports support for the present study from Region Stockholm and Karolinska Institutet, grants from Region Stockholm and Karolinska Institutet and the Childhood Foundation of the Swedish Order of Freemasons, royalties from Studentlitteratur AB, consultancy fees from Swedish Patient Insurance, payment or honoraria for lectures, presentations, manuscript writing or educational events from Chiese Pharma, and support for attending meetings from Chiese Pharma. R. Sindelar reports payment for expert testimony as External Auditor of Applications for Governmental Funding in paediatric, gynaecological/obstetrical, nephrological and urogenital diseases, Karolinska Institutet/Hospital Region Stockholm; and unpaid Chairman of the BPD Collaborative International Committee; and a leadership or fiduciary role as unpaid President for Neonatal Pulmonology, Swedish Neonatal Society, Swedish Paediatric Association; unpaid Board Member Neonatal Pulmonology, European Society of Paediatric Research; unpaid Member of the BPD Collaborative Executive Board, USA. F. Serenius reports support for the present manuscript from the Swedish Research Council (grant/award 2006-3858, 2009-4250). P. Um-Bergström has nothing to disclose.
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