Multicentre prospective observational study exploring the predictive value of functional echocardiographic indices for early identification of preterm neonates at risk of developing chronic pulmonary hypertension secondary to chronic neonatal lung disease

IntroductionAlthough chronic pulmonary hypertension (cPH) secondary to chronic neonatal lung disease is associated with increased mortality and respiratory and neurodevelopmental morbidities, late diagnosis (typically ≥36 weeks postmenstrual age, PMA) and the use of qualitative echocardiographic diagnostic criterion (flat interventricular septum in systole) remain significant limitations in clinical care. Our objective in this study is to evaluate the utility of relevant quantitative echocardiographic indices to identify cPH in preterm neonates, early in postnatal course and to develop a diagnostic test based on the best combination of markers.Methods and analysisIn this ongoing international prospective multicentre observational diagnostic accuracy study, we aim to recruit 350 neonates born <27 weeks PMA and/or birth weight <1000 g and perform echocardiograms in the third week of age and at 32 weeks PMA (early diagnostic assessments, EDA) in addition to the standard diagnostic assessment (SDA) for cPH at 36 weeks PMA. Predefined echocardiographic markers under investigation will be measured at each EDA and examined to create a scoring system to identify neonates who subsequently meet the primary outcome of cPH/death at SDA. Diagnostic test characteristics will be defined for each EDA. Pulmonary artery acceleration time and tricuspid annular plane systolic excursion are the primary markers of interest.Ethics and disseminationEthics approval has been received by the Mount Sinai Hospital Research Ethics Board (REB) (#16-0111-E), Sunnybrook Health Sciences Centre REB (#228-2016), NHS Health Research Authority (IRAS 266498), University of Iowa Human Subjects Office/Institutional Review Board (201903736), Rotunda Hospital Research and Ethics Committee (REC-2019-008), and UBC Children’s and Women’s REB (H19-02738), and is under review at Boston Children’s Hospital Institutional Review Board. Study results will be disseminated to participating families in lay format, presented to the scientific community at paediatric and critical care conferences and published in relevant peer-reviewed journals.Trail registration numberNCT04402645.

Predictors of home oxygen duration in chronic neonatal lung disease

Aims: In infants with chronic neonatal lung disease (CNLD), we aimed to identify predictors of home oxygen duration, predictors of discharge oxygen flow rates and the association of oxygen flow rates with respiratory outcomes. Methods: Retrospective review of infants with CNLD requiring home oxygen in 2016 and 2017. Hazard ratios (HR) were estimated from Cox proportional hazards regression models in the cohort. A multinomial logistic regression model examined the effects of maternal and infant variables on discharge oxygen flow rates. Kruskal-Wallis test with univariate linear regression and Fisher’s exact test with binomial univariate logistic regression were used to examine associations between oxygen flow groups and post-discharge clinical variables. Results: 149 infants were included. Median corrected gestational age (CGA) at oxygen cessation was 6.8 months (IQR 4.4) with 87.2% of infants weaned by 12 months CGA. Shorter initial neonatal intensive care unit (NICU) stay predicted faster oxygen weaning at 9 months (HR 0.99, 95%CI 0.98-1.00, p=0.02) and 12 months (HR 0.99, 95%CI 0.98-1.00, p=0.02). Infants with hypercarbia at discharge or discharged from NICU at higher CGA had higher odds of requiring ≥200mL/min relative to ≤125 mL/min oxygen. Infants discharged with >250mL/min oxygen were more likely to have a respiratory related admission before two years chronologic age. Conclusion: Shorter initial NICU stay was the best predictor of earlier home oxygen cessation. At NICU discharge, infants with hypercarbia or a higher CGA may require more home oxygen and experience more respiratory related hospital admission in the first two years of chronological age.