Cardiorespiratory coupling during high-frequency oscillatory ventilation with volume guarantee in extremely preterm infants.

UNLABELLED: This study aims to evaluate associations between PCA-derived cardiovascular components and respiratory burden during high-frequency oscillatory ventilation with volume guarantee (HFOV-VG). This retrospective cohort study included infants born before 30 weeks of gestation who received HFOV-VG and underwent targeted neonatal echocardiography during respiratory support. Echocardiography assessed ventricular systolic function, cardiac output, myocardial deformation, and pulmonary vascular loading. Principal component analysis (PCA) derived integrated cardiovascular components. Multivariate regression models evaluated associations with respiratory support, haemodynamic support, and clinical outcomes, including mortality, moderate-to-severe bronchopulmonary dysplasia (BPD), and the composite outcome of death or moderate-to-severe BPD. Sixty-two infants were included (gestational age 26.0 [25.0-27.0] weeks; birth weight 860 [700-1000] g). Median FiO₂ during HFOV-VG was 0.35 (0.31-0.52). Right ventricular strain demonstrated the strongest association with FiO₂ (rho = 0.53, q < 0.001). The first principal component (PC1), representing a cardiopulmonary loading component characterised by less favourable ventricular performance, reduced cardiac output, altered myocardial deformation, and increased septal loading, explained 65.9% of echocardiographic variance. Each one standard deviation increase in PC1 was associated with a 0.60 standard deviation increase in FiO₂ (95% CI 0.38-0.82; p < 0.001). Higher PC1 was independently associated with mortality (OR 3.01, 95% CI 1.44-6.29; p = 0.004), higher peak vasoactive-inotropic score, longer inotropic support, increased odds of inotrope use, and lower odds of haemodynamically significant patent ductus arteriosus (all p < 0.05). CONCLUSION: In preterm infants receiving HFOV-VG, the first cardiovascular principal component was independently associated with oxygenation burden, haemodynamic support requirements, and mortality. PCA-derived cardiovascular assessment may complement conventional respiratory assessment during HFOV-VG. WHAT IS KNOWN: • Oxygenation during high-frequency oscillatory ventilation is influenced by both respiratory and cardiovascular factors. • Targeted neonatal echocardioghraphy can assess multiple aspects of cardiovascular function, but most studies have evaluated individual haemodynamic variables rather than integrated cardiovascular profiles. WHAT IS NEW: • Exploratory principal component analysis identified a cardiovascular component independently associated with oxygen requirements during HFOV-VG. • The first principal component was independently associated with oxygenation burden, haemodynamic support requirements, and mortality, supporting an integrated cardiorespiratory approach to physiological assessment during HFOV-VG.