High-frequency oscillatory ventilation during physiological-based cord clamping attenuates inflammation in preterm lambs

BACKGROUND: Adequate lung aeration at birth is essential for a successful transition to extrauterine life. Premature infants are especially vulnerable to injury caused by mechanical ventilation, particularly when exposed to excessive tidal volumes during initial respiratory support. OBJECTIVE: To evaluate whether high-frequency oscillatory ventilation (HFOV) initiated at birth facilitates lung aeration and reduces lung inflammation and injury, compared with conventional mechanical ventilation (CMV) in preterm lambs. DESIGN: Preterm lambs (126±1 days' gestation, term ~148 days) were instrumented to assess blood flow, pressure, oxygenation and blood gases. Lambs were allocated to HFOV (n=6), CMV (n=7) or unventilated control (UVC, n=8) groups. In ventilated groups, respiratory support was initiated during physiological-based cord clamping (PBCC). Lung aeration was assessed by lung ultrasound (LUS) in HFOV lambs. Postmortem lung tissues underwent histological and molecular analyses of inflammation and injury. RESULTS: HFOV achieved effective respiratory stabilisation using significantly lower tidal volumes compared with CMV (1.7±0.4 vs 6.2±1.5 mL/kg, p