摘要Background Since 2010,most tertiary care hospitals in Australia have changed how they care for extremely premature infants.However,in-hospital and longer-term outcome data have suggested unchanged or even worse health outcomes in later epochs,especially respiratory outcomes.This study examined the trend in outcomes since these changes were introduced,particularly the prevalence of chronic neonatal lung disease(CLD).Methods This is a retrospective cross-sectional analysis of data from the Neonatal Intensive Care Units'(NICUS)database of all perinatal intensive care units in New South Wales and the Australian Capital Territory,including infants born at ≥24 and≤28 weeks of gestational age in tertiary perinatal units between January 1,2010,and December 31,2020.Temporal trends and changes in primary outcome were examined by linear and adjusted multivariable logistic regression models.Results This study included 3258 infants.We saw significant changes in antenatal magnesium sulfate(75％increase),delayed cord clamping(66％increase),delivery room intubations(30％decrease),any time(20％decrease),duration on mechanical ventilation(100-hour decrease),and hours on noninvasive ventilation(200-hour increase).Mortality decreased from 17％to 6％.The incidence of CLD increased significantly even when adjusted for confounders(15％increase).Any time and mean hours spent on mechanical ventilation significantly increased the odds of CLD.This study could not find a significant association of any of the protective antenatal treatments on CLD.Conclusions The last decade saw a significant improvement in survival and survival to discharge without major morbidity.There was increased use of magnesium sulfate,delayed cord clamping,and less invasive respiratory management of extremely preterm infants.The avoidance of mechanical ventilation may impact the incidence of CLD.