Objective:To explore the influence of high-dose poractant alfa injection combined with high frequency oscillatory ventilation(HFOV)or continuous positive airway pressure(CPAP)on blood gas indexes in children with very low birth weight infants(VLBWI)complicated with respiratory distress syndrome.Methods:166 patients with VLBWI complicated with respiratory distress syndrome were retrospectively enrolled.According to the different methods of respiratory support,they were divided into control group(poractant alfa+CPAP,n=88)and observation group(poractant alfa+HFOV,n=78),both groups were treated for 7 days.The blood gas indexes,weaning time,symptom relief time,oxygen therapy time,hospitalization time and adverse reactions were compared be-tween both groups of children.Results:After treatment,the arterial partial pressure of oxygen(PaO2)in the observation group was higher than that in the control group(P<0.05),while the partial pressure of carbon dioxide(PaCO2)fraction of inspiration oxygen(FiO2),and oxygenation index(OI)were all lower than those in the control group(P<0.05).The hospitalization time,symptom relief time and incidence rates of adverse reactions were not statistically different between the two groups(P>0.05),and the weaning time and oxygen therapy time were shorter in the observation group(P<0.05).Conclusion:Poractant alfa injection combined with HFOV or CPAP can quickly improve the blood gas indexes and enhance oxygenation in children.However,poractant alfa injection combined with HFOV is more effective.