Objective To explore the effect and predictive value of blood lactate level on bronchopulmonary dysplasia(BPD)in newborns with neonatal respiratory distress syndrome(NRDS).Methods A total of 78 children with NRDS admitted to the First People's Hospital of Pingdingshan from January 2019 to December 2022 were selected as the research subjects.Based on whether they had BPD,the children were divided into a BPD group and a non-BPD group.The general clinical data of the children,including gestational age,gender,birth weight,1-minute Apgar score,5-minute Apgar score,and premature rupture of membranes,were collected.At admission,1 mL of arterial blood was extracted from the children,and the blood lactate level,arterial partial pressure of oxygen(PaO2),arterial partial pressure of carbon dioxide(PaCO2),pH value,and oxygenation index(OI)were measured using a JM1113-739853 blood gas analyzer;3 mL of peripheral venous blood was extracted from the children,and the level of interleukin-6(IL-6)in the serum was detected by enzyme-linked immunosorbent assay,while the levels of C-reactive protein(CRP)and procalcitonin(PCT)in the plasma were detected by double antibody sandwich method.The general information,blood lactate levels,PaO2,PaCO2,pH value,OI,serum IL-6 levels,plasma CRP and PCT levels of children were compared between the two groups.The correlation between blood lactate levels and NRDS complicated with BPD was determined by point-biserial correlation analysis,the influencing factors of NRDS complicated with BPD was analyzed by logistic regression,and the predictive value of blood lactate levels for NRDS complicated with BPD was analyzed by receiver operating characteristic curve.Results The blood lactate levels of 78 children with RDS ranged from 3.35 to 6.64(5.04±0.72)mmol·L-1.There were 16 children with BPD,with an incidence rate of 20.51％(16/78).The birth weight and OI of children in the BPD group were significantly lower than those in the non-BPD group,while the serum IL-6,plasma CRP,and blood lactate levels were significantly higher than those in the non-BPD group(P＜0.05).There was no statistically significant difference in gestational age,gender,1-minute Apgar score,5-minute Apgar score,premature rupture of membranes,PaO2,PaCO2,pH value,and PCT of children between the two groups(P＞0.05).The point-biserial correlation analysis showed that blood lactate,serum IL-6,and plasma CRP levels were positively correlated with the risk of BPD in children with NRDS(r=0.502,0.475,0.507;P＜0.05);while birth weight and OI were negatively correlated with the risk of BPD in children with NRDS(r=-0.242,-0.403;P＜0.05).Logistic regression analysis showed that blood lactate accumulation,high expression of serum IL-6,high expression of plasma CRP,and decreased OI were risk factors for BPD in children with NRDS(P＜0.05).The area under the curve for predicting BPD in children with NRDS based on blood lactate was 0.865,with a 95％confidence interval of 0.776 to 0.955;when the cut-off value of blood lactate was 5.065 mmol·L-1,the sensitivity and specificity of predicting BPD in children with NRDS were 0.938 and 0.501,respectively.Conclusion There is a positive correlation between blood lactate levels and the risk of BPD in children with NRDS.Blood lactate accumulation is a risk factor for NRDS complicated with BPD,and blood lactate level has a certain predictive value for NRDS complicated with BPD.