PURPOSE: This retrospective study was designed to identify the incidence, outcome and analyze risk factors of perioperative pulmonary complications in children with mediastinal mass so that to achieve the Enhanced Recovery After Surgery(ERAS). METHODS: This study enrolled 247 pediatric patients undergoing mediastinal mass resection from June 2016 to June 2022. Medical record was reviewed for basic characteristics, presenting symptoms, preoperative imaging results, intraoperative data, and the occurrence of any pulmonary complications. Perioperative pulmonary complication was defined as intraoperative hypoxemia, postoperative respiratory failure, postoperative pulmonary infection or atelectasis. Univariate analysis and multivariate logistic regression were used to analyze the risk factors for perioperative pulmonary complications. RESULTS: The incidence of perioperative pulmonary complications was 25.9% and postoperative pneumonia was most common. children with perioperative pulmonary complications had longer mechanical ventilation time (186.5 min), ICU stay (1.5d) and hospital stay (9d, all P <
0.001). After multivariable analysis, preoperative cardiopulmonary compression symptoms (OR 21.337, P <
0.001), malignant tumor (OR 2.681, P = 0.043), anterior mediastinum(OR 2.616, P = 0.037), standardized tumor volume ≥ 0.65(OR 3.607, P = 0.003), intraoperative transfusion(OR 1.991, P = 0.004), surgery time ≥ 150 min (OR 2.363, P = 0.056) were the risk factors for perioperative pulmonary complications. CONCLUSIONS: Pulmonary complications were still common in children with mediastinal mass during or after surgery, which can influence the recovery after surgery with the prolonged mechanical ventilation time, ICU stay and hospital stay. Preoperative cardiopulmonary compression symptoms, malignant tumor, anterior mediastinum, standardized tumor volume ≥ 0.65, intraoperative transfusion and longer surgery time are associated with the occurance of perioperative pulmonary complications.