The effect of sequential nutrition support on 5 congenital chylothorax infants，1 Wang Wenqiao, 2 Wang Yuqi, 1 Long Qi, 1 Zhang Ting, 1 Chen Fei, 1 Chen Yuzhi, 1 Ma Ming 1 Department of Clinical Nutrition, the Children Hospital, Zhejiang University of Medicine/National Clinical Research Center for Child Health, Hangzhou 310052, Zhejiang, China; 2 Department of Respiratory Medicine, the Children Hospital, Zhejiang University of Medi‑ cine/National Clinical Research Center for Child Health, Hangzhou 310052, Zhejiang, China Abstract: Objective This research aims to explore the effect of sequential nutritional support on congenital chylothorax in infants, and to provide the basis for standardized treatment. Methods We collected five infants who were diagnosed with congenital chylothorax at Children′s Hospital of Medicine of Zhejiang University from January 2017 to December 2019, and retrospectively summarized clinical manifestation and analyzed the effect of the sequential nutritional support. Results A total of five infants with congenital chylothorax were recruited, including two males and three females. The average age of diagnosis was (75±17) days. All the 5 patients were characterized by cough and tachypnea, with 1 case accompanied by gastrointestinal symptoms (vomiting and diarrhea). The prenatal ultrasound detected pleural effusion in five patients, four of which presented with right pleural effusion, and the remaining one with bilateral pleural effusion. The average hydrothorax volume was (3.6±1.8) cm. All the five patients received sequential nutritional support (total parenteral nutrition to high MCT enteral nutrition) and recovered from conservative treatment. The height and weight of patients were both increased after treatment［ (61.9±2.2)cm vs (67.0±2.0)cm, t=23.3, P<0.001; (5.7±0.6)kg vs (7.2±0.6)kg, t=12.7, P<0.001, respectively］. The average values of length for age Z score（HAZ）、weight for age Z score（WAZ）、weight for length Z score（WHZ）before and after treatment were 1.45 and 1.48 (t=0.35, P=0.75), 0.004 and -0.39 (t=2.91, P=0.04), -0.83 and -0.59 (t=-0.58, P=0.59), and the incidence of malnutrition was 60% and 20%, respectively. The level of prealbumin in patients increased significantly after treatment［ (0.12±0.04) g/L vs (0.16± 0.02)g/L, t=-4.67, P=0.01］; while the change of albumin level had no statistical significance［(41.6±3.4)g/L vs (42.1±3.1)g/L, t= -0.75, P=0.49］. Through follow⁃up of two months, all the patients had no relapse of pleural effusion. Conclusion Patients with congenital chylothorax have high malnutrition risk. Nutritional support is an essential part of conservative treatment in patients with congenital chylothorax. The clinical symptoms and nutritional status of five cases were all improved after receiving sequential nutritional support. Key Words: Congenital chylothorax；Sequential nutrition treatment；Pleural effusion