Abstract: Objective  To explore the effect of bronchial blocker(BB) on arterial blood gas index, lung collapse and incidence of atelectasis in children undergoing surgery for pulmonary hydatid cyst(PHC). 
Methods  A total of 63 children undergoing surgery for PHC were selected as the research subjects, and they were divided into the control group(n=30) and the research group(n=33) based on the random number table method. The control group was ventilated with a double-lumen bronchial catheter during surgery, and the research group was ventilated with a BB during surgery. Arterial blood gas indexes［partial pressure of carbon dioxide(PaCO2) and partial pressure of oxygen(PaO2)］, excellent and good rate of lung collapse, length of hospital stay, incidence of atelectasis and chest invasion were compared between two groups. 
Results  PaO2 in the two groups showed a gradual decrease, while PaCO2 showed a gradual increase. The PaO2 was lower while the PaCO2 was higher in the research group than in the control group. There were statistical differences in interaction between groups, time points, and time points between groups(P＜0.05). The excellent and good rate of intraoperative lung collapse at 20 min of single-lung ventilation in the two groups was higher than that of the same group at 10 min of single-lung ventilation, and the excellent and good rate of intraoperative lung collapse at 30 min of single-lung ventilation was higher than that of the same group at 10 and 20 min of single-lung ventilation. The excellent and good rate of lung collapse in the research group was significantly higher than that of the control group at 30 min of one-lung ventilation, and the difference was statistically significant(P＜0.05). There was no significant difference in the postoperative hospital stay, the incidence of atelectasis and chest infiltration between two groups(P＞0.05). 
Conclusion  The BB used in surgery for PHC in children can effectively improve the arterial blood gas function and increase the excellent and good rate of lung collapse during surgery. It is safer and has less impact on the incidence of atelectasis.

Key words: echinococcosis, pulmonary； bronchial blocker, arterial blood gas index