Objective     To observe the effects of single or double lung venti

lation on intrapulmonary shunt fraction and oxygenation in esophageal cancer patients treated with thoraco-laparoscopic esophagectomy under artificial pneumothorax. Methods     Sixty esophageal cancer patients who underwent thoracolaparoscopic esophagectomy under artificial pneumothorax in the department of thoracic surgery of our hospital from January to December 2015 were randomly divided into single （O） and double (T) groups

with each group of 30 cases. The O group (26 males and 4 females) aged from 48 to 73 years (mean 60±13 years)， and weighted 48~73 kg. The  T group  (24 males and 6 females) were 44~74 years old (mean 58±16 years)

with a weight ranging from 50 to 71 kg. All the patients were anesthetized by double lumen endotracheal intubation. Blood gas analysis was measured from radial artery blood and right atrium blood before operation（T1），in 20 min（T2），40 min（T3） and 60 min（T4）under the procedure of  artificial pneumothorax

and at the end of operation（T5）. The intrapulmonary shunt fraction（Qs/Qt） and oxygenation index（P

a

O

2

/F

i

O

2

）were calculated. The hemodynamic parameters and quality of lung collapse  were recorded.  Results       The blood gas analysis showed that in both groups

Qs/Qt and P

a

CO

2

were significantly increased (P0.05）and P

a

O

2

/F

i

O

2

were significantly decreased (P0.05) in the artificial pneumothorax T2~T4 compared with in T1. No significant difference of  Qs/Qt，P

a

O

2

，P

a

O

2

/F

i

O

2

and P

a

CO

2

was found between the 2 groups at T1 and T5 (P0.05）.  At T2

T3

and T4

Qs/Qt values for T group were 27.5±8.2， 28.9±7.8 and 26.6±6.4

which were significantly lower than the corresponding Qs/Qt values (33.8±7.5，39.4±8.6 and 36.1±7.1) in O group（P0.05）. Also

PaO2 and PaO2 /FiO2 at T2， T3 and T4 were significantly higher in the T group（202±53， 215±46， 223±47） compared with in the O group（161±40， 149±54， 157±

39）（P0.05）. P

a

CO

2

were not significantly different between 2 groups （P0.05）. In addition

a significant better  quality of lung collapse was observed in the O group compared with the T group （P0.05）. Conclusion       Double lung ventilation has less impact on intrapulmonary shunt fraction and better oxygenation than single lung ventilation in the treatment of esophageal cancer patients with thoraco-laparoscopic esophagectomy under artificial pneumothorax.