The study hypothesized that a relative low oxygen concentration (40%) supplemental would be advantageous to protect the pulmonary function of patients, comparied with conventional high oxygen concentration (80%). Therefore we raise this prospective randomized controlled research.

Patients underwent minimally invasive esophagectomy in Zhongshan Hospital of Fudan University will be enrolled and be randomizedly assigned to low oxygen concentration (40%) supplemental or high oxygen concentration(80%) supplemental group. Intra-operative and post-operative pressure of Oxygen in Arterial Blood will be examined, and the surgical outcome will be recorded in the two groups.

Inclusion Criteria:

1. Clinical Staged T1-3N0M0 esophageal cancer patients or: patients who were restaged as T1-3N0M0 esophageal cancer after neo-adjuvant therapy.
2. Patients underwent minimally invasive esophagectomy(Thoracolaparoscopic McKeown procedure).

Exclusion Criteria:

1. Patients with previous thoracic surgery history.
2. Patients with severe Co-morbidity.
3. Pulmonary function is abnormal in the examination before surgery.