To study whether three concentrations of oxygen used during operation Will affect the ability to fight infections undergoing in patients under going surgery for cancer of large intestine – An experimental study

Intervention1: Group_0.5: Group_0.5 will receive 50% oxygen during the operation
Intervention2: Group_0.8: Group_0.8 will receive 80% oxygen during the operation
Control Intervention1: Group_0.3: Group_0.3 will receive 30% oxygen during the operation
Primary outcome(s): The primary end point of the study will be effect of different FiO2 on NK cell count (CD56, CD6)Timepoint: Perioperative period
Study Design: Randomized, Parallel Group, Multiple Arm Trial Method of generating randomization sequence:Computer generated randomization Method of allocation concealment:On-site computer system Blinding and masking:Participant, Investigator and Outcome Assessor Blinded