Effects Of Different Fraction Of Inspired Oxygen On SOD, 8-isoprostane And HsCRP During Gastrointestinal Tumor Resection

Objective:To evaluate effects of different fraction of inspired oxygen on oxidative stress and inflammatory response during gastrointestinal surgery by measuring SOD,8-isoprostane and hsCRP.Methods:19 patients(ASAⅠ～Ⅲ) undergoing elective gastrointestinal tumor resection enrolled in the study.After induction with midazolam,fentanyl and vecuronium followed by endotracheal intubation, patients were randomly assigned to two groups:group A for FiO₂=50% (n=10) and group B for FiO₂=100%(n=9).Anesthesia was maintained with sevoflurane combined with remifentanil,cis atracurium and fentanyl. Patients were ventilated with volume-controlled mode(8-10ml/kg).ECG, SPO₂,PetCO₂,NIBP,IBP were monitored during surgery;blood and gas analysis were performed if necessary.Two blood samples were obtained from each patient:5 min after the ventilation started(T₀) and 3 hours after ventilation(T₁) for SOD,8-isoprostane and hsCRP tests.Results:Sex ratio,age,BMI are all similar in both groups of patients(P＞0.05).Surgery duration,anesthesia duration,blood loss and fluid administration are comparable in the two groups(P＞0.05).The vital signs of patients were stable.1.Changes of SOD and 8-isoprostane:SOD and 8-isoprostane levels were similar in both groups at T₀.SOD decreased and 8-isoprostane increased significantly in both groups at T₁(P＜0.01),but 8-isoprostane level was higher and SOD was lower in group B than those in group A(P＜0.05).2.Changes of hsCRP:hsCRP was similar in both groups at T₀. HsCRP increased significantly in both groups at T₁(P＜0.01),and the increase was similar in the two groups(P＞0.05).Conclusion:1.Compared to 50%inspired oxygen,100%inspired oxygen has more obvious impact on SOD and 8-isoprostane.The oxidative stress is more severe in patients with 100%inspired oxygen.2.There is no significant difference in the effect of 50%inspired oxygen and 100%inspired oxygen on hsCRP.