Objective:To test whether the level of serum inflammatory factors could predict the occurrence of ventilator-associated pneumonia(VAP) undergoing cardiopulmonary bypass(CPB) cardiac surgery. Methods:Twenty valve replacement patients were categorized into two groups based on the occurence of VAP following CPB,VAP group(A) and NVAP group (B). The blood samples of left atrium were collected in both groups at the time points of preoperation(T1),20 min after CPB(T2),40 min after CPB(T3) and end(T4) of CPB. Expression of serum IL-10,IL-1β and TNF-α were detected by ELISA. The common and CPB data of all cases in two groups were compared. Results:There was no significant difference in TNF-α and IL-1β in each time point between VAP group and NVAP group. The expression of IL-10 and IL-10/TNF-α ratio in NVAP group at the time points of T3 and T4 were significantly higher than VAP group (P < 0.05). The occurance of VAP was correlated with the CPB time. Conclusion:The increase of the expression of IL-10 could significantly decrease the occurence of VAP.