Objective To explore the influence of dexmedetomidine on blood gas and inflammation cytokines in patients with one-lung ventilation (OLV).Methods Sixty-two patients undergoing radical resection of pulmonary carcinoma were divided into observation group and control group in sequence,31 cases in each group.All patients treated with intravenous sufentanil 0.3-0.5 μg/kg,propofol 1.5-2.5 mg/kg,midazolam 0.5 mg/kg and rocuronium 0.9 mg/kg for induction of anesthesia;intravenous infusion of propofol 6-8 mg·kg-1 ·h-1 and remifentanil 0.1-0.5 μg·kg-1 ·min-1,intermittent intravenous injection of cisatracurium for anesthesia maintenance.The patients in the observation group were given 1μg/kg loading dose dexmedetomidine 10 min before anesthesia induction (infusion in 10 min),maintaining at 0.5 μg·kg-1 ·h-1 until 30 min before the end of surgery.The patients in the control group were given the same amount of saline as a control.The blood gas analysis index,pH,partial oxygen pressure (PaO2),CO2 partial pressure (PaCO2) and such inflammation cytokines as tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6) at OLV (T0),after OLVlh (T1),the end of OLV (T2) were respectively tested,the dosage of propofol in the two groups were recorded.Results The dosage of propofol in observation group was significantly lower than that in the control group (P＜0.05);pH declined in the two groups (P＜0.05),but the difference had no statistical significance;PaO2 was rising then declined in the two groups (P＜0.05),but it was significantly higher in the observation group than in the control group(P＜0.05);PaCO2 in the two groups increased gradually(P＜0.05),it was significantly lower in the observation group than in the control group (P＜0.05);The serum TNF-α,IL-6 in the two groups showed a trend of increasing (P＜0.05),it was significantly lower in the observation group than in the control group (P＜0.05).Conclusion Dexmedetomidine can maintain blood gas stability and reduce inflammation caused by single lung ventilation.