The Protective Effect Of Sevoflurane Preconditioning On Lung Injury During One Lung Ventilation

Objective One-lung ventilation(OLV) is widely used in thoracic surgery for providing a good operating environment for operation and preventing the contralateral lung from the pollution. Meanwhile, OLV also can cause the decrease of lung compliance, the occurrence of hypoxia, the changes of lung morphology and the lung injury caused by the release of inflammatory factors. Sevoflurane provide a protective effect on the lung injury and sevoflurane preconditioning can inhibit airway inflammation caused by a variety of reasons. To investigate the role of sevoflurane preconditioning play in lung injury during one-lung ventilation and its mechanism, this study observed the influence of sevoflurane preconditioning on lung compliance,oxygenation index, atelectatic lungs’ pathological morphological changes and inflammatory cytokines IL- 6, IL 8, IL-10 and HMGB1.Methods In this study, sixty patients, ASA I orⅡ, scheduled for pulmonary surgeries were enrolled, and randomly divided into two groups: sevoflurane preconditioning group(group S, n=30) and control group(group P, n=30). For preconditioning, patients in group S were administrated with 2%(1.0MAC) sevoflurane for 30 min after general anesthesia induction and then followed with total intravenous anesthesia. While in group P, only intravenous anesthetic agents were administrated for maintaining of anesthesia after induction. Record FEV1, FEV1/FVC, OLV time and operation time during operation. The indexes of hemodynamics, pulse oximeter(Sp O2), plateau pressure(Pplat), lung compliance(Cdyn) were recorded at the following time points:before anesthesia(T0), after anesthesia induction at laternal position TLV 30 min(T1), 30 min after OLV(T2), 60 min after OLV(T3) and recovering TLV20 min(T4). Arterial blood samples were taken to measure partial pressure of oxygen(P a O2), p H, partial pressure of carbon dioxide(P a CO2) and oxygenation index(P a O2/Fi O2) at the following time points: T1, T2, T3, T4. To measure the plasma levels of IL-6, IL-8, IL-10 and HMGB1, take arterial blood at T1-4 and 24 h after surgery(T5). Take a piece of lung tissue from the cut lung tissue(far away from the tumor mass > 5cm) to HE staining and to compare expression of HMGB1. Statistical analysis: using SPSS 13.0 statistical analysis software for data processing. Measurement data are expressed as mean ±standard deviation(—x±s). The t test was applied in the intergroup comparison, while repeated measures ANOVA was used within group comparison. Categorical data using chi-square test to compare. P < 0.05 difference is statistically significant.Results(1) Comparison of general datas: Two groups of patients’ gender, age, BMI,FEV1, FEV1 / FVC, OLV time, operation time differences had no statistical significance(P > 0.05).(2) Comparison of oxygenation index and lung compliance: Compared with T1, the oxygenation index and lung compliance decreased significantly at T2、T3(P <0.05).Compared with group P, the lung compliance was obviously higher than that in group S at T2、T3(P <0.05). There were no significantly differences in the oxygenation index between group P and group S at all time points(P>0.05).(3) Comparison of pathologic morphology of H.E staining in lung tissue: Interstitial edema, inflammatory cell infiltration in the alveoli and interstitium and disordered lung lobule structure was detected in P group. While in S group, the lungs showed almost normal lung architecture and only minor signs of cell influx. Compared with group P,lung tissue pathological changes is lighter in group S.(4) The changes of IL-6, IL-8, IL–10 and HMGB1 in plasma: Compared with T1, each group increased at T2, T3, T4,(P <0.05), especially in P group increased more obviously,the difference was statistically significant(P < 0.05) between the two groups. Compared with T4, HMGB1 was increased significantly at T5 in two groups(P < 0.05). Compared with group P, HMGB1 apparently increased in group S(P < 0.05).(5) The expression of HMGB1 in lung tissue: Compared with group P, the expression of HMGB1 in group S was significant higher(P < 0.05).Conclusion In summary, this study showed that(1) The IL–6, IL–8, IL–10, HMGB1 are involved in the lung injury caused by OLV.(2) In OLV, sevoflurane preconditioning contributes to improve lung compliance and pathomorphism changes, reduce leves of IL–6, IL–8, IL–10 and HMGB1 and expression of HMGB1.(3) Sevoflurane preconditioning has certain protective effect on one lung ventilation induced lung injury.