Effects Of Sevoflurane Preconditioning On Pulmonary Function In Patients Undergoing Cardiac Valve Replacement With Cardiopulmonary Bypass

Objective:To investigate the effects of sevoflurane preconditioning on pulmonary function in patients undergoing cardiac valve replacement with cardiopulmonary bypass(CPB).Methods:Forty ASA Ⅱ-Ⅲ patients of both sexes, aged 40-60 yr, with NYHA Ⅱ-Ⅲ, LVEF≥45%, scheduled for cardiac valve replacement (mitral valve or aortic valve) with cardiopulmonary bypass, were randomly divided into 2 groups:control group (Prop group, n=20) and sevoflurane preconditioning group (Sevo group, n=20). After general anesthesia induction and intubation, patients in Sevo group received sevoflurane at 1.0 minimum alveolar concentration (MAC) for 30min as a preconditioning and then replaced by oxygen for a complete rapid gas exchange to reduce the sevoflurane inhalation concentration to 0 before CPB. While in Prop group, only intravenous anesthetic agents rather than sevoflurane, were administrated before CPB. Blood samples were taken from radial artery 5min after intubation (TO),2h(T1), 4h(T2) and 6h(T3) after weaning from CPB for blood gas analysis to calculate oxygenation index(OI). Plasma was obtained by centrifugation of whole blood at 3000r/min for 10min. Thereafter, plasma was aliquoted and stored at - 196℃ for later analysis. Plasma Krebs Von den Lungen-6(KL-6) and surfactant protein-D(SP-D) was measured by means of sandwich ELISA.Results:There was no significant difference in gender, age, BMI, the types of procedures, transfusion volume, CPB and aortic clamp time between the two groups (p>0.05). There were no significant differences between the two groups with regard to baseline OI, plasma KL-6 and SP-D concentration(p>0.05). When compared with TO, the OI in both groups significant decreased at T1,T2 and T3 (p<0.05), and dropped to the lowest point at T1, after which it gradually returned to baseline; while the plasm lung injury biomarkers in both groups significant increased at T1 and T2 (p<0.05), and peaking at T1, after which it gradually returned to baseline. The concentrations of plasm KL-6 and SP-D in Sevo group were decreased significantly at T1 and T2 (p<0.05) when compared with those in Prop group, the OI in Sevo group was significantly increased at T1 and T2 (p<0.05), while the was no significant difference between the two groups at T3 (p>0.05)Conclusion:Sevoflurane preconditioning may significantly decrease the short-term plasm biomarkers of lung injury and the extent of lung injury in patients undergoing cardiac valve replacement with CPB, but its long-term effect need to be further researched in the future.