Effects Of Sevoflurarie Postcoaditioning On Lung Injury After Cardiopulmonary Bypass

Objective: Cardiopulmonary bypass（CPB） can result in Lung Injury.To investigate the effects of sevoflurane postconditioning on lung injury in patientsundergoing heart valve prosthesis implantation with CPB by determining the lungfunction index and the concentration of IL-17A,NE and MMP-9.Methods: Thirty patients, scheduled for heart valve prosthesis implantation, wererandomly divided into control group（C） and sevoflurane postconditioninggroup（S）（n=15）. Morphine0.2mg/kg and penehyclidine0.02mg/kg were injectedintramuscularly in all patients at30min before operation. All patients were monitoredwith ECG, SpO₂, BP, BIS in the operating room. Anesthesia are induced withintravenous anesthetics including midazolam, etomidate, fentanyl, rocuronium.Anesthesia was maintained with intermittently iv injection of midazolam, fentanyl andpipecuronium.Patients in2groups were ventilated mechanically after anesthesiainduction（VT:8¹0ml/kg，RR:12¹5B/min）. Jostra HL20heart-lung machine,MAQUET membrane oxygenate and microembolus filter were used for CPB. In groupS,2%sevoflurane was inhaled2min before aortic unclamping and inhaledcontinuously after aortic unclamping for15min. The patients in2groups entered intoICU after operation. Before and after CPB, dopamine, dobutamine anddeoxyepinephrine were injected to maintain BP and HR steadily. Blood samples weretaken at before anesthesia（T₁）, after sternum splitting（T₂）,30min after CPB（T₃）,6（T₄）,12（T₅） and24h（T₆） after operation, and the PaO₂and SaO₂, airway peakpressure（Ppeak） and airway plateau（Pplat） pressure during the time of mechanicalventilation were recorded. Oxygen index （OI）, alveolar arterial oxygen tensiondifference（AaDO₂）, dynamic pulmonary compliance （Cdyn） and static pulmonarycompliance（Cstat） were calculated. The concentration of IL-17A,NE and MMP-9were determined at T₁,T₃,T₄andT₆.Results: The difference in each lung function index before and after CPB, except Cdynin group S, was statistically significant（P<0.05）. There were some regular changes inlung function index in both groups:the highest value of OI and Cstatemerged at T₂,andit decreased gradually during the period of T₂to T₄.The lowest value emerged at T₄.The lowest value of AaDO₂emerged at T₁, and it increased gradually during the periodof T₁toT₃.The highest value emerged at T₃.Then it decreased. The highest value ofPaO₂emerged at T₂, and it decreased graduallyduring the period of T₂to T₅.The lowestvalue emerged at T₅. The lowest value of SO₂emerged at T₅.Compared with groupC,in group S,.the value of OI was higher during the period of T₄to T₆; the value ofAaDO₂was lower during during the period of T₅to T₆; the value of PaO₂was higherduring the period of T₅to T₆;the value of Cdynand Cstatwere higher at T₄point （P<0.05）.The highest concentration of IL-17A,NE and MMP-9emerged at T₃,then decreasedgradually in both groups. Compared with group C,in group S,. the concentration ofIL-17A,NE and MMP-9were higher during the period of T₃to T₆.Conclusion: CPB leads to lung injury. However, to some extent, the2%sevofluranepostconditioning could protect lung function in patients undergoing cardiac valvereplacement with CPB by reducing ischemic injury and inhibiting inflammatoryreaction probably.