Abstract: [Abstract]   Objective   To investigate the effects of sevoflurane postconditioning on lung function in patients undergoing heart valve prosthesis implantation with cardiopulmonary bypass (CPB). Methods   Thirty patients, scheduled for heart valve prosthesis implantation, were randomly divided into control group (C, n=15) and sevoflurane postconditioning group (S,n=15). Anesthesia was maintained by intermittent intravenous injection of midazolam, fentanyl and pipecuronium. In group S, 2% sevoflurane was inhaled continuously for 15 min , 2 min before aortic unclamping. Blood samples were taken at 30 min before CPB (T2), 30 min after CPB (T3), 6 h (T4), 12 h (T5) and 24 h (T6) after operation. The values of p（O2）, SaO2, airway peak pressure (Ppeak) and airway plateau (Pplat) pressure during the time of mechanical ventilation were recorded. Oxygen index (OI), alveolar arterial oxygen tension difference (AaDO2), dynamic pulmonary compliance (Cdyn) and static pulmonary compliance (Cstat) were calculated. Results  Compared with group C, the values of SaO2 and Cdynwere significantly higher in group S after 30 min of CPB. The values of OI, p（O2）, Cdyn and Cstat were significantly higher in group S than those of group C after 6h of operation. The value of AaDO2 was significantly lower 12 h and 24 h after operation than that of group C (P < 0.05).Conclusion   CPB led to the lung injury. The sevoflurane postconditioning has a protective effect on lung function in patients undergoing cardiac valve replacement with CPB.

Key words: halothane, Anesthetics, inhalation, Cardiopulmonary bypass, respiratory function tests, Respiratory function test