Objective To evaluate the application effect of positive end-expiratory pressure(PEEP)guided by driving pressure on intraoperative oxygenation and postoperative complications in patients undergoing orthotopic liver transplantation(OLT).Methods A total of 118 patients underwent OLT from January 2020 to September 2023,89 males and 29 females,aged 18-70 years,BMI＜28 kg/m2,ASA physical status Ⅲ or Ⅳ.Patients were divided into two groups using the random number table method:drive pressure group(group D)and PEEP group(group P),59 patients in each group.Volume controlled ventilation was used during general anesthesia in two groups,I:E 1:2,VT 6 ml/kg(ideal body weight),RR 10-15 beats/minute.In group D,the PEEP titration test was started after 5 minutes of mechanical ven-tilation,gradually increasing PEEP from 2 to 10 cmH2O,selecting the PEEP that produced the lowest driv-ing pressure,and maintaining this PEEP until the end of the surgery.In group P,the PEEP was maintained at 5 cmH2O during surgery.The amount of intraoperative out put and intake,and the use of vasoactive drugs were recorded.The HR,SBP,DBP,peak airway pressure(Ppeak),airway plateau pressure(Pplat),PEEP,and blood gas analysis results were recorded 5 minutes after intubation(T1),during the anhepatic phase(T2),during the neohepatic phase(T3),and at the end of the operation(T4),and driving pres-sure,dynamic pulmonary compliance(Cdyn),oxygenation index(OI),and dead space fraction(VD/VT)were calculated.The occurrence of postoperative pulmonary complications(PPCs)within 7 days after opera-tion was recorded.Results Compared with group P,the amount of crystalloid and the usage frequencies of norepinephrine,phenylephrine,and epinephrine in group D were significantly increased(P＜0.05).Com-pared with T2,HR was significantly decreased,SBP and DBP were significantly increased at T1,T3,and T4 in the two groups(P＜0.05).Compared with T1,Ppeak,Pplat,driving pressure,and OI were signifi-cantly increased at T2-T4,and Cdyn was significantly decreased at T3 and T4 in the two groups(P＜0.05).Compared with group P,the incidence of PPCs in group D was significantly decreased(P＜0.05).There were no significant differences in other indexes between the two groups.Conclusion The driving pressure guided PEEP ventilation improves intraoperative oxygenation and reduces the incidence of PPCs in patients undergoing OLT,but the use of intraoperative vasoactive drugs increases.