The Effects Of Individualized Lung-protective Ventilation With Driving Pressure-guided Positive End-expiratory Pressure Titration On Postoperative Pulmonary Complications

Objective:Postoperative pulmonary complications?PPCs?are prone to occur in patients after major upper abdominal surgery,which are one of the important causes for perioperative mortality.Although the protective ventilation of low tidal volume,positive end-expiratory pressure?PEEP?and lung recruitment has been applied to reduce PPCs,the efficacy of the strategy still needs to be improved,and there is no optimal PEEP recommendation.Recent studies have suggested that driving pressure??P?is an important independent risk factor for PPCs.Therefore,we focused on?P to investigate the effects and potential mechanisms of individualized lung-protective ventilation with?P-guided PEEP titration?iPGT?on PPCs and to explore the optimal PEEP in this study.Methods:The study is a randomized controlled trial.We enrolled patients who were aged 18 years or older,were scheduled to have open upper abdominal surgery with an expected time of longer than 2 and had intermediate-to-high-risk of developing PPCs.Patients were randomly assigned?1:1?to receive one of two lung-protective ventilation strategies using low tidal volume plus PEEP:iPGT?tidal volume of 6ml/kg predicted bodyweight plus individualized PEEP for minimizing?P?and STD?standard intraoperative ventilation of tidal volume of 6ml/kg predicted bodyweight plus fixed PEEP of 6 cmH₂O?.The primary outcome was the incidence and severity of PPCs in the first 7 postoperative days;the secondary outcomes included composites of PPCs type,hospital length of stay,30-day mortality,ICU occupancy rate;other measurements included?P,respiratory work,oxygenation index,alveolar-arterial oxygen partial pressure difference,heart index and other respiratory and circulatory function parameters.Results:A total of 63 patients were included in the analysis.Patients in the iPGT group had significantly lower incidence?p=0.044?and severity ratings?p=0.038?of PPCs than those in the STD group.The PPCs in the two groups were mainly pleural effusion and atelectasis,and the incidence rate was both about 90%.The severity of postoperative atelectasis was significantly lower in PGT group than in the STD group?p=0.036?.There was no significant difference in postoperative length of stay in hospital,ICU occupancy rate and 30-day mortality between the two groups.The?P,alveolar-arterial oxygen pressure difference and the incidence of intrapulmonary shunt for patients in the iPGT group decreased significantly?p<0.01?,and the oxygen index,pulmonary dynamic compliance,respiratory work and the ratio of ventilation in the lower lung dorsal region were significantly increased?p<0.01?compared with the STD group.The individualized PEEP of?P-guided PEEP titration was 9?8¹0?cmH₂O.Conclusion:iPGT significantly reduced the incidence and severity of PPCs,improved pulmonary function without increasing the incidence of other complications compared with the STD.The potential mechanisms may be related to the significant reduction in ventilator-induce lung injury and atelectasis.