Effect Of Lung Protective Ventilation Strategy On Oxygenation Function And Respiratory Mechanics In Patients Undergoing Robotic Bariatric Surgery

ObjectiveTo investigate the effects of LPVS on lung oxygenation function and respiratory mechanics in patients undergoing robotic bariatric surgery.To find the most suitable ventilation strategy for patients undergoing robotic bariatric surgery in order to provide reference for clinical practice.Methods40 obese patients underwent robotic bariatric surgery were randomly divided into a lung protective ventilation strategy group（group P）and a control group（group C）.The volume control mode is adopted to assist ventilation,and the I:E is 1:2.The VT was set according to PBW throughout the procedure.Group C:VT 9ml/kg,no PEEP,60%Fi O₂;Group P:Ventilation pattern from tracheal intubation to the beginning of pneumoperitoneum for 10 minutes as in Group C,VT 7ml/kg,PEEP 6cm H2O,40%Fi O₂after 10 minutes of pneumoperitoneum,keeping the P_plate<30 cm H₂O throughout.The flow rate is 2L/min and Sp O₂is maintained at≥95%,if not,the patient’s oxygenation can be improved by adjusting ventilation parameters and strategies;at the same time,the RR is adjusted to maintain P_ETCO₂at 35-45 mm Hg.Respiratory mechanical indicators:VT,RR,P_Peak,and P_Platewere recorded 5 minutes after endotracheal intubation（T0）,10 minutes after pneumoperitoneum began（T1）,60minutes after pneumoperitoneum began（T2）,120 minutes after pneumoperitoneum began（T3）,and 10 minutes after pneumoperitoneum closed（T4）,and Cdyn was calculated;hemodynamic parameters:HR,BP,MAP,and Sp O₂.Arterial blood was drawn at T0,T1,T2,T3,and T4,respectively,and Pa O₂and Pa CO₂were measured and the OI was calculated.Record operative time,intraoperative fluid consumption,urine volume,and bleeding volume.Record intraoperative ventilatory complications.Follow patients on postoperative days 1,3,and 5 for pulmonary complications.ResultsThe general data of the patients in the two groups were not statistically different（P>0.05）and were comparable.Compared with group C,group P had lower P_Peakin patients at T1,T2,and T3（P<0.05）;lower P_Plateat T2（P<0.05）;higher P_ETCO₂at T2（P<0.01）;lower MAP at T3 and T4（P<0.01）;higher OI at T1,T2,and T4（P<0.05,of which P<0.01）;Pa O₂was higher at T1（P<0.05）.There was no statistical difference in the incidence of PPC and intraoperative ventilation complications between the two groups（P>0.05）.Regression analysis of possible PPC risk factors showed that increased Fi O₂was an independent risk factor for the development of PPC in patients undergoing bariatric surgery（OR 1.088,95%CI 1.010-1.172,P<0.05）.ConclusionLPVS can improve respiratory mechanics and oxygenation in patients undergoing robotic bariatric surgery.In this study,LPVS could not reduce the incidence of PPC in obese patients,and increased Fi O₂was an independent risk factor for the development of PPC.