Effects Of Individualized Positive End-expiratory Pressure On Respiratory Function Of Patients Undergoing Abdominal Surgery

Objective : The aim of this study was to investigate the effect of individualized positive end-expiratory pressure on respiratory function in patients undergoing abdominal surgery.Methods: 40 patients with abdominal operation were selected,including 20 cases in laparoscopic group and 20 cases in open group.PEEP titration was performed in both groups,and the individualized PEEP was determined according to the principle of maximum lung compliance.Then,each group was randomly divided into two subgroups including 5-PEEP group and I-PEEP group.There were four subgroups with 10 cases in each subgroup.The PEEP of 5-PEEP groups was kept at 5cm H2 O until the end of operation,and the PEEP of I-PEEP groups was individualized until the end of operation.Observe and record the lung compliance,airway plateau pressure,inspiratory peak pressure,end expiratory carbon dioxide and mean arterial pressure at the time after induction(before pneumoperitoneum establishment)(T0),during the PEEP titration,before the second grouping after titration(T1),1 hour after the second grouping(T2)and before abdominal closure(or before the end of pneumoperitoneum)(T3).The arterial O2 partial pressure(Pa O2)and arterial CO2 partial pressure(Pa CO2)were obtained by blood gas analysis in the time of before the second grouping after titration(T1),1 hour after the second grouping(T2)and before abdominal closure(or before the end of pneumoperitoneum)(T3).The postoperative pulmonary complications data was obtained by follow-up.Results:During PEEP titration test,there was positive correlation between CVP and PEEP and negative correlation between MAP and PEEP.The individualized PEEP in laparoscopic group was significantly higher than that in open group.In the time of T2,laparoscopic group,the lung compliance in I-PEEP group was higher than that in5-PEEP group,the Pa O2 in I-PEEP group was higher than that in 5-PEEP group.In the time of T3,in laparoscopic group,the pulmonary compliance in I-PEEP group was higher than that in the 5-PEEP group,the Pa O2 in I-PEEP group was higher than that in the 5-PEEP group;and in open group,the lung compliance in I-PEEP group was also higher than that in 5-PEEP group.There was no significant difference in the incidence of pulmonary complications between I-PEEP group and 5-PEEP group.Conclusions:The small tidal volume combined with individualized positive end-expiratory pressure titrated by pulmonary compliance can improve the intraoperative oxygen partial pressure and lung compliance during laparoscopic surgery,but the PEEP titration test process has certain effect on hemodynamic stability.