Effects Of Ventilation With Positive End-expiratory Pressure (PEEP) During Different Periods On Postoperative Pulmonary Function And Short-term Prognosis In Elderly Patients With Abdominal Surgery

Objective To reduce the incidence of postoperative pulmonary complications,and to investigate the effects of ventilation with low tidal volume and positive end-expiratory pressure(PEEP)during different periods on postoperative pulmonary function and short-term prognosis in aged patients undergoing abdominal surgery.Methods 80 aged patients undergoing selective open abdominal surgery scheduled for general anesthesia,24 males and 56 females,were randomized into 4 groups(n=20).Patients in group A did not receive PEEP intraoperatively;Patients in group B received PEEP 1 h after the beginning of surgery;patients in group C received PEEP 1 h before tracheal extubation;patients in group D received PEEP intraoperatively.The modified clinical pulmonary infection score indexes(temperature,the WBC count,secretion score)in preoperative,postoperative 24 h and 72 h respectively,and the arterial blood gas analysis indexes(PaCO2,PaO2,A-aDO2,PaO2/FiO2 calculation)in preoperative,postoperative 1 h and 24 h,and intraoperative vascular active drug usage were recorded.Results Compared with preoperative,in postoperative 1 h,PaCO2 increased obviously in all groups,PaO2 decreased in group A and group C,A-aDO2 increased in group A and group B(P<0.05);in postoperative 24 h,PaCO2 was significantly increased in group A,group C and group D,PaO2 decreased in group A obviously,Temperature and the WBC level increased significantly,PaO2/FiO2 decreased in group A and group C(P<0.05).Compared with postoperative 1 h,in postoperative 24 h,PaCO2 and A-aDO2 decreased obviously in group B(P<0.05),PaO2 increased and A-aDO2 decreased in group A(P<0.05).Compared with postoperative 24 h,in postoperative 72 h,PaO2/FiO2 and Temperature significantly increased in group A,the WBC level decreased obviously in all groups.There were no differences in postoperative secretions score in the 4 groups.Conclusion Ventilation with low tidal volume and positive end-expiratory pressure(PEEP)in 1 h after the beginning of surgery,1 h before tracheal extubation or during the whole operation can improve postoperative arterial blood gas analysis indexes,especially PEEP in 1 h after the beginning of surgery and PEEP during the whole operation,can improve pulmonary oxygenation function in postoperative 1 h and postoperative 24 h,but PEEP 1 h before tracheal extubation improve oxygenation in postoperative 24 h only,poor effects on postoperative 1 h.Ventilation with low tidal volume and PEEP in 1 h after the beginning of surgery,1 h before tracheal extubation or during the whole operation has no obviously help on mCPIS indexes(temperature,the WBC level,secretions score),short-term prognosis of pulmonary function meaningless.