Combining Laryngeal Mask Airway And Lung Protective Ventilation Strategy Reduces Postoperative Pulmonary Complications

Objective: To investigate the effects of combining laryngeal mask airway(LMA)and lung protective ventilation strategy(LPVS)on postoperative pulmonary complications(PPCs)in patients undergoing abdominal surgery with general anesthesia.Methods : 172 patients aged 18 to 65 years,with American Society of Anesthesiologists(ASA)II~III,undergoing elective abdominal surgery were initially recruited and randomly divided into 4 group : the endotracheal intubation and high tidal volume group(IH group),the endotracheal intubation and protective ventilation group(IP group),the laryngeal mask airway and high tidal volume group(LH group),the laryngeal mask airway and protective ventilation group(LP group).There were 43 patients in each group.The endotracheal tube was used in IH and IP groups,while the LMA was used in LH and LP groups.The mechanical ventilation parameters in IH and LH groups were tidal volume(VT)8~10ml/kg,without positive end expiratory pressure(PEEP)or recruitment maneuvers(RMs).On the contrast,the parameters in IP and LP groups were VT 6~8ml/kg with PEEP5 cm H2O and RMs every 30 minutes.The change of heart rate and mean arterial pressure were recorded at intubation and extubation.Arterial blood gas analysis and airway peak pressure were tested before surgeries(T1),1 hour of mechanical ventilation(T2)and at the end of surgeries(T3).Serum levels of high mobility group box 1 protein(HMGB1)and surfactant protein A(SP-A)were detected by enzyme linked immunosorbent assay(ELISA)at preoperation and 1st day postoperation.Outcome measurements included fever,cough,expectoration,lung auscultation,post-intubation complications within 3 days after surgery,severe PPCs within 7 days after surgery,patient satisfaction,postoperative hospitalization days and mortality within 30 days after surgery.Results: 121 patients were included in the final analysis including 30 in IH group,31 in IP group,30 in LH group and 30 in LP group.Severe PPCs were observed in 12 patients.There were some significant differences about PPCs incidence rate between IH and LP group(P<0.05).Serum levels of HMGB1 and SP-A in IH group and LH group at 1st day postoperation were higher than before operation,and higher than in IP group and LP group at 1st day postoperation,too.The change of heart rate and mean arterial pressure were statistically significant between the groups using endotracheal intubation and the groups using the LMA(P<0.05).There were no statistically significant differences among four groups in terms of main ventilation index,fever,cough,expectoration,lung auscultation,post-intubation complications,patient satisfaction and postoperative hospitalization days(P(29)0.05).No patient died within 30 days.Conclusion : Combining LMA and LPVS significantly reduces the incidence of PPCs.Using LMA or LPVS alone does not affect PPCs in non-elderly patients undergoing abdominal surgery.