Effects Of Lung Protective Ventilation On Mucin MUC5AC Expression Of One-Lung Ventilation(OLV) Patients’ Tissuse

Objective:To evaluate the effects of Lung-protective ventilation on mucin MUC5AC expression of one-lung ventilation（OLV）patients’tissuse,to investigate the effect of mucin MUC5AC on lung injury induced by one-lung ventilation,so as to provide theoretical basis for lung protection of OLV.Methods:Schedule a thoracoscopic surgery of pulmonary lobectomy for 50 patients of no gender limit,aged 45～75,Body Mass Index（BMI）18～25 kg/m²,and American Society of Anesthesiologists Physical Status（ASA）I or II,and pulmonary function tests were basically normal,without serious heart,liver,kidney,brain or other important organ dysfunction,and without serious pleural adhesions or chest wall deformities occurred,and the operation time was less than 4 hours.Use random number table to divide them into 2groups（n=25）:conventional strategy（CV group）and protective strategy（PV group）.CV group:V_T 10 ml/kg（TLV）,V_T 7 ml/kg（OLV）,10～15 times/min,PEEP 0 cm H₂O.PV group:V_T7 ml/kg（TLV）,V_T 5 ml/kg（OLV）,10～15 times/min,PEEP 5 cm H₂O,recrui-tment maneuver every 45 minutes（recruitment maneuver:PEEP 30 cm H₂O,30 s）.If the blood pressure is less than 90/60 mm Hg,lung recruitment should be stopped until the blood pressure is stabilized.Radial artery blood was collected for blood gas analysis before induction（T₁）,30 minutes of one-lung ventilation（T2）,15 minutes of double-lung venti-lation（T3）and 24 hours after operation（T4）,and respiratory index（RI）and oxygenation index（OI）were calculated.Serum samples were collected from internal jugular vein and the concentrations of IL-6 and TNF-αin serum were determined by ELISA.Two speci-mens of 15 mm x 15 mm x 3 mm were taken from the lesion area>2 cm after the lung tissue was take out during the operation.The specimens were immobilized in 10%formalin solution for 24 hours.Then the lung tissue was sent to pathology department for routine paraffin embedding and section.The expression of airway mucin MUC5AC was detected by immunohistochemistry and the pathological changes of lung tissue were observed by HE staining.The incidence of pulmonary complications（pneumonia,atelectasis,respiratory failure）and the length of hospital stay were recorded within 48hours after operation.Results:（1）Compared with CV group,there were no significant differences in preoperative evaluation indicators:age,sex composition,weight,ASA classification,intraoperative related indicators（infusion volume,blood loss,OLV time,operation time）between PV group and CV group（P>0.05）.（2）HE staining showed that the infiltration of inflamm-atory cells in non-ventilated lung tissue of CV group was significantly higher than that of PV group,and some patients had alveolar wall thickening and rupture.The lung injury score in CV group（2.7+0.9）was significantly higher than that in PV group（2.2+0.6）（P<0.05）.（3）The results of immunohistochemical analysis showed that the number of cases with high expression of MUC5AC protein in lung tissue of PV group was lower than that of CV group（P<0.05）.（4）There was no significant difference in RI and OI at T1 between the two groups（P>0.05）;RI increased and OI decreased at T2-T4 between the two groups（P<0.05）;RI decreased and OI increased at T2-T4 in the PV group（P<0.05）.（5）Compared with T1,the concentration of IL-6 and TNF-alpha increased at T2-T4 in both groups（P<0.05）,while the concentration of IL-6 and TNF-alpha decreased at T2-T4 in PV group（P<0.05）.（6）Compared with CV group,the incidence of pneumonia,atelectasis and hospitalization time in PV group had no significant difference（P>0.05）,and no respiratory failure occurred in both groups.Conclusion and significance:Lung protective ventilation strategy can reduce the release of inflammatory factors,reduce the expression of airway mucin MUC5AC,and alleviate non-ventilated lung tissue injury in patients with one-lung ventilation.This study provides theoretical guidance for future clinical work.