Lung-protective Effects Of Pressure-controlled Ventilation-volume Guaranteed Combined With Open-lung Approach In Patients Undergoing One-lung Ventilation

Objective:The study aimed to evaluate the lung-protective effects of pressure-controlled ventilation-volume guaranteed（PCV-VG）mode combined with open-lung approach during one-lung ventilation（OLV）in patients scheduled for thoracoscopic lung surgery.Methods:There were 176 patients scheduled for elective thoracoscopic lung surgery,aged≥18 years,body mass index less than 35kg/m²,of ASA physical status grade I～Ⅲ.All patients were randomly assigned into four groups:group VC（volume-controlled ventilation mode plus conventional lung-protective ventilation strategy during OLV）,group VO（volume-controlled ventilation mode plus open-lung approach during OLV）,group PC（PCV-VG plus conventional lung-protective ventilation strategy during OLV）and group PO（PCV-VG plus open-lung approach during OLV）.Open-lung approach consisted of alveolar recruitment manoeuvres immediately followed by a decremental positive-end expiratory pressure（PEEP）decrement trial according to the best dynamic compliance（Cdyn）.Heart rate（HR）,mean arterial pressure（MAP）,tidal volume,PEEP,peak airway pressure(P_peak),mean airway pressure(P_mean)and Cdyn were recorded at three time points:total-lung ventilation 10 min after intubation（T₁）,OLV for 45 min（T₂）,and total-lung ventilation 10 min after OLV（T₃）.Radial artery blood samples were collected at T₁-T₃for blood gas analysis,and oxygenation index（OI）,respiratory index（RI）,intrapulmonary shunt rate（Qs/Qt）and dead space fraction（V_D/V_T）were calculated.The blood samples of radial artery were collected at T₁and T₃,and the concentration of plasma neutrophil elastase（NE）was measured.The incidence of postoperative pulmonary complications（PPCs）,postoperative surgical intensive care unit（SICU）length of stay,postoperative chest drainage time,and postoperative hospital stay were recorded.ResultsCompared with group VC,Pa O₂was increased in groups PO and VO at T₂（P<0.05）.Compared with groups VC and PC,the level of optimal PEEP was higher in groups PO and VO（P<0.05）.Compared with groups VC and VO,P_peakwas decreased in groups PO and PC at T₂（P<0.05）.Compared with group VO,P_peakwas decreased in groups PC and VC at T₃（P<0.05）.Compared with groups VC and PC,P_meanand Cdyn were increased in groups PO and VO at T₂（P<0.05）,P_meanwas increased in groups PO and VO at T₃（P<0.05）,and Cdyn was increased in group PO at T₃（P<0.05）.Compared with group VC,Cdyn was increased in groups PC and VO at T₃（P<0.05）.Compared with groups PC and VC,V_D/V_Twas decreased in groups PO and VO at T₂（P<0.05）,Qs/Qt was decreased in group PO at T₂（P<0.05）,and V_D/V_Twas decreased in group PO at T₃（P<0.05）.Compared with group VC,OI was increased in groups PO and VO at T₂（P<0.05）,and RI was decreased in group PO at T₂（P<0.05）.Compared with groups VC,VO and PC,the concentration of NE was decreased in group PO at T₃（P<0.05）.Compared with group VC,the concentration of NE was decreased in groups VO and PC at T₃（P<0.05）.Compared with group VC,the overall incidence of PPCs was lower in group PO（P<0.05）.Compared with groups VC,VO and PC,the postoperative SICU length of stay was shorter in group PO（P<0.05）.Compared with groups PC and VC,postoperative chest drainage time was shorter in group PO（P<0.05）.Conclusion:During one-lung ventilation,the ventilation strategy of PCV-VG combined with open-lung approach can optimize respiratory mechanics and ventilation efficiency,reduce the inflammatory response and then produce the effects of lung protection and improve the prognosis of patients.