The Study On PEEP Selection In Patients With Artificial Pneumothorax Based On LPVS

Background and ObjectiveMechanical ventilation is the most basic medical technology to maintain the normal life activities of patients with general anesthesia.It has an irreplaceable effect on giving patients respiratory support,improving ventilation,promoting oxygenation and preventing hypoxia and CO₂ accumulation.However,inappropriate mechanical ventilation may change the structure and function of normal lung tissue in patients,and even cause ventilator-associated lung injury?VALI?,increasing the incidence of pulmonary complications and affecting the body's prognosis.As one of the most common malignant tumors in China,esophageal cancer,the most effective treatment is surgical resection.The traditional thoracotomy for esophageal cancer has a relatively high trauma to patients.In particular,the incidence of complications is high in elderly patients who recover more slowly.In recent years,with the development of minimally invasive surgical techniques,television assisted thoracoscopy?VATS?esophageal cancer radical surgery is increasingly prevailing among patients and surgeons.However,the double-lumen endotracheal intubation and single lung ventilation strategy are applied to traditional thoracoscopic esophageal cancer patients.Double-lumen bronchial catheter is not only misalignment,repeated debugging easy to damage the airway,intubation technology requires high and costs a lot,but also cause some patients hypoxemia during surgery,who can not tolerate a single lung ventilation for a long time.In recent years,endoscopic esophagectomy through artificial CO₂ pneumothorax and single lumen endotracheal tube has developed rapidly.Artificial CO₂ pneumothorax and single lumen endotracheal tube have become a new technology other than single lumen bronchial tube,double lumen bronchial tube and bronchial occluder.The principle is to inject CO₂ gas into the pleural cavity continuously and control its flow rate,so that the pleural cavity maintain a certain positive pressure level,to achieve the purpose of lung collapse and surgical field exposure.Flotrac/Vigileo monitoring system has the advantages of minimally invasive,simple operation and less complication.The hemodynamic parameters such as CO,SV,CI and SVV can be calculated continuously by analyzing the peripheral arterial pressure waveform information and can be controlled by central venous pressure and arterial?DO₂I?and other numerical values.In recent years,Flotrac/Vigileo was applied in large quantities to the patients whose dieases changes quickly and needed for continuous hemodynamic monitoring.The lung protective ventilation strategy?LPVS?is mean to use the small tidal volume?VT?ventilation based on ideal body weight,the choice of appropriate positive end expiratory pressure?PEEP?,reduce the concentration of inhaled oxygen,limit a certain platform pressure?Pplat?and allow appropriate range of hypercapnia,however,LPVS has not been reported in the literature on lung protection of patients with endoscopic esophagectomy through artificial CO₂ pneumothorax and single lumen endotracheal tubeThis study focused on the impact of LPVS on pulmonary function and postoperative pulmonary complications in patients undergoing endoscopic esophagectomy through artificial CO₂ pneumothorax and single lumen endotracheal tube and to explore how to choose the optimum PEEP based on Flo Trac / Vigileo hemodynamics monitoring and respiratory function monitoring to achieve a better lung protection for patients Materials and Methods300 cases of patients undergoing the VATS thoracoscopic esophageal cancer radical surgery were randomly divided into six groups: group V0,group V1,group V2,group V3,group V4 and group V5.The six groups of VT were set to 5ml/kg,inhalation oxygen concentration?FiO₂ = 0.6?and maintained PETCO₂?55mm Hg during the operation.PEEP= 0 cm H₂O for the group V0,PEEP= 2 cm H₂O for the group V1,PEEP= 4 cm H₂O for the group V2,PEEP= 6 cm H₂O for the group V3,PEEP= 8 cm H₂O for the group V4,PEEP= 10 cm H₂O for the group V5.Arterial blood samples were collected and analysed after anesthesia induction and turning the left lateral position?T0?and 60 mins after establishing CO₂ pneumothorax?T1?.Meanwhile,Pplat,CL,CI,SVV,DO₂I and exhaled air condensate p H of patients were recorded during the operation and registered the time of removing endotracheal tube after surgery.The Qs/Qt,Vd/Vt and RI were calculated according to the corresponding time points.The patients were followed up for one day after surgery and the arterial blood was extracted and calculated RI.The incidence of pulmonary complications in patients,the proportion of transferring into ICU and the length of hospitalization were registered.Statistical analysisSPSS 21.0 statistical software was used for analysis.For the quantitative data consistent with the normal distribution were expressed as mean ± standard deviation????± s?,the comparison between the two groups of independent samples is analyzed by t test;comparison between multiple groups using single factor analysis of variance.Qualitative data were compared withX2 test.The level of significance test was ? = 0.05 Results 1.The comparison of Qs/Qt,Vd/Vt,RI and CLCompared with T0,Qs / Qt,Vd / Vt and RI of patients in six groups increased significantly at T1?P <0.05?,CL decreased significantly at the same time?P <0.05?.Compared with V0 group,Qs / Qt,Vd / Vt and RI decreased in V3,V4 and V5 groups?P <0.05?,CL increased?P <0.05?.Compared with V0 group,there was no significant difference in Qs / Qt,Vd / Vt,RI,CL between V1 and V2 group?P> 0.05?.The difference of Qs / Qt,Vd / Vt,RI,CL between V3,V4 and V5 groups was not significant at T1.?P> 0.05?.2.The comparison of CI,SVV and DO₂I Compared with T0,CI and DO₂I in six groups of patients decreased significantly at T1?P <0.05?,SVV was significantly increased?P <0.05?.Compared with V0 group,DO₂I in V3,V4 and V5 group increased?P <0.05?,CI decreased and SVV increased?P <0.05?.Compared with V0 group,there was no significant difference in CI,SVV and DO₂I between V1 and V2 group at T1?P> 0.05?.Compared with V0 group,there was no significant difference in CI and SVV between V3 and V4 group at T1?P> 0.05?.The difference of CI,SVV and DO₂I between V3,V4 and V5 groups was not significant at T1.?P> 0.05?.3.The comparison of PplatCompared with T0,Pplat among six groups of patients was significantly increased at T1?P <0.05?.Compared with V0,Pplat in V5 was significantly increased at T1?P <0.05?.Compared with V0 group,there was no significant difference in Pplat between V1,V2,V3 and V4 group at T1?P> 0.05?.The difference of Pplat between V3,V4 and V5 groups was not significant at T1.?P> 0.05?.4.The comparison of exhaled air condensate p HCompared with T0,the exhaled air condensate p H in six groups of patients decreased significantly at T1?P <0.05?.Compared with V0,the exhaled air condensate p H in V3,V4 and V5 was significantly increased at T1?P <0.05?.Compared with V0 group,there was no significant difference in exhaled air condensate p H between V1 and V2 group at T1?P> 0.05?.The difference of the exhaled air condensate p H between V3,V4 and V5 groups was not significant at T1.?P> 0.05?.5.Comparison of the extubation time and postoperative 24 h RICompared with V0 group,the extubation time of V3,V4,V5 group shortened,RI decreased after 24 hour of postoperation?P <0.05?.Compared with V0 group,there were no significant differences in postoperative extubation time,RI of V1 and V2?P> 0.05?.The difference of the extubation time and postoperative 24 h RI between V3,V4 and V5 groups was not significant at T1.?P> 0.05?.6.Comparison of incidence and severity of postoperative pulmonary complicationsCompared with V0 group,the incidence of postoperative pulmonary complications was reduced in V3,V4 and V5 groups,and the length of hospitalization was shortened?P <0.05?.Compared with V0 group,the occurrence rate of postoperative pulmonary complications and the length of hospitalization in V1 and V2 groups were not statistically significant?P> 0.05?.The difference of the incidence of postoperative pulmonary complications and the length of hospitalization between V3,V4 and V5 groups was not significant at T1.?P> 0.05?.In the V0 group,there were 3 cases of ICU,2 cases were found in V1 and V2 group,and no ICU cases were found in V3,V4 and V5 groups.ConclusionArtificial CO₂ pneumothorax single lumen cannula with esophageal cancer radical surgery in patients with PEEP 6 8cm H₂O may be more appropriate.It can significantly improve the patient's intraoperative oxygenation status and accelerated postoperative rehabilitation,and had less effect on intraoperative hemodynamics.