Effects Of Adaptively Increasing Tidal Volume On Lung Injury And Oxidative Stress In Patients Undergoing Robotic Laparoscopic Radical Resection Of Rectal Cancer

BackgroundAccording to the concept of ventilator-induced lung injury(VILI)put forward by Parker et al in 1993,it is generally believed that mechanical ventilation is one of the main causes of lung injury.Ventilator-induced lung injury is the result of the interaction between ventilator transporting gas to the lung parenchyma and receiving it.Healthy patients can tolerate the pressure and tension caused by mechanical ventilation to a certain extent,but for long-term surgery,lung injury may affect the normal recovery of postoperative lung function.Leonardo da Vinci robotic laparoscopic surgery has been widely used in many surgical diagnosis and treatment processes in recent years.Pneumoperitoneum and non-physiological posture required for robotic surgery can increase cardiopulmonary risk,affect respiratory mechanics,and aggravate VILI.This burden is due to the effect of abdominal inflation on the mechanical properties of the chest wall and the effect of diaphragm displacement on the compression of the basal lung region.The emergence of these factors can easily lead to atelectasis and potentially increase the probability of VILI.Lung tissue is an"elastic system",and the composition of its extracellular matrix takes a period of time to adapt to stress changes.In animal experiments,it has been found that adaptive increase of tidal volume(VT)can reduce lung injury,but clinical studies have not been carried out.ObjectiveTo investigate the effect of adaptive increase in tidal volume on lung injury and oxidative stress in patients undergoing laparoscopic radical resection of rectal cancer and provide reference material for future clinical practice.MethodPatients who underwent Leonardo da Vinci robot laparoscopic radical resection of rectal cancer in our hospital from January 2020 to August 2020 were selected.The age ranged from 51 to 80 years old,and the BMI 18～25 kg/m2,ASA grade was I or II.According to the random number table,the patients were divided into three groups:no adaptation time group(N group),shorter adaptation time group(S group)and longer adaptation time group(L group).The respiratory parameters were adjusted 5 minutes after the pneumoperitoneum was stable and adjusted to Trendelenburg position,and the VT was set to 6 ml/kg and 5 PEEP according to PBW to maintain the above respiratory parameters for 1 hour in the group N,while the group S gradually increased the VT after the above setting lasted for 30 minutes.Considering the limitation of adjusting the respiratory parameters of the anesthetic machine,the speed was set to 0.3-0.4 mL/kg/5min.In group L,the VT was gradually increased 5 minutes after the pneumoperitoneum was stable,and the speed was 0.1～0.2 mL/kg/5min.All the patients in the three groups adjusted VT to 8 mL/kg and 5 PEEP one hour later.Lung reopening was performed in all patients every 30 minutes.The arterial blood samples of HR,MAP,SV,SVV,CI,PETCO2,Ppeak and Ppiat,were recorded at 10 minutes after pneumoperitoneum and adjusted to Trendelenburg position(T1),1 hour after T1(T2)and 2 hours after T1(T3).Among them,2 mL was used for blood gas analysis,and the rest of PaO2 and PaCO2;were stored in cryopreservation to measure the concentration of sRAGE,IL-6 and other inflammatory factors.Postoperative pulmonary complications(PPCs)were recorded within 7 days after operation.Result1.General situation:There was no statistically significant difference in the general situation of the three groups of patients(P>0.05).2.Hemodynamic indicators:In the comparison between the groups,there was no statistically significant difference between the three groups of patients(P>0.05).In the intra-group comparison,the SVV of the three groups of patients was significantly increased at T2 and T3 compared to T1(P<0.05),and T3 was significantly higher than that of T2(P<0.05).3.Respiration parameters and arterial blood gas analysis:In the comparison between the groups,the PETCO2 and PaCO2 of the S group and the L group were significantly reduced at T2 and T3 compared to the N group(Bonferroni correction,P<0.017),and there was no statistically significant difference between the other index groups(P>0.05).In the intra-group comparison,the N group had a significant decrease in PETCO2 and PaCO2 at T3 compared to T1 and T2(P<0.05);S group and L group had a significant decrease in PETCO2 and PaCO2 compared to Ti at T2 and T3(P<0.05);the three groups of patients had significant increases in Ppeak and Ppiat compared to T1 at T2 and T3(P<0.05),and there was no difference in PaO2 within the group statistical significance(P>0.05).4.Expression of lung injury and related inflammatory factors:sRAGE concentration:Compared with the N group,the sRAGE concentration level of the S group and the L group was significantly lower at T3(Bonferroni correction,P<0.017),and that in L group was significantly lower than that in S group(Bonferroni correction,P<0.017).IL-6 concentration:Compared with group N,there was no significant difference in IL-6 concentration between group S and group L at T3(P>0.05).8-iso-PGF2α concentration:Compared with the N group,the 8-iso-PGF2αconcentration levels of the S group and the L group at T3 were significantly lower(Bonferroni correction,P<0.017).5.The expression of macrophage-related inflammatory factors:IL-12 concentration:Compared with the N group,the IL-12 concentration level within the S group and the L group was significantly lower at T3(Bonferroni correction,P<0.017),and that in L group was significantly lower than that in S group(Bonferroni correction,P<0.017).IL-23 concentration:Compared with the N group,the IL-23 concentration level within the S group and the L group was significantly lower at T3(Bonferroni correction,P<0.017),and that in L group was significantly lower than that in S group(Bonferroni correction,P<0.017).TGF-β concentration:Compared with the N group,the TGF-β concentration level of the S group and the L group at T3 was significantly increased(Bonferroni correction,P<0.017),and that in L group was significantly increased than that in S group(Bonferroni correction,P<0.017).6.Postoperative pulmonary complications:Compared with group N,the probability of PPCs in group S and group L was significantly lower,and the difference was statistically significant(Bonferroni correction,P<0.017).There was no significant difference in the probability of PPCs between group S and group L(Bonferroni correction,P>0.017).Conclusion1.For patients undergoing robotic laparoscopic radical resection of rectal cancer,gradually increasing tidal volume with time to adapt can effectively reduce lung injury and oxidative stress caused by mechanical ventilation during perioperative period.2.Adaptability gradually increases the tidal volume,which can affect the expression of IL-12,IL-23 and TGF-β associated with macrophages.