Effect Of Remote Ischemic Preconditioning On Oxidative Stress Response And Lung Oxygenation Function In Patients Undergoing Thoracoscopic Pneumonectomy

Objective:To study the effect of remote ischemicpreconditioning(RIPC)on oxidative stress responsein thoracoscopic pneumonectomy,combined with thelung injury and lung oxygenation function makers,to explore whether RIPC has the function of lung protection.Methods:Forty patients who underwent thoracoscopic pneumonectomy were selected.ASA grade Ⅰ or Ⅱ;age 18～60years old;BMI 18.5～28kg/m2.They were randomly divided into two groups:the control group(group C)and the remote ischemic preconditioning group(group R)with 20 cases in each group.Group C:the cuff was fixed at 1～2cm under the popliteal fossa of the left lower limb without inflating and deflating.Group R:the cuff was fixed at 1～2cm under the popliteal fossa of the left lower limb,and 3 cycles of 5min ischemia(inflated to 200mmHg)and 5min reperfusion(complete deflation of the cuff)were given after anesthesia induction to the beginning of the operation.The anesthetic methods of the two groups were the same:midazolam 0.05mg/kg,propofol 1.5mg/kg,rocuronium 0.6mg/kg,and sufentanil 0.5μg/kg were given during anesthesia induction.After oxygen and nitrogen removal by mask,the double-lumen bronchial catheter was intubated,the position of the catheter was determined by fiberoptic bronchoscope and properly fixed,and mechanically ventilated.The ventilator parameters were the same:tidal volume(VT)was 8mL/kg during two-lung ventilation,respiratoryrate(RR)was 10～12times/min,during one-lung ventilation VT was 6mL/kg,RR was 14～16times/min.Inspirationandexpirationratio,I:E was 1:2,the oxygen flow rate was 2L/min,and the oxygen concentration was 100%.During the operation,PetCO2 was maintained at 35～45mmHg and peak airway pressure ≤30cmH2O.3minutes beforeoperation,given sufentanil 0.2μg/kg and rocuronium 0.1mg/kg.Sufentanil and rocuronium were added according to intraoperative conditions,sevoflurane inhalation was 2%～2.5%,maintaining BIS 40～60.The oxidative stress markers such as Malondialdehyde(MDA),Superoxide dismutase(SOD).Lung injury marker such as Pulmonary surfactant associated protein-A(SP-A).Pulmonary function index:Alveolar-arterial oxygen partial pressure difference[P(A-a)O2],Oxygenation Index(OI),Respiratory Index(RI)in arterial blood were measured at six-time points:5min after trachealintubation(T0),5min before recovery ventilation of both lungs(T1),5min after recovery ventilation of both lungs(T2),30min after recovery ventilation of both lungs(T3),1 hour after recovery ventilation of both lungs(T4),2 hours after recovery ventilation ofboth lungs(T5).Results:1.There was no significant difference in the general conditions of patients between the two groups(P>0.05).2.There was no significant difference in operation time and other operation indexes of patients between the two groups(P>0.05).3.Basic vital signs:Compare between groups:There was no significant difference in SpO2,MAP,and HR between the two groups at each time point(P>0.05).Compare within groups:There was no significant difference in SpO2 between the two groups at any two-time points(P>0.05);Compared with T3,MAP and HR in group C and group R increased significantly at T4 and T5(P<0.05).4.Oxidative stress:Compare between groups:Compared with group C,The concentration of serum MDA in the group R were significantly lower than those in the group C at T1～T5 time points(P<0.05);Compared with group C,the concentration of serum SOD in the group R were significantly higher than those in the group C at T1～T5 time points(P<0.05).Compare within groups:Compared with T0,the concentration of serum MDA at the time points of T1～T5 in the two groups were significantly higher(P<0.05);The concentration of serum MDA in the two groups increased to the highest at T3,T4～T5 decreased gradually;Compared with T0,the concentration of serum SOD at the time points of T1～T5 in the two groups were significantly lower(P<0.05);The concentration of serum SOD in the two groups decreased to the lowest at T3,T4～T5 increased gradually.5.Lung injury marker:Compare between groups:Compared with group C,The concentration of serum SP-A in group R wassignificantly lower than those in group C at T1-T5 time points(P<0.05).Compare within groups:Compared with T0,the concentration of serum SP-A at the time points of T1～T5 in the two groupswere significantly higher(P<0.05);The concentration of serum SP-A in the two groups increased to the highest at T3,T4～T5 decreased gradually.6.Oxygenation function:Compare between groups:Compared with group C,the P(A-a)O2,RI wassignificantly lower than those in group C at T2～T5 time points(P<0.05);Compared with group C,the OI wassignificantly higher than those in group C at T2～T5 time points(P<0.05).Compare within groups:Compared with T0,P(A-a)O2 and RI at T1～T5 time points in group C and group R were significantly higher(P<0.05).Compared with T0,OI at T1～T5 time points in group C and group R were significantly lower than those in T0(P<0.05).Conclusions:Remote ischemic preconditioning can reduce the concentration of serum malondialdehyde and pulmonary surfactant protein-A in patients undergoing thoracoscopic lobectomy,increase the level of serum superoxide dismutase;Reduce alveolar-arterial oxygen partial pressure difference and respiratory index,improve oxygenation index;Remote ischemic preconditioning can reduce lung injury and protect lung by increasing the ability of antioxidant stress and reducing oxidative stress.