The Effect Of Remote Limb Ischemic Preconditioning On TLR4 Expression In Monocytes In Patients Undergoing Pulmonary Lobectomy

Objective Observe the effects of ischemic preconditioning of remote limb on the expression of TLR4 in monocytes and inflammatory cytokines after lobectomy,as well as the changes of the pulmonary function and postoperative pulmonary complications in patients,and explore the lung protective effect and mechanisms of remote limb ischemic preconditioning,which may provide clinical reference for perioperative pulmonary protection.Methods This study was approved by the Medical Ethics Committee of Qingdao Municipal Hospital,and the patients or their family members signed the informed consent.Forty patients?male 26 and female 14,BMI 20-28 kg/m²,ASA I or?,aged 45-64 years old?scheduled for elective pulmonary lobectomy via a thoracoscope,were divided into two groups using random number table method:limb ischemic preconditioning group?group P?and contro1 group?group C?,with 20 patients in each group.The two groups were induced by the same anesthesia:Induction of anesthesia was initiated with intravenous midazolam?0.05mg/kg?,etomidate?0.3mg/kg?,sufentanil?0.3?g/kg?,cisatracurium?0.15mg/kg?.After rapid intravenous induction,double-lumen bronchotracheal intubation was performed,the position of the catheter was confirmed by fiberoptic bronchoscopy adjustment.The mechanical ventilation was conducted using volumetric controlled ventilation mode,and the respiratory parameters were set?VT8?10ml/kg,RR10?12 times/min during two-lung ventilation;VT 6?8ml/kg,RR12?16times/min during one-lung ventilation?to maintain P_ETCO₂ 30?40mmHg,SpO₂>95%,and the airway pressure less than 30cmH₂O.Anesthesia was maintained with a continuous infusion of propofol(4?8mg·kg^-1·h^-1)and remifentanil(0.2?1.0?g·kg^-1·min^-1),inhalation of sevoflurane?1%?2%?,and intermittent intravenous of cisatracurium?0.05mg/kg?.Remote limb ischemic preconditioning:after the anesthetic induction and before the start of surgery,the group P had the left leg roots tied with a tourniquet,lower limb blood flow aerated blocked for 5 min when the doppler blood flow survey meter could not detect the blood flow of dorsalis pedis artery,then deflated to restore blood flow for 5 min,the cycle was repeated three times;the group C had the 1eft leg rooots tied but not charged for 30 min.Specimen collection and detection:venous blood samples were collected at the time of admission and at 6 h,12 h and 24 h after surgery to detect the expression of toll-like receptor?TLR4?in monocytes of blood using flow cytometry,the level of inflammatory cytokines TNF-?and IL-6 in plasma using enzyme linked immunosorbent assay?ELISA?.Arterial blood samples were collected at the above time points for blood gas analysis to calculate the alveolar-arterial oxygen pressure difference(P_A-aO₂),respiratory index?RI?and oxygenation index?OI?.The pulmonary complications within 48 h after operation were recorded.The adverse reactions of the left lower extremity of the group P were recorded.Results?1?Compared with T0,the expression of TLR4 and the level of TNF-?and IL-6were significantly increased in both groups at T1-T3?P<0.05?;compared with group C,the expression of TLR4 and the level of TNF-?and IL-6 were significantly decreased?P<0.05?.The expression of TLR4 was positively correlated with the level of TNF-?and IL-6 in both groups?P<0.05?.?2?Compared with T0,P_A-aO₂ and RI were significantly increased?P<0.05?,and OI was significantly decreased in both groups at T1-T3?P<0.05?;Compared with group C,PA-aO2 and RI were significantly decreased?P<0.05?,and OI was significantly increased in group P?P<0.05?.?3?There was no statistically significant difference in the incidence of pneumonia,atelectasis and respiratory failure in the two groups after operation?P>0.05?.The left lower limb of two groups had no adverse reactions,such as rupture of skin,thromboembolism,and nerve injury.Conclusion The remote limb ischemic preconditioning can improve oxygenation,and postoperative pulmonary function,and have the lung protective effect on patients with pulmonary lobectomy.The mechanism may be related to down-regulation of TLR4expression in monocytes and the reduction of the systemic inflammatory response.