The Effect Of Lidocaine On Pulmonary Gas Exchange During Acute Lung Injury In Septic Rats

Objective:To investigate the effect of intravenous infusion of lidocaine on pulmonary gas exchange function during acute lung injury in septic rats.Methods:Thirty clean-grade healthy male SD rats,2 to 3 months of age,weighing 220 to 280 g,were divided into 3 groups（n=10）at random:group control（C）,group sepsis（S）and group lidocaine（L）.Model of acute lung injury in septic rats was prepared by intraperitoneal injection of LPS 10 mg/kg in the groups S and L,and the group C was injected with an equal dose of normal saline.A loading dose of lidocaine 10 mg/kg was given to group L immediately,with continuous infusion for 3 h at a rate of 10 mg·kg^-1·h^-1,and the groups C and S were replaced with equal dose of normal saline.Rats were anesthetized again at 24 h after LPS injection,the aorta abdominalis was exposed,blood collected for blood gas analysis,and calculated for oxygenation index（OI）,alveolar-arterial oxygen difference（A-a DO₂）and respiratory index（RI）.The rats were sacrificed by anesthesia overdose immediately after arterial blood collection,the left lung tissue was then immediately removed by thoracotomy to determine the levels of tumor necrosis factor-α（TNF-α）,heme oxygenase-1（HO-1）and reactive oxygen species（ROS）by ELISA.The right upper lung tissue was taken,and the alveolar structure and pulmonary edema were observed under light microscope,and the right lower lung tissue was taken to observe the vascular endothelial structure under transmission electron microscope.Results:Compared with the group C,the level of A-a DO₂,RI,TNF-α,HO-1and ROS were increased in both group S and group L（P<0.05）,while both the Pa O₂and OI were decreased,there were no significant differences in Pa CO₂levels（P>0.05）;Compared with the group S,the level of A-a DO₂,RI,TNF-αand ROS were decreased in group L（P<0.05）,while the Pa O₂,OI and HO-1 were increased,there were no significant differences in Pa CO₂levels（P>0.05）.The histopathological damage of the lung in the group L was reduced compared with the group S.Conclusion:Intravenous infusion of lidocaine improved pulmonary gas exchange function in acute lung injury in septic rats.