Clinical Study On The Effect Of Continuous Pulmonary Artery Perfusion With Oxygenated Warm Blood Contain L-arginine On Lung Injury During Cardiopulmonary Bypass

Objective: To establish a protective surgical method and pulmonary artery perfusion technical platform by studying the protective effect of continuous pulmonary artery perfusion with oxygenated blood on lung injury during cardiopulmonary bypass(CPB) and to evaluate continuous pulmonary artery perfusion with oxygenated blood and protective effect of L-arginine on lung injury induced by CPB. Methods: Forty five cases of mitral valve replacement were randomly divided into 3 groups: groupⅠ,control group (n=15) routine procedure of CPB; groupⅡ,continuous pulmonary artery perfusion with oxygenated blood (n=15); groupⅢ,continuous pulmonary artery perfusion with oxygenated blood Contain L-arginine (200mg/kg) (n=15). Vital sign observation system was established at the same time of intravenous respiration combined anesthesia,all of the patients received mechanical ventilation after single lumen endotracheal intubations. All 3 groups received routine procedure of CPB, in groupⅡand groupⅢoxygenated blood temperature 28～32℃, perfusion speed 15ml·kg- 1·min-1, perfusion pressure 10～20mmHg,were continuously infused from the root of pulmonary artery during routine CPB,and pulmonary artery perfusion pressure were detected by Y-tube manometer,and the perfusion pressure and speed were adjusted by cardiopulmonary bypass pump. GroupⅢcontinuously received L-arginine (200mg/kg) till the releasing of blocked aorta. All 3 groups were under the supervision of anesthetic machine before and after blocking the caval vein: tidal volume (Vt) 10ml/kg,frequency 12 bpm,FiO2 100%,PEEP 5cmH2O, I:E=1:2, supervision after going back to ICU: Vt 10ml/kg,frequency 12 bpm,FiO2 50%, PEEP 5cm H2O, I:E=1:2.Blood samples were drawn from the radial artery at the following time points: after anaesthesia,1 hours after opening of aorta,being taken back to ICU 0,6,12,24 hours. The expression of tumor necrosis factor-α(TNF-α),interleukin-6(IL-6) and interleukin-10(IL-10) were evaluated by ELISA test. After the approval of patients and family members,1.0cm×1.0cm×1.0cm of right lower lobe were removed before establishing of CPB and 30 minutes after stopping the CPB,and pathomorphological changes were analyzed under the microscope. Result: (1).All the patients were totally recovered. (2). TNF-α,IL-6 level in groupⅡand groupⅢwere lower than groupⅠ(P<0.05)after releasing of blocked aorta,groupⅢwas superior to groupⅡ. IL-10 level in groupⅡand groupⅢwere higher than groupⅠ(P<0.05), groupⅢwas superior to groupⅡ,and the highest in groupⅢ. (3)Pulmonary interstitial edema,intra-alveolus neutrophilic granulocyte exudation,karyorrhexis were more pronounced in groupⅠ, at the same time there were low-grade capillary vessel hyperaemia and pulmonary interstitial lymphocyte exudation in groupⅡand almost normal lung tissue structure were detected in groupⅢ. Conclusion: continuous pulmonary artery perfusion with oxygenated blood during cardiopulmonary bypass can not only reduce the lung temperature, ATP consumption,but also improve ischemia and hypoxia of lungs,and significantly suppress the composition and release of inflammatory factor,thus reduce pulmonary inflammatory reaction,which demonstrates that continuous pulmonary artery perfusion with oxygenated blood during CPB can protect lung injury and this also demonstrates the protective effects of L-arginine on lung injury induced by CPB.