The Experimental Study Of Non-heart-beating Donor Lung's Acquisition Procedure And Security Warm Ischemia Time

Objective: Simulating non-heart-beating donor lung acquisition process in clinic and establish rabbit non-heart-beating donor lung acquisition procedure.This procedure including pretreatment with methylprednisolone,chest cavity irrigation with cold sodium chloride during warm ischemia time,mechanical ventilation with machine, dabbling with LPD liquid,cold storaged with aeration etc.Investigate non-heart-beating donor lung's security ischemia time under this procedure.Methods: Sixty New Zealand albino rabbits were randomly divided into four groups: heart-beating-donor groups(A groups), non-heart-beating donor with 30 minutes of warm ischemia time groups(B groups),non-heart-beating donor with 60 minutes of warm ischemia time groups(C groups) and non-heart-beating donor with 90 minutes of warm ischemia time groups(D groups).Each group contained 15 rabbits (the donors, the recipients and blood supply rabbits were 5 each).The HBD group rabbits were performed with tracheotomy to animal's respirator,thoracotomy after heparinization,perfusion with the 4℃improved LPD.When the lungs had been inflated with perfusion moderately,cut the heart and lungs and put into the 4℃improved LPD for 5 hours.The B,C,D group rabbits were performed with tracheal intubation to animal's respirator,intravenous injection with 10%KCL 10ml to stop heart beat,closed cardiac massage to maintain circulation,and intravenous injection with heparin (3mg/kg) and methylprednisolone (10mg/kg) and go on with cardiac massage to achieve systemic drugs. With mechanical ventilation,the hibateral chest cavity was filled with 4℃Sodium Chloride.After each group reaching the presumptive times(30minutes/60minutes/90minutes),the same procedures of perfusion and cold preservation as group A were conducted. The donor lung and the recipient rabbits were established experimental model of by-pass ex vivo.Every group by-passed for 90 minutes and was measured PaO₂,PaCO₂,peek airway pressure and TNF-aduring by-pass.After by-pass for 90 minutes all lung specimens were gained to detect malonaldehyde (MDA),myeloid peroxidase (MPO) content and wet/dry weight ratio of pulmonary tissue.Finally the morphological changes of the lung tissue were obserbed through optical microscopy and electron microscopy.Result: 1,This perfusion model worked well.2,PaO₂ and PaCO₂:PaO₂ of each group after reperfusion for 30 minute,60minute,90minute had dropped significantly.The largest decline was observed in group D,compared with group A showing significant difference (P<0.05),but no significant difference compared with group B and C(P>0.05).PaCO₂ of each group after reperfusion for 30 minute,60minute,90minute was significantly increased,the most increment was also observed in group D,compared with group A showing significant difference(P<0.05),but no significant difference with group B and C(P>0.05).3,pAwP: Peak airway pressure of each group was not significant difference initially,but after reperfusion pAwP was increased significantly.The largest increasement was observed in group D,compared with group A in the 30 minutes,60 minutes,90 minutes measured showing significant difference(P<0.05).But compared with group A ,there was no significant difference between group B and group C (P<0.05).4,The FNF-α: FNF-a of each group after reperfusion for 30 minute,60minute,90minute was significantly increased,the largest increment was observed in group D,compared with group A showing significant difference (P <0.05),but no significant difference with group B and C (P> 0.05).5,MDA levels,MPO activity in lung tissue and The ratio of W/D:MDA levels and MPO activity of each group lung tissue was significantly increased.The largest increment after reperfusion was observed in group D.Compared with group A showing significant difference (P<0.05),but no significant difference with group B and group C (P>0.05).6,Histological evaluation of lung tissue: The four groups had different pathological damages:Pulmonary tissue of group D was injuried seriously,with alveolar interval infiltration and lung cavity saturation of inflammatory cells and bleeding.Pathological changes in group A,B and C were minuteor,with no significance on infiltration of inflammatory cells and inflammation exudation.Conclusion: 1,The model can be used in the investigation of lung explantation and protection.2,In our non-heart-beating donor lung's acquire procedure.Under the comprehended protections including pretreatment with methylprednisolone,chest cavity irrigation with cold sodium chloride during warm ischemia,mechanical ventilation, dabbling with LPD liquid,cold preserved with aeration.The NHBD lung's security warm ischemia time can be extend to 60 minutes.