Establishment Of Blast Lung Injury Model In Rabbits And Experimental Study Of The Early Application Of Protective Lung Ventilation Strategy

Objective:Through the establishment of blast lung injury(BLI)model in Rabbits,and to observe the pathological and physiological characteristics after BLI;To investigate the application of early protective lung ventilation strategy(PLVS)treatment after BLI rabbit.Method:1.Twenty-one local health white rabbits according to the random number table method and the distance between the center of rabbit chest and detonator were divided into :group A(d = 7 cm,n = 5),group B(d = 10 cm,n = 8),group C(d = 13 cm,n = 8).Rabbit after anesthesia,epilation,femoral artery and vein catheterization and other operations,then prone to the self-blasting test-bed,the implementation of electronic set off the explosion source in rabbit bone directly.After the blast give corresponding simple treatment.Closely monitored before injury,after injury 1/4h,1h,2h,4h,8h and 24 h each time point animal respiration,heart rate,mean arterial pressure and arterial blood gas changes;femoral artery bleeding quickly after death,24 h after injury measured ratio lung water,lung tissue HE staining pathological and lung injury scale.2.Sixteen local health white rabbits,according to the above method established BLI rabbit models at d = 10 cm,were randomly methods divided into: conventional mechanical ventilation group(CMV group,n = 8),low tidal volume + PEEP ventilation group(SVT + PEEP group,n = 8).Closely monitored before injury,after injury ventilation 1/4h,1h,2h,4h,8h and 24 h each time point arterial blood gas analysis,respiratory mechanics change,the pre-injury and after ventilation therapy24 h each group of lung CT scan examination,then quickly femoral artery were sacrificed,measured ratio lung water and lung tissue HE staining pathological.Results:1.The rabbits of group B and C no death within 24 hours;four rabbits of Group A were died within 2-4h after injury and the another rabbit was died at 6h after injury.The respiratory rate,heart rate of group A within 6h injury and group B within 24 h injury and group C within 2h raised significantly higher than that before injury(P<0.05).Comparing with before injury,the MAP of group A and B consistently below(P <0.05).group C was not statistically significant;The p H value of Group A after injury significantly decreased than before injury(P <0.05);The p H value of group B after injury 1h start to reduce and maintaining at a low state(P <0.05);The p H value of Group C changed no significant.The Pa O2 levels of group A statistical significance after injury gradually reduce;The group B gradually reduced within 2-4h after injury(P <0.05),after rising slightly but still significantly lower than before the injury(P<0.05).The group C gradually reduced the lowest at 2 hour after injury(P <0.05),then with a slight increase,at 8h after injury recovered to pre-injury level(P> 0.05).The Pa CO2 of group A gradually increased with statistical significance after injury,group B increased significantly at 1h after injury(P <0.05),then continued at a high level,but still significantly lower than before injury(P <0.05),the group C was not statistically significant compared with pre-injury level(P> 0.05).The ratio lung water(RLW)of group A and B raised more significantly than group A(P <0.05).RLW of Group C changed no significant.In the light microscope,Group A lung hemorrhage significantly,showing a large number of leukocyte infiltration,alveolar partial fusion,part of the alveolar wall rupture,interval widened,some alveolar atrophy,interstitial pulmonary edema.Group B and C corresponds to alleviate disease due to increased distance.The lung injury of group A,B and C were graded according to assessment of lung injury was severe,moderate,mild injury.2.The p H value of model group after injury 1 hour significantly decreased than before injury(P<0.05).Comparing with before injury,the p H value of CMV group continues to rise after ventilation 1-24 h,had difference was statistically significant(P<0.05);The p H value of SVT + PEEP group comparing with CMV at different phases of 1-24 h after injury were statistically significant.The Pa O2 and OI levels of CMV group and SVT +PEEP group were significantly decreased,and gradually increased after treatment 1h,and CMV group increased higher.The Pa CO2 level of CMV group and SVT +PEEP group were increased slightly,and CMV group gradually increased after treatment 1h,SVT + PEEP group gradually increased after injury 1h,comparing with before injury and CMV group phase point differences were statistically significant(P <0.05).SVT +PEEP group peak airway pressure and mean airway pressure was significantly decreased,and the immediate post-injury time points and CMV group difference was statistically significant(P <0.05).CMV group and SVT+PEEP group after treatment 24 h,CT examination were found the lung bleeding and edema were reduced,there is no clear difference between the two groups compared.Comparing with model group and CMV group,RLW of SVT +PEEP group was obviously lower than pure injuries and CMV group treated without ventilation,and the difference was statistically significant(P < 0.05).CMV group and SVT + PEEP ventilation after treatment,inflammation cells infiltration,alveolar atrophy and pulmonary edema degree is lighter than pure injury treated without ventilation,but CMV group of alveolar fusion and alveolar wall rupture increases.Conclusions:1、The model of the distance between the center of rabbit chest and detonator was 10 cm,can show changes of lung injury and observe a series of indicators,the model is reproducible and can be used to blast injury in lungs related research.2、The SVT +PEEP as a PLVS,can effectively improve the oxygen of BLI,alleviate pulmonary inflammation and improve lung edema,can decrease the alveolar over-expansion,thereby reducing secondary lung injury.