An Experimental Study On The Characteristics And Its Mechanism Of Lung Impact Injury Occurrence Under Closure Of Glottis

The lung impact injury is a kind of occlusive injuries most of which are resulted from direct impact on the thorax by passive violence. Its usual causes are traffic accident, falling down from high place and strike with great force etc. Chest trauma is responsible for more than 56% mortality annually. Broken, tracheobronchial, lung 1aceration, hemathorax, rib fracture, pulmonary contsion and cardiovascular injury incurred by BCT are those risking factors of death. Clinically, symptoms of some chest trauma cases are atypical finally resulting in delay of treatment since most are occlusive injuries,However,a few reports have been published on study of BCT and its mechanism remains unclear.Especially, there are still discrepancy on the characteristics and its mechanism of lung impact injury occurrence under the open and closure of glottis due to the lack of consensus of experimental data.Thus, based on the characteristics of lung impact injury, We in this study establish a model of lung impact injury by bumping directly in the chest of rabbits with BIM-â…¡ Bio-impactor to examine the effects of various injurying parameters on the lung under the open and closure of glottis;to comparatively analyze the diagnostic values of single photon emission computerized tomography (SPECT),thoracic computed tomography, and chest X-ray on diagnosis of chest trauma by observing the development of lung impact injury under the closure of glottis. And to comprehend the alteration of the pulmonary microvascular permeability after lung impact injury by detecting the effects of impact injuries serum on the expression of endothelial VE-cadherin in primarily cultured pulmonary microvascular endothelial cells. And to investigate the relation between the expression of proinflammatory cytokines and inflammatory reaction after lung impact injury by detecting their expression levels in the injuried pulmonary tissues. Taken together, the results will build a theoretical basis for diagnosing and treating blunt cheat trauma. The main results and conclusions of this study are as follows:1.Open and closure of glottis states is simulated by opening and closing tracheal tube.the model of lung impact injury caused by BIM-â…¡ Bio-impactor were made directly on the chest in rabbits to observe the effects of injuries parameters on the lung under the open and closure of glottis,The result showed that combination of drive pressure 800kPa and compress percentage 30% was tested to be the suitable impact parameter for injury, and the established model by this parameter is relatively simple, easily controllable and highly repeatable, which could be used as a feasible model for the study of chest trauma.No matter what the glottis states were, the bigger the driving pressure was, the more severe of the lung injury on the condition of compress percentage is not changed. Also, the bigger the compress percentage was, the more severe of the lung injury on the condition of driving pressure was not changed. The severity of lung injury in the glottis closure state was significantly higher than that in glottis open state.Furthermore, there were some characteristics of lung impact injury in glottis closure state: â‘  severity of injury; â‘¡ increased mortality; â‘¢ more early occurrence of traumatic acute lung injury. The left lung tissue was injuried obviously too although the right thorax was designed to be impacted, indicating that secondary injury could happen in the left lung tissue once the right is stuck.2.To comparatively analyze the diagnostic values of single photon emission computerized tomography (SPECT), thoracic computed tomography, and chest X-ray on diagnosis of chest trauma by observing the development of lung impact injury with SPECT.The conclusion was that X-ray is the superior tool for diagnosis of lung impact due to its feasibility and economy, while CT can define quickly the position, nature and degree of injury because of its high sensibility. SPECT can indicate the location and size as well as the change of injury so that it can provide v...