Establishment Of The Sheep Model Of Acute Large Area Of Pulmonary Embolism And Change Of Brain Natriuretic Peptide

Objective: The morbidity of pulmonary embolism raised year by year, it threatenpatients'health and life, especially the large area pulmonary embolism which involvestwo or more lobes. The case fatality is very high, many patients died before treatment.Our experiment intends to investigate (1)whether the method of putting tube intopulmonary artery through sheep's femoral vein and infusing auto-thrombus can formthe large area pulmonary embolism model volantly and exactly and whether is betterthan the method of infusing auto-thrombus through peripheral vein and the method ofobstructing pulmonary artery by sacculus proprius.(2)the change of indexes of bloodgas analysis after a large area pulmonary embolism according to the time.(3)whetherBNP (Brain natriuretic peptide), a blood vessel active facter which prognosticate leftventricular insufficiency; can also prognosticate the dysfunction of right ventricle andhelp to the early diagnosis and prognosis of large area pulmonary embolism.Methods: 18 healthy sheep were chosen, and divided into 3 groups randomly, 6in each group. Group 1 and group 2 were for experiment, the large area pulmonaryembolism models were formed by infusing auto-thrombus through tube in thepulmonary artery and by sacculus proprius respectively. The third group was blank.All the animals were monitored the mean artery pressure, mean pulmonary arterypressure, central vein pressure and saturation of blood oxygen, experiment group atthe moment of foundation of the model and 0.5hour,1hour,2hour,4hour,6hour,8hour after it. The blank group was also observed for 8hours.Took blood in the same time.All the samples were centrifuged and took plasma to measure the level of BNP.Compared the changing tendency of indexes of the blood gas analysis among thethree groups, and cornpared the level of BNP among the three groups. At last, datawere completed by using SPSS 12.0 statistical software.Results: After obstructing the right artery of sheep either by infusingauto-thrombus or gasing sacculus proprius in the two experimental groups, the largearea pulmonary embolism models are formed. Heart and respiratory rate accelerated,the pulmonary artery pressure raised up. The SaO₂ of auto-thrombus group loweredmore than 25ï¼…, PaO₂ and SaO₂ lowered to the wave trough in 0.5 hour, andcontinued to the end of the experiment, the difference between experiment group andblank group was statistical.PCO₂ rose to the peak, then slowly decreased, while inthe blank group no such change was observed. In the sacculus proprius group PaO₂and SaO₂ lowered to the wave trough in 0.5 hour, but return to normal in 1-2 hours.PA once rose but rebounded gradually. The level of BNP of sheep in the experimentgroup was related to PA, and much higher than the blank group. In the sacculusproprius group the level of BNP falled after the pulmonary artery drop to normal.Conclusion: Large area pulmonary embolism model can be quickly establishedusing the intercurrent method leading by X ray. Auto thrombus can be infused intopulmonary artery directly. And the accuracyis better than infusing thrombus through peripheral vein, and easy to control. Themodel of Auto thrombus is more approximate to the PE patient's physiologicalfunctions. Rising of the level of BNP may hint right ventricle dysfunction, it can alsohelp to diagnose and prognoses acute pulmonary embolism.