内固定对股骨干骨折合并失血性休克犬凝血机能的影响

Influence of intramedullary nailing fixation on coagulative responses of canine with femoral fracture and hemorrhagic shock

目的探讨犬股骨干骨折合并失血性休克复苏后不同内固定方法对凝血机能的影响。方法18条健康杂种犬,股动、静脉插管,右颈外静脉置入Swan-Ganz漂浮导管,放血后制成股骨干骨折合并失血性休克模型,复苏后分别采用钢板（plate,P）、不扩髓钉（Unreamed femoral nailing,UFN）和扩髓钉（Reamed femoral nailing,RFN）内固定。在手术开始前至术后8h内7个不同时间点测定静脉血内纤维蛋白原（fibrinogen,Fbg）水平,血浆抗凝血酶Ⅲ（antithrombin-Ⅲ,AT-Ⅲ）、血浆蛋白C（protein-C,PC）、D-二聚体（D-dimer）含量,并进行血小板计数。结果RFN组术后Fbg含量有明显降低,血小板数量减少,AT-Ⅲ和PC活性降低,D-dimer含量均有升高,8h仍未恢复至基础值;UFN和P组表现相同趋势,但变化较小,2-8h均恢复正常;三组间比较,多个时间段差异具有显著性（P〈0.05）。结论犬股骨干骨折合并失血性休克复苏后早期扩髓固定,可造成凝血系统、抗凝血系统和纤溶系统激活,血浆纤维蛋白原和血小板消耗性减少,AT-Ⅲ和PC活性降低,D-二聚体含量升高，和不扩髓及钢板固定相比，扩髓固定对凝血-抗凝血系统产生更大影响。

Objective To investigate the impact of different fixation methods on coagulative responses of canine with femoral fracture and hemorrhagic shock. Method Eighteen adult mixed breed dogs were used in this study. Catheters were inserted into left femoral artery and vein through a cut-down. Swan- Gans catheter was placed into pulmonary artery through right external jugular vein. Hemorrhagic shock was induced by withdrawal of blood from the arterial catheter. Mean arterial pressure was maintained 5.33-6.67kPa for one hour. The resuscitation was started by retransfusion of the shed blood plus Ringer＇s solution.Then the dogs were divided into three groups depended on the different internal fixation methods： plate, unreamed intramedullary nailing and reamed intramedullary nailing. The venous blood samples of the animals was withdrawal to assay the levels and activity of mass concentration of fibrinogen （Fbg）, antithrombin-Ⅲ （AT-Ⅲ）, protein-C （PC） and D-dimer from the beginning of procedure to 8h after the fixation when the dogs were sacrificed. The numbers of platelet （plt） was also counted. Result Fbg, numbers of platelet, AT-Ⅲ level and PC activity reduced at the end of operation. While the D-dimer levels rised. They didn＇t restore baseline till 8h after the operation in RFN. The alterations of group UFN and P had the similar trend, but this was not found to be statistically significant. Compared with each other , the differences were significant among the three groups in most of the time points （P〈0.05）. Conclusion After resuscitation of canine with femoral fracture and hemorrhagic shock, early fixation of fracture with reamed nailing will yield greater influence on the coagulative systems compared with plate and unreamed nailing.