扩髓及髓腔内固定引发肺脂肪栓塞病理变化的实验研究

目的：探讨临床股骨骨折内固定或人工全髋关节置换术中扩髓，髓腔内固定导致的肺脂肪栓塞的病理变化。方法：精雄性SPF大鼠14只。分为实验组及对照组，每组7只，对照组除扩髓髓腔内固定外，皆同实验组。分别测定两组不同时间的动脉血气，血像，实验后取大鼠左肺行髓过氧化物酶（MPO）检查，大鼠右肺采用肺灌注后行HE染色，光镜下观察。计数骨碎片及骨髓脂肪组织栓塞的肺小动脉及毛细血管数，白细胞栓子形成的肺内血管数，伴有血管周围水肿（“水肿袖”）的血管数，肺泡水肿，肺泡扩张破坏面积，由此计算出肺损伤分数.结果：（1）运用因气显示两组动物在扩髓髓腔内固定后即150min时，Po2差异显著（P＜0．05）；(2)MPO差异显著（P＜0．05）。（3）肺损伤分数两组差异显著（P＜0．05）。结论：扩髓髓腔内固定导致肺小动脉及毛细血管 内骨碎片及骨髓脂肪组织的机械栓塞，以及肺内血管白细胞栓子形成， 中性粒细胞，巨噬细胞浸润等炎性改变，并由此引起肺损伤。

Pathological Changes of Pulmonary Fat Embolism After Reaming and Intramedullary Fixation

Objective: Our aim was to investigate the pathological changes of pulmonary fat embolism after reaming and intramedullary fixation in femoral fracture treatment or artificial hip replacement. Methods: We strictly selected and divided 14 male Sprague-Dawley SPF rats into experimental and control groups. The procedure for control group was exactly the same as the experimental group except reaming and intramedullary fixation. Blood gas and routine blood test were taken at different time. After the experiment, the left lung of the rat was taken for myeloperoxidase (MPO) examination, and the right lung was perfused with formalin (20%) and HE staining was taken. Bone debris, bone marrows and fat cells emboli-zed pulmonary arterioles and capillaries. Blood vessels with embolus of white blood cells, blood vessels with perivascular edema, and area of intraalveolar edema and pulmonary distension were calculated to get further derived lung injury score. Results: 1. The P o 2 was significantly decreased immediately after reaming and intramedullary fixation i.e. 150 min in the experimental procedure. 2. The MPO was significantly high in the experimental group. 3. The lung injury score showed significance in the experimental group. Conclusion: Reaming and intramedullary fixation induced the mechanical obstruction of bone debris, bone marrow and fat cells in pulmonary arterioles and capillaries. The formation of embolus of white blood cells, and the infiltration of neutrophil and macrophage could further lead to lung injury.