静吸复合麻醉对特重度烧伤患者凝血功能障碍的影响

目的收集特重度烧伤(总TBSA50%以上或三度TBSA20%以上或伴有严重并发症者)患者围术期凝血指标(APTT、PT、FIB、DD和PLT)，分析静吸复合麻醉对患者凝血功能的影响及其临床意义。 方法选取近3年内蒙古医科大学第三附属医院烧伤外科收治的特重度烧伤患者148例，根据入院14 d内的预后分为死亡组和生存组，生存组男性129例，女性9例；年龄24~59岁，平均(43.30±12.90)岁。死亡组男性8例，女性2例；年龄26~63岁，平均(46.19±15.41)岁。收集入院时(T0)，术前(早晨入手术室前，T1)，术毕(送至PACU未拔除气管导管前，T2)及术后2 d(T3)4个时间点的凝血指标，比较两组凝血指标动态差异。 结果死亡组休克期输液量、累计血浆、红细胞输入量显著高于生存组(P<0.01)。T0时，生存组的FIB(1.78±0.32)显著高于死亡组(1.26±0.07)(P<0.05)；T2时，两组APTT、PT均显著缩短(P<0.05)，生存组的FIB(3.86±0.40)显著高于死亡组(2.45±1.02)(P<0.05)；T3时，死亡组PLT显著低于生存组(P<0.01)。 结论特重度烧伤患者在围手术期易出现高凝状态，并且这可能导致患者死亡。静吸复合麻醉和围术期大量液体复苏会促进患者的高凝状态。     

Three-dimensional finite element analysis of intramedullary nail with different materials in the treatment of intertrochanteric fractures

Intramedullary nails are the common treatment options for femoral intertrochanteric fractures. However, aseptic loosening is considered to be one of the primary forms of failure that can be caused by the stress shielding between the bone and implants. The matching in mechanical properties of implant and bone is a key issue to prevent this failure. Polyetheretherketone (PEEK) and Function-graded (FG) materials are widely used in clinical because of their excellent mechanical properties. In this study, to investigate the biomechanical behaviors of intramedullary nails made of Ti-6Al-4V alloy, Stainless Steel (SS), PEEK and two FG materials, three-dimensional finite element models of intertrochanteric fracture femur with intramedullary nail were constructed with ABAQUS. The maximum von Mises stress on the femoral fracture surface fixed by PEEK intramedullary nail was the largest, followed by FG intramedullary nail, which help stimulate bone growth and subsequently reduce fracture healing time. Compared with traditional metal intramedullary nails, PEEK and FG implants might increase von Mises stress along the same path in the proximal femur. The results showed that PEEK and FG intramedullary nails obviously changed the stress distributions in the bone and reduced stress shielding. This finding indicated that PEEK and FG intramedullary nails have the potential to become alternatives to the conventional metal intramedullary nails.