便携超声辅助高速破片致肝脏穿透伤动物模型的建立及评价

Establishment and Evaluation of A High-Speed Fragment-Induced Penetrating Liver Injury Model Assisted by Portable Ultrasound

目的采用便携超声辅助定位建立高速破片致肝脏穿透伤动物模型,并即刻评价建模的可行性。材料与方法使用便携超声辅助,对10只长白猪的呼气末肝脏下缘和吸气末右侧胸腔下缘行体表定位,描记瞄准线,确定瞄准点及投射方向,通过实验用弹道枪投射高速(速度约627 m/s)破片模拟弹致肝脏穿透伤。射击前15 min和射击后20 min记录血压、心率、呼吸频率、脉搏血氧饱和度等生理学指标。致伤后20 min,超声检查肝脏有无损伤及损伤程度,致伤后现场使用便携超声观察肝脏致伤及腹腔积液情况,记录肝脏创伤灶大小、肝脏损伤分级和腹腔积液部位及最大深度,并与大体病理结果进行比较,评估肝损伤程度。结果10只实验猪中,9只均成功造成肝穿透伤,破片致肝脏穿透伤成功率占90%(9/10),合并腹腔其他脏器损伤占22.22%(2/9),膈肌穿透伤占22.22%(2/9),均未造成明显血气胸。致伤后,实验猪的收缩压、舒张压、脉搏血氧饱和度降低[(132.44±12.65)mmHg比(103.33±33.43)mmHg,(96.44±12.27)mmHg比(70.89±24.21)mmHg,(89.44±8.49)%比(76.00±13.41)%;t=2.440、2.651、4.084,均P<0.05],心率增快[(94.00±17.39)次/min比(139.89±37.21)次/min;t=3.534,P<0.05]。致伤后20 min便携式超声检查,所有肝脏损伤表现为片状不均匀稍强回声区,边界较清楚,形态不规则,局部肝包膜连续性中断;其中8只实验猪呈现腹腔积液,最大深度(4.16±1.35)cm。动物处死后大体病理参考美国创伤外科学会肝损伤分级,显示II级6只、III级3只。超声测量短径与病理实质裂伤深度呈正相关(r=0.945,P<0.001);肝创伤的超声美国创伤外科学会分级与大体标本比较,符合率为88.89%(8/9)。结论便携超声辅助高速破片致伤实验猪肝脏建模准确、稳定性好,并可实时有效评估肝脏穿透伤模型伤情况,为肝脏火器伤的救治研究提供实验依据。

Purpose To establish and evaluate a high-speed fragment-induced penetrating liver injury model in pigs assisted by portable ultrasound.Materials and Methods With the aid of portable ultrasound,the lower edge of the liver at the end of expiration and the lower edge of the right chest at the end of inspiration of 10 Landrace pigs were positioned on the body surface.Then the sighting line was traced to determine the direction of projection and the sighting point.High-speed(about 627 m/s)fragments were projected through an experimental ballistic gun to induce penetrating liver injury.Blood pressure,heart rate,respiratory rate,pulse oxygen saturation and other physiological indexes were measured 15 minutes before shooting and 20 minutes after shooting.20 minutes after injury,the liver injury and the degree of injury were examined by ultrasound.After injury,the liver injury and abdominal fluid accumulation were observed by on-site portable ultrasound,and the size of liver trauma,liver injury grade,abdominal fluid accumulation location and maximum depth were recorded.The degree of liver injury was evaluated by comparison with the gross pathological results.Results Nine out of ten pigs were successfully modeled.The success rate of penetrating liver injury induced by fragments was 90%(9/10),other organ injury in abdominal cavity was 22.22%(2/9),and diaphragm penetrating injury was 22.22%(2/9),which did not occur obvious hemopneumothorax.After injury,the systolic blood pressure,diastolic blood pressure,and pulse oxygen saturation of the pigs decreased[(132.44±12.65)mmHg vs.(103.33±33.43)mmHg,(96.44±12.27)mmHg vs.(70.89±24.21)mmHg,(89.44±8.49)%vs.(76.00±13.41)%;t=2.440,2.651,4.084,all P<0.05],and the heart rate increased[(94.00±17.39)times/min vs.(139.89±37.21)times/min;t=3.534,P<0.05].Within 20 minutes after modeling,portable ultrasound images showed that the liver injury was a patchy,heterogeneous,slightly strong echo area with clear and irregular boundary,and the continuity of the local liver capsule was interrupted.The ascites appeared in the abdominal cavity with the maximum depth of(4.16±1.35)cm.The American association for the surgery of trauma(AAST)liver injury grading of gross pathology after the animals were killed showed that there were 6 cases of grade II and 3 cases of grade III.Along the fragment projection direction,the short diameter measured by ultrasound was positively correlated with the depth of gross pathological laceration(r=0.945,P<0.001).Compared with the gross specimen,the accuracy rate of ultrasonic AAST grading of liver injury was 88.89%(8/9).Conclusion The model of high-speed fragment-induced liver injury in pigs assisted by portable ultrasound is accurate and stable,and portable ultrasound can effectively evaluate the penetrating liver injury,which provides a basis for the treatment of liver firearm injury.