Establishment and Evaluation of A High-Speed Fragment-Induced Penetrating Liver Injury Model Assisted by Portable Ultrasound / 中国医学影像学杂志

ABSTRACT

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.