Selective Non-Operative Management After Abdominal Gunshot and Blast Injuries in A Porcine Model

The role of selective non-operative management (SNOM) after gunshot and blast injuries has been increasingly recognized but not explored in animal models. Overall, 24 male pigs were prepared, of which 12 were used to create a gunshot wound model, and the remaining 12 a blast injury model. Animals in each injury model were randomly divided into immediate surgery and SNOM groups using a computer-generated random sequence. Gunshot injury was created by firing a 7 mm, 1.45 g steel ball at the right upper abdomen from 10 cm under 170 bar. Blast injury was created by exposing the right upper abdomen to a high-pressure shock wave from 6 cm under 170-190 bar. In the SNOM group, focused assessment with sonography for trauma (FAST) was performed immediately after modeling and repeated when hemodynamic instability or clinical deterioration was suspected. Conversion to surgery was triggered by persistent heterogeneous echogenicity or hypoechoic fluid on FAST, hemodynamic instability, or progressive clinical deterioration. The primary outcome was the 7-day SNOM outcome. SNOM failure was defined as conversion to surgery or death. After gunshot injury modeling, the 7-day survival rate was 91.67% (11/12). In the immediate surgery group, 2 pigs underwent therapeutic laparotomy, and 4 underwent negative laparotomy. In the SNOM group, 1 pig underwent conversion to surgery, 1 died of hemorrhagic shock on day 1 after modeling, and 4 successfully completed SNOM. After blast injury modeling, the 7-day survival rate was 100% (12/12). In the immediate surgery group, 3 pigs underwent therapeutic laparotomy, and 3 underwent negative laparotomy. In the SNOM group, 2 pigs underwent conversion to surgery, and 4 completed successful SNOM. This work describes the establishment of preliminary injured porcine models, presents representative outcomes of the SNOM and immediate laparotomy strategies, and underscores the need for close monitoring when using the SNOM strategy.