Effect of infection on secondary necrosis of soft tissue blast injury in pigs

    LI Jinª²Qing, LI Xueª²Yong, CHEN Shaoª²Zong, LI Wangª²Zhou, LI Yueª²Jun

    Department of Plastics and Burns, Tangdu Hospital, Fourth Military Medical University, Xi¬ðan 710038, China

    ¡¾Abstract¡¿ AIM: To observe the influence of infection on the secondary necrosis of soft tissue blast injury in pigs. METHODS: Twentyª²four blast wounds£¬created by explosion of a specific type of electric detonators which were fixed at 1 cm over the skin of the shoulders and hips of 6 small white domestic pigs (15-20) kg, were divided into 2 groups: group A which was treated with conventional dressing change, and group B which was not treaed until the 3rd day after injury. Tissue specimens, collected from the wounds on day 3, 6, and 9 after injury, were weighed and underwent bacteria counting. Meanwhile, the wound areas and depths were measured on the corresponding time points after injury. RESULTS: Six hours after injury, the mean area and depth of all wounds were (7.34¡À0.99) cm2 and (0.85¡À0.126) cm, without statistical significance between group A and B in both wound area and depth (P>0.05). Three days after injury, the bacteria load, area, and depth of the wounds in group A were (0.157¡À0.171)¡Á105 coloryª²forming unit/g (cfu/g), (9.17¡À0.60) cm2, and (1.43¡À0.13) cm, while those in group B were (323.417¡À30.631)¡Á105 cfu/g, (10.81¡À0.32) cm2, and (1.66¡À0.09) cm, respectively, showing significant statistical differences between group A and B in the three definite measurements of wounds (P<0.01). Wound areas of group B on day 6 and 9 after injury were (13.33¡À0.46) and (11.38¡À0.39) cm2, both being significantly different from those of group B on day 3 after injury (P<0.01). Wound depths of group B on day 6 and 9 after injury were (2.42¡À0.22) and (2.46¡À0.25) cm, both of which had significant statistical differences as compared with those of group B on day 3 after injury (P<0.01). CONCLUSION: Infection aggravates the secondary necrosis of soft tissue blast injury, and under the treatment of conventional dressing change, infection can cause about 1 cm tissue in the wound and the about 0.5 cm skin around the wound to necrosis. ......