INJURY SEVERITY DICTATES INDIVIDUALIZED ANTIBIOTIC-THERAPY IN PENETRATING ABDOMINAL-TRAUMA

Antibiotics play a crucial role in reducing the risk of postoperative infection in patients suffering penetrating abdominal trauma. The infe ction rate for patients with these injuries ranges from 7% to 16%. Sin gle agents with broad-spectrum activity have proven efficacy, but dosa ge and duration are still controversial. A prospective, double-blinded study was performed on 102 patients randomized to receive one of thre e antibiotics for a total of 12 hours: cefoxitin (3 doses, 31 patients ); ceftizoxime (2 doses, 36 patients); or mezlocillin (3 doses, 35 pat ients). Two distinct groups at risk for postoperative infection were e vident depending on the severity of injury: Group A were those with no colon injury or a colon injury that could be repaired, no evidence of shock, or fewer than 3 organs injured; Group B were those requiring a colostomy, evidence of shock on presentation, or three or more organs injured. All comparisons of the patient populations receiving the dif ferent antibiotics showed the two groups to be equivalent. The mean pe netrating abdominal trauma index for Group A was 8.8 and 28.2 for Grou p B. The overall infection rate for Group A was 10.3% and 42.3% for Gr oup B. There was a significant increase in infection rate for all anti biotics except ceftizoxime in Group B compared with group A. The penet rating abdominal trauma index was significantly higher in all patients who developed infection for all antibiotics. In addition, if the surg ical wound was closed primarily, patients with colon injuries develope d wound infections 71% of the time, and those with small-bowel injurie s did so 30% of the time. Therefore, it seems appropriate that patient s with mild to moderate penetrating injuries to the abdomen require no more than 12 hours of perioperative antibiotic coverage. In addition, antibiotics with extended half-lives are more than adequate. The pene trating abdominal trauma index appears to correlate well with the risk of infection, and those patients with gastrointestinal tract violatio n should have surgical wounds managed by delayed primary closure becau se the risk of primary wound infection is unacceptably high.