LAS VEGAS – Trauma patients should not get antibiotics after damage control or primarily closed laparotomies because this treatment may increase the risk of postsurgical intra-abdominal infections, according to a study from Virginia Commonwealth University, Richmond, a Level 1 trauma center.
The abdomen is often left open for a while after a damage control laparotomy (DCL), especially when patients are coagulopathic, acidotic, or at risk for an abdominal compartment syndrome. In those cases, "people just automatically assume ‘Open abdomen: Throw on the antibiotics.’ What we are showing here is don’t throw on the antibiotics," said lead investigator Dr. Stephanie Goldberg of the trauma, critical care, and emergency surgery faculty at VCU. The worry is probably the same for primarily closed (PC) laparotomies, when the fascia is closed but skin is sometimes left open.
The findings are important because although – and as the team found – preoperative antibiotics are known to reduce the risk of postsurgical abdominal infections, there’s not much evidence in either direction for their use after trauma laparotomies, so "no one knows what to do." Some surgeons opt for antibiotics, others don’t, Dr. Goldberg said.
To help figure out the right approach, her team analyzed perioperative antibiotic use and infection rates in 28 DCL patients whose abdomens were left open, and 93 PC patients. The PC group had a mean injury severity score of 18; 35.5% (33) had bowel injuries. The DCL group was in worse shape, with a mean severity score of 31.4 and bowel injuries in 53.6% (15).
Everyone should have been dosed with an antibiotic before surgery; 94.6% (88) PC patients, but only 69.2% (19) DCL patients, actually were. "It’s likely," in the DCL cases especially, "that patients were so sick and there was so much chaos in the operating room that giving pre-op antibiotics got missed," Dr. Goldberg said.
Postop antibiotic use differed significantly between the groups; 50.5% (47) of PC patients got no antibiotics, 21.5% (20) got a day’s worth, and 28% (26) were treated for more than a day. In the DCL group, 21.4% (6) got no antibiotics, 25.0% (7) a 1-day course, and 53.6% (15) more than a 1-day course.
As expected, preop antibiotics protected against intra-abdominal infections (odds ratio, 0.20; 95% confidence interval 0.05-0.91; P = .037). Postoperative antibiotics, however, substantially increased the risk (OR, 6.7; 95% CI 1.33 – 33.8; P= .044).
The longer patients were on antibiotics, the greater that risk became. Among the 6 DCL patients who received no postsurgical antibiotics, 16.7% (1) developed an intra-abdominal infection. Among the 7 treated for a day, 28.6% (2) developed an intra-abdominal infection; 40% (6) did so among the 15 treated for more than a day. The trend was similar for PC patients, although the overall infection rates were lower.
Antimicrobial resistance could be to blame. As normal flora were wiped out, maybe the field was cleared for "bugs to cause problems that otherwise would not have," explained senior investigator Dr. Thèrese Duane of the department of surgery at VCU. Surgeons there tend to favor Zosyn or Cefoxitin.
The project was just the first step toward building a robust evidence base about antibiotic use after trauma laparotomies. Next on the team’s agenda is a multicenter, prospective trial.
"We need more numbers," Dr. Duane said.
Dr. Goldberg has no relevant disclosures. Dr. Duane speaks for Pfizer on behalf of its antibiotic, linezolid.