Preventative antibiotics for penetrating abdominal trauma--single agent or combination therapy?

Prophylactic antibiotics for penetrating abdominal trauma: duration of use and antibiotic choice

BACKGROUND

Penetrating abdominal trauma (PAT) is a common type of trauma leading to admission to hospital, which often progresses to septic complications. Antibiotics are commonly administered as prophylaxis prior to laparotomy for PAT. However, an earlier Cochrane Review intending to compare antibiotics with placebo identified no relevant randomised controlled trials (RCTs). Despite this, many RCTs have been carried out that compare different agents and durations of antibiotic therapy. To date, no systematic review of these trials has been performed.

OBJECTIVES

To assess the effects of antibiotics in penetrating abdominal trauma, with respect to the type of agent administered and the duration of therapy.

SEARCH METHODS

We searched the following electronic databases for relevant randomised controlled trials, from database inception to 23 July 2019; Cochrane Injuries Group's Specialised Register, CENTRAL, MEDLINE Ovid, MEDLINE Ovid In-Process & Other Non-Indexed Citations, MEDLINE Ovid Daily and Ovid OLDMEDLINE, Embase Classic + Embase Ovid, ISI Web of Science (SCI-EXPANDED, SSCI, CPCI-S & CPSI-SSH), and two clinical trials registers. We also searched reference lists from included studies. We applied no restrictions on language or date of publication.

SELECTION CRITERIA

We included RCTs only. We included studies involving participants of all ages, which were conducted in secondary care hospitals only. We included studies of participants who had an isolated penetrating abdominal wound that breached the peritoneum, who were not already taking antibiotics.

DATA COLLECTION AND ANALYSIS

Two study authors independently extracted data and assessed risk of bias. We used standard Cochrane methods. We aggregated study results using a random-effects model. We also conducted trial sequential analysis (TSA) to help reduce type I and II errors in our analyses.

MAIN RESULTS

We included 29 RCTs, involving a total of 4458 participants. We deemed 23 trials to be at high risk of bias in at least one domain. We are uncertain of the effect of a long course of antibiotic prophylaxis (> 24 hours) compared to a short course (≤ 24 hours) on abdominal surgical site infection (RR 1.00, 95% CI 0.81 to 1.23; I² = 0%; 7 studies, 1261 participants; very low-quality evidence), mortality (Peto OR 1.67, 95% CI 0.73 to 3.82; I² = 8%; 7 studies, 1261 participants; very low-quality evidence), or intra-abdominal infection (RR 1.23, 95% CI 0.84 to 1.80; I² = 0%; 6 studies, 111 participants; very-low quality evidence). Based on very low-quality evidence from fifteen studies, involving 2020 participants, which compared different drug regimens with activity against three classes of gastrointestinal flora (gram positive, gram negative, anaerobic), we are uncertain whether there is a benefit of one regimen over another. TSA showed the majority of comparisons did not cross the alpha adjusted boundary for benefit or harm, or reached the required information size, indicating that further studies are required for these analyses. However, in the three analyses which crossed the boundary for futility, further studies are unlikely to show benefit or harm.

AUTHORS' CONCLUSIONS

Very low-quality evidence means that we are uncertain about the effect of either the duration of antibiotic prophylaxis, or the superiority of one drug regimen over another for penetrating abdominal trauma on abdominal surgical site infection rates, mortality, or intra-abdominal infections. Future RCTs should be adequately powered, test currently used antibiotics, known to be effective against gut flora, use methodology to minimise the risk of bias, and adequately report the level of peritoneal contamination encountered at laparotomy.

Ceftizoxime use in trauma celiotomy: pharmacokinetics and patient outcomes

Seriously injured patients undergo vigorous resuscitation upon arrival at the emergency department and through the immediate perioperative period. Although resuscitation leads to volume loading and fluid shifts, drug dosing and dosing intervals are often not altered to account for changes in total body volume or circulatory volume. To address this, a prospective study of pharmacokinetics of ceftizoxime in 53 injured adults who underwent emergency celiotomy was conducted. Further, the relationship between serum ceftizoxime concentrations and infectious outcomes was evaluated. Per protocol, injured adults undergoing emergency celiotomy received prophylactic ceftizoxime treatment according to standard dosing regimens. Of the patients, 6 (11.5%) experienced postoperative infections and had lower peak serum ceftizoxime levels in the recovery room than patients not experiencing infection. For severely injured adults with extensive blood loss or undergoing lengthy operations requiring rigorous volume resuscitation, doses of ceftizoxime, and indeed all antibiotics, may need to be increased beyond conventional standards to minimize infectious complications.

Pre-, intra-, and postoperative antibiotics

Endogenous contamination from perforation or rupture of the gastrointestinal tract; exogenous contamination from missiles, knives, or invasive lines and tubes; and immunodepression related to the severity of injury are responsible for the increased infectious complications noted in patients who have undergone laparotomy for abdominal trauma. Perioperative use of clindamycin and an aminoglycoside, a second- or third-generation cephalosporin, or an enhanced-spectrum penicillin is clearly beneficial in lowering the incidence of intra-abdominal and wound infections. A 12- to 48-hour length of administration of antibiotics after operation is as effective as regimens of longer duration, although presently used dosages may be inadequate in severely injured patients. Adjunctive surgical maneuvers such as peritoneal irrigation with saline-containing antibiotic(s) remain controversial. Perioperative use of antibiotic prophylaxis, coupled with early operation and appropriate surgical technique, results in a 4.4% rate of intra-abdominal abscesses and a 5.1% rate of wound infections after laparotomy for abdominal trauma in modern trauma centers.

Antibiotics for penetrating abdominal trauma: a prospective comparative trial of single agent cephalosporin therapy versus combination therapy

In this prospective, comparative study, 129 patients who sustained penetrating abdominal trauma were randomized to receive preoperatively, and for 3-5 days postoperatively, one of three antibiotic regimens: Group I--cefotaxime (CTX) (2 Gm Q8H), Group II--cefoxitin (2 Gm Q6H), or Group III--clindamycin (900 mg Q8H) and gentamicin (3-5 mg/kg/day in divided doses Q8H). The three groups were similar in terms of the following: age, sex, severity of injury, number of organs injured, colon injuries, shock, blood transfusions, or positive intraoperative cultures. Septic complications occurred as follows: Group I--6.9%, Group II--2.3%, and Group III--6.9%. The three regimens ranked as follows in terms of therapy costs: CTX less than cefoxitin less than clindamycin and gentamicin. It is concluded that single agent therapy with a cephalosporin is preferable to combination therapy on the basis of equivalent effectiveness, lower toxicity, and lower costs.