Cefamandole preparation for colonic surgery

Preoperative combined mechanical and oral antibiotic bowel preparation for preventing complications in elective colorectal surgery

BACKGROUND

The success of elective colorectal surgery is mainly influenced by the surgical procedure and postoperative complications. The most serious complications include anastomotic leakages and surgical site infections (SSI)s, which can lead to prolonged recovery with impaired long-term health.  Compared with other abdominal procedures, colorectal resections have an increased risk of adverse events due to the physiological bacterial colonisation of the large bowel. Preoperative bowel preparation is used to remove faeces from the bowel lumen and reduce bacterial colonisation. This bowel preparation can be performed mechanically and/or with oral antibiotics. While mechanical bowel preparation alone is not beneficial, the benefits and harms of combined mechanical and oral antibiotic bowel preparation is still unclear.

OBJECTIVES

To assess the evidence for the use of combined mechanical and oral antibiotic bowel preparation for preventing complications in elective colorectal surgery.

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL and trial registries on 15 December 2021. In addition, we searched reference lists and contacted colorectal surgery organisations.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) of adult participants undergoing elective colorectal surgery comparing combined mechanical and oral antibiotic bowel preparation (MBP+oAB) with either MBP alone, oAB alone, or no bowel preparation (nBP). We excluded studies in which no perioperative intravenous antibiotic prophylaxis was given.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as recommended by Cochrane. Pooled results were reported as mean difference (MD) or risk ratio (RR) and 95 % confidence intervals (CIs) using the Mantel-Haenszel method. The certainty of the evidence was assessed with GRADE.

MAIN RESULTS

We included 21 RCTs analysing 5264 participants who underwent elective colorectal surgery. None of the included studies had a high risk of bias, but two-thirds of the included studies raised some concerns. This was mainly due to the lack of a predefined analysis plan or missing information about the randomisation process. Most included studies investigated both colon and rectal resections due to malignant and benign surgical indications. For MBP as well as oAB, the included studies used different regimens in terms of agent(s), dosage and timing.  Data for all predefined outcomes could be extracted from the included studies. However, only four studies reported on side effects of bowel preparation, and none recorded the occurrence of adverse effects such as dehydration, electrolyte imbalances or the need to discontinue the intervention due to side effects. Seventeen trials compared MBP+oAB with sole MBP. The incidence of SSI could be reduced through MBP+oAB by 44% (RR 0.56, 95% CI 0.42 to 0.74; 3917 participants from 16 studies; moderate-certainty evidence) and the risk of anastomotic leakage could be reduced by 40% (RR 0.60, 95% CI 0.36 to 0.99; 2356 participants from 10 studies; moderate-certainty evidence). No difference between the two comparison groups was found with regard to mortality (RR 0.87, 95% CI 0.27 to 2.82; 639 participants from 3 studies; moderate-certainty evidence), the incidence of postoperative ileus (RR 0.89, 95% CI 0.59 to 1.32; 2013 participants from 6 studies, low-certainty of evidence) and length of hospital stay (MD -0.19, 95% CI -1.81 to 1.44; 621 participants from 3 studies; moderate-certainty evidence). Three trials compared MBP+oAB with sole oAB. No difference was demonstrated between the two treatment alternatives in terms of SSI (RR 0.87, 95% CI 0.34 to 2.21; 960 participants from 3 studies; very low-certainty evidence), anastomotic leakage (RR 0.84, 95% CI 0.21 to 3.45; 960 participants from 3 studies; low-certainty evidence), mortality (RR 1.02, 95% CI 0.30 to 3.50; 709 participants from 2 studies; low-certainty evidence), incidence of postoperative ileus (RR 1.25, 95% CI 0.68 to 2.33; 709 participants from 2 studies; low-certainty evidence) or length of hospital stay (MD 0.1 respectively 0.2, 95% CI -0.68 to 1.08; data from 2 studies; moderate-certainty evidence). One trial (396 participants) compared MBP+oAB versus nBP. The evidence is uncertain about the effect of MBP+oAB on the incidence of SSI as well as mortality (RR 0.63, 95% CI 0.33 to 1.23 respectively RR 0.20, 95% CI 0.01 to 4.22; low-certainty evidence), while no effect on the risk of anastomotic leakages (RR 0.89, 95% CI 0.33 to 2.42; low-certainty evidence), the incidence of postoperative ileus (RR 1.18, 95% CI 0.77 to 1.81; low-certainty evidence) or the length of hospital stay (MD 0.1, 95% CI -0.8 to 1; low-certainty evidence) could be demonstrated.

AUTHORS' CONCLUSIONS

Based on moderate-certainty evidence, our results suggest that MBP+oAB is probably more effective than MBP alone in preventing postoperative complications. In particular, with respect to our primary outcomes, SSI and anastomotic leakage, a lower incidence was demonstrated using MBP+oAB. Whether oAB alone is actually equivalent to MBP+oAB, or leads to a reduction or increase in the risk of postoperative complications, cannot be clarified in light of the low- to very low-certainty evidence. Similarly, it remains unclear whether omitting preoperative bowel preparation leads to an increase in the risk of postoperative complications due to limited evidence. Additional RCTs, particularly on the comparisons of MBP+oAB versus oAB alone or nBP, are needed to assess the impact of oAB alone or nBP compared with MBP+oAB on postoperative complications and to improve confidence in the estimated effect. In addition, RCTs focusing on subgroups (e.g. in relation to type and location of colon resections) or reporting side effects of the intervention are needed to determine the most effective approach of preoperative bowel preparation.

Strategies for Antibiotic Administration for Bowel Preparation Among Patients Undergoing Elective Colorectal Surgery: A Network Meta-analysis

Importance

There are discrepancies in guidelines on preparation for colorectal surgery. While intravenous (IV) antibiotics are usually administered, the use of mechanical bowel preparation (MBP), enemas, and/or oral antibiotics (OA) is controversial.

Objective

To summarize all data from randomized clinical trials (RCTs) that met selection criteria using network meta-analysis (NMA) to determine the ranking of different bowel preparation treatment strategies for their associations with postoperative outcomes.

Data Sources

Data sources included MEDLINE, Embase, Cochrane, and Scopus databases with no language constraints, including abstracts and articles published prior to 2021.

Study Selection

Randomized studies of adults undergoing elective colorectal surgery with appropriate aerobic and anaerobic antibiotic cover that reported on incisional surgical site infection (SSI) or anastomotic leak were selected for inclusion in the analysis. These were selected by multiple reviewers and adjudicated by a separate lead investigator. A total of 167 of 6833 screened studies met initial selection criteria.

Data Extraction and Synthesis

NMA was performed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. Data were extracted by multiple independent observers and pooled in a random-effects model.

Main Outcomes and Measures

Primary outcomes were incisional SSI and anastomotic leak. Secondary outcomes included other infections, mortality, ileus, and adverse effects of preparation.

Results

A total of 35 RCTs that included 8377 patients were identified. Treatments compared IV antibiotics (2762 patients [33%]), IV antibiotics with enema (222 patients [3%]), IV antibiotics with OA with or without enema (628 patients [7%]), MBP with IV antibiotics (2712 patients [32%]), MBP with IV antibiotics with OA (with good IV antibiotic cover in 925 patients [11%] and with good overall antibiotic cover in 375 patients [4%]), MBP with OA (267 patients [3%]), and OA (486 patients [6%]). The likelihood of incisional SSI was significantly lower for those receiving IV antibiotics with OA with or without enema (rank 1) and MBP with adequate IV antibiotics with OA (rank 2) compared with all other treatment options. The addition of OA to IV antibiotics, both with and without MBP, was associated with a reduction in incisional SSI by greater than 50%. There were minimal differences between treatments in anastomotic leak and in any of the secondary outcomes.

Conclusions and Relevance

This NMA demonstrated that the addition of OA to IV antibiotics were associated with a reduction in incisional SSI by greater than 50%. The results support the addition of OA to IV antibiotics to reduce incisional SSI among patients undergoing elective colorectal surgery.

Antimicrobial prophylaxis for colorectal surgery

BACKGROUND

Research shows that administration of prophylactic antibiotics before colorectal surgery prevents postoperative surgical wound infection. The best antibiotic choice, timing of administration and route of administration remain undetermined.

OBJECTIVES

To establish the effectiveness of antimicrobial prophylaxis for the prevention of surgical wound infection in patients undergoing colorectal surgery. Specifically to determine:1. whether antimicrobial prophylaxis reduces the risk of surgical wound infection;2. the target spectrum of bacteria (aerobic or anaerobic bacteria, or both);3. the best timing and duration of antibiotic administration;4. the most effective route of antibiotic administration (intravenous, oral or both);5. whether any antibiotic is clearly more effective than the currently recommended gold standard specified in published guidelines;6. whether antibiotics should be given before or after surgery.

SEARCH METHODS

For the original review published in 2009 we searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE (Ovid) and EMBASE (Ovid). For the update of this review we rewrote the search strategies and extended the search to cover from 1954 for MEDLINE and 1974 for EMBASE up to 7 January 2013. We searched CENTRAL on the same date (Issue 12, 2012).

SELECTION CRITERIA

Randomised controlled trials of prophylactic antibiotic use in elective and emergency colorectal surgery, with surgical wound infection as an outcome.

DATA COLLECTION AND ANALYSIS

Data were abstracted and reviewed by one review author and checked by another only for the single, dichotomous outcome of surgical wound infection. Quality of evidence was assessed using GRADE methods.

MAIN RESULTS

This updated review includes 260 trials and 68 different antibiotics, including 24 cephalosporins and 43,451 participants. Many studies had multiple variables that separated the two study groups; these could not be compared to other studies that tested one antibiotic and had a single variable separating the two groups. We did not consider the risk of bias arising from attrition and lack of blinding of outcome assessors to affect the results for surgical wound infection.Meta-analyses demonstrated a statistically significant difference in postoperative surgical wound infection when prophylactic antibiotics were compared to placebo/no treatment (risk ratio (RR) 0.34, 95% confidence interval (CI) 0.28 to 0.41, high quality evidence). This translates to a reduction in risk from 39% to 13% with prophylactic antibiotics. The slightly higher risk of wound infection with short-term compared with long-term duration antibiotic did not reach statistical significance (RR 1.10, 95% CI 0.93 to 1.30). Similarly risk of would infection was slightly higher with single-dose antibiotics when compared with multiple dose antibiotics, but the results are compatible with benefit and harm (RR 1.30, 95% CI 0.81 to 2.10). Additional aerobic coverage and additional anaerobic coverage both showed statistically significant improvements in surgical wound infection rates (RR 0.44, 95% CI 0.29 to 0.68 and RR 0.47, 95% CI 0.31 to 0.71, respectively), as did combined oral and intravenous antibiotic prophylaxis when compared to intravenous alone (RR 0.56, 95% CI 0.43 to 0.74), or oral alone (RR 0.56, 95% CI 0.40 to 0.76). Comparison of an antibiotic with anaerobic specificity to one with aerobic specificity showed no significant advantage for either one (RR 0.84, 95% CI 0.30 to 2.36). Two small studies compared giving antibiotics before or after surgery and no significant difference in this timing was found (RR 0.67, 95% CI 0.21 to 2.15). Established gold-standard regimens recommended in major guidelines were no less effective than any other antibiotic choice.

AUTHORS' CONCLUSIONS

This review has found high quality evidence that antibiotics covering aerobic and anaerobic bacteria delivered orally or intravenously (or both) prior to elective colorectal surgery reduce the risk of surgical wound infection. Our review shows that antibiotics delivered within this framework can reduce the risk of postoperative surgical wound infection by as much as 75%. It is not known whether oral antibiotics would still have these effects when the colon is not empty. This aspect of antibiotic dosing has not been tested. Further research is required to establish the optimal timing and duration of dosing, and the frequency of longer-term adverse effects such as Clostridium difficile pseudomembranous colitis.

Single-dose amoxycillin-clavulanic acid vs. cefotetan for prophylaxis in elective colorectal surgery: a multicentre, prospective, randomized study. The PRODIGE Group

A prospective, multicentre, randomized trial was carried out in 19 hospitals in order to compare the efficacy of amoxycillin-clavulanic acid with cefotetan as antibiotic prophylaxis in patients undergoing elective colorectal surgery. Since the main purpose of the study was to demonstrate equivalence between the two regimens, the protocol planned the inclusion of 200 patients. Eligible patients were randomly assigned to receive either amoxycillin-clavulanic acid (2.2 g) or cefotetan (2 g) in a single infusion on the induction of anaesthesia. Failure of prophylaxis was defined as occurrence of infection of intestinal origin, either minor (wound cellulitis) or major (abscess, peritonitis, septicaemia) within the 30-day postoperative period. Among 221 randomized patients, 208 (105 amoxycillin-clavulanic acid, 103 cefotetan) aged 66 +/- 12 years (mean +/- SD) were evaluated while 13 were withdrawn. Colorectal cancer was the indication for surgery in 73% of cases. Eleven (10 +/- 6%, 95% confidence interval) and 13 (13 +/- 7%) failures were observed in the amoxycillin-clavulanic acid and cefotetan groups (P = 0.63 chi-square test) respectively. Most infections occurred before the 10th postoperative day (8% failures at this time, estimated by the Kaplan-Meier method). The results of the trial demonstrate that amoxycillin-clavulanic acid and cefotetan have similar efficacy when used for prophylaxis of infection after elective colorectal surgery.

Prophylactic antibiotics in elective colorectal surgery

In an effort to determine whether or not the addition of parenteral antibiotics to orally administered erythromycin and neomycin would diminish postoperative septic complications in elective colorectal operations, a randomized, double-blind, controlled trial was conducted comparing three groups. All patients received vigorous preoperative mechanical bowel preparation, 3 g erythromycin and 3 g neomycin orally, the day prior to operation. Patients in Group O received three doses of saline intravenously as placebo, patients in Group C received cefazolin, 1 g, immediately preoperatively and 1 g every 6 hours postoperatively, intravenously, for two doses, and patients in Group T received a single immediate preoperative dose of 6 g of ticarcillin intravenously and two saline placebo doses intravenously, postoperatively. The patients' progress was followed in the hospital and for one month postoperatively. Septic complications occurred in 35 per cent of patients in Group O, 7 per cent of patients in Group C, and 5 per cent of patients in Group T. Wound infections comprised most of these complications, occurring in 29 per cent of Group O, 4.7 per cent of Group C, and 2.3 per cent of Group T patients. Thus, the addition of either parenteral cefazolin or ticarcillin in this study significantly reduced wound infections in elective colorectal surgery.

The prophylactic use of antimicrobials in surgery

During the period August 1976 to June 1982, there were 98 reports of antimicrobial prophylaxis in human surgery that were judged unevaluable. Our review, coupled with that of Chodak and Plaut, identified studies of 126 antibiotic regimens that were considered evaluable and a total of 205 studies considered unevaluable. A decrease in infection rate in antibiotic-treated patients compared to non-antibiotic-treated patients was seen in 120 (95%) of the evaluable regimens. Ninety-nine (79%) of these 120 regimens produced statistically significant reductions in the infection rate (P less than .05, chi 2 analysis). The majority of the antibiotic regimens were tested in procedures that were classified as clean-contaminated. Of the regimens that yielded a statistically significant reduction in infection rate with antimicrobial therapy, in 66 (67%) the agents were used for 24 hours or less. Five regimens were identified in which a higher infection rate occurred in specific patient groups when prophylactic antibiotics were used, but the differences were not statistically significant. In the overwhelming majority of evaluable studies, antibiotics decreased the incidence of surgical infection compared with non-antibiotic groups. The available data also support the effectiveness of short prophylactic antibiotic courses of 24 hours' duration or less. The duration necessary for antibiotic prophylaxis was specifically tested in nine regimens. In all nine, a short course (less than 24 hours) of antibiotic prophylaxis was as effective as longer periods of therapy (24 hours to 5 days) in preventing infection.