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OBJECTIVE: The aim of this study was to determine the effect of preoperative surgical antibiotic prophylaxis (SAP) with additional intraoperative redosing compared to single-dose preoperative surgical antibiotic prophylaxis on the incidence of surgical site infections (SSI). SUMMARY BACKGROUND DATA: Preoperative SAP is standard care for the prevention of SSI. During long surgical procedures, additional intraoperative redosing of SAP is advised, but there is great variability in redosing strategies and compliance rates. METHODS: We performed a systematic search of MEDLINE (PubMed), Embase, CINAHL and CENTRAL on June 25th, 2021 according to PROSPERO registration CRD42021229035. We included studies that compared the effect of preoperative SAP with additional intraoperative redosing to single dose preoperative SAP (no redosing) on SSI incidence in patients undergoing any type of surgery. Two researchers performed data appraisal and extraction of summary data independently. Meta-analyses were stratified per study type. We used a generic inverse variance random-effects model to estimate a pooled odds ratio with corresponding 95% confidence intervals (CIs). RESULTS: We included 2 randomized controlled trials (RCT) and 8 cohort studies comprising of 9470 patients. Pooled odds ratios for SSI in patients receiving intraoperative redosing compared to those without redosing were 0.47 (95% CI: 0.19-1.16. I2 = 36%) for RCTs and 0.55 (95% CI: 0.38-0.79, I2 = 56%) for observational cohorts. There was considerable clinical heterogeneity among antibiotics used and redosing protocols. GRADE-assessment showed overall low certainty of evidence. CONCLUSION: Intraoperative redosing of SAP may reduce incidence of SSI compared to a single dose preoperative SAP in any type of surgery, based on studies with considerable heterogeneity of antibiotic regimens and redosing protocols.

This Guide to Statistics and Methods discusses key statistical considerations in the conduct of randomized clinical trials in surgery.

Intra-abdominal infections (IAIs) are common surgical emergencies and have been reported as major contributors to non-trauma deaths in hospitals worldwide. The cornerstones of effective treatment of IAIs include early recognition, adequate source control, appropriate antimicrobial therapy, and prompt physiologic stabilization using a critical care environment, combined with an optimal surgical approach. Together, the World Society of Emergency Surgery (WSES), the Global Alliance for Infections in Surgery (GAIS), the Surgical Infection Society-Europe (SIS-E), the World Surgical Infection Society (WSIS), and the American Association for the Surgery of Trauma (AAST) have jointly completed an international multi-society document in order to facilitate clinical management of patients with IAIs worldwide building evidence-based clinical pathways for the most common IAIs. An extensive non-systematic review was conducted using the PubMed and MEDLINE databases, limited to the English language. The resulting information was shared by an international task force from 46 countries with different clinical backgrounds. The aim of the document is to promote global standards of care in IAIs providing guidance to clinicians by describing reasonable approaches to the management of IAIs.

Summary Background Antibiotic prophylaxis is frequently continued for 1 day or more after surgery to prevent surgical site infection. Continuing antibiotic prophylaxis after an operation might have no advantage compared with its immediate discontinuation, and it unnecessarily exposes patients to risks associated with antibiotic use. In 2016, WHO recommended discontinuation of antibiotic prophylaxis after surgery. We aimed to update the evidence that formed the basis for that recommendation. Methods For this systematic review and meta-analysis, we searched MEDLINE, Embase, CINAHL, CENTRAL, and WHO regional medical databases for randomised controlled trials (RCTs) on postoperative antibiotic prophylaxis that were published from Jan 1, 1990, to July 24, 2018. RCTs comparing the effect of postoperative continuation versus discontinuation of antibiotic prophylaxis on the incidence of surgical site infection in patients undergoing any surgical procedure with an indication for antibiotic prophylaxis were eligible. The primary outcome was the effect of postoperative surgical antibiotic prophylaxis continuation versus its immediate discontinuation on the occurrence of surgical site infection, with a prespecified subgroup analysis for studies that did and did not adhere to current best practice standards for surgical antibiotic prophylaxis. We calculated summary relative risks (RRs) with corresponding 95% CIs using a random effects model (DerSimonian and Laird). We evaluated heterogeneity with the χ2 test, I2, and τ2, and visually assesed publication bias with a contour-enhanced funnel plot. This study is registered with PROSPERO, CRD42017060829. Findings We identified 83 relevant RCTs, of which 52 RCTs with 19 273 participants were included in the primary meta-analysis. The pooled RR of surgical site infection with postoperative continuation of antibiotic prophylaxis versus its immediate discontinuation was 0·89 (95% CI 0·79–1·00), with low heterogeneity in effect size between studies (τ2=0·001, χ2 p=0·46, I2=0·7%). Our prespecified subgroup analysis showed a significant association between the effect estimate and adherence to best practice standards of surgical antibiotic prophylaxis: the RR of surgical site infection was reduced with continued antibiotic prophylaxis after surgery compared with its immediate discontinuation in trials that did not meet best practice standards (0·79 [95% CI 0·67–0·94]) but not in trials that did (1·04 [0·85–1·27]; p=0·048). Whether studies adhered to best practice standards explained all variance in the pooled estimate from the primary meta-analysis. Interpretation Overall, we identified no conclusive evidence for a benefit of postoperative continuation of antibiotic prophylaxis over its discontinuation. When best practice standards were followed, postoperative continuation of antibiotic prophylaxis did not yield any additional benefit in reducing the incidence of surgical site infection. These findings support WHO recommendations against this practice. Funding None.

IntroductionSurgical site infections (SSI) are a common postoperative complication. During the development of the new WHO guidelines on SSI prevention, also in the Netherlands was concluded that perioperative care could be optimised beyond the current standard practice. We selected a limited set of readily available, cheap and evidence-based interventions from these new guidelines that are not part of standard practice in the Netherlands and formulated an Enhanced PeriOperative Care and Health bundle (EPOCH). Here, we describe the protocol for an open-label, randomised controlled, parallel-group, superiority trial to test the effect of the EPOCH bundle added to (national) standard care in comparison to standard care alone on the incidence of SSI.Methods and analysisEPOCH consists of intraoperative high fractional inspired oxygen (0.80); goal-directed fluid therapy; active preoperative, intraoperative and postoperative warming; perioperative glucose control and treatment of severe hyperglycaemia (>10 mmoll-1) and standardised surgical site handling. Patients scheduled for elective abdominal surgery with an incision larger than 5 cm are eligible for inclusion. Participants are randomised daily, 1:1 according to variable block sizes, and stratified per participating centre to either EPOCH added to standard care or standard care only. The primary endpoint will be SSI incidence according to the Centers for Disease Control and Prevention (CDC) definition within 30 days as part of routine clinical follow-up. Four additional questionnaires will be sent out over the course of 90 days to capture disability and costs. Other secondary endpoints include anastomotic leakage, incidence of incisional hernia, serious adverse events, hospital readmissions, length of stay and cost effectiveness. Analysis of the primary endpoint will be on an intention-to-treat basis.Ethics and disseminationEthics approval is granted by the Amsterdam UMC Medical Ethics Committee (reference 2015_121). Results will be disseminated through peer-reviewed journals and summaries shared with stakeholders. This protocol is published before analysis of the results.Trial registration numberRegistered in the Dutch Trial Register: NL5572.

The use of an inspiratory oxygen fraction of 0.80 during surgery is a topic of ongoing debate. Opponents claim that increased oxidative stress, atelectasis, and impaired oxygen delivery due to hyperoxic vasoconstriction are detrimental. Proponents point to the beneficial effects on the incidence of surgical site infections and postoperative nausea and vomiting. Also, hyperoxygenation is thought to extend the safety margin in case of acute intraoperative emergencies. This review provides a comprehensive risk-benefit analysis for the use of perioperative hyperoxia in noncritically ill adults based on clinical evidence and supported by physiological deduction where needed. Data from the field of hyperbaric medicine, as a model of extreme hyperoxygenation, are extrapolated to the perioperative setting. We ultimately conclude that current evidence is in favour of hyperoxia in noncritically ill intubated adult surgical patients.

INTRODUCTION: Registration of clinical trials has been initiated in order to assess adherence of the reported results to the original trial protocol. This study aimed to investigate the publication rates, timely dissemination of results, and the prevalence of consistency in hypothesis, sample size, and primary endpoint of Dutch investigator-initiated randomized controlled clinical trials (RCTs). METHODS: All Dutch investigator-initiated RCTs with a completion date between December 31, 2010, and January 1, 2012, and registered in the Trial Register of The Netherlands database were included. PubMed was searched for the publication of these RCT results until September 2016, and the time to the publication date was calculated. Consistency in hypothesis, sample size, and primary endpoint compared with the registry data were assessed. RESULTS: The search resulted in a total of 168 Dutch investigator-initiated RCTs. In September 2016, the results of 129 (77%) trials had been published, of which 50 (39%) within 2 years after completion of accrual. Consistency in hypothesis with the original protocol was observed in 108 (84%) RCTs; in 71 trials (55%), the planned sample size was reached; and 103 trials (80%) presented the original primary endpoint. Consistency in all three parameters was observed in 50 studies (39%). CONCLUSION: This study shows that approximately one out of four Dutch investigator-initiated RCTs remains unpublished 5 years after initiation. The observed low overall consistency with the initial study outline is a matter of concern and warrants improvements in trial design and assessment of trial feasibility.

IntroductionAcute abdominal wound dehiscence (AWD) or burst abdomen is a severe complication after abdominal surgery with an incidence up to 3.8%. Surgical site infection (SSI) is the biggest risk factor for the development of AWD. It is strongly suggested that the use of triclosan-coated sutures (TCS) for wound closure reduces the risk of SSI. We hypothesise that the use of TCS for abdominal wound closure may reduce the risk of AWD. Current randomised controlled trials (RCTs) lack power to investigate this. Therefore, the purpose of this individual participant data meta-analysis is to evaluate the effect of TCS for abdominal wound closure on the incidence of AWD.Methods and analysisWe will conduct a systematic review of Medline, Embase and Cochrane Central Register of Controlled Trials for RCTs investigating the effect of TCS compared with non-coated sutures for abdominal wound closure in adult participants scheduled for open abdominal surgery. Two independent reviewers will assess eligible studies for inclusion and methodological quality. Authors of eligible studies will be invited to collaborate and share individual participant data. The primary outcome will be AWD within 30 days after surgery requiring reoperation. Secondary outcomes include SSI, all-cause reoperations, length of hospital stay and all-cause mortality within 30 days after surgery. Data will be analysed with a one-step approach, followed by a two-step approach. In the one-step approach, treatment effects will be estimated as a risk ratio with corresponding 95% CI in a generalised linear mixed model framework with a log link and binomial distribution assumption. The quality of evidence will be judged using the Grading of Recommendations Assessment Development and Evaluation approach.Ethics and disseminationThe medical ethics committee of the Amsterdam UMC, location AMC in the Netherlands waived the necessity for a formal approval of this study, as this research does not fall under the Medical Research involving Human Subjects Act. Collaborating investigators will deidentify data before sharing. The results will be submitted to a peer-reviewed journal.PROSPERO registration numberCRD42019121173.

Objective To test the hypothesis that surgical site infection (SSI) risk differs, after administration of surgical antibiotic prophylaxis (SAP) within 60-30 or 30-0 minutes before incision. Background The importance of appropriate timing of SAP before surgery has long been recognized. However, available evidence is contradictive on the best timing within a 60-0 minutes time interval before incision. Here, we aim to evaluate previous contradictions with a carefully designed observational cohort. Methods An observational cohort study was conducted in a Dutch tertiary referral center. For 2 years, consecutive patients with SAP indication undergoing general, orthopedic, or gynecologic surgery were followed for the occurrence of superficial and deep SSI as defined by the Center of Disease Control and Prevention. The association between timing of SAP and SSI was assessed using multivariable logistic regression. Results After 3001 surgical procedures, 161 SSIs were detected. In 87% of the procedures, SAP was administered within 60 minutes before incision. Only antibiotics with short infusion time were used. Multivariable logistic regression indicated there was no conclusive evidence of a difference in SSI risk after SAP administration 60-30 minutes or 30-0 minutes before incision [odds ratio: 0.82; 95% confidence interval (0.57-1.19)]. Conclusions For SAP with short infusion time no clear superior timing interval within the 60-minute interval before incision could be identified in this cohort. We were unable to reproduce differences in SSI risk found in earlier studies.

Background In 2016, the World Health Organization (WHO) strongly recommended the use of a high fraction of inspired oxygen (FiO2) in adult patients undergoing general anaesthesia to reduce the risk of surgical site infection (SSI). Since then, further trials have been published, trials included previously have come under scrutiny, and one article was retracted. We updated the systematic review on which the recommendation was based. Methods We performed a systematic literature search from January 1990 to April 2018 for RCTs comparing the effect of high (80%) vs standard (30–35%) FiO2 on the incidence of SSI. Studies retracted or under investigation were excluded. A random effects model was used for meta-analyses; the sources of heterogeneity were explored using meta-regression. Results Of 21 RCTs included, six were newly identified since the publication of the WHO guideline review; 17 could be included in the final analyses. Overall, no evidence for a reduction of SSI after the use of high FiO2 was found [relative risk (RR): 0.89; 95% confidence interval (CI): 0.73–1.07]. There was evidence that high FiO2 was beneficial in intubated patients [RR: 0.80 (95% CI: 0.64–0.99)], but not in non-intubated patients [RR: 1.20 (95% CI: 0.91–1.58); test of interaction; P=0.048]. Conclusions The WHO updated analyses did not show definite beneficial effect of the use of high perioperative FiO2, overall, but there was evidence of effect of reducing the SSI risk in surgical patients under general anaesthesia with tracheal intubation. However, the evidence for this beneficial effect has become weaker and the strength of the recommendation needs to be reconsidered.

Background Evidence-based guidelines from the World Health Organization (WHO) have recommended a high (80%) fraction of inspired oxygen (FiO2) to reduce surgical site infection in adult surgical patients undergoing general anaesthesia with tracheal intubation. However, there is ongoing debate over the safety of high FiO2. We performed a systematic review to define the relative risk of clinically relevant adverse events (AE) associated with high FiO2. Methods We reviewed potentially relevant articles from the WHO review supporting the recommendation, including an updated (July 2018) search of EMBASE and PubMed for randomised and non-randomised controlled studies reporting AE in surgical patients receiving 80% FiO2 compared with 30–35% FiO2. We assessed study quality and performed meta-analyses of risk ratios (RR) comparing 80% FiO2 against 30–35% for major complications, mortality, and intensive care admission. Results We included 17 moderate–good quality trials and two non-randomised studies with serious-critical risk of bias. No evidence of harm with high FiO2 was found for major AE in the meta-analysis of randomised trials: atelectasis RR 0.91 [95% confidence interval (CI) 0.59–1.42); cardiovascular events RR 0.90 (95% CI 0.32–2.54); intensive care admission RR 0.93 (95% CI 0.7–1.12); and death during the trial RR 0.49 (95% CI 0.17–1.37). One non-randomised study reported that high FiO2 was associated with major respiratory AE [RR 1.99 (95% CI 1.72–2.31)]. Conclusions No definite signal of harm with 80% FiO2 in adult surgical patients undergoing general anaesthesia was demonstrated and there is little evidence on safety-related issues to discourage its use in this population.

World Health Organization Responds to Concerns about Surgical Site Infection Prevention Recommendations.

Supplemental Digital Content is available in the text, The aim of the study was to assess the effect of timing of preoperative surgical antibiotic prophylaxis (SAP) on surgical site infection (SSI) and compare the different timing intervals. The benefit of routine use of SAP prior to surgery has long been recognized. However, the optimal timing has not been defined. For the purpose of developing recommendations for the World Health Organization guideline for SSI prevention, a systematic review and meta-analysis of all relevant evidence was conducted. Major medical databases were searched from 1990 to 2016. The primary outcome was SSI after preoperative-SAP comparing different timing intervals. Adjusted odds ratios (OR) with 95% confidence intervals (CI) were extracted and pooled for each comparison with a random effects model. Fourteen papers with 54,552 patients were included in this review. In a quantitative analysis, there was no significant difference when SAP was administered 120–60 minutes prior to incision compared to administration 60–0 minutes prior to incision. Studies investigating different timing intervals within the last 60 minutes time frame reported contradictive results. The risk of SSI almost doubled when SAP was administered after first incision (OR:1.89; 95%CI:[1.05–3.40]) and was 5 times higher when administered more than 120 minutes prior to incision (OR5.26; 95%CI:[3.29–8.39]). Administration of antibiotic prophylaxis more than 120 minutes before incision or after incision is associated a higher risk of surgical site infections than administration less than 120 minutes before incision. Within this 120-minute time frame prior to incision, no differential effects could be identified. The broadly accepted recommendation to administer prophylaxis within a 60-minute time frame prior to incision could not be substantiated.

Background Surgical site infections (SSIs) are one of the most common hospital-acquired infections. To reduce SSIs, prophylactic intra-operative wound irrigation (pIOWI) has been advocated, although the results to date are equivocal. To develop recommendations for the new World Health Organization (WHO) SSI prevention guidelines, a systematic literature review and a meta-analysis were conducted on the effectiveness of pIOWI using different agents as a means of reducing SSI. Methods The PUBMED, Embase, CENTRAL, CINAHL, and WHO databases were searched. Randomized controlled trials (RCTs) comparing either pIOWI with no pIOWI or with pIOWI using different solutions and techniques were retrieved with SSI as the primary outcome. Meta-analyses were performed, and odds ratios (OR) and the mean difference with 95% confidence intervals (CI) were extracted and pooled with a random effects model. Results Twenty-one studies were suitable for analysis, and a distinction was made between intra-peritoneal, mediastinal, and incisional wound irrigation. A low quality of evidence demonstrated a statistically significant benefit for incisional wound irrigation with an aqueous povidone-iodine (PVP-I) solution in clean and clean contaminated wounds (OR 0.31; 95% CI 0.13-0.73; p = 0.007); 50 fewer SSIs per 1,000 procedures (from 19 fewer to 64 fewer)). Antibiotic irrigation had no significant effect in reducing SSIs (OR 1.16; 95% CI 0.64-2.12; p = 0.63). Conclusion Low-quality evidence suggests considering the use of prophylactic incisional wound irrigation to prevent SSI with an aqueous povidone-iodine solution. Antibiotic irrigation does not show a benefit and therefore is discouraged.

Surgical site infections (SSIs) are the most common health-care-associated infections in developing countries, but they also represent a substantial epidemiological burden in high-income countries. The prevention of these infections is complex and requires the integration of a range of preventive measures before, during, and after surgery. No international guidelines are available and inconsistencies in the interpretation of evidence and recommendations in national guidelines have been identifi ed. Considering the prevention of SSIs as a priority for patient safety, WHO has developed evidencebased and expert consensus-based recommendations on the basis of an extensive list of preventive measures. We present in this Review 16 recommendations specifi c to the intraoperative and postoperative periods. The WHO recommendations were developed with a global perspective and they take into account the balance between benefi ts and harms, the evidence quality level, cost and resource use implications, and patient values and preferences.

Surgical site infection (SSI) is a common complication of surgery and a major cause of morbidity, mortality and health care costs. Several patient and perioperative care related factors play a role in SSI, which above all is the result of a complex process. Timing of antibiotic prophylaxis (AP) is a process indicator that has been described extensively. However, the optimal timing remains controversial. A large SSI reduction was initially shown for administration of AP within two hours before incision. Later the optimal timing seemed to be 30-60 minutes or the final 30 minutes before incision. Recently, it has been shown that there is no significant association between timing and SSI. This controversy is reflected in several guidelines with dissimilar advice. If there is no optimal AP timing, it should not be a process indicator. Other SSI risk factors that are presently not the focus of attention may be more important process indicators.