Evaluating the Impact of a Perioperative Care Bundle on Surgical Site Infection Prevention After Abdominal Surgery: Insights from the EPO2CH Trial

Introduction

Surgical site infections (SSIs) are among the most common postoperative complications, significantly impacting patient outcomes, healthcare costs, and resource utilization. Despite advances in surgical techniques and infection control practices, the incidence of SSIs remains high, particularly in abdominal surgeries. The need for effective prevention strategies has led to numerous guidelines endorsing various perioperative interventions.

This article critically examines the EPO2CH trial—a large, multicenter, pragmatic randomized controlled trial—designed to evaluate whether an integrated care bundle added to standard care can reduce SSIs in patients undergoing abdominal surgery. The trial’s design, findings, and clinical implications provide valuable insights into the potential and limitations of multifaceted prevention approaches.

Study Background and Rationale

SSIs account for a significant proportion of postoperative morbidity, with rates varying by surgical site, patient factors, and adherence to infection prevention measures. Current guidelines, such as those from the World Health Organization (WHO) and Centers for Disease Control and Prevention (CDC), recommend various interventions including optimized surgical technique, antibiotic prophylaxis, normothermia, and wound care.

The concept of care bundles—a set of evidence-based practices implemented collectively—aims to enhance adherence and synergize their preventive effects. The EPO2CH trial was designed to test whether a specific bundle comprising intraoperative high inspired oxygen, goal-directed fluid therapy, normothermia, perioperative glucose control, and incisional wound irrigation could reduce SSI rates beyond standard care.

Study Design and Methods

The EPO2CH trial adopted an open-label, pragmatic, randomized, controlled, multicenter design in seven Dutch hospitals. Eligible participants were adults scheduled for elective abdominal surgery with incisions exceeding five centimeters, reflecting a population at high risk for SSIs.

Participants were randomized equally into two groups: standard perioperative care and standard care plus the EPO2CH bundle. Randomization was conducted per hospital per day using an automated system, with secure allocation concealment.

The primary endpoint was the incidence of SSI within 30 days postoperatively, classified according to CDC criteria. Secondary outcomes included adverse events, length of hospital stay, and other postoperative complications. Safety assessments monitored adverse events and serious adverse events, considering the high-risk nature of the interventions.

Key Results

Data from 1,777 patients indicated that the implementation of the intervention bundle did not significantly reduce SSI rates compared with standard care alone. The cumulative incidence was 18.4% in the intervention group versus 18.9% in controls, with a relative risk (RR) of 0.98 (95% CI: 0.81-1.18). The per-protocol analysis yielded a similar RR of 0.91 (95% CI: 0.60-1.37), suggesting no robust benefit.

Importantly, the rate of serious adverse events was comparable between groups—33.3% versus 33.5%—with an RR of 0.99, indicating no increased risk from the bundle. These findings point to the conclusion that, despite the theoretical benefits of each component, the combined bundle did not translate into a statistically or clinically significant reduction in SSI rates.

Discussion of Findings

The null results underscore several considerations. First, the high baseline adherence to infection prevention measures, including perioperative antibiotics and skin preparation, may have limited the incremental benefit of additional bundle components. Second, variability in implementation fidelity, despite pragmatic design, could have diluted potential effects.

Furthermore, the specific components chosen, although evidence-based individually, might not synergize as expected or may not sufficiently address all SSI risk factors. This highlights the complexity of SSI prevention, which involves multifactorial determinants spanning patient, surgical, and organizational factors.

Limitations of the study include the open-label design, which might introduce bias, although secondary outcomes and SSI assessment were blinded. The generalizability beyond high-income settings with well-established infection control practices also warrants caution.

Implications for Clinical Practice and Future Research

The findings suggest that a carefully implemented, evidence-based bundle may not always produce measurable improvements in SSI rates in developed healthcare settings. This does not diminish the importance of standard preventive measures but points to the need for targeted, personalized interventions.

Future research should explore tailored approaches, address organizational factors influencing compliance, and investigate novel strategies such as antimicrobial stewardship, enhanced wound healing techniques, and patient engagement.

Additionally, high-quality observational studies and adaptive trials could help identify subpopulations that benefit most from specific interventions, optimizing resource use and patient outcomes.

Conclusion

The EPO2CH trial demonstrates that adding a comprehensive perioperative care bundle to standard care does not significantly reduce SSIs after abdominal surgery in high-income settings. While multifaceted interventions hold promise, their effectiveness is context-dependent, and continued efforts are needed to refine prevention strategies, address implementation challenges, and explore innovative solutions.

Funding for this study was provided by the Netherlands Organisation for Health Research and Development (ZonMW), co-financed by Innovatiefonds Zorgverzekeraars, and Ethicon. The trial is registered at the CCMO register (NL-OMON50566). Current guidelines should continue to emphasize core preventive measures, with ongoing research into personalized and system-level interventions to further reduce SSI burden in surgical populations.