Interventions to prevent surgical site infection in adults undergoing cardiac surgery.

BACKGROUND

Surgical site infection (SSI) is a common type of hospital-acquired infection and affects up to a third of patients following surgical procedures. It is associated with significant mortality and morbidity. In the United Kingdom alone, it is estimated to add another £30 million to the cost of adult cardiac surgery. Although generic guidance for SSI prevention exists, this is not specific to adult cardiac surgery. Furthermore, many of the risk factors for SSI are prevalent within the cardiac surgery population. Despite this, there is currently no standard of care for SSI prevention in adults undergoing cardiac surgery throughout the preoperative, intraoperative and postoperative periods of care, with variations in practice existing throughout from risk stratification, decontamination strategies and surveillance.

OBJECTIVES

Primary objective: to assess the clinical effectiveness of pre-, intra-, and postoperative interventions in the prevention of cardiac SSI.

SECONDARY OBJECTIVES

(i) to evaluate the effects of SSI prevention interventions on morbidity, mortality, and resource use; (ii) to evaluate the effects of SSI prevention care bundles on morbidity, mortality, and resource use.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, MEDLINE (Ovid, from inception) and Embase (Ovid, from inception) on 31 May 2021.

CLINICALTRIALS

gov and the WHO International Clinical Trials Registry Platform (ICTRP) were also searched for ongoing or unpublished trials on 21 May 2021. No language restrictions were imposed.

SELECTION CRITERIA

We included RCTs evaluating interventions to reduce SSI in adults (≥ 18 years of age) who have undergone any cardiac surgery.

DATA COLLECTION AND ANALYSIS

We followed the methods as per our published Cochrane protocol. Our primary outcome was surgical site infection. Our secondary outcomes were all-cause mortality, reoperation for SSI, hospital length of stay, hospital readmissions for SSI, healthcare costs and cost-effectiveness, quality of life (QoL), and adverse effects. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

A total of 118 studies involving 51,854 participants were included. Twenty-two interventions to reduce SSI in adults undergoing cardiac surgery were identified. The risk of bias was judged to be high in the majority of studies. There was heterogeneity in the study populations and interventions; consequently, meta-analysis was not appropriate for many of the comparisons and these are presented as narrative summaries. We focused our reporting of findings on four comparisons deemed to be of great clinical relevance by all review authors. Decolonisation versus no decolonisation Pooled data from three studies (n = 1564) using preoperative topical oral/nasal decontamination in all patients demonstrated an uncertain direction of treatment effect in relation to total SSI (RR 0.98, 95% CI 0.70 to 1.36; I = 0%; very low-certainty evidence). A single study reported that decolonisation likely results in little to no difference in superficial SSI (RR 1.35, 95% CI 0.84 to 2.15; moderate-certainty evidence) and a reduction in deep SSI (RR 0.36, 95% CI 0.17 to 0.77; high-certainty evidence). The evidence on all-cause mortality from three studies (n = 1564) is very uncertain (RR 0.66, 95% CI 0.24 to 1.84; I = 49%; very low-certainty evidence). A single study (n = 954) demonstrated that decolonisation may result in little to no difference in hospital readmission for SSI (RR 0.80, 95% CI 0.44 to 1.45; low-certainty evidence). A single study (n = 954) reported one case of temporary discolouration of teeth in the decolonisation arm (low-certainty-evidence. Reoperation for SSI was not reported. Tight glucose control versus standard glucose control Pooled data from seven studies (n = 880) showed that tight glucose control may reduce total SSI, but the evidence is very uncertain (RR 0.41, 95% CI 0.19 to 0.85; I = 29%; numbers need to treat to benefit (NNTB) = 13; very-low certainty evidence). Pooled data from seven studies (n = 3334) showed tight glucose control may reduce all-cause mortality, but the evidence is very uncertain (RR 0.61, 95% CI 0.41 to 0.91; I = 0%; very low-certainty evidence). Based on four studies (n = 2793), there may be little to no difference in episodes of hypoglycaemia between tight control vs. standard control, but the evidence is very uncertain (RR 2.12, 95% CI 0.51 to 8.76; I = 72%; very low-certainty evidence). No studies reported superficial/deep SSI, reoperation for SSI, or hospital readmission for SSI. Negative pressure wound therapy (NPWT) versus standard dressings NPWT was assessed in two studies (n = 144) and it may reduce total SSI, but the evidence is very uncertain (RR 0.17, 95% CI 0.03 to 0.97; I = 0%; NNTB = 10; very low-certainty evidence). A single study (n = 80) reported reoperation for SSI. The relative effect could not be estimated. The certainty of evidence was judged to be very low. No studies reported superficial/deep SSI, all-cause mortality, hospital readmission for SSI, or adverse effects. Topical antimicrobials versus no topical antimicrobials Five studies (n = 5382) evaluated topical gentamicin sponge, which may reduce total SSI (RR 0.62, 95% CI 0.46 to 0.84; I = 48%; NNTB = 32), superficial SSI (RR 0.60, 95% CI 0.37 to 0.98; I = 69%), and deep SSI (RR 0.67, 95% CI 0.47 to 0.96; I = 5%; low-certainty evidence. Four studies (n = 4662) demonstrated that topical gentamicin sponge may result in little to no difference in all-cause mortality, but the evidence is very uncertain (RR 0.96, 95% CI 0.65 to 1.42; I = 0%; very low-certainty evidence). Reoperation for SSI, hospital readmission for SSI, and adverse effects were not reported in any included studies.

AUTHORS' CONCLUSIONS: This review provides the broadest and most recent review of the current evidence base for interventions to reduce SSI in adults undergoing cardiac surgery. Twenty-one interventions were identified across the perioperative period. Evidence is of low to very low certainty primarily due to significant heterogeneity in how interventions were implemented and the definitions of SSI used. Knowledge gaps have been identified across a number of practices that should represent key areas for future research. Efforts to standardise SSI outcome reporting are warranted.