Cyanoacrylate microbial sealants for skin preparation prior to surgery
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To assess the effects of the preoperative application of microbial sealants on rates of surgical site infection in people undergoing surgery.
Background
Description of the condition
Surgical Site Infections (SSIs) are a continuing concern in health care. SSI is defined an infection occurring as a result of a surgical incision manifesting as pus, or a swab with >106 colony forming units (cfu) per mm³ tissue and at least one of the following signs or symptoms: pain, localised swelling, redness or heat and occurs within 30 days following surgery (Mangram 1999). Surgical incisions result in 25 to 38% of hospital acquired infections in surgical patients (Mangram 1999; Neumayer 2007). In clean surgery, the patient's own skin flora is a highly likely source of bacteria leading to SSI (Dohmen 2008).
The Scottish Surveillance of Healthcare Associated Infection Programme (SSHAIP 2004) in the UK estimated that SSI occurs in one in twenty cases of surgery with an associated National Health Service (NHS) expenditure of £1billion annually. It also highlighted that the true cost in relation to SSIs is much higher than figures would suggest due to variability in the conduct of audit and collection of data. The reported incidence of SSI depends on various factors including the definition of infection used, the intensity of surveillance, nature and duration of patient follow‐up and the prevalence of risk factors in the population studied (Smyth 2000). In the UK the National Audit Office 2004 notes that cases of infection can be associated with seven additional hospital bed days.
Various preventative measures can be instigated to minimise SSI risk including patient skin preparation (Edwards 2004), preoperative hair removal (Tanner 2006), prophylactic antibiotics and the use of sterile disposable materials (Webster 2007).
The risk of SSI infection is influenced heavily by the nature of the surgery and there is a widely used classification system that indicates the likelihood of SSI infection based on the risk of contamination during surgery (Appendix 1)(McLaws 2000). SSI is least likely to occur after clean surgery (infection rate of 3 to 5%). However, when surgery involves body cavities where there is infected, dead or dirty tissue, for example in colorectal surgery (contaminated surgery), then surgical site infection rates are typically higher, at between 10% and 30%.
Description of the intervention
Microbial sealants are liquids applied to the skin in the operating theatre, using an aseptic technique, prior to surgery. The microbial sealant is applied to the surgical site immediately pre‐surgery, after preoperative skin preparation (cleansing and draping) is complete. The sealants dry to form a breathable barrier that prevents microbial migration and can be used in any type of surgery apart from that involving mucous membranes or the eyes. Instances of allergy and hypersensitivity to cyanoacrylate have been noted and since cyanoacrylate is an adhesive it is suggested that accidental prolonged contact should be avoided (Kimberly‐Clark 2008). Cyanoacrylate sealants are supplied as a single use sterile pack with an applicator in differing sizes depending on the surgery involved.
The use of cyanoacrylate microbial sealants to reduce SSI is relatively new. Cyanoacrylate forms the basis of current products used under the term microbial sealant. Recently the Food and Drug Administration (FDA) reclassified topical skin adhesives. Therefore technological advances in development of products such as cyanoacrylate may result in a number of types becoming available (Singer 2008). The focus of this review will be on cyanoacrylate based liquid microbial sealants.
How the intervention might work
Since the patient's own skin flora is the common source of the bacteria that result in SSIs (Nichols 1996) the aim of pre‐operative skin preparation is to ensure the skin around the intended surgical site is as free as possible from endogenous bacteria that may enter the surgical wound. Skin disinfection prior to surgery significantly reduces the number of bacteria on the skin surface however re‐colonisation with bacteria from deeper skin layers and hair follicles may occur during the operation (Fleischmann 1996). Cyanoacrylate based microbial sealant is applied before surgery in order to dry and seal skin flora beneath a breathable film.
Why it is important to do this review
Microbial sealants are currently being used as a method of skin preparation prior to surgery and no systematic review exists to determine its effect on patient outcomes. It is therefore important to identify any positive or negative outcomes associated with the use of microbial sealants on important outcomes such as rates of surgical site infection (SSI), the time wounds take to heal, length of stay and cost effectiveness. This review is of importance in determining the strength of evidence to support the use of microbial sealants for skin preparation prior to surgery.
Objectives
To assess the effects of the preoperative application of microbial sealants on rates of surgical site infection in people undergoing surgery.
Methods
Criteria for considering studies for this review
Types of studies
All published and unpublished randomised controlled trials (RCTs) that allocate surgical patients individually to receive microbial sealants in the immediate preoperative phase or no microbial sealant. Trials are eligible for inclusion whether or not participants receive usual preoperative skin preparation (e.g., chlorhexidine, povidone iodine). Quasi‐randomised trials will not be included (e.g. trials that allocate treatment by sequential record number, sequential admitting number, day of the week).
Types of participants
Trials involving participants undergoing any type of surgery in an operating theatre.
Types of interventions
Microbial sealant applied to the surgical incision site immediately preoperatively compared with:
-
no application of microbial sealant
-
use of traditional pre‐operative preparations solutions such as povidone iodine or chlorhexidine
Types of outcome measures
Primary outcomes
Rates of SSI as defined in the background (Mangram 1999) or by the study authors.
Secondary outcomes
-
All cause mortality
-
Length of hospital stay;
-
Rates of hospital re‐admissions;
-
Adverse reactions (e.g. contact dermatitis, anaphylaxis);
-
Post‐operative antibiotic use.
-
Costs;
-
Other serious infection or infectious complication such as septicaemia or septic shock.
Search methods for identification of studies
Electronic searches
The following electronic databases will be searched:
The Cochrane Wounds Group Specialised Register;
The Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library (Latest issue);
Ovid MEDLINE (1950 to present);
Ovid EMBASE (1980 to present);
EBSCO CINAHL (1982 to present)
The Cochrane Central Register of Controlled Trials (CENTRAL) will be searched using the following proposed search string:
#1 MeSH descriptor Tissue Adhesives explode all trees
#2 MeSH descriptor Fibrin Tissue Adhesive explode all trees
#3 skin sealant*:ti,ab,kw
#4 microbial sealant*:ti,ab,kw
#5 MeSH descriptor Acrylates explode all trees
#6 (acrylate* or cyanoacrylate* or octylcyanoacrylate* or butylcyanoacrylate* or bucrylate* or enbucrilate* or dermabond):ti,ab,kw
#7 (#1 OR #2 OR #3 OR #4 OR #5 OR #6)
#8 MeSH descriptor Surgical Wound Infection explode all trees
#9 MeSH descriptor Surgical Wound Dehiscence explode all trees
#10 surg* NEAR/5 infect*:ti,ab,kw
#11 surg* NEAR/5 wound*:ti,ab,kw
#12 surg* NEAR/5 site*:ti,ab,kw
#13 surg* NEAR/5 incision*:ti,ab,kw
#14 (#8 OR #9 OR #10 OR #11 OR #12 OR #13)
#15 (#7 AND #14)
This strategy will be adapted to search Ovid MEDLINE, Ovid EMBASE and EBSCO CINAHL. The Ovid MEDLINE search will be combined with the Cochrane Highly Sensitive Search Strategy for identifying randomized trials in MEDLINE: sensitivity‐ and precision‐maximizing version (2008 revision) (Lefebvre 2008). The EMBASE and CINAHL searches will be combined with the trial filters developed by the Scottish Intercollegiate Guidelines Network (SIGN 2009). There will be no restrictions on the basis of date or language of publication.
Searching other resources
We will contact researchers and manufacturers in order to obtain any unpublished data. Reference lists of potentially eligible reports will also be searched for further references.
Data collection and analysis
Selection of studies
All review authors will independently assess the titles and abstracts of references identified by the search strategy according to selection criteria. Full versions of articles will be obtained if, from this initial assessment, they satisfy the inclusion criteria. Full papers will be checked independently to identify those that could fit the criteria. Any disagreement will be resolved by discussion and if necessary referred to a third review author for adjudication.
Reference lists of retrieved studies will be screened to identify further studies which will also be retrieved. Differences of opinion will be settled by consensus or referral to the editorial base of the Wounds Group.
Data extraction and management
Details of the studies will be extracted and summarised using a piloted data extraction sheet. Data extraction will be undertaken by all review authors independently and then discussed. Any disagreement will be resolved by consulting a fourth party. If data are missing from reports then attempts will be made to contact the authors to obtain missing information. Studies that have been published in duplicate will be included only once, but all possible data will be extracted.
The following data will be extracted from each study, type of study, study setting, number of participants, gender, mean age, predisposing risk factors, type of adhesive films, use of prophylactic antibiotics, procedure and timing of adhesive application, period of postoperative follow up, all primary and secondary outcome descriptions and outcome measures reported, including infection rates and authors' conclusions.
Assessment of risk of bias in included studies
Two review authors will independently assess each included study using the Cochrane Collaboration tool for assessing risk of bias Higgins 2008. This tool addresses six specific domains, namely sequence generation, allocation concealment, blinding, incomplete outcome data, selective outcome reporting and other issues (e.g. extreme baseline imbalance) see Appendix 2 for details of criteria on which the judgement will be based). Blinding and completeness of outcome data will be assessed for each outcome separately. We will complete a risk of bias table for each eligible study. We will discuss any disagreement amongst all review authors to achieve a consensus.
We will present assessment of risk of bias using a 'risk of bias summary figure', which presents all of the judgments in a cross‐tabulation of study by entry. This display of internal validity indicates the weight the reader may give the results of each study.
Measures of treatment effect
For dichotomous variables (e.g., infection rates) we will calculate the risk ratio with 95% confidence interval (CI). For continuous outcomes we plan to enter the mean and standard deviation data into RevMan and calculate the mean difference with 95% CI.
Assessment of heterogeneity
Heterogeneity will be assessed by inspection of graphical display of the estimated treatment effects from the included trials. The chi‐squared statistic will be used with significance set at p <0.10. Any data below this threshold shows evidence of heterogeneity of intervention effects. In addition, the degree of heterogeneity will be investigated by calculating the I2 statistic (Higgins 2003).
Data synthesis
Data will be entered into and analysed using Cochrane RevMan software. Results will be presented with 95% confidence intervals (CI). Estimates for dichotomous outcomes (e.g. number of infections ‐ yes or no) will be reported as relative risk (RR). Any continuous data will be presented as mean difference with 95% CI. Methods of synthesising the studies will depend on the quality, design and heterogeneity of the studies identified.
Subgroup analysis and investigation of heterogeneity
A meta‐analysis will be performed using a fixed effect model if I2 is less than 30%, a random effects model if I2 is between 30%and 60% and no meta analysis will be performed if I2 is greater than 60%. In addition to any statistical synthesis of data we will conduct a narrative review of eligible studies. If data are available we will consider a subgroup analysis for trials in clean surgery compared with contaminated surgery.
