Pre‐operative bathing or showering with skin antiseptics to reduce surgical site infection
Abstract
This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:
To review the evidence for preoperative bathing or showering with antiseptics for the prevention of nosocomial surgical site infection.
Background
Surgical site infections (SSIs) are wound infections that occur following invasive procedures. Among all hospital patients, surgical site infection (SSI) is the third most frequently acquired nosocomial infection (Smyth 2000). The Centers for Disease Control and Prevention have been monitoring nosocomial infections in acute care hospitals in the United States using the National Nosocomial Infections Surveillance (NNIS) system since 1970. In the decade between 1986 and 1996 approximately 600,000 operations were studied. Surgical site infections developed after three percent (15,523) of these operations. During the period of data collection, 551 patients developed a SSI and subsequently died, and 77% of deaths were attributed to the infection (Mangram 1999). Apart from the morbidity and mortality associated with SSIs, there are significant cost implications. A recent study, using the NNIS system found patients developing a surgical site infection cost over $3,000 more to treat than non‐infected patients. These costs were attributable to a greater likelihood of admission to ICU, a longer average post‐operative stay (5 days) and an increased rate of hospital re‐admission (Kirkland 1999). Litigation is also a concern when a SSI is diagnosed (Rubinstein 1999). Consequently, preventing surgical site infection has become a priority for health care facilities.
The identification of SSI is dependent on the interpretation of clinical and laboratory findings. The CDC has developed a set of standardised criteria for defining SSI in an attempt to make surveillance and SSI rate calculation more accurate and more amenable to comparison. SSIs are classified as being superficial incisional (involving only skin or subcutaneous tissues), deep incisional (involving deeper soft tissue and fascia) or organ/space (involving any other part of the anatomy that was opened or manipulated). To aid in prediction of SSI risk, surgical wounds can be dichotomised preoperatively as clean or non‐clean and classified into one of four categories with clearly defined definitions: Class 1 (clean), Class II (clean‐contaminated),Class III (contaminated) and Class IV (dirty/infected) (Mangram 1999). Clean wounds are defined as an uninfected surgical wounds in which the respiratory, alimentary, genital or uninfected urinary tract is not entered and in which no inflammation is encountered. Non‐clean wounds are defined according to the anatomical area of operation, aetiology of wound, presence of existing clinical infection, and intraoperative contamination. Clean wounds are less likely to become infected therefore SSIs arising following clean surgery are probably due to either (1) patient risk factors, such as age, nutritional status, diabetes and obesity, (2) risk factors associated with the procedure including preoperative hand and forearm antisepsis, length of surgical procedure and surgical technique, or (3) risk factors associated with preparation of the patient preoperatively, for example antimicrobial prophylaxis, preoperative hair removal and preoperative antiseptic showering (Mangram 1999).
Skin is not sterile. Thousand of bacteria live on our skin permanently and contribute to health by maintaining a steady colony inhibiting yeast and fungi, these are called resident flora. A number of bacteria are present on the skin for a short period due to transfer from other people or the environment, these are called transient flora. Whole body bathing or showering with skin antiseptic is widespread practice before surgery for the prevention of SSIs. The aim of the procedure is to make the skin as clean as possible by removing transient flora and some resident flora. Chlorhexidine 4% in detergent ('Hibiscrub' or 'Hibiclens') or a triclosan preparation is usually used for this purpose and there is evidence that the number of bacteria on the skin are reduced when it is applied (Kaiser 1988; Byrne 1991). Moreover, the use of a skin antiseptic on consecutive days has been shown not only to reduce microbial counts from baseline measurements but also to progressively reduce the counts over time (Paulson 1993). Although this body of evidence demonstrates the effectiveness of antiseptics as skin cleansing agents, the more important question is whether preoperative bathing or showering with an antiseptic reduces the incidence of surgical site infection. In a 10‐year prospective surveillance study, the surgical site infection rate was lower amongst patients showering with hexachlorophene before surgery than in those who either did not shower or showered using a non‐medicated soap (Cruse 1980). In addition, at least two studies have used a before and after design to test the effect of introducing preoperative showering with triclosan to control methicillin‐resistant Staphylococcal aureus (MRSA) surgical site infection. In the first of these, showering before and after surgery was introduced to reduce the MRSA surgical site infection rate. However, this intervention was only one of a battery of measures introduced, so it was not possible to determine the independent effect of pre‐operative showering (Brady 1990). In the second, the incidence of MRSA surgical site infection was reduced amongst orthopaedic patients after triclosan showering before surgery was introduced, however, patients in this study were also treated with nasal mupirocin for five days before surgery (Wilcox 2003). While these observational studies provide some support for the practice of preoperative showering with an antiseptic the evidence is not definitive.
Patterns of resistance have developed with some antiseptics (Thomas 2000) leading to calls to restrict their use to situations where effectiveness is able to be demonstrated. In addition, hypersensitivity to chlorhexidine is not uncommon indicating the potential benefits need to be assessed against the potential for harm (Beaudounin 2004; Krautheim 2004). As it is unclear whether or not the use of antiseptics for preoperative bathing or showering leads to lower surgical site infection, a systematic review is justified to guide practice in this area.
Objectives
To review the evidence for preoperative bathing or showering with antiseptics for the prevention of nosocomial surgical site infection.
Methods
Criteria for considering studies for this review
Types of studies
All published and unpublished randomised controlled trials that allocate patients individually or by cluster, comparing any antiseptic preparation used for preoperative full body bathing or showering with non‐antiseptic preparations in patients undergoing surgery. Quasi‐randomised trials will not be included (e.g. trials that allocate treatment by day of the week, medical record number, sequential admitting order).
Types of participants
Men, women and children undergoing any type of surgery.
Types of interventions
Any type of antiseptic solution (any strength, any regimen at any time before surgery) used for preoperative tub or bed bathing or showering compared with:
-
non‐antiseptic soap
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non‐antiseptic soap solution,
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no shower or bath.
Antiseptic solutions are defined as liquid soap products containing an antimicrobial ingredient such as chlorhexidine, triclosan, hexachlorophene, povidone‐iodine or benzalkonium chloride. Trials comparing different types of antiseptic with each other will be compared if the evidence for the benefit of showering is either, equivocal or if there is evidence of benefit with showering with antiseptic.
Types of outcome measures
Trials will be considered if they report the primary outcome:
Primary outcome
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Surgical site infection. (Note: Despite development of standardised criteria for defining SSI, the diagnosis of SSIs continues to vary between studies. We will therefore accept the definition used by the original authors to determine the proportion of patients who, before or after discharge develop any SSI).
Secondary outcomes:
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Mortality (any cause)
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Allergic reactions (e.g. contact dermatitis, anaphylaxis)
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Post operative antibiotic use
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Length of hospital stay
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Re‐admission to hospital
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Cost
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Other serious infection or infectious complication, such as septicaemia or septic shock
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Postoperative fever of >38 degrees on at least two occasions more than 4 hours apart, excluding the day of surgery
Secondary outcomes will only be extracted if the primary outcome is reported.
Search methods for identification of studies
We will search the Cochrane Wounds Group Specialised Register and the Cochrane Central Register of Controlled Trials (CENTRAL) using the following strategy:
1. DETERGENTS explode all trees (MeSH)
2. POVIDONE‐IODINE explode all trees (MeSH)
3. CHLORHEXIDINE explode all trees (MeSH)
4. DISINFECTION explode all trees (MeSH)
5. ALCOHOL DETERRENTS explode all trees (MeSH)
6. detergent*
7. betadine
8. chlorhexidine
9. (povidone and iodine)
10. (alcohol or alcohols or soap)
11. ANTI‐INFECTIVE AGENTS LOCAL single term (MeSH)
12. antiseptic*
13. iodophor*
14. (#1 or #2 or #3 or #4 or #5 or #6 or #7)
15. (#8 or #9 or #10 or #11 or #12 or #13)
16. (#14 or #15)
17. SURGICAL WOUND INFECTION explode all trees (MeSH)
18. PREOPERATIVE CARE explode all trees (MeSH)
19. PERIOPERATIVE CARE explode all trees (MeSH)
20. (preoperative near care)
21. (perioperative near care)
22. (wound* near infect*)
23. (surg* near infect*)
24. (surg* near wound*)
25. (#17 or #18 or #19 or #20 or #21 or #22 or #23 or #24)
26. shower*
27. bath*
28. wash*
29. clean*
30. (#26 or #27 or #28 or #29)
31. (#16 and #25 and #30)
The Cochrane Wounds Group Specialised Register is maintained by searching of:
1) MEDLINE, CINAHL and EMBASE;
2) the Cochrane Central Register of Controlled Trials (CENTRAL);
3) hand searching of wound care journals and relevant conference proceedings
In addition, we will search MEDLINE (2002 to present) to allow for any lag‐time in the Wounds Group Specialised Register.
Data collection and analysis
STUDY SELECTION
Both reviewers will independently assess the title and abstracts of references identified by the search strategy. Full reports of all potentially relevant trials will then be retrieved for further assessment of eligibility based on the inclusion criteria. 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.
METHODOLOGICAL QUALITY ASSESSMENT
The quality of eligible trials will be assessed independently by the two reviewers. A pre‐defined quality assessment form based, on the following assessment criteria will be used for this purpose. Disagreements between reviewers will again be resolved by consensus or referral to the editorial base of the Wounds Group. Investigators of included trials will be contacted to resolve any ambiguities.
Trials that meet eligibility criteria will be assessed as follows:
For generation of random allocation sequence
A Adequate (if the method used is described and the resulting sequences are unpredictable);
B Unclear ( if the method was not described);
C Inadequate (for sequences such as alternative allocation).
For allocation concealment
A Adequate (if participants and the investigators enrolling participants cannot foresee assignment);
B Unclear (method not described);
C inadequate (if investigators enrolling participants can foresee next assignment).
For blinding of intervention
A Double blind (neither the participant nor the person providing the intervention know which treatment is given),
B Single blind (the participant or person providing the intervention know which treatment is given);
C No blinding (all parties are aware of treatment);
D Unclear (method no described).
For blinding of outcome assessment
A Yes;
B Cannot tell;
C No.
For intention to treat analysis (analysed according to allocated treatment group, irrespective of adherence to treatment)
A Yes;
B Cannot tell;
C No.
For completeness of primary outcome reporting
A Adequate (more than 90% of all participants randomized were included in the analysis);
B Unclear (not clear how many participants were originally randomized);
C Inadequate (less than 90% of those randomized were included in the analysis).
High quality trials will be defined as those receiving an A rating for the criterion of allocation concealment (central computerised randomisation service or sealed opaque envelopes) and for blinding of the intervention (from the person providing the intervention and from trial participants).
DATA EXTRACTION
Using a piloted data extraction sheet, the following data will be extracted from each study by both reviewers independently: type of study, study setting, number of participants, sex, mean age, predisposing risk factors, type of antiseptic solutions, procedure and timing for full body wash, all primary and secondary outcome descriptions and outcome measures reported, including infection rates and authors' conclusions.
DATA SYNTHESIS
Analyses will be performed using the RevMan 4.2.6 software. Relative risks and 95% confidence intervals (CI) will be calculated for dichotomous outcomes, and mean differences and 95% CI calculated for continuous outcomes. Results of comparable trials will be pooled using the fixed effects model and 95% CI. Heterogeneity will be investigated by calculating the I2 statistic (Higgins 2002). If evidence of significant heterogeneity is identified, potential sources of heterogeneity will be explored and a random effects approach to the analysis undertaken. A narrative review of eligible studies will be conducted where statistical synthesis of data from more than one study is not possible or considered not appropriate.
We will include all eligible trials in the initial analysis and will carry out sensitivity analyses to evaluate the effect of trial quality. This will be done by excluding trials most susceptible to bias based on the quality assessment: those with inadequate allocation concealment; high levels of post randomisation losses or exclusions; or unblinded outcome assessment; or blinding of outcome assessment uncertain.
Sub‐group analyses will be:
(1) Clean surgery vs clean contaminated surgery
(2) One pre‐operative bath or shower vs more than one pre‐operative bath or shower
