Veterinary practices in the United Kingdom were surveyed to compare their surgical draping practices with Royal College of Veterinary Surgeons (RCVS) accreditation tier and other surgery-related factors. Using descriptive statistics and logistic or ordinal regression analysis (where appropriate), the relationships between draping material and accreditation tier and other surgery-related factors were assessed. Procedures were categorised as short or long. Two hundred and sixty-nine surveys were completed. Reusable drapes were used in 66 per cent of practices. Antibiotics were administered routinely in 38 per cent of short and 93 per cent of long procedures. Practices accredited as a Veterinary Hospital (VH) were 6.3–7.2 (short and long surgeries, respectively) times more likely to use disposable drapes, when compared with non-accredited practices. Use of dedicated surgical attire, draping the whole animal/table, and routine antibiotic usage were also positively correlated with disposable drape usage. Fifty-one per cent of practices rated infection rate as most important when choosing drape material. ‘Best practice’ techniques are associated with lower importance given to infection rate, and higher importance given to financial cost, when choosing drape material. Disposable drape use correlates with RCVS accreditation and with other aspects of surgical technique. Importance ratings awarded correlate with best practice procedures. Clinical relevance ‘Best practice’ draping procedures, that are not governed by RCVS accreditation scheme, are also more frequently performed in accredited VHs.
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Surgical draping practices in veterinary practice in the UK are poorly documented although subjectively they appear to be extremely variable. Drapes are reported to be one of many factors implicated in contributing to the rate of infections (Schmon 2003). Postoperative surgical site infections (SSI) in animals are a significant problem in terms of welfare, financial effects and owner and veterinarian anxiety. Published wound infection rates for clean elective surgical procedures in animals range from 2.5 to 5.8 per cent (Vasseur and others 1988, Brown and others 1997, Heldmann and others 1999, Whittem and others 1999, Beal and others 2000, Eugster and others 2004). Higher rates are experienced for clean-contaminated, contaminated and dirty procedures (Vasseur and others 1988, Nicholson and others 2002). The most common type of contaminants experienced during and after clean surgical procedures are normal skin flora, such as Staphylococcus spp (Sturgeon and others 2000, Owen and others 2009).
Wound contamination/infection levels in clean surgery have been shown to correlate with duration of anaesthesia (Vasseur and others 1988, Beal and others 2000, Nicholson and others 2002, Owen and others 2009), duration of surgery (Eugster and others 2004) and type of induction agent used (Heldmann and others 1999). Garibaldi and others (1991) have shown that preoperative American Society of Anaesthesiologists physical status also affects the rate of SSI.
The Royal College of Veterinary Surgeons (RCVS) provides a voluntary accreditation scheme, called the Practice Standards Scheme (PSS), for veterinary practices in the UK which allows those practices to advertise their level of accreditation. This signifies that they have fulfilled certain criteria to qualify for that particular accreditation. Previously called Tier 1, Tier 2 and Tier 3, the categories are now labelled as accredited to core standards (CS) (Tier 1), as a general practice (GP) (Tier 2), and as a Veterinary Hospital (VH) (Tier 3). Each Tier signifies an increased level of hospital management, record keeping, clinical standards and equipment/diagnostic standards (http://www.rcvs.org.uk/document-library/practice-standards-rules/). The overall aim of the PSS is to provide the public with a degree of confidence that they are attending a practice which is striving to improve clinical standards and increase the safety with which their animal is treated. While some of the clinical choices regarding surgical patient and surgeon preparation are governed by the criteria dictated by the PSS, many factors are not, including the type of surgical drape material, sterile gown material, surgical glove usage and methods of surgical skin antisepsis.
The Oxford Online Dictionary defines ‘best practice’ as a commercial or professional procedure that is accepted or prescribed as being correct or most effective (Pearsall 2012). In veterinary surgery, these ‘best practice’ techniques include use of protective apparel, such as clean scrub suits, sterile surgical gloves and sterile operating gowns, increasing barrier function of surgical drapes, where disposable drapes tend to perform better, and area of surgical site draped, with the recommendation that the edges of the surgical table and instrument trolleys are covered (Schmon 2003). Use of reusable cloth drapes compared with disposable non-woven drapes has not been compared in a prospective manner in veterinary surgery. However, a retrospective study by Billings and others (1990) found no significant difference in SSI rates in 720 cases in a veterinary teaching hospital.
Our study aim was to survey a proportion of the UK small-animal veterinary community to determine the type of surgical draping practices used, and to establish if practice accreditation was associated with the type of drape used. We also aimed to examine the association of drape type used with other factors, such as antibiotic usage and use of other barrier materials, such as gloves, gowns and masks. Our hypothesis was that level of practice accreditation would be a significant determinant of the level of surgical ‘best practice’.
Materials and methods
A survey was formulated to determine the surgical draping practices in use in UK small-animal veterinary establishments. The internet-based survey (Appendix 1) was trialled with several veterinarians in our staff for ease of completion and clarity of questioning. It was then made publicly available online using the University of Bristol Online Survey programme (http://www.survey.bris.ac.uk/awb/drapes). Practices were selected using RCVS practice database. All practices listed as performing ‘small animal’, ‘mixed’, or those whose practice type was not recorded were initially selected, however, only a proportion of these had email address contact details available. The 2009 RCVS database revealed there were a total of 4216 practices listed on the database, and of these, 3929 practices were listed as performing small-animal practice (n = 2342), mixed practice (n = 1202), or did not have the type of practice recorded (n = 285). Of these practices, 2764 had email addresses listed. Several practices were branch practices with a central group email address for all branch practices. A total of 2074 unique email addresses were identified from the practice database to which emails were sent. Of the 2074 emails sent, 195 were undeliverable. A total of 1879 emails were therefore delivered. According to the RCVS, in 2011 there are a total of 4562 practices in the UK, and 2488 (54.5 per cent) of them are in the PSS, although some of these are registered as farm animal or equine practices/hospitals (Esther Gent, RCVS office, personal communication). We required a sufficient sample size to achieve a confidence interval (CI) of ±7.5 per cent at the 95 per cent confidence level; therefore, using a population size of 3929, a sample size of 164 returned questionnaires was required. A link to this survey was provided to allow survey participants to connect directly to the survey after reading a short introductory page. Practices with multiple branches, yet only one central email address, were asked to complete the survey separately. The number of emails sent and not returned undelivered were collated and kept for calculation of the approximate response rate. Respondents were asked to complete individual surveys for each branch within a related group of clinics if they performed surgery. In addition, a letter (Delisser and Friend 2010) was sent to the editor of the Veterinary Record journal, also requesting readers to complete the online survey. The online survey was made available for a period of three months between November 13, 2010 and February 13, 2011.
Answers from the questionnaire were entered into a spreadsheet (Excel, Microsoft, USA) and analysed using a statistical analysis programme (PASW Statistics 18, IBM Corp, Somers, New York, USA). Data were assessed for normality. Frequencies and percentages were calculated (Table 1), and the explanatory variables were analysed for significant relationships with the type of drape using binary logistic regression analysis (Table 2). Explanatory variables were divided into categorical variables where this allowed a more suitable statistical evaluation. The exp b or odds ratio (OR) was calculated and used to demonstrate the increased (OR > 1) or reduced likelihood (OR < 1) of disposable drapes being used in relation to a number of variables. ORs are presented in parenthesis in the text with their 95 per cent CI; these are the odds of the respondents in the associated category using disposable drapes compared with the reference category which has an OR = 1. The R2 values for significant variables are presented and represent the proportion of the response that can be explained by those independent variables. All associations were analysed separately for both short (<60 minutes) and long (>60 minutes or with permanent surgical implants) procedures. Once significant variables had been established these were used in multiple logistic regression analysis. Respondents were also asked to rank the order of importance of (1) financial cost, (3) environmental cost, (4) infection rate, (5) laundering or staff cost and (6) cost of replacing drape stock in their decision on choice of drape on a five-point scale, from very unimportant (5) to very important (1). Ordinal logistic regression was used to determine the likelihood of practices reporting the next increasing level of importance (eg, from very unimportant to unimportart), when comparing with the other questionnaire variables. ORs were also calculated for this regression and indicate the odds of respondents rating a certain category one point higher when considering a given independent variable. Effectively, OR > 1 means a practice was more likely, and OR < 1 means they were less likely to report a higher importance for a particular importance factor in relation to other surgical factors recorded.
A total of 269 surveys were completed, giving a response rate of 14.3 per cent of the emailed practices. This would equate to a CI of 5.8 per cent at the 95 per cent confidence limit.
There were 103 practices not accredited by the RCVS PSS. Practices numbering 10, 122 and 34, were accredited to CS, GP and VH standards, respectively. Thirty-eight per cent of respondents did not have RCVS accreditation. Forty-three out of 269 (16 per cent) practices performed 80 per cent or less, and 226/269 (84 per cent) performed more than 80 per cent of their caseload as small animals.
Table 1 displays answers given for accreditation type, clothing usage in theatre, mask/gown/gloves/hat usage, drape material usage and routine antibiosis frequency. In relation to either short or long surgery, 66.2 per cent of practices reported use of reusable drapes in some form. In short surgeries, 73 per cent of practices covered only the local area surrounding the surgical site, whereas, only 5.6 per cent of practices covered the whole patient and table. In long surgeries, 29 per cent of practices still only covered the local area surrounding the incision, although 36 per cent covered the whole table. In short and long surgeries, respectively, 76.5 per cent and 82.4 per cent of VHs used disposable drapes.
An adhesive-incise drape was used in selected cases in 40/269 practices. The most common explanation for use of an adhesive-incise drape was for orthopaedic surgery (29/40) and abdominal surgery with a fluid effusion or lavage expected (9/40 cases). With respect to the coverage of the distal limb during limb surgery, 63 per cent of practices used a permeable sterilised layer, whereas, 29 per cent used an impermeable sterilised layer to cover the foot.
Of 178 respondents who use reusable drapes, 154 (86.5 per cent) of the practices replaced the cloth drapes only when visibly worn, with a further 19 (10.6 per cent) waiting until the drape had visible defects in it. Only 4/178 (2.2 per cent) of respondents used more strict criteria, such as number of washes or a given age as their criteria for replacement. None of the respondents who used reusable drapes had been given a recommendation or guideline to follow from the drape manufacturer with regards to expected wash-cycle lifespan.
Fig 1 shows a graphical representation of the respective rankings awarded to five different factors involved in drape material selection. Perceived efficacy at reducing SSI was considered the most important factor. The cost of replacing existing drape stock was considered the least important factor.
Factors affecting the choice of drape type
The collinearity statistics produced tolerance values of more than 0.1 for all variables and variance inflation factor (VIF) values of less than 10, suggesting that there were no problems with collinearity (Field 2005). The tolerance and VIF of accreditation and level of accreditation were close to both 0.1 and 10.
Results from the binary logistic regression are tabulated in Table 2 for short and long surgeries. Accredited veterinary practices were 72 per cent and 67 per cent more likely to use disposable drapes than non-accredited veterinarians (OR = 1.72; CI = 1.04–2.87; P < 0.05 and OR = 1.67; CI = 1.01–2.75; P < 0.05) in short and long procedures, respectively. VHs were 6.3 and 7.2 times more likely to use disposable drapes than non-accredited veterinarians (OR = 6.31; CI = 2.59–15.39; P < 0.001 and OR = 7.23; CI = 2.75–19.03; P < 0.001) in short and long procedures, respectively. There was no significant difference between CS- or GP-accredited practices and non-accredited practices.
In short procedures, those who use antibiotics (46.6 per cent) and those who do not (39.2 per cent) were not significantly different with regards to their choice of drape material. In longer procedures, those who do not use antibiotics are 81 per cent less likely to use disposable drapes than those who do use antibiotics (OR = 0.19; CI = 0.06–0.68; p < 0.01). Those who cover the whole animal and edge of the surgery table were 22 and 4.4 times more likely to use disposable drapes than those who only cover the incision site (OR = 22.11; CI = 2.85–171.54; P < 0.01 and OR = 4.40; CI = 2.32–8.33; P < 0.001) in short and long surgeries, respectively.
However, when all the significant parameters were used in the multiple regression model, the only parameter that remained significant in the model in the short surgery analysis, was the method of covering the distal limb during surgery. Those who use a sterilised, permeable covering for the foot for surgery are 86 per cent less likely to use disposable drapes compared with those that use a sterilised non-permeable layer during surgery (OR = 0.14; CI = 0.07–0.27; P < 0.001). Twenty-two per cent of the variation seen in this model is explained by the type of foot coverage (R2 = 0.22; p < 0.01). In the long surgery analysis, when all the significant parameters were used in one regression model, three parameters remained significant. The first was whether or not antibiotics were used, where those using routine antibiosis were 5.2 times more likely to use disposable drapes (OR = 5.24; CI = 1.21–22.7; P < 0.05). The second factor was covering of the distal limb, with 89 per cent lower likelihood of disposable drape usage in cases with a sterilised permeable foot covering when compared with a sterilised non-permeable foot covering (OR = 0.11; CI = 0.05–0.24; P < 0.001). Finally, where no adhesive drapes were used there was an 80 per cent lower likelihood of disposable drape usage compared with when an adhesive drape was used (OR = 0.2; CI = 0.05–0.75; P < 0.05)
Considering all these factors together in the regression model, 32 per cent of the variation (R2 = 0.32, P < 0.001) could be explained by the factors' routine antibiotic usage, coverage of the distal limb and use of adhesive drapes.
Ranked importance of factors influencing choice of drape
Accreditation was not associated with importance scores awarded by respondents. The respective factors that were significantly more or less likely to report the next level of increasing importance with respect to the score awarded to infection rate and financial cost are listed in Table 3, along with their ORs and CIs.
When considering the importance of staff costs for laundering and re-sterilisation, practices who used reusable drapes were 3.2 and 2.8 times more likely (OR = 3.2; CI = 2.1–5.2; P < 0.001, and OR = 2.8; CI = 1.8–4.4; P < 0.001) to rank the importance of those costs one point higher in short and long surgeries, respectively.
Based on the results of this survey, a majority of small-animal veterinary practices that responded are still using reusable woven cloth surgical drapes in either short or long surgery. Additionally, those who use disposable drapes are more likely to employ other ‘best practice’ protocols, such as use of sterile gowns, theatre hats and masks, and other draping practices, such as use of adhesive-incise drapes and impermeable covering of the foot during limb surgery, and are more likely to use routine antibiosis in long surgery when compared with those who use reusable drapes. Finally, those who use disposable drapes are more likely to assign more importance to financial cost of the drape material and less likely to assign more importance to risk of SSI when compared with those who use reusable drapes.
Placement of an effective barrier between the surgeon/prepared surgical site and unprepared areas of the animal allows protection from bacteria migrating and subsequently contaminating the surgical site (Mann and others 2011). It is clear that reusable drapes are less effective as a barrier than disposable drapes, however, their clinical performance, compared with disposable drapes, at reducing SSI is less clear. Non-woven drapes have been shown to produce lower particle counts in theatre (Jalovaara and Puranen 1989), and slow fluid and bacterial transfer when compared with woven, reusable alternatives (Laufman and others 1975). Blom and others (2002) showed bacterial strike-through was almost instant in wet cloth woven drapes. Disposable drapes are far more resistant to penetration by bacteria than cloth reusable drapes in the same laboratory conditions (Blom and others 2007). However, given the inevitable multifactorial nature of acquiring an SSI, formulating scientific studies to determine the clinical significance of the type of drape material is always confounded to some degree by other factors. Some studies report reduced infection rates with use of disposable drapes/gowns compared with reusable drapes (Baldwin and others 1981, Moylan and others 1987), however, many studies report no statistically significant reduction in either SSI or wound contamination when comparing reusable with disposable draping (Cruse and Foord 1980, Garibaldi and others 1986, Billings and others 1990, Treggiari and others 1992, Bellchambers and others 1999).
The RCVS PSS requires fulfilment of certain criteria for each level of accreditation. Of the questions asked in the survey, some are requirements of the PSS (http://www.rcvs.org.uk/document-library/practice-standards-manual/) to qualify as a VH, namely, the requirement to wear theatre hats and clean scrub suits. Some of these will thus be linked to the analyses performed, and could make interpretation of the significance of these factors more difficult as they are not independent variables. Even still, the practices with accreditation as a VH were much more likely to use disposable drapes, which in itself is not a requirement of the PSS. This indicates the increased likelihood of VHs performing procedures to a perceived higher standard than their non-accredited counterparts, although not all do. Use of surgical hats, masks and sterile gowns were all positively correlated with disposable drape usage. To the authors' knowledge, there are no reports in the scientific literature documenting the type of surgical attire worn under sterile protective attire, or prevalence of usage of surgical hats and masks, or sterile surgical gloves and gowns in small-animal veterinary practice in the UK, or for that matter, worldwide.
Use of sterile impermeable foot covers in surgery was associated with disposable drape usage. Inclusion of a sterile, impermeable layer in the draping of experimental ex vivo dogs' legs eliminated bacterial strike-through (Vince and others 2008), although this may not necessarily translate into less surgical wound contamination. The use of adhesive-incise drapes is controversial. One study of 100 dogs showed no difference in wound contamination rates between cases that used adhesive-incise drapes and those that did not (Owen and others 2009). Osuna and others (1992) showed an increase in contamination rates with adhesive-incise drape/alcohol preparation compared with routine povidone-iodine skin preparation and no adhesive-incise drape in 30 dogs. One human meta-analysis of seven different studies with 4195 patients in total showed an increase in infection rates with plain adhesive-incise drapes over no drapes, and no difference in infection rates between iodine-impregnated adhesive drapes and no drapes (Webster and Alghamdi 2007).
A recent survey of 1121 UK veterinary clinics reported around 30 per cent of respondents giving antibiotics to every case (Knights and others 2010). This was published in abstract form only. This is similar to 38.6 per cent antibiotic usage in short procedures reported herein. Short, clean surgical procedures do not require antibiosis unless the risk of contamination is high, or there are significant consequences to getting an SSI (Cimino Brown 2011). According to our survey, a significant number of practices surveyed are still administering routine prophylactic antibiosis in short, clean surgeries. Use of antibiotics associated with disposable drapes in long procedures/with surgical implants is in line with current clinical recommendations (Mann and others 2011).
Accreditation level was not significantly associated with importance rankings awarded, however, the importance awarded to reducing SSI showed an inverse relationship with several clinical factors linked with ‘best practice’, including use of sterile gowns and reusable drape material, increased drape coverage, impermeable material foot covering and use of adhesive-incise drapes. Financial cost of purchasing a surgical draping material was viewed as more important where clinics used theatre masks and sterilised gowns, and drape coverage of the whole table during surgery compared with just the local area. These results indicate that those practices that follow these ‘best practice’ techniques are more likely to feel that financial cost is important when choosing a drape material. This is interesting, given the fact that disposable drapes are often perceived as more expensive to use compared with reusable drapes. The lifecycle costs of reusable systems compared with disposable systems have been assessed in large hospitals for humans, with contradictory conclusions (Moylan and others 1987, DiGiacomo and others 1992, Murphy 1993). To the authors' knowledge, there are no comparisons in a veterinary practice setting. In this survey, practices that used reusable drapes were more likely to rank the importance of staffing costs higher in relation to laundering and re-sterilisation, when compared with practices that used disposable drapes.
There are some significant limitations in this report. Only 14.3 per cent of veterinary practices emailed answered the questionnaire, and it is not possible to determine the exact response rate. While this is hopefully still a representative sample of the small-animal veterinary profession in the UK, the electronic nature of the survey may have biased the survey to being completed by those with more technological knowledge of computers and those with email addresses for their practices. However, the electronic version of the survey is more rigid and ensured standardised answers, and also that all respondents completed all questions. The proportions of practice types responding are roughly similar to the proportions of these types of practice in the UK overall. Potentially, using a postal-based survey and mailing the questionnaire to all practices in the country may have achieved a greater response rate, similar to Knights and others (2010). Additionally, completion bias may have skewed the results, with more conscientious practitioners, especially those who have enrolled in the PSS, completing the survey preferentially. The proportion of non-accredited practices who responded (38.2 per cent) is similar to the current total proportion of non-accredited practices (45.5 per cent) nationwide.
The nature of the questions, and attempts to keep respondents anonymous disallowed distinguishing between individual practices who completed the survey, and branches within a larger organisation. Additionally, although the questions were designed to be as neutral as possible, the nature of the questions asked may have inadvertently biased answers for certain questions. For ease of statistical analysis, some of the answers to certain questions were categorised into ranges to allow for more meaningful interpretation, although these groupings may have also inadvertently skewed the results.
The categorical and multifactorial nature of the data makes clear interpretation difficult. This is highlighted by the low R2 values achieved in the regression models, indicating, at best, a moderate explanatory effect of the significant variables on the overall model. Other unmeasured variables must affect the outcome. The regression analyses do help draw some conclusions regarding the relationships between type of surgical drape material used and other factors associated with practice management and surgery, and also the relative importance of clinical, financial and environmental factors, and their relationship to surgical draping practices.
Cloth drapes are still used in a majority of surveyed practices. The practices most likely to use disposable drapes were those with VH accreditation and those who use non-permeable coverings for the distal limb in limb surgery. However, there is still inconsistency within each accreditation level. Additionally, other factors were significantly associated with use of disposable drapes. Use of hats, masks, gowns and adhesive-incise drapes were all positively associated with disposable drape use. According to this survey, reducing SSI is perceived as the most important factor in the choice of surgical drape used with those practices who rate reducing SSI most important being less likely to use ‘best practice’ surgical draping techniques.
Provenance: not commissioned; externally peer reviewed
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