Surgical Site Infection and its Prevention T R Wilson

SSI Background Incidence – 1 in 5 of all health care (iatrogenic) infections – 1 in 20 all surgical patients will get SSI – 30-40% of all abdominal surgery Cost – Average doubling of hospital stay – Average additional cost per SSI = £ £10,000

NICE Recommendations 2008 Pre-Theatre – Shower or bathe with soap day of/before surgery – Do not routinely remove hair (↑ risk SSI) If necessary use clippers just prior to surgery – Do not routine use nasal decontamination Pre-Surgery – Minimise non-essential trips from theatre in blues – Wash hands at start of list with surgical prep – If visibly clean, can use alcohol gel between cases – Consider double gloving

NICE Recommendations 2008 Intraoperative – Antibiotic prophylaxis All potentially contaminated surgery (i.e. not clean) All clean surgery involving placement prosthesis Relative Risk Reduction of 0.3 – Clean skin with surgical prep Aqueous or Alcoholic povidone iodine or Chlorhexidine – Do not use diathermy for skin incisions – Do not use routine lavage

NICE Recommendations 2008 Postoperative – Cover wound with appropriate dressing <48 hours use sterile saline to irrigate any wounds >48 can shower as normal – Maintain homeostasis intra and perioperatively Temperature Oxygenation Circulation

Other (non-NICE) adjuncts Type of skin preparation Topical iodine Triclosan coated sutures Wound protectors Topical gentamycin impregnated collagen Incisional Negative Pressure Cost Negligible <£10 <£100 >£100

TASK – Use of Adjuncts in Abdominal Surgery Aim to review evidence for these approaches Will be given one of 6 systematic reviews – 10 minutes to read paper and make notes – 5 minutes to discuss in 6 groups – 10 minutes to feedback (one person per group) Aim to answer the following – Good points of article – Limitations of article – What conclusions would you draw for clinical practice

Assessing Systematic Review Systematic review – Refers to process of systematically collecting evidence to answer a specific question Meta-analysis – Refers to the statistical process of combining quantitative data from papers PRISMA statement/checklist 2009 – 27 items – Systematic review should have clear aim – Reproducible methodology

Salient PRISMA items 1. Introduction: Clear question for review – Participants, intervention, comparison, outcomes, study design 2. Methods – Study eligibility – Information sources (e.g. pubmed) – Search strategies (terms used) – How studies selected and data extracted – Data items extracted – Assessment studies for bias

Salient PRISMA items 3. Metanalysis – Is summary measure appropriate? – Test of heterogeneity of studies (I 2 ) Percentage of variability due to study heterogeneity Up to 25% is good, 50% moderate, 75% poor – Sensitivity analysis (stability of findings) Repeat analysis with studies added or removed 4. Results (reporting) – Flow diagram (study selection) – Forrest plot

Generalisability Study may be well conducted – Good internal validity Is the study valid to your population? – Good external validity For Systematic Reviews – Need to look at each included study What was the population for that study What were the exclusion criteria for that study

Points to feedback Good points of article Limitations of article Conclusions for clinical practice

Type of skin prep StrengthsWeaknessesConclusions Well conduced study Mostly general surgery Mostly clean/clean- contaminated Methodological quality of studies questionable OR (0.68) in favour Chlorhexidine Generalisability questionable Cost of change is minimal

Topical Iodine StrengthsWeaknessesConclusions Well Conducted study Studies assessed for quality Only includes good quality RCTs High number include studies with abdominal procedures Iodine put on before or after (topical or spray) Are studies with unclear randomisation of good quality? Many studies are old No modern studies with abdominal surgery Little evidence to definitely support BUT little cost

Wound protector StrengthsWeaknessesConclusions Limited to GI surgery SSI defined I 2 Used Studies assessed for quality Sensitivity analysis performed Sub-group analysis of type of wound protector RR – 0.55 RR – 0.31 for dual ring Good evidence to support dual ring protector significantly reducing SSI Single ring - likely to have little benefit (if taking into account results of ROSSINI trial

Triclosan sutures StrengthsWeakness Conclusions Well conducted Heterogeneous populations Evidence of benefit in wide populations Difficulty generalising to different groups Cost likely to make this attractive option

Incisional Negative Pressure StrengthsWeaknessesConclusions Clear Methodology Quality of RCT assessed No assessment of quality English language only 70% limb surgery 50% low quality RCTs All clean surgery No definition SSI One dominant study Some studies showing some benefit in clean abdominal surgery Insufficient evidence to justify use in GI

Gentamycin Collagen StrengthsWeaknessesConclusions Focus on GI surgery Quality of RCTs assessed Sensitivity analysis SSI defined ?Limited Search Reasonable evidence for use in perineal wounds

Dealing with the infected wound