Reducing the incidence of surgical site infection: A personal story in three acts

Transcription

1 Reducing the incidence of surgical site infection: A personal story in three acts Robert G. Sawyer, M.D. Professor of Surgery and Public Health Sciences At the Midpoint of the Odyssey Defining the real rate of surgical site infection Getting better using current recommendations Can we get even better? Defining the Real Rate of Surgical Site Infection- Act I

2 Hospitalized Patients Crabtree TD et al. Shock 2007;17: January to December 1997 Compared infection rates determined by infection control practitioners (ICP) and 3x weekly chart survey by RGS Identical CDC definitions used Hospitalized patients only Who Were These People? Crabtree et al, Shock 2002 Differences in Rates Crabtree et al, Shock 2002

3 Why? Crabtree et al, Shock 2002 We are Not Geniuses (at all) Crabtree et al, Shock 2002 Defining the Real Rate of Surgical Site Infection- Part II

4 Risk of Surgical Site Infection After Colorectal Surgery Risk Index No. of infections Infection rates, % NNIS rates, % P Weiss CA et al. Arch Surg. 1999;134: Curiosity Kills the Dog(ma)? Chip Foley is a very honest colorectal surgeon who was convinced his SSI rate was significantly higher than the 5-8% predicted by the CDC He reviewed his results based on the premise that his outcomes were bad He consider a failure any wound that was closed primarily but did not heal without incident Chip s story Smith RL et al, Ann Surg 2004;239: years Retrospective experience of a single colorectal surgeon 176 colorectal resections No simple creation or reversal of stomata

5 Major Outcomes 26% SSI rate (45 SSI) 49% of SSI (22 SSI) diagnosed after discharge Median time to diagnosis 9 days, interquartile range = 5-19 days 5 SSI diagnosed more than 30 days postoperatively (37, 43, 48, 65, and 73 days) Univariate Risk Factors Smith RL et al, Ann Surg 2004 Univariate Risk Factors Smith RL et al, Ann Surg 2004

6 Predictors of SSI Smith RL et al, Ann Surg 2004 Timing of Diagnosis of SSI Days from Operation to Infection Smith RL et al, Ann Surg 2004 Summary 1 Current SSI rates are probably a lot higher than those documented either from drug studies or standard surveillance Colorectal surgery SSI rates may be remarkably high The harder you look, the more you find

7 Getting Better Using Current Recommendations- Act II SCIP and General Surgery Hedrick TL et al, Surg Infect 2007;8: months of baseline data, four months after change in protocol 379 patients before, 390 after General surgery patients followed as part of the National Surgical Quality Improvement Project (NSQIP) SCIP Inspired Changes Hedrick TL et al, Surg Infect 2007

8 SCIP Inspired Changes Hedrick TL et al, Surg Infect 2007 Timing of Changes Hedrick TL et al, Surg Infect 2007 Process Changes Hedrick TL et al, Surg Infect 2007

9 SSI Rates, All Comers Hedrick TL et al, Surg Infect 2007 SSI by Type of Procedure Hedrick TL et al, Surg Infect 2007 SSI by Type of Procedure Hedrick TL et al, Surg Infect 2007

10 Predictors of SSI Hedrick TL et al, Surg Infect 2007 SCIP and Colorectal Surgery Hedrick TL et al. J Am Coll Surg 2007;205: Remember Chip? February 2000 to January 2002 versus January 2005 to August 2005 SCIP measures, plus penrose drain in subcutaneous tissue if BMI 25 Patient Characteristics Hedrick TL et al, J Am Coll Surg 2007

11 Patient Characteristics Hedrick TL et al, J Am Coll Surg 2007 Operative Characteristics Hedrick TL et al, J Am Coll Surg 2007 Operative Characteristics Hedrick TL et al, J Am Coll Surg 2007

12 Process Measures Hedrick TL et al, J Am Coll Surg 2007 Surgical Site Infection Incidence 30.0% 25.0% 20.0% 15.0% 10.0% 5.0% 25.6% 15.9% 39% * Baseline Study * (p 0.05) 0.0% Hedrick TL et al, J Am Coll Surg 2007 Predictors of SSI Hedrick TL et al, J Am Coll Surg 2007

13 Summary 2 Application of evidence-based interventions, as exemplified by the SCIP process, can lead to a significant improvement in SSI rates Some standards are easier to achieve than others It takes a lot of hard work Can We Get Even Better?- Act III The effects of preoperative skin preparation on postoperative wound infection: a prospective study of three skin preparation protocols Published in Infection Control and Hospital Epidemiology October 2009 Brian R. Swenson, M.D., M.S., Traci Hedrick, M.D., Hugo Bonatti, M.D., Rosemarie Metzger, M.D., Timothy L. Pruett, M.D., and Robert G. Sawyer, M.D.

14 Background-Joseph Lister Inspired by Louis Pasteur Proved that gangrene was caused by microorganisms Used a sewage deodorizer (5% carbolic acid) to sterilize instruments/clean wounds Lowered surgical site gangrene incidence (Lancet (90) 2299, 1867) Joseph Lister Background Many compounds and formulations are currently approved for preoperative surgical site skin preparation Most commonly used include: Chlorhexidine (most commonly used biocide today) Broad spectrum, low irritation Thought to collapse bacterial cell membrane potential Iodine based compounds (iodophors) Broad spectrum, rapid killing mechanism of action unknown Isopropyl Alcohol Broad spectrum Limited residual activity (usually used as an adjunct) Background Skin prep research over the past several decades has focused on surrogate endpoints In vitro studies Post-prep skin cultures Post procedure skin/wound cultures Serial skin swab cultures after prep treatment Very few studies examine SSI as the endpoint Central venous catheter studies

15 Study Aim As an institution, can we affect the SSI rates in general surgery patients by changing the standard skin preparation modality? Given reports of lower catheter-associated bloodstream infections with ChloraPrep we hypothesized that we would see similar results in general surgery Methods Official preferred skin prep in general surgery patients at UVA was standardized for six month blocks 6 months UVA traditional prep betadine soap/etoh/betadine paint 6 months ChloraPrep 6 months DuraPrep Local ACS-NSQIP database used to track comorbidies, perioperative data, and 30 day outcomes, specifically SSI as defined by the CDC Analysis by intent-to-treat Results January 06 June 07, 3,209 patients were followed 182 SSI (5.7%) identified The three periods were well matched in terms of age, race, ASA class, weight classification, wound classification, and most major comorbidities Minor variations were seen in gender, smoking status, preoperative sepsis, and OR time

16 Results-outcomes >2.5% p<0.05 >1.8% p<0.05 Results-Univariate analysis Variables associated with higher SSI rate Female gender Diabetes Cancer Preoperative sepsis Recent weight loss Wound classification OR time Prep solution actually used Results-outcomes by prep received 3.4% p<0.05 ~2.2% p<0.05

17 Results-subgroup analysis Where are we seeing a difference? Analysis of SSI outcomes comparing iodophor based preps to ChloraPrep stratified by wound classification Reduction in superficial SSI in clean cases Reduction in all SSI in dirty cases Logistic regression Variable OR P Value Female gender Medical history Diabetes Cancer Sepsis Weight loss OR time (per min) <0.001 Variable OR P Value Wound class Clean Clean-contam <0.001 Contaminated 6.84 <0.001 Dirty 6.59 <0.001 Prep used Iodophor ChloraPrep Conclusions We report a large, single center, prospective, unblinded, phase IV comparison of three skin preparation modalities in an attempt to lower SSI rates Primary objective was successful Significantly lower SSI rates ( 1.8%) seen in period 3 when DuraPrep was utilized as the official prep solution Contrary to our hypothesis!

18 Conclusions In subgroup analysis no difference was identified between the traditional betadine soap/etoh/betadine paint and DuraPrep Significant differences, however, were seen between iodophor based preps and ChloraPrep 2-3% lower rates with iodophor based preps Differences were seen in superficial SSI in clean cases Conjecture Why are our results different from what has been published about central venous catheter infection rates? Fundamentally different environment Why better results with Iodophor preps? Does betadine kill more (no), better (not really), or longer? Mechanical component to the prep? Study not designed to answer this question Moving forward DuraPrep has been adopted at our institution as the preferred skin preparation modality for general surgery cases Additional multicenter studies are needed to confirm theses results

19 Summary 3 Perhaps iodine-based skin preparations perform better than other skin preparations Confirmatory data are required Other interventions may be available to further reduce the risk of SSI Overall Conclusions SSI rates are still too high 0% is probably impossible, but let s pretend it isn t There are dozens of areas for intervention, many of which have not been tested Improvement will depend on research AND changes in practice Thank you rws2k@virginia.edu

20 Questions?