Transcript Document 7124861

Prevention of Surgical Site
Infections: Considerations in
Measuring Effectiveness
Michele L. Pearson, MD
Division of Healthcare Quality Promotion
National Center for Infectious Diseases
Objectives
• Provide overview of epidemiology of
surgical site infections (SSI)
• Discuss SSI prevention strategies
• Highlight current surveillance systems for
SSI
• Provide overview of HICPAC/CDC process
for developing recommendations for
prevention healthcare-associated infections
Public Health Importance of
Surgical Site Infections
• In U.S., >40 million inpatient surgical
procedures each year; 2-5% complicated by
surgical site infection
• SSIs second most common nosocomial
infection (24% of all nosocomial infections)
• Prolong hospital stay by 7.4 days
• Cost $400-$2,600 per infection (TOTAL:
$130-$845 million/year)
CDC Definition of Surgical Site
Infections
SSI level classification
Incisional SSI
- Superficial incisional = skin and
subcutaneous tissue
- Deep incisional = involving deeper soft
tissue
Organ/Space SSI
- Involve any part of the anatomy (organs
and spaces), other than the incision,
opened or manipulated during operations
Cross Section of Abdominal Wall
Depicting CDC SSI Classifications
Source of SSI Pathogens
• Endogenous flora of the patient
• Operating theater environment
• Hospital personnel (MDs/RNs/staff)
• Seeding of the operative site from distant
focus of infection (prosthetic device, implants)
Microbiology of SSIs
1986-1989
(N=16,727)
1990-1996
(N=17,671)
Pseudomonas Staphylococcus
aureus
aeruginosa
17%
8%
Pseudomonas Staphylococcus
aureus
aeruginosa
20%
8%
Enterococcus
spp.
8%
Escherichia
coli
10%
Enterococcus
spp.
12%
Coagulase neg.
staphylococci
12%
Escherichia
coli
8%
Coagulase neg.
staphylococci
14%
Microbiology of SSIs
• Unusual pathogens
• Rhizopus oryzea - elastoplast adhesive
bandage
• Clostridium perfringens - elastic bandages
• Rhodococcus bronchialis - colonized
health care personnel
• Legionella dumoffii and pneumophila - tap
water
• Pseudomonas multivorans - disinfectant
solution
Pathogenesis of SSI
• Relationship equation
Dose of bacterial contamination x Virulence
Resistance of host
SSI Risk
SSI Risk Factors
•
•
•
•
•
Age
Obesity
Diabetes
Malnutrition
Prolonged preoperative
stay
• Infection at remote site
• Systemic steroid use
• Nicotine use
•
•
•
•
•
Hair removal/Shaving
Duration of surgery
Surgical technique
Presence of drains
Inappropriate use of
antimicrobial prophylaxis
Perioperative Preventive
Measures
Role of Antimicrobial Prophylaxis
(AP) in Preventing SSI
• Refers to very brief course of an
antimicrobial agent initiated just before the
operation begins
• Should be viewed as an adjunctive
preventive measure
• Appropriately administered AP associated
with a 5-fold decrease in SSI rates
Importance of Timing of Surgical
Antimicrobial Prophylaxis (AP)
• Prospective study of 2,847 elective clean
and clean-contaminated procedures
• Early AP (2-24 hrs before incision): 3.8%
Postop AP (3-24 hrs after incision): 3.3%
Periop AP (< 3 hrs after incision):
1.4%
Preop AP (<2 hrs before incision): 0.6%
Classen, 1992 (NEJM 326:281-286)
Impact of Prolonged Surgical
Prophylaxis
• DESIGN: Prospective
• POPULATION: CABG patients (N=2641)
Group 1: pts who received < 48 hours of
AP
Group 2: pts who received > 48 hrs of AP
Impact of Prolonged Surgical AP
• OUTCOMES
• Incidence of SSI
• Isolation of a resistant pathogen
• RESULTS: 43% of patients received AP > 48 hr
SSI Incidence
• <48 hrs group: 8.7% (131/1502) vs
• >48 hrs group: 8.8% (100/1139), p=1.0
Antimicrobial resistant pathogen
•
OR 1.6 (95% CI 1.1-2.6)
Enhanced Perioperative Glucose
Control in Diabetic Patients
• DESIGN: Prospective, sequential study
• POPULATION: Diabetic patients undergoing
cardiac surgery (N=2467) during 1987-1997
Controls: pts who received intermittent
subQ insulin (SQI)
Treated: pts who received continuous
intravenous (IV) insulin
Furnary AP; Ann Thorac Surg, 2000
Enhanced Perioperative Glucose
Control in Diabetic Patients
• OUTCOMES
• Blood glucose <200 mg/dl in first two
days postop
• Incidence of deep sternal SSI
• RESULTS
• SQI group: 2.0% (19/968) vs
• IVI group: 0.8% (12/1499), p=0.01
Furnary AP; Ann Thorac Surg, 2000
Supplemental Perioperative O2
• DESIGN: Randomized controlled trial,
double blind
• POPULATION: Colorectal surgery (N=500)
• INTERVENTION: 30% vs 80% inspired
oxygen during and up to hours after surgery
• RESULTS: SSI incidence 5.2% (80% O2) vs
11.2% (30% O2), p=0.01
Greif, R, et al , NEJM, 2000
Pre-operative Antiseptic Showers/Baths
Most studies examine effects on skin colony counts
antiseptic showering decreases colony counts
Few studies examine effect on SSI rates
Cruse, 1973
No Shower
2.3%
Shower
1.3%
Ayliffe, 1983
4.9%
5.4%
Rooter, 1988
2.4%
2.6%
Pre-operative Shaving/Hair Removal
Seropian, 1971
Method of hair removal
Razor
= 5.6% SSI rates
Depilatory
= 0.6% SSI rates
No hair removal = 0.6% SSI rates
Timing of hair removal
Shaving immediately before
Shaving  24 hours before
Shaving >24 hours before
= 3.1% SSI rates
= 7.1% SSI rates
= 20% SSI rates
Pre-operative Shaving/Hair Removal
Multiple studies show
- Clipping immediately before operation
associated with lower SSI risk than
shaving or clipping the night before
operation
CENTERS FOR DISEASE CONTROL
AND PREVENTION
Surgical Attire
• Scrub suits
• Cap/hoods
• Shoe covers
• Masks
• Gloves
• Gowns
Surgical Technique
•
•
•
•
•
•
Removing devitalized tissue
Maintaining effective hemostasis
Gently handling tissues
Eradicating dead space
Avoiding inadvertent entries into a viscus
Using drains and suture material
appropriately
Parameters for Operating Room
Ventilation*
• Temperature:68o-73oF, depending on
normal ambient temp
• Relative humidity: 30%-60%
• Air movement:
from “clean to less clean”
areas
• Air changes:
>15 total per hour
>3 outdoor air per hour
*American Institute of Architects, 1996
Role of Laminar Air Flow
(Ultraclean Air) in Preventing SSI
• Most studies involve only orthopedic
operations
• Lidwell et al: 8,000 total hip and knee
replacements
ultraclean air: SSI rate 3.4% to 1.6%
antimicrobial prophylaxis (AP): SSI rate
3.4% to 0.8%
ultraclean air + AP: SSI rate 3.4% to 0.7%
Status of SSI Surveillance
CDC Surveillance Systems
NNIS
DSN
NaSH
Nosocomial
infections in
critical care and
surgical patients
Bloodstream and
vascular access
infections in
dialysis
outpatients
Exposure to
bloodborne
pathogens; TB
skin testing and
exposure;
Vaccine: history,
receipt, and
adverse events
1970-2004
1999-2004
1996-present
Characteristics of NNIS Hospitals,
2000
 300 hospitals
 58% are MAJOR TEACHING
 10% are Graduate Teaching
 15% are Limited Teaching
 16% are Non Affiliated Hospitals
 Bed Size
 Median: 360 beds
 No facilities < 100 beds
Variables Collected in Surgical
Patient Component, NNIS













Age
Sex
ASA score
Wound class
Trauma-related
Type of anesthesia
Emergency vs elective
Duration of surgery
Length of postoperative stay
Infection site (skin/soft tissue, organ space)
Pathogen
Mortality
Hospital demographics (bed-size, affiliation)
SSI Risk Index
• From the U.S. National Nosocomial Infections
Surveillance (NNIS) system
– American Society of Anesthesiologists (ASA)
score
• 1 to 5, from 1=“normal, healthy” to 5=“patient not
expected to survive for 24 hours with OR without
operation
– Wound Class
• Clean, clean-contaminated, contaminated, dirty
– Duration of surgery
SSIs per 100 operations
Surgical Site Infection (SSI) Rates By Risk
Category, NNIS System, 1986-1999
16
Low risk
12
Medium
low risk
Medium
high risk
High risk
8
4
0
Years
SSI Definitions: Period of
Surveillance
• Infection occurs within 30 days after the
operative procedure if no implant is left in
place or within 1 year if implant is in place
and the infection appears to be related to the
operative procedure
Challenges to Surveillance for SSIs
1995
Change
1975
Admissions
5%
37,700,000 35,900,000
Patient-days
299,000,000 190,000,000 36%
Length of Stay
5.3 days
33%
7.9 days
Inpatient Surgical Procedures 18,300,000 13,300,000 27%
Nosocomial Infection Rate
per 1,000 Patient-days
9.8
36%
7.2
CENTERS FOR DISEASE CONTROL
AND PREVENTION
What Is NHSN?
Integration of CDC’s three
patient and healthcare personnel
surveillance systems
NNIS
NaSH
DSN
NHSN Premises
• Maintain the goals of predecessor systems
• Minimize data collection and manual data entry
burden
– Streamline existing surveillance protocols
– Increase capacity for capturing electronic data (e.g.,
Laboratory information systems, operating room,
pharmacy, clinical, administrative databases)
• Extensible web-based application
Priority Areas for NHSN
Development
• Inclusion of process measures linked to
outcomes
– Surgical prophylaxis
– Central line insertion practices
• Completion of HCP Safety Component
– NaSH  NHSN
• Influenza pilot: vaccine coverage and use of antiviral
medications
How do we develop policy?
Healthcare Infection Control
Practices Advisory Committee
(HICPAC)
Healthcare Infection Control Practices
Advisory Committee
MISSION
• Advise the US Secretary of Health and the
Director of CDC regarding the practice of
infection control and strategies for
surveillance, prevention and control of
antimicrobial resistance, and related adverse
events in healthcare settings
CDC/HICPAC
GUIDELINE SCOPE
• TARGET AUDIENCE:
• clinicians
• infection control professionals
• public health officials
• regulators
• TARGET SETTINGS:
• Inpatient
• Outpatient
• Home care
• Long term care
Ranking Scheme for HICPAC
Recommendations (2001)
• CATEGORY IA. Strongly recommended for all hospitals and strongly
supported by well-designed experimental or epidemiologic studies.
• CATEGORY IB. Strongly recommended for all hospitals and viewed as
effective by experts in the field and a consensus of HICPAC based on
strong rationale and suggestive evidence, even though definitive
scientific studies may not have been done.
• CATEGORY IC. Required for implementation, as mandated by federal or
state regulation or standard.
CATEGORY II. Suggested for implementation in many hospitals.
Recommendations may be supported by suggestive clinical or
epidemiologic studies, a strong theoretical rationale, or definitive studies
applicable to some but not all hospitals.
• NO RECOMMENDATION; UNRESOLVED ISSUE. Practices for which
insufficient evidence or consensus regarding efficacy exists.
CDC/HICPAC Guideline
RATING SYSTEM
CATEGORY
EVIDENCE
PRACTICE
IA/IB
STRONG
RECOMMENDED
IC
LACKING
REQUIRED BY
REGULATION
II
GOOD
SUGGESTED
NO REC
INSUFFICIENT
UNRESOLVED
CONTRADICTORY
Challenges/Issues
• Subject matter experts vs. methodologic
experts
• Resources for systematic reviews
• Limited randomized trials
• User needs vs available science (e.g.,
expansion to non-hospital settings)
Healthcare Infection Control Practices Advisory
Committee
GUIDELINE FORMAT
• PART I: Provides review and synthesis of
available research on guideline topic and
established scientific rationale for
recommendations
• PART II: Provides summary of practice
recommendations
• PART III: Provides performance indicators for
institutions to monitor success in
implementing recommended practices
Summary
• Prevention of SSI require a multifaceted approach
targeting pre-, intra-, and postoperative factors
• Current surveillance systems do collect data on
perioperative processes
• Increasing shift of surgical procedures to outpatient
settings and decrease in postoperative length of
stay complicate surveillance efforts
• Incidence is generally low; so studies would require
large sample size
• Some prevention practices (e.g. hand hygiene)
would be difficult to study using traditional
randomized controlled trial research design
PREVENTION
IS PRIMARY!
Protect patients…protect healthcare personnel…
promote quality healthcare!
Division of Healthcare Quality Promotion
To obtain HICPAC guidelines visit the
Division of Healthcare Quality
Promotion (DHQP) website
http://www.cdc.gov/ncidod/hip/default.htm