Wound Infection(1)
Transcript of Wound Infection(1)
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Wound Infection
Definitions of SSI
Superficial incisional SSI: Infection involves only skin and
subcutaneous tissue of incision.
Deep incisional SSI: Infection involves deep tissues, such asfascial and muscle layers also superficial and deep incisionsites and organ/space SSI draining through incision.
Organ/space SSI: Infection involves any part of theanatomy in organs and spaces other than the incision,which was opened or manipulated during operation.
Surgical site infections (SSI)
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Types of SSI
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Superficial incisional SSI Occurs within 30 days after the operation
Involves only the skin or subcutaneous tissue
At least 1 of the following: Purulent drainage is present. Organisms are isolated from fluid/tissue of the
superficial incision.
At least 1 sign of inflammation (eg, pain or tenderness,induration, erythema, local warmth of the wound) ispresent.
The wound is deliberately opened by the surgeon. The surgeon or attending physician declares the woundinfected
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Deep incisional SSI
Occurs within 30 days of the operation or within 1year if an implant is present
Involves deep soft tissues of the incision
At least 1 of the following: Purulent drainage is present from the deep incision but
without organ/space involvement.
Fascial dehiscence or fascia is deliberately separatedby the surgeon because of signs of inflammation.
A deep abscess is identified by direct examination or
during reoperation, by histopathology, or by radiologicexamination.
The surgeon or attending physician declares that adeep incisional infection is present
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Organ/space SSI
Organ/space SSI Occurs within 30 days of the operation or within 1 year if an
implant is present
Involves anatomical structures not opened or manipulatedduring the operation
At least 1 of the following: Purulent drainage is present from a drain placed by a stab
wound into the organ/space.
Organisms are isolated from the organ/space by asepticculturing technique.
An abscess in the organ/space is identified by directexamination, during reoperation, or by histopathologic orradiologic examination.
A diagnosis of organ/space SSI is made by the surgeon orattending physician
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Causes
Microbiology Most SSIs are contaminated by the patient's
own endogenous flora
The usual pathogens on skin and mucosal
surfaces are gram-positive cocci gastrointestinal surgery intrinsic bowel flora,
gram-negative bacilli, and gram-positivemicrobes, including enterococci and anaerobicorganisms
Gram-positive organisms, particularlystaphylococci and streptococci, account formost exogenous flora involved in SSIs
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Pathogens causing Wound
InfectionsPathogen Frequency (%)
Staphylococcus aureus 20
Coagulase-negative staphylococci 14
Enterococci 12Escherichia coli 8
Pseudomonas aeruginosa 8
Enterobacterspecies 7
Proteus mirabilis 3
Klebsiella pneumoniae 3Other streptococci 3
Candida albicans 3
Group D streptococci 2
Other gram-positive aerobes 2
Bacteroides fragilis 2
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Host factors Systemic factors: age, malnutrition, hypovolemia, poor
tissue perfusion, obesity, diabetes, steroids, and otherimmunosuppressants.
Wound characteristics: nonviable tissue in wound;hematoma; foreign material, including drains and sutures;dead space; poor skin preparation, including shaving; andpreexistent sepsis (local or distant).
Operative characteristics: poor surgical technique; lengthyoperation (>2 h); intraoperative contamination, including
infected theater staff and instruments and inadequatetheater ventilation; prolonged preoperative stay in thehospital; and hypothermia
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Risk Factors for Development of Surgical Site Infections
Patient factors
Older age
Immunosuppression
Obesity
Diabetes mellitus
Chronic inflammatory process
Malnutrition, Anemia
Peripheral vascular disease
Radiation
Carrier state (e.g., chronic Staphylococcus carriage)
Local factors
Poor skin preparation
Contamination of instruments
Inadequate antibiotic prophylaxis
Prolonged procedure
Local tissue necrosis
Hypoxia, hypothermia
Microbial factors
Prolonged hospitalization (leading to nosocomial organisms)
Toxin secretion
Resistance to clearance (e.g., capsule formation)
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WoundC
ontaminationClassification Description Risk (%)
Clean
(Class I)
Uninfected operative wound
No acute inflammation
Closed primarily
Respiratory, gastrointestinal, biliary, and urinary tracts not entered
No break in aseptic techniqueClosed drainage used if necessary
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The National Nosocomial Infection Surveillance (NNIS)
risk index
risk index
(1) American Society of Anesthesiologists
(ASA) Physical Status score >2
(2) class III/IV wound
(3) duration of operation greater than the
75th percentile for that particularprocedure
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American Society of
Anesthesiologists (ASA)
Classification of Physical Status
ASAScore Characteristics
1 Normal healthypatient
2 Patient with mild systemic disease
3Patient with a severe systemic disease that limits
activity but is not incapacitating
4 Patient with an incapacitating systemic disease that isa constant threat to life
5Moribund patient not expected to survive 24 hours with
or without operation
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Predictive Percentage of SSI
Occurrence byRisk Index
At Risk Index Predictive Percentage ofSSI
0 1.5
1 2.9
26
.8
3 13.0
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Time Relations
Early (24-48h); streptococci and
clostridia, Immunosuppression
Usual; (5-10d); others
Delayed (2-4w); infection of hematoma or
seroma
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Lab
Staining methods: Gram stain simple, quick.
Culture techniques: both aerobic and anaerobic. Fungalcultures. Then sensitivity testing
Newer techniques Tests for antigens from the organism through enzyme-
linked immunoassay (ELISA) or radioimmunoassay
Detection of antibody response in the host sera
Detection ofRNA or DNA sequences orprotein from theinfective organism
Polymerase chain reaction (PCR) to detect small amountsof microbe DNA.
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RECOMMENDATIONS FROM THE HOSPITAL INFECTION CONTROL
PRACTICESADVISORY COMMITTEE FOR THE PREVENTION OF
SURGICALSITE INFECTIONS
Do not operate on patients with active infections
Do not shave patient in advance
Control glucose in diabetic patients
Stop tobacco use in patient
Have patient shower with antiseptic soap
Prepare skin with appropriate agent
Surgeon's nails should be short
Surgeons scrub hands
Exclude infected surgeons
Give prophylactic antibiotics when indicated
Maintain prophylactic antibiotic levels during operation
Keep O.R. doors closed
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RECOMMENDATIONS FROM THE HOSPITAL INFECTION CONTROL
PRACTICESADVISORY COMMITTEE FOR THE PREVENTION OF
SURGICALSITE INFECTIONS
Use sterile instruments Avoid flash sterilization
Wear a mask
Cover all hair
Wear sterile gloves
Use gowns and drapes that resist fluid penetration
Gentle tissue handling
Closed suction drains (when used)
Delayed primary closure for heavily contaminatedwounds
Sterile dressing for24- 48 hr
SSI surveillance with feedback to surgeons
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Recommendations for
Prophylactic Antibiotics
antibiotics had to be in the circulatory
system at a high enough dose at the time
of incision to be effective clean-contaminated and contaminated
wounds
clean procedures in which prosthetic
devices is implanted
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Recommendations for
Prophylactic Antibiotics The antibiotic should be administeredpreoperatively as close to the time of theincision as is practical before induction of
anesthesia in most situations.
The antibiotic should have activity against thepathogens likely to be encountered.
Postoperative administration ofpreventive
systemic antibiotics beyond 24
hours has notbeen demonstrated to reduce the risk of SSIs.
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Recommendations for
Prophylactic Antibiotics
good tissue penetration to reach wound
involved.
cost effectiveness.
minimal disturbance to intrinsic body flora
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Antibiotics as Indicated by Probable Infective
Microorganism
Operation ExpectedP
athogens RecommendedA
ntibioticOrthopedic surgery (including
prosthesis insertion), cardiac
surgery, neurosurgery, breast
surgery, noncardiac thoracic
procedures
S aureus, coagulase-negative
staphylococciCefazolin 1-2 g
Appendectomy, biliaryprocedures Gram-negative bacilli and anaerobes Cefazolin 1-2 g
Colorectal surgery Gram-negative bacilli and anaerobes Cefoxitin 1-2 g
Gastroduodenal surgeryGram-negative bacilli and
streptococciCefazolin 1-2 g
Vascular surgeryS aureus, Staphylococcus
epidermidis, gram-negativebacilli
Cefazolin 1-2 g
Head and neck surgeryS aureus, streptococci, anaerobes
and streptococcipresent in an
oropharyngeal approach
Cefazolin 1-2 g
Obstetric and gynecological
procedures
Gram-negative bacilli, enterococci,
anaerobes, group B streptococciCefazolin 1-2 g
Urologyprocedures Gram-negative bacilli Cefazolin 1-2 g
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Special situations
Elective colon surgery: Mechanical cleansing andantibiotics
Dietary restrictions.
Whole gut lavage ; 10% mannitol solution, Fleet's phospho-soda, orpolyethylene glycol, usually is performed on theday of surgical intervention.
Enteral antibiotic regimes with oral neomycin anderythromycin being the most popular combination,metronidazole and tetracycline.
Catheter- related infections: Morbidity and mortality (up to20% in patients with catheter-related bloodstreaminfections).
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Newer concepts in the prevention
of SSIs
close regulation of blood sugar in patients withdiabetes,.
body temperature; failure to maintain
intraoperative core body temperature within 1-1.5C of normal increases the SSI rate by afactor of2.
oxygenation. Maintaining or increasing oxygendelivery to the wound by increasing the inspired
oxygen concentration administered to the patientperioperatively has also been shown to reducethe incidence of SSIs.
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Treatment
incision and drainage without the addition
of antibiotics.
Antibiotic therapy is reserved forpatientsin whom evidence of severe cellulitis is
present, or who manifest concurrent
sepsis syndrome.
The open wound often is allowed to heal
by secondary intention
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Further Care
Inpatient Care:
increased hospital stay due to SSI 7-10 days
increasing costs by20%
Occasionally, wound debridement and subsequent packingand frequent dressing is necessary to allow healing bysecondary intention.
Outpatient Care:
Most patients with wound infections are managed in thecommunity. Management usually takes the form of dressingchanges, which usually is by secondary intention.