2. OBJECTIVES
• Epidemiology.
• Definitions.
• Criteria for defining surgical site infections.
• Wound classification.
• Different scoring systems.
• Pathogenesis.
• Factors that determine surgical site infections.
• Treatment of SSIs.
• CDC recommendations to prevent SSI.
3. EPIDEMIOLOGY
• SSI is MOST COMMON hospital acquired infection in surgical
patients.
-2/3rd incisional
-1/3rd organs/spaces
• 3rd most common hospital acquired infection.
• Accounting for 38% of nosocomial infections.
• Incidence of SSI ranges from 2 to 5%(for clean surgeries) and
20%(emergency colon surgeries) of more than 30million patients
undergoing surgical procedures each year.
• Over one-third of postoperative deaths.
4. • In ambulatory surgical settings it is relatively low.
• Poor scar, persistent pain and itching, restriction of movement and
a significant impact on emotional wellbeing.
• Prolong the hospital stay (7.3 days).
• Increases hospital expenditure(upto 3000$).
• Preventable.
5. What is SSI??
• Infections that occur in the wound created by an invasive surgical
procedure are generally referred to as surgical site infections.
• Infections occurring up to 30 days after
surgery (or up to one year after surgery in
patients receiving implants) and affecting
either the incision or deep tissue at the
operation site.
6. When the Infection occurs
• Surgical site infection remains a clinical diagnosis.
• Presenting signs and symptoms depend on the depth of infection, typically
as early as POD 4th to 5th day .
• Exception for this is necrotising SSIs caused by clostridium perfringens and
streptococcus pyogenes which may develop with in 24 hrs of surgery.
• Clinical signs range from local induration to hallmarks of infection.
• In organ /space SSIs symptoms specific to involved organ are usually
predominant.
7. Important Definitions
• Colonization
• Bacteria present in a wound with no signs or symptoms of systemic inflammation
• Usually less than 105 cfu/mL.
• Contamination
• Transient exposure of a wound to bacteria.
• Varying concentrations of bacteria possible.
• Time of exposure suggested to be < 6 hours.
• SSI prophylaxis best strategy.
• Infection
• Systemic and local signs of inflammation.
• Bacterial counts ≥ 105 cfu/mL.
• Purulent versus nonpurulent.
• Surgical wound infection is SSI ..
15. FURTHER CLASSIFICATION
Etiology
• Primary: Microbes present in or on the host and so acquired from an
endogenous source (such as an SSI following contamination of the
wound from a perforated appendix).
• Secondary or exogenous (HAI): acquired from a source outside the
body such as the operating theatre or the ward.
16. • Time
a) Early
Infection presents within 30 days of procedure
b) Intermediate
Occurs between one and three months
c) Late
Presents more than three months after surgery
17. • Severity
a) Minor
Minor wound infections may discharge pus or infected serous fluid but should not be
associated with excessive discomfort,systemic signs or delay in return home.
b) Major
When there is pus discharge with tissue breakdown , Partial or total dehiscence of the
deep fascial layers of wound or if systemic illness is present or it needs a secondary
procedure to drain it.
major
minor
20. • Other risk scoring systems are—
SENIC(STUDY OF THE EFFICACY OF NOSOSCOMIAL INFECTION CONTROL).
-- Predicts risk associated with abdominal surgery , operations lasting for 2
hours, contaminated or dirty wounds and operation on patients with 3 or
more discharge diagnoses.
NNIS (NATIONAL NOSOCOMIAL INFECTIONS SURVEILLANCE)
-- 3 independent variables associated with SSI risk.
• Contaminated or dirty/infected wound classification.
• ASA score > 3 (chronic active medical illness).
• Length of operation > 75th percentile of the specific operation being
performed.
NHSN(NATIONAL HEALTH CARE SAFETY NETWORK)
• Successor programme of NNIS.
21. classification of surgical wounds
Clean wounds
Class I
• no infection is present.
• no hollow viscus is entered.
• only skin microflora potentially contaminate the wound.
• No breaks in aseptic technique.
• elective procedure.
• 75% 0f all wounds.
22. Clean/contaminated wounds
Class II
• a hollow viscus such as the respiratory,alimentary, or genitourinary
tracts with indigenous bacterial flora is opened under controlled
circumstances.
• without significant spillage of contents.
• No inflammation.
• Minor break in aseptic technique.
• Bowel preparation preoperatively.
23. Contaminated wounds
Class III
• open traumatic wounds encountered early after injury.
• those with extensive introduction of bacteria into a normally sterile area
of the body due to major breaks in sterile technique (e.g., open cardiac
massage),
• gross spillage of viscus contents such as from the intestine, or incision
through inflamed tissue.
• Apparent inflammation.
• Major break in aseptic technique.
24. Dirty wounds
Class IV
• traumatic wounds with significant delay in treatment and in which
necrotic tissue is present.
• those created in the presence of overt infection (purulent material).
• those created to access a perforated viscus with high degree of
contamination.
25. pathogenesis
• Microbial contamination of the surgical site either exogenous or
endogenous infection is a precursor for SSI.
• Quantitatively ,if a surgical site is contaminated with >10⁵ microbes
per gram of tissue ,the risk of SSI markedly increased.
• The dose of contaminating microbes required to produce infection
may be much lower when foreign material is present at the site.
26. dose of bacterial contamination X virulence
= Risk of SSI
resistance of the host patient
Bacterial dose
Virulence
Impaired
host resistance
27. Microbiology
• The most common microbes causing SSIs are
-- staphylococcus aureus (20%)
-- coagulase negative staphylococcus (14%)
-- enterococcus (12%)
29. Patient characteristics
• Extremes of Age
• Diabetes, uremia, jaundice.
• Smoking
• Steroid Use
• Malnutrition
• Obesity
• hypoxemia
• Altered immune response
• Prolonged preoperative stay
• Preoperative colonization with S.aureus in nares.
• Perioperative transfusion
• Coexistent infection at a remote body site.
• hypocholesterolemia
30. Diabetes
• Significant relationship between increasing levels of HgA1c and SSI rates.
• Increased glucose levels (>200 mg/dL) in the immediate postoperative period
(<48 hours) were associated with increased SSI risk.
• Hyperglycaemia induces immune cell dysfunction.
• Increased peripheral insulin resistance & decreased insulin stimulated
chemokinesis.
Smoking
• Nicotine use delays primary wound healing.
• Independent risk factors for SSIs are ascites,diabetes,postoperative anemia,
and recent weight loss.
31. Steroid use
• Patients who are receiving steroids or other immunosuppressive drugs may be
predisposed to developing SSI.( 2 to 3 fold )
Malnutrition
• Nutritional support is crucial , considering that anabolism requires
calories and nitrogen in excess of basal requirements of 25 to 30Kcal
and 1g nitrogen /day.
• It is challenging to provide calories and proteins while
simultaneously avoiding hyperglycaemia.
32. Preoperative blood transfusion
• Blood transfusion apparently doubles the risk for SSI.
• Transfusions express immunosuppression through altered
leucocyte antigen presentation and a shift to the T helper 2
phenotype.
• There is currently no scientific basis for withholding necessary blood
products from surgical patients as a means of SSI risk reduction.
33. CDC recommendations to prevent SSI
Preoperative Factors
Preparation of the patient:
1. Identify and treat all infections remote from the surgical site and postpone
elective surgery until infection has resolved.
2. Do not remove hair unless it interferes with surgery.
3. Ensure good blood glucose control in diabetic patients and avoid
hyperglycemia.
4. Encourage cessation of tobacco use .
5. Require the patient to shower or bathe with an antiseptic solution the night
before surgery.
6. Apply preoperative antiseptic solution for skin preparation in concentric circles
moving outward toward the periphery.
34. How to Prepare the Patients
• Shaving:
• immediately before the operation: SSI rates 3.1%
• shaving within 24 hours preoperatively: 7.1%
• having performed >24 hours: SSI rate > 20%.
• Depilatories:
• lower SSI risk than shaving .
• hypersensitivity reactions
• Electrical clippers are preferred over the shaving and cream
depilation.
35. Hand/forearm antisepsis for surgical team:
1. Keep nails short and do not wear artificial nails.
2. Perform a preoperative scrub for at least 2 to 5 minutes up to the
elbows.
3. After performing the surgical scrub, keep the hands up and away
from the body (elbows flexed) so that the water runs from the tips
of fingers toward the elbows.
3. Dry hands with a sterile towel and don a sterile gown and gloves.
5. Do not wear hand or arm jewelry.
36.
37.
38. • Surgical attire and drapes:
1. Wear a surgical mask that fully covers the mouth and nose .
2. Wear a cap or hood to fully cover hair on the head and face.
3. Wear sterile gloves if scrubbed as a surgical team member. Put
on gloves after donning the sterile gown.
4. Use surgical gowns and drapes that are elective barriers when
wet.
5. Change scrub suits that are visibly soiled, contaminated, and/or
penetrated by blood or other potentially infectious material.
41. • Antibiotic prophylaxis(principles)
1. Administer a prophylactic antimicrobial agent only when indicated, and
select it based on its efficacy against the most common pathogens
causing SSIs for a specific operation.
2. Maintain therapeutic levels of the agent in serum and tissues throughout
the operation, and for a few hours after the incision has been
closed.(best time is 30 to 60min prior to incision).
3. Before elective colorectal operations, in addition to the above measures,
mechanically prepare the bowel by using enemas and cathartic agents.
42. 5. Do not routinely use vancomycin for prophylaxis.
6. Irrational use of antibiotics leads to selection pressure over the pathogens
and leads to MDR pathogens .
7. Prophylaxis may be administered for up to 48 hours for cardiac surgery; for
all other cases, the limit is 24 hours.
8. Vancomycin is acceptable with a physician-documented justification for use
in the patient’s medical record.
43. • Antibiotics with short half lives < 2hrs (cefazolin,cefoxitin) should be
redosed every 3 to 4 hrs if the operation prolonged or bloody.
SCIP(surgical care improvement project) and NSIP(national surgical
infection prevention project)
– these two projects mainly focused on the quality of antibiotic
prophylaxis, including choice of agent , timing of administration,
duration of prophylaxis.
44.
45. For ß-lactam allergy, acceptable choices are the following:
• For cardio vascular and orthopaedic surgeries– clindamycin ,
vancomycin
• For colorectal surgeries and hysterectomy– clindamycin + gentamicin
fluoroquinolone or aztreonam
metronidazole + gentamicin
• For caesarean – metronidazole/doxycycline, after cord clamping
clindamycin monotherapy
• gastroduodenal & hepatobiliary procedures ,genitourinary–
gentamicin + metronidazole
46. Intraoperative factors
• Ventilation:
1. Maintain positive pressure ventilation in the operating room with respect
to the corridors and adjacent area.
2. Maintain a minimum of 15 air changes per hour, of which at least 3
should be fresh air.
3. Introduce all air at the ceiling, and exhaust air near the floor.
4. Avoid hypothermia and ensure supplemental oxygen in recovery.
5. Keep operating suite doors closed except as need for passage of
equipment, personnel, or patients.
.
47. • Cleaning and disinfection of environmental surfaces
1. use an Environmental Protection Agency (EPA)-approved hospital
disinfectant to clean the affected areas before the next operation.
2. Do not use tacky mats at the entrance to the operating room suite or
individual operating rooms for infection control.
4. Wet vacuum the operating floor with an EPA-approved disinfectant
after the last operation of the day or night.
48. • Microbiological sampling:
1. Do not perform routine environmental sampling of the operating room.
Sterilization of surgical instruments:
1. Sterilize all surgical instruments according to published guidelines.
2. Perform ash sterilization only for patient care items that will be used
immediately. Do not ash sterilize for reasons of convenience or to save time.
49. • Asepsis and surgical technique:
1. Adhere to principles of asepsis when placing intravascular devices,spinal
or epidural anesthesia catheters, or when dispensing or administering IV
drugs.
2. Handle tissue gently, maintain elective hemostasis, minimize devitalized
tissue and foreign bodies, and eradicate dead space at the surgical site.
3. Use delayed primary skin closure or leave an incision open if the surgeon
considers the surgical site to be heavily contaminated.
4. If drain is necessary, use closed suction drain, and place it through a
separate incision distant from the operating incision. Remove the drain
as soon as possible.
50. • Postoperative Incision Care
1. Protect an incision that has been closed primarily with a sterile dressing
for 24 to 48 hours postoperatively.
2. Wash hands before and after dressing changes and before and after any
contact with surgical site.
3. When an incision dressing must be changed, use a sterile technique.
4. Educate the patient and family regarding proper incision care,
symptoms of SSI, and the need to report such symptoms.
51. Discharge planning
The intent of discharge planning:
maintain integrity of the healing incision.
educate the patient about the signs and symptoms of
infection.
advise the patient about whom to contact to report of any
problems.
52. Symptoms include
• Redness and pain around the area where
Surgery has been done.
• Drainage of cloudy fluid from your
surgical wound.
• Fever.
• Incisional site giveaway.
53. How to Deal with Problem
• The first steps in the treatment of SSIs are to open and Inspect the
incision for signs of infection.
• If the infection confined to skin and superficial underlying subcutaneous
tissue,opening the incision and providing local wound care may be all
the treatment necessary.
• Antibiotic therapy of superficial SSIs is only indicated when erythema
extending beyond wound margins or systemic symptoms.
• Deeper SSIs -- surgical exploration and debridement.
• Organ/space SSIs -- surgical exploration or drainage procedure.
54. Indications for antibiotics in surgical practice for treating SSI
• Cellulitis
• Lymphangitis
• Bacteremia
• Systemic inflammatory response & multiple organ dysfunction syndrome
• Definite pathogens
• Large number of organisms
• Poor host defenses
55. Cleaning an incision
• Gently wash it with soap and water to remove the crust.
• Do not scrub or soak the wound.
• Do not use rubbing alcohol, hydrogen peroxide,or iodine, which can
harm the tissue and slow wound healing.
• Air-dry the incision or pat it dry with a clean, fresh towel before
reapplying the dressing.
56. Skin closure
• Class I and II wounds -- closed primarily.
• Class III and IV wounds -- delayed primary closure or healing by secondary
intention.
57. Standardized infection ratio
•The standardized infection ratio (SIR) is a summary
measure used to track HAIs at a national, state, or facility
level over time.
SIR = actual number of infections
predicted number of infections
58. • If SIR < 1 facility’s performance labelled as better than expected.
• If SIR > 1 facility’s performance labelled as worse than expected .
• If SIR = 1 facility’s performance labelled as in the expcted range.
59. References
Sabiston 20th edition.
Maingot’s Abdominal operations 12th edition.
Schwartz’s Principles of surgery.
CDC criteria.
Bailey and love 26th edition.
AORN journal.
National collaborating centre for women's and children's health 2008.
Internet.
