Asepsis & Antisepsis Flashcards
Define Asepsis.
Freedom from infection or prevention of contact with microorganisms
Define Aseptic Technique.
Instruments, air, drapes, gloves and gowns are free from microorganisms
Define Antisepsis.
Prevention of sepsis by inhibition or destruction of agents
What is the Aseptic Technique?
- Wash hands and instruments with carbolic acid
- Wear gloves
- Spray OT with carbolic acid
Lister and Lancet 1867 states that amputation mortality is reduced from?
46 to 15%
Current Asepsis Technique in the Operating Theatre
- 20 air changes per hour
- Filtered air
- Laminar flow
Current Asepsis Technique of the Surgeon
- Hand scrub iodophors or hexachlorophene solution
- Sterile gloves
- Sterile gown
- Aseptic technique
Current Asepsis Technique of the Patient
- Pre-operative MRSA swab (If positive, treat with bactroban ointment
- Pre-operative body wash with hibiscrub
- Shave only on the day of operation
- Skin preparation
- Sterile drape
- Protect wound
- Beware long surgery, drains and other illnesses
Current Asepsis Technique on Instruments
Autoclave or gas sterilised
What are the common bacteria removed by Antisepsis?
- Resident bacterial flora: Coag -ve Staphylococcus, Corneybacterium, Acinetobacter, enterobacterium
- Transient: Staph aureus, MRSA
Why do we need Asepsis?
To prevent surgical site infection
What are the characteristics of surgical site infection?
- 10-15% of nosocomial infections
- 60% at incision site
- Significant morbidity and mortality for severe infection
- Increased hospital stay and costs
What are the types of Surgical Site Infection?
- Superficial Incisional SSI
- Deep incisional SSI
- Organ/Space SSI
What is a Superficial Incisional SSI?
Occurs within 30 days and involves skin or subcutaneous tissue and one of the following
- Purulent discharge
- Positive culture
- Clinical signs of infection
- Clinical diagnosis
What is a Deep Incisional SSI?
Occurs within 30 days if no implant left in situ
Occurs within 1 year if implant left in situ and one of the following
- Purulent discharge from deep infection
- Dehiscence of deep incision
- Discharging abscess
- Clinical diagnosis
What is a Organ SSI?
Occurs within 30 days if no implant left in situ
Occurs within 1 year if implant left in situ and one of the following
- Infection involves organ/space or related anatomy
- Purulent discharge from deep space
- Positive culture
- Deep abscess confirmed clinically or radiologically
- Clinical diagnosis
Surgical Wound Classification: Clean/Class I
*Popular exam question
Uninfected operative wound in which no inflammation is encountered.
Primary closure with closed drainage
Respiratory, alimentary and genito-urinary tracks
1.5% risk of SSI
Surgical Wound Classification: Clean-contaminated/ Class II
*Popular exam question
Any operative wound in which the respiratory, alimentary or genito-urinary tracks are opened in a controlled manner without contamination
8% risk of SSI
Surgical Wound Classification: Contaminated
*Popular exam question
Open fresh accidental wounds
Operations with major break in sterile techniques
Gross contamination or major spillage
Non-purulent inflammation
10-15% risk of SSI
Surgical Wound Classification: Dirty-infected/ Class IV
*Popular exam question
Old traumatic wounds with devitalised tissue and those that involve existing clinical infection or perforated viscera.
Organisms involved were present in the operative field before the operation
25% risk of SSI
What are the Patient Risk Factors for SSI?
- Age, nutrition
- DM, obesity, smoking
- Colonisation, immunosuppression
- Blood transfusion, anaemia
- Malignancy, co-existing infection
- Length of pre-operative stay
What are the Operative Risk Factors for SSI?
- Category and duration of operation
- Skin asepsis, surgical scrub, preoperative shaving, preoperative skin prep
- Ab prophylaxis
- OT sterilisation
- Foreign material
- Surgical drains, surgical technique
- Poor haemostasis, dead space obliteration
- Tissue trauma
What is the normal flora at the Head and Neck region?
Staphylococcus (Aureus and coag negative)
Streptococcus
Cornybacteria, Neisseria, Haemophilus, Anaerobes
What is the normal flora at the Thorax region?
Staphylococcus (Aureus and coag negative)
What is the normal flora at the Upper GI region?
Gram-negative rods such as enterobacter, lactobacilli
What is the normal flora at the Lower GI region?
Aerobic gram-negative rods including enterobacter, enterococci
Anaerobes such as bacteroides, clostridium yeasts
What is the normal flora at the female genital tract?
Staph, strep, corneybacteria, lactobacilli
When should you clean your hands? (5 situations)
- Before touching a patient
- Before an aseptic procedure
- After body fluid exposure risk
- After touching a patient
5.After touching patient surroundings
Equation for risk of SSI
Dose of bacterial contamination X virulence/resistance of patient
Characteristics of Hygienic Hand Rub
- Bactericidal agent which is alcohol based without addition of water
- Contains emollient
- Fast acting and easy to use
- Can be used repeatedly
How to clean fingernails?
Sub-ungal regions harbour bacteria
- Trimmed nails
- No varnish or artificial nails
- Use a scrub
What is the purpose of a Surgical Scrub?
To remove debris and transient micro-organisms from fingernails, fingers and forearms
Reduce resident flora to a minimum
Inhibit rapid rebound growth on bacterial flora
The anti-microbial agent should reduce micoroganisms on intact skin, be non-irritant, broad spectrum, fast acting and have a residual effect
Notes on Surgical Drapes
- Aseptic barrier
- Cotton vs disposable
- Wet drapes provide ideal culture medium
Characteristics of Antiseptic agents
1.Fast acting
- Persistent effect
- Broad spectrum
- Non-irritant and acceptable
- Reduce microorganisms on intact skin
- Binds to stratum corneum
Not done
