1
Q
What is sterilization?
A
- Any process that eliminates (removes) or kills all forms of life, including transmissible agents (such as fungi, bacteria, viruses, spore forms, etc.)
- Includes such forms of life that are present on a surface, contained in a fluid, in medication, in something such as a biological culture media
- May not destroy prions
- Methods:
> Applying moist heat + pressure (autoclaving)
> Ionizing radiation
> UV radiation
> Chemicals
> Filtration
> Combos of these - Chemical germicides and filtration are often not efficient at effecting sterilization
2
Q
What is disinfection?
A
- Destroy microorganisms (but not endospores and viruses) found on non-living objects by destroying the cell wall or interfering with the cell metabolism
3
Q
What is antisepsis?
A
- Process of using heat, chemicals, or UV rays to kill most or nearly all microorganisms (pathogenic or not) on skin, in wounds, on mucous membranes, on clothing, and on hard surfaces
- Antimicrobial substances that are applied to living tissue/skin to inhibit or kill microorganisms (both transient and resident)
> Decreases total bacterial count
> Decreases possibility of infection, sepsis, or putrefaction
4
Q
Commonly Used Antiseptic - 60-90% Alcohol Solutions
A
- Ethyl, isopropyl, or “methylated spirit”
Pros
- Excellent antiseptics
- Commonly available
- Inexpensive
Cons
- Not good cleaning agent
- Easily inactivated by organic materials (dirt, blood, foreign bodies, etc.)
- Flammable (keep in cool, well-vented storage)
- Static electricity or cautery devices may ignite residual alcohol when using antiseptic hand scrub if hands are not allowed to dry thoroughly
- Damage latex over time
Range of Effectiveness
- Rapidly kill all fungi, bacteria (including mycobacteria), most viruses (including HBV, HCV, and HIV) on skin and under gloves
- No residual killing effect
- Ethyl alcohol is less drying to the skin than isopropyl alcohol and better for frequent use on skin
> Preparations with an added emollient help prevent dryness - Avoid use on mucous membranes due to dryness and irritation leading to growth of microorganisms
5
Q
Commonly Used Antiseptics - Iodine and Iodophor Solutions
A
- 3% iodine (aqueous iodine and alcohol-containing (tincture of iodine) products)
- 7.5-10% Iodophors (Betadine or Wescodyne)
Pros
- Inexpensive
- Effective
- Widely available
- Broad spectrum of antimicrobial action (can kill vegetative bacteria, mycobacteria, viruses, and fungi)
- Generally nonirritating to mucous membranes or skin (ideal for vaginal use) (up to 3% solutions; over that can be irritating)
Cons
- Require at least 2 minutes of contact time to release free iodine (the active chemical)
- Must release enough free iodine to produce adequate level of antimicrobial activity
- Have little residual antimicrobial effect
- Rapidly inactivated by organic materials, such as blood, sputum, foreign bodies, etc.
- Absorption of free iodine through skin and mucous membranes may cause hypothyroidism in newborns
- Allergic reactions can occur (check for history of allergies to iodine and shellfish)
Available formulations
- 3% iodine solutions in aqueous or tincture (iodine in 70% alcohol) solutions
- 7.5-10% iodophors are solutions of iodine mixed with a carrier such as polyvinyl pyrrolidone that releases small amounts of iodine
- Povidone-iodine (Betadine) is most common iodophor used, and is the best pre-surgical antiseptic
> Surgical Scrub (7.5% povidone-iodine)
> Solution (aqueous solution of 10% povidone-iodine without detergent)
> Solution Swabsticks (impregnated with 10% povidone-iodine solution; convenient, flexible; good for minor surgery)
6
Q
Commonly Used Antiseptics - Chlorhexidine Gluconate (CHG) - Hibiclens
A
2-4% Chlorhexidine gluconate is recommended concentration
- Hibiclens, Hibiscrub, or Hibitane
Pros
- Good alternative to iodophors
- Broad antimicrobial spectrum
- Safe for use on newborn infants
- Persistent skin action (6+ hours)
- Increased inhibition of numbers of microbes with repeated use
- Minimally affected by organic material
Cons
- Expensive
- Action is reduced/neutralized by natural soaps, substances found in hard tap water, and some hand creams
- Not effective against tubercle bacillus, only fairly active against fungi
- Decomposes if used above pH of 8
- Avoid contact with eyes as it can cause conjunctivitis
7
Q
Commonly Used Antiseptics - Triclosan
A
- Added as an antimicrobial in many soaps and body products and household products
- Historically used as surgical scrub and for hand-washing
- Used as body wash to eradicate MRSA
- Now used as an alternative surgical scrub in patients sensitive to iodophors
Pros
- Broad spectrum of activity (concentrations of 0.2-2.0%) - moderate antimicrobial activity against mycobacteria, gram+ cocci, and yeast
- Excellent persistent action
- Minimally affected by organic matter
Cons
- Not affective against P. aeruginosa or other gram- bacilli
- Bacteriostatic (only inhibits growth)
- Debated that there might be resistance to skin flora in long-term studies
- Banned by FDA in hand and body soaps now!
- Triclosan does more harm than good!
8
Q
Commonly Used Antiseptics - Hydrogen Peroxide
A
- Best limited to use on intact skin or cleaning very dirty wounds and those encrusted with blood
- Natural hemolytic
> Very good to remove blood and iodine from clothing
Complications of Use
- Do not use on freshly sutured wounds
- It's the most wound-damaging agent
> Can cause ulceration of newly formed tissue and lead to delayed healing
> Toxic to fibroblasts
> Never use to pack sinus tracts
> Never use for forceful irrigation
9
Q
Commonly Used Antiseptics - Nonionic Surfactants
A
- Newer type wound cleaner
- Examples: Shur-Clens and Pharma-Clens
- Surface-active agents with the cleaning properties of soap, but virtually no tissue toxicity, including the eye and cornea
- No demonstrable adverse effects in wounds and lacerations
Cons
- Have no antibacterial activity
10
Q
What characteristics should be considered when choosing an antiseptic?
A
- Can it physically remove dirt and other material as well as some transient microorganisms from the skin? (Plain soap and clean water alone works well for this)
- Does it have a “residual effect” - a killing action that continues for a period of time after the antiseptic has been applied to skin or mucous membranes?
- Is there evidence of product safety?
- Are there risks of absorption, toxicity, or allergies?
- Cost
11
Q
Which is considered the best pre-surgical antiseptic?
A
- Betadine
> Povidone-iodine
> Most commonly used iodophor
> Available globally
12
Q
What are the pros/cons of nonionic surfactants?
A
Pros
- Virtually no tissue toxicity, even to eye and cornea
- No demonstrable adverse effects in wounds and lacerations
Cons
- No antibacterial activity
13
Q
What risk factors determine post-operative infection?
A
- Number of microorganisms entering the wound
- Type and virulence of the bacteria
- Strength of the patient’s defense mechanisms
- External factors (surgery over 4 hours in duration, length of stay in hospital, etc)
14
Q
What are the pros/cons of shaving skin before prepping for surgery?
A
Pros
- Easier to see body?
Cons
- Hairy areas (like eyebrows) may not grow back
- Shaving leads to multiple areas of nicking of the skin, which provides a portal of entry for secondary infections
- Cut back hair with scissors
- Surgical “clippers” are routinely used in the O.R.
- Use wide tape to pick up the loose cut hairs
15
Q
How do you establish a sterile field for the patient?
A
- Do not shave them
- For visibly soiled skin, gently wash it with soap and clean water or alcohol before applying the antiseptic
- Work in ever expanding concentric circles starting at the focus of the wound or operative site
> Keeps contaminated debris moving out and away from the surgical site - Prepare an area of the skin well beyond the size of the opening in the fenestrated drape
- Can’t be too clean or clean too much!
- Dry the area before applying the antiseptic
- Thoroughly scrub (or “paint”) with an effective antiseptic (preferably Betadine swab stick) three or more concentric circles starting in the center, being careful not to miss any area of skin
> Be sure patient is not allergic to iodine
> Must remove Betadine completely after the procedure - Drape with a simple fenestrated drape or sterile clothes
> Drapes with adhesive on the back help to anchor it securely during surgery - Allow the antiseptic enough time to be effective before beginning
16
Q
How do you set up a sterile field for the doctor?
A
- Cover hair and mouth prior to scrubbing, when needed
- Hand scrubbing is of extreme importance because this is the part of the physician’s body that comes into direct contact with the surgical site even though they are gloved
- If for some reason the glove tears or is punctured, proper preoperative hand scrubbing may provide that extra layer of defense necessary to prevent contamination/infection
- Clean nails with a nail file
- Repeatedly cleanse (at least three times - up to 5 minutes) from the hand up to the elbow, always insuring that the contaminated debris is moved away from the fingers
- When scrubbing is complete, hold the hands a little above the elbows to allow excess water to drip off at the elbows to prevent contaminants from being washed back to the hands
- Gloving is the single most important technique that the physician must master because the glove is the material that will come in direct contact with the patient’s tissue (need to be properly applied and never contaminated)
- Gloves must fit snugly
17
Q
How do you set up a sterile field for the instrument stand?
A
- Includes the space immediately above the stand, so nothing should violate that space except the gloved hands of the surgeon
18
Q
What are the pros/cons of using alcohol for skin prep for injections?
A
Pros
- Makes patient feel like something has been done?
Cons
- Swabbing the skin with an antiseptic prior to injection does not lower the risks of infection
