Essay 2 (there's no 1) - Asepsis and antisepsis in oral surgery. Preparation of the patient and surgical team

definition of asepsis

absence of infectious organisms

goals of asepsis

prevent contamination of wounds, tissues, instruments and fluids

how is asepsis achieved

sterile techniques, barrier protection and environmental control

define antisepsis

destruction of microorganisms on tissues or in wounds

purpose of antisepsis

prevent and treat infection locally

sources of infection

• endogenous = patient's own flora (Skin, mucosa)

• exogenous = airborne microbes, droplets, contact with unclean hands, contaminated tools

transmission

• direct contact = by touching → physical for example kissing or touching

• indirect contact = contaminated surfaces

• droplet = coughing or sneezing

• airborne = suspended in air, entering respiratory tract

• faecal- oral = infecting digestive tract For example food or water

• Vector bourne = animals for example flies or rats

source of Entry

• preoperative → nasal carriage, ward, bed covers

• during operation → improper preparation of skin, damaged or lack of protective wear, operative theatre

• post operative → non sterile dressing

Spaudling’s classification - potential infection risk (1968)

preparation of the patient

• MRSA screening

• minimise hospital stay (prefer same day admission)

• preoperative skin disinfection: Chlorhexidine or providone-iodine

• shaving: only just before surgery, by trained staff

• sterile draping: reusable reusable disposable or antimicrobial adhesive drapes,

preparation of surgical instruments

1. Cleaning - removal of blood, debris (manual or detergent wash)

2. disinfection - using chemical disinfectants (low, medium or high level)

3. sterilisation- complete elimination of microorganisms

sterilisation methods of surgical instruments

• dry heat - 160-180 degrees

• steam (autoclave) - 10-135 degrees, most common method

• ethylene oxide - for heat sensitive items (e.g endoscope)

• formaldehyde gas and low temperature steam

• chemical immersion- In Emergencies

• irradiation - for disposable products for disposable products (e.g sutures, catheters)

preparation of the surgeon

• hand disinfection

— remove jewellery, trim nails

— agents:

- Chlorhexidine = long lasting

- providone-iodine = broad spectrum

- alcohol rubs = rapid effect, up to six hours of protection

— historical and alternative methods: ethanol, iodine, pervomur, ultrasonic baths etc

• Gloving

— sterile gloves Mandatory

— double gloving offers extra protection

— gloves may have micro perforations - proper hand hygiene still critical

• masks, visors and hair covers

— protect both patient and surgeon

— Integrated Shields available

— cover hair to reduce airborne contamination

• gowns

— prevent microbial shedding

— Use elastic cuffs to Seal sleeves

preparation of the operating theatre

• design = double door entry/exit, separate dirty/clean zones

• Temperature = 19-22 degrees

• humidity = 45-55%

• ventilation = 3-4 air changes/hour

• air disinfection = UV lamps

• scrub area = direct connexion to OR

classic methods of hand disinfection

1. Alfred method = wipe hands for five minutes with 96% ethyl alcohol; nail phalanxis and back interphalangeal folds cleaned with 5% iodine sol

2. Furbringer method = hand wiped for one minute by sol. mercuric chloride → 96% Alcohol 3 min → nail beds 5% iodine

3. spasokukotsky-Kochergin = running water with soap, 10 mins→ warm, 0.5% liquid ammonia Sol. hands washed in two basins, 2× 3mins. Sterile napkin with 96% alcohol 2× 2.5 min → finger tips/nail walls and beds/ finger skin folds smeared with 5% alcoholic iodine

quick method of hand disinfection

1. pervomur

2. Chlorhexidine Bigluconate

3. detergents

4. iodophorm

5. ultrasounds