skin preparation

General

· skin cannot be sterilised

· 20% of resident flora beyond reach of surgical antiseptics

· goal of preparation is to

· remove transient and pathological bacteria

· reduce resident flora to low level

types

· currently used antiseptics are

· chlorhexidine

· iodine

· povidine-iodine

Chlorhexidine

Chemistry

· cationic molecule

· incompatible with soaps and other anionic materials

· combined with non-ionic surfactants

· to act as lathering agent

· to prevent precipitation in hard water

Presentation

· TM Hibitane, Hibiclens

· skin preparation

· 0.5% chlorhexidine gluconate in 70% alcohol

· surgical scrub

· 5% chlorhexidine gluconate with lathering agent

Efficacy

· effective against wide range of

· G+ and G- bacteria

· moulds, yeasts and viruses

· only sporicidal at elevated temperatures

Clinical

· immediate action

· minimum skin contact time of 2 minutes recommended

· binds to protein in stratum corneum

· provides persistent residue

· prevents systemic absorption

· occasional allergy

Iodine

Chemistry

· elemental iodine

Presentation

· skin preparation

· weak iodine - 2.5% iodine in 70% alcohol

· tincture - 2.5% iodine + 2.5% potassium iodide

Efficacy

· effective against wide range of

· G+ and G- bacteria

· moulds, yeasts and viruses

· sporicidal after prolonged contact

Clinical effect

· poor residual activity

· tincture of iodine more residual

· percutaneous absorption may lead to iodisim

· high incidence of skin sensitivity reactions

Povidine-iodine

Chemistry

· organic complex of

· iodine

· povidine (polyvinyl-pyrrol-idone)

· combined with detergent base containing anionic surfactants as lathering agents

Presentation

· Betadine

· presented as

· preparation - 10% aqueous solution or 10% in 70% alcohol

· scrub - 7.5% povidine-iodine with soaps

· same spectrum of activity as iodine

· introduced to decrease irritative effect

· variable residual activity

· minimal skin absorption

· decreased skin sensitivity reactions

Role of alcohol

· effective against all common pathogens

· not effective against spores

· can destroy 90% of cutaneous bacteria in 2 minutes

· not adequate alone

· may increase efficacy of other antiseptics when used concomitantly

· defatting effect

Uses

Hand scrub

· 5-minute preoperative wash

Skin preparation

· reduces bacterial count by 80% alone

· needs to be in contact and moist for 2 minutes

Preoperative wash

· optimises reduction in skin count

· skin count reduced by 99% with combination of

· three 2-minute showers with skin cleanser

· skin preparation as above

Comparison

· no product clearly superior for skin preparation

· chlorhexidine reportedly more effective as hand scrub

Compatibility

· chlorhexidine in all forms is incompatible with anionic surfactants

· povidine-iodine surgical scrub

· soap