Asepsis

Asepsis- all living organisms removed or eliminated important to prevent contamination and infection

disinfection - destruction of vegetive forms of bacteria - not spores sterilization - complete destruction/elimination of all living organisms (including viruses and bact spores) from an inorganic material antiseptic - used to disinfect organic tissue (Kennel Care vs Chlorhexadine)

Aseptic Technique - limit contamination as much as possible sterilize sx instruments sx ste cleanliness pt prep sx team scrub/etiquette time/trauma/trash contamination cannot always be avoided

microorganisms contaminate surgery via 2 routes exogenous - air, instruments, pt skin, sx team (outside the pt) endogenous - bacteremia, oral cavity (inside the patient) exogenous factors are the ones we can best control

risk of contamination doubles every hour under anesthesia contamination does not mean infection dependent on pt health, tissue damage, virulence and quantity of agent, use of perioperative antimicrobials

clean - permanent implants (orthopedic) clean-contaminated - (enterotomy) contaminated - (broken asepsis) dry/dirty - (cutaneous abscess)

sx classification affects use of sterile or cold sterile instruments, level of PPE, location of procedure, perioperative meds, etc

Physical Sterilization filtration radiation heat

filtration - materials separated from microorganisms (pharmaceuticals) radiation - destruction of microorganism without significant increase in temperature (gloves,suture) filtration and radiation are typically performed by the manufacturer before shipments - anything that comes pre-sterilized or cannot be heat sterilized

heat - most common sterilization technique dependent on temperature and duration of exposure dry heat - materials that cannot be wet (pharmaceuticals) does not rust materials (not corrosive to sharpened edges) more difficult to control, take much longer tha wet heat, requires higher temperatures ie - glass bead sterilizer

wet heat - boiling or pressure/steam boiling is unreliable (can add an alkalinizing agent to increase efficacy) - cannot be used for rubber or glass pressure/steam - autoclave

Autoclave - used most commonly for “packs” steam must penetrate the center of the pack gravity displacement (downward displacement) - steam is released from the top of the chamber and pushes air out the bottom pre-vacuum sterilizers - air is removed prior to release of steam, more rapid sterilization and even penetration

proper pack preparation is also critical materials must be steam permeable woven or non woven double thickness muslin crepe paper, polypropylene fabric, plastic pouch/tube many practices double wrap

standard autoclaving degrees F AT TEMPERATURE for 13 minutes (30-45 minutes total) - for the common grav dips unit flash sterilization - instruments are placed in a perforated metal tray, 250 for 3 mins, removed with detachable handles and carried to surgery, instruments must cool before use - typically in prevac units

after standard autoclaving, packs must cool slowly to prevent condensation (wick bacteria, weakened binding, rust metal, tear paper) door should be cracked to vent slowly minutes don’t leave paper in autoclave more than needed, dries the paper, makes more brittle, easy to tear or even crack

QC ensure proper technique autoclave maintenance sterility indicators - autoclave tape, fusible melting pellet glass, culture tests, chemical sterility indicator strips must be used in combination as none cover all requirements

autoclave tape - the pack was exposed to steam pellet glass degrees F was reached culture - microorganisms were destroyed ster. ind. strip - placed in center of pack, center of pack was steamed

handling sterile packs - the outside is not sterile dust free, dry, well-ventilated, away from contaminated areas - closed cabinet is safer than open broken sterility - tape is broken, dropped on floor, wet, broken outer wrap when in doubt - autoclave again monitor dates for expired sterility (clinic protocol)

Chemical sterilization - liquid or gas used to eliminate microorganisms liquid - glutaraldehyde (CidexPlus) - only liquid to date that can STERILIZE and instrument gas - ethylene oxide or hydrogen peroxide gas plasma

EO - at room temperature is a colorless gas, flammable and explosive, toxic (skin burns, resp irritation, V, headaches, birth defects) requires special unit with ventilation and proper training, is known to be very expensive

multiple packs are placed in a specific plastic bag, bag is sealed and placed in unit, exposed to gas safe for almost any instrument including rubber and electrical devices and no risk of rusting metal own “autoclave” tape and sterility indicators sterility is proportional to gas concentration, exposure time, temperature, relative humidity

chamber is typically kept at degrees F double dose exposure can half duration minimum 35% humidity required 48 mins - 24 hrs (12 hrs at room temperature) packs must be quarantined in well ventilate area for 7 day or an aerator for hrs after sterilization basically - 24 hrs to sterilize with EO

Gas Plasma - Hydrogen Peroxide Gas Plasma cannot be used for wood, paper, linen, some plastics, liquids debate over use on endoscopes wrap in non-woven polypropylene fabric or plastic pouch packs placed in chamber (or suite), vacuum is drawn, hydrogen peroxide is vaporized, after 50 minutes pressure is lowered and radio waves crate gas plasma - free radicals kill microorganisms - sterilization in 1 hr total

Cold Sterilization - CidexPlus Cold “Sterilization” - chlorhexadine

instruments are immersed in a liquid disinfectant with intent to dramatically decrease or completely eliminate microorganisms cold tray - a metal tray, usually with a shelf system, dedicated to cold sterilization glutaraldehyde for 20 minutes - sterile used for arthroscopes an endoscopes has to be reconstituted and will expire must rinse instrument before rising on living tissue chlorhexadine - good for dirty surgery, dentistry - do not leave in for more than 3 hrs