ASEPTIC TECHNIQUE AND STERILIZATION METHODS

CTVT PGS 1158-1168

Objectives:

Understand aseptic technique and it’s importance in surgery.

Learn how to properly sterilize instruments and equipment.

Asepsis- condition of sterility where no living organisms are present

Aseptic technique- all steps taken to prevent contamination of surgical site by infectious agents

Goal: to “maintain asepsis“ and watch for “breaks” in aseptic technique

Where do contaminants come from?

Exogenous sources:o You, patient’s fur/skin, instruments, air

Endogenous:o Inside the patient reach the incision

through blood stream

Ways to Maintain Aseptic Technique

Disinfection - destruction of pathogens on inanimate objects (Kennel Care, Accel)o Doesn’t effect bacteria spores

Sanitization - acceptable level of contaminants present

Antiseptic – inhibits growth of infectious agents on living tissue (Chlorhexidine)

Sterilization - complete destruction or elimination of all living organismso Including viruses and bacterial spores o Always inorganic material

When does aseptic technique begin?

It’s always happening!o Cleaning of instrumentso Surgery suite sanitation/disinfectiono Patient prepo Sx team scrubo Surgical suite etiquette

Contamination cannot always be avoidedo Skin abscess, dental disease

Contamination Risk of contamination doubles every hour under Ax

Contamination does not mean infection

Infection is dependent on:

o Patient health

o Tissue damage

o Virulence and quantity of agent

The level of contamination determines:

o Use of perioperative antimicrobials

o Degree of asepsis required

Classification of Surgical Procedures

Clean = non-contaminated, routine, placement of hardware

o Ex. permanent implants (IM pins), benign laparotomy

Clean-contaminated = entering a hollow organ

o Ex. enterotomy, cystotomy

Contaminated = leakage during Sx or major breach of aseptic technique

o Ex. enterotomy, cystotomy

Dirty = previously ruptured hollow organ or abscess

o Ex. cutaneous abscess, septic peritonitis, ruptured pyo

Methods of Sterilization

1. Physical Sterilization Filtration Radiation Heat

2. Chemical Sterilization Liquid Gas

Filtration Sterilization

Filtration – microorganisms separated from liquid materials o Pharmaceuticalso Can be placed on IV line or syringe

Radiation Sterilization

Radiation - destruction of microorganism without significant increase in temperature o Gloves and suture material

*Filtration and radiation are typically performed by the manufacturer before shipments

- anything that comes pre-sterilized

- a lot of “one time use” products

- items which cannot be heat sterilized

Heat Sterilization

Most common sterilization technique Destroys bacteria by denaturing their proteins

1. Dry Heat Sterilizationo High temperatures for a long period of time

2. Wet Heat Sterilizationo Creating steam under pressure at high

temperatures o Ex. Autoclave

Dry Heat Sterilization Does not involve moisture (no rust, no corrosion)

Takes longer than wet heat and requires higher temperatures

(no steam to achieve the higher temperature)

Ex. 300°f for 2 ½ hours

Wet Heat: Autoclave Sterilization

Pack must be able to withstand heat AND moisture!

1. Pre-vacuum sterilizer A pump evacuates the air before the steam enterso More even penetration of steamo Shorter duration

2. Gravity Displacement Sterilizer Steam enters the top and forces air to bottom Most commonly used type

Autoclave Sterilization (Gravity Displacement)

Used most commonly for “packs”

Heat = 250 °F minimum

Pressure = 20 PSI

Time = 13 minutes at temp (exposure time)o Total cycle =Heat-up + exposure + dry timeo Usually 30 - 45 minute cycle

Always use distilled water!*Every machine is different, refer to the operator's manual

(usually have pre-set buttons to use)

There should be space between each pack!

Steam should be allowed to flow around every surface of each pack

Use multiple racks if sterilizing a lot of packs

Pack Preparation

Proper pack preparation is critical Instruments must be clean and dry All locking instruments should be unlocked Wrap materials must be steam permeable

1. Woven = double thickness muslino Reusable

2. Non-woven =crepe paper or plastic poucho One time use …(mostly)

Many practices double wrap (AAHA)

Pouch Preparation

Peel packs – clear plastic pouches

made of plastic and paper

o Self-sealing or heat sealedo Instrument is placed into pouch with

the handles toward the closed ino Plastic side should face downo Pack will be opened from the closed end

Labeling of Packs

Three requirements: What is in it Initials of who prepared it Date it was sterilized

*VTI- which patient it is for

Sterility Indicators1. Tape – outside of pack was exposed to steam

2. Chemical Indicator Strips- change color when exposed to steam for adequate time

Examples:

o Peel packs – indicator on the outside of the paper

o OK Strip - can be placed in the center of the pack

o Stickers- can be placed anywhere (mostly for gas)

Sterility Indicators

3. Pellet glass – glass ampule containing a temperature sensitive pellet that melts between 244-250 °F

4. Biological/Culture tests – contain a spore population of bacteria (usually Bacillus sp.)

o Takes minimum of 24 hours for resultso Confirms that microorganisms

were in fact killed if the sample does

not grow anything

Autoclave Quality Control

Performed by technicians- ensures proper technique Sterility Indicators

Must be used in combination, as not just one will cover all requirements

Temperature graphs Autoclave maintenance - autoclave cleaner

o Ex. Speed-Clean – mixed in the water

o Ex. Chamber Brite – powder is sprinkled on the bottom of cold chamber; cycle is ran without drying

o Both require a “rinse” cycle to be ran after use

After the Autoclave Cycle Packs must cool slowly to prevent condensation which could:o Wick bacteriao Rust metalo Tear paper

Let the dry cycle finish completely!

Door should be cracked to vent slowly ~ 10-20 minuteso Opening door wide causes steam to condense inside

the pack becomes wet wicks bacteria

Don’t leave paper packs in autoclave longer than needed (makes paper more brittle, easy to tear)

Maintaining Sterile Packs

The outside is not sterile

Storage: dust free, dry, well-ventilated, away from contaminated areas - closed cabinet is safer than open

Broken sterility: dropped on floor, wet, broken outer wrap (instruments penetrates paper)

o Never assume sterility - autoclave again

o Error on the side of caution

Monitor dates for expired sterility

(clinic protocol)

Length of Sterility Table on page 1163 in CTVT

1. Date related practice: Which one lasts longer? Double vs. single wrapped Non-woven vs. Woven Closed vs. open cabinet Heat sealed vs. Self-sealed

2. Event related practice: item is sterile until an event in which the sterility is broken

Flash Sterilization (Emergency situation)

Instruments are placed unwrapped in a perforated metal tray

270°F for 3 minute exposure time

Removed with detachable metal handles and carried straight to surgery (or huck towel)

Instruments must cool before use

Some machines have a preset for this