Equipment Washers and Sterilizers
2016-01-02 rev
this is now slide 1
do not print it to pdf
things to do (check off when complete):
x add revision date to cover page
x remove triangles
x create list for pages to print in the handout
2-11,15,17-18,28,31-33,37,39-40,44,47,54,57-66,69-74
add captions for photo slides
incorporate notes taken during presentation
Equipment Washers
and Sterilizers
Joseph Lister
© D. J. McMahon 150104
rev cewood 2016-01-02
Definitions
- Antiseptic: germicide for use on living tissue
- Antibiotics or antibacterials: a type of antimicrobial used in the treatment and
prevention of bacterial infection. They may either kill or inhibit the growth of bacteria
- Cleaning: removal of foreign material, using disinfectant and friction
- Disinfection: process that only kills vegetative bacteria
( Can be low, intermediate, and high levels )
- Decontamination: process that renders a surface safe to handle
but not totally free of microorganisms
- Sterilization: any process that renders a surface completely free of microorganisms
- Pasteurization: High-level disinfection (HLD)
by the use of moderate heat (71-76° C) for ~30 minutes
Sterilization:
Sterility occurs when all microorganisms are killed by
breaking open the capsule or wall of the organism.
We can do this with heat, chemicals, or various types of radiation.
Methods of Sterilization:
Live Steam:
the ‘gold standard’
> basic exposure is steam at 121°C (250°F)
and 15psi for 15 minutes (note: > 14.7 psi)
> heat and time duration vary depending on
the type and volume of material being processed
> biological “controls” are used to verify that sterilization
occurred
> Autoclave: Any system that sterilizes instruments or
packs by means of wet heat under pressure.
Methods of Sterilization:
Chemical Methods - Ethylene oxide (EtO) gas
> exposure in a closed chamber
> kills almost all microorganisms
> toxic and carcinogenic
- Cidex™ (glutaraldehyde)
> liquid solution of 1% glutaraldehyde
> used mostly for instruments or (rigid) scopes
> technically a disinfectant only
Methods of Sterilization:
Chemical Methods
continued -
- Peracetic Acid
> powder diluted in hot water
> used in Steris’ “System 1”
> used primarily for endoscopes
- Peroxide in Plasma
> exposure to hydrogen peroxide in a
chamber with an electric field
> “Sterrad” system by ASP
> esp. good for fragile, plastic items
> substitute for EtO
Methods of Sterilization:
Ionizing Energy Methods Used for bulk quantities in manufacturing
- Electron Beam > created by e-beam generators
> low penetration, high dose
- Gamma Ray
> emitted from Cobalt-60 source
> better for larger, denser items
Olympic (Natus) Pasteurmatic System --
Pasteurmatic cycles:
Bulk sterilization by gamma radiation --
Washers:
> Not sterilizers
> Automated washing systems for decontaminating
large volumes of trays of surgical instruments
> Usually found in Central Services
> Often in a ‘pass-through’ wall to the “clean side” of
the CS Dept, where instrument trays and sets are
reassembled before sterilization
CDC and FDA agree on the “Spaulding
Classification” for processing devices:
Critical devices: enter a surgical field or the vascular system
- these require sterilization
Semicritical devices: contact mucous membranes, do not break tissue
- should be at least high-level disinfected if not sterilized
Noncritical devices: touch only intact skin
- can be cleaned by low-level disinfection
ANSI/AAMI ST79 –
Recommended Practice for Hospital Steam Sterilization
Primary reference for autoclave users
Expiration Dates for sterile packages are now
“Event-Related” (vs “Time-Related”):
A properly sterilized package can be considered sterile
indefinitely as long as it is not torn, does not become wet or
damaged and is not suspected of being compromised.
All packages are dated for date of sterilization, and the package
with the earliest date is always picked.
When The Joint Commission inspects a facility, they want to see
a policy for management of sterile supplies, and consistent
compliance with that policy.
Maintenance & Repair of Autoclaves –
 Service schools are provided by major autoclave makers
 Get the book out before opening-up any autoclave
 Many hospitals outsource autoclave maintenance to ISO’s
- eg Seattle Surgical or Omega Mechtronics
 Typical city or state “boiler inspection” regulations require
autoclaves to be inspected every 2 years by the city or
county inspectors.
- includes checks of safety valves, overall condition,
documentation.
In order to work effectively, steam autoclaves
must first force all air out of the chamber.
Most are the “gravity fill” type: steam enters at the top of the chamber
and displaces all the air.
Other methods use an evacuation pump.
Table-top autoclaves -
Maintenance of Tabletops –
Major players in large autoclaves:
- Steris (was Amsco)
- Getinge-Castle
- Vernitron
Major players in table-tops:
- Midmark-Ritter
- Pelton & Crane
- Tuttnauer
Third party parts provider for autoclaves and related equipment:
Replacement Parts, Inc (RPI)
www.rpiparts.com
Chemical Sterilization:
Sterilization by gluteraldehyde –
 “Cold” sterilization
 Usually sold as Cidex™ 1% solution
 Immersion for ~30 minutes, and thorough rinsing
 Cidex is toxic and used in limited amounts
 Best for ‘lensed’ instruments and flexible scopes
EvoTech scope washer from ASP -
uses Cidex™
Chemical Sterilization:
Sterilization by Peracetic Acid:
Endoscope washer/sterilizers
Automated systems that sterilize fiberoptic
scopes, cameras, or ultrasound probes in chemical
sterilants (usually peracetic acid).
 Include a way to expose all internal lumens
(which can be .5mm) and recessed areas to the
sterilant solution to assure that all microorganisms
are killed.
Olympus MD-2 system -
Steris System-1 (now System-1E)
Specifically for endoscopic scopes
Exposes items to peracetic acid solution
Entire cycle ~40 minutes
Can be high-maintenance: requires very hot water
supply, several high-level filters, and will shut down
under many conditions
Has been redesigned (2012) by Steris per the FDA
Steris System 1e -
replaced System1
System 1e requires highly filtered hot water -
Chemical Sterilization:
Sterilization by Peroxide Plasma
Sterrad™ sterilization system –
>> Proprietary to ASP Corp
>> Exposes items to hydrogen peroxide (H2O2)
in an electrical field
>> Entire cycle ~ 45 minutes
>> Good for small, fragile, heat-sensitive items
Table-top Sterrad model NX -
Chemical Sterilization:
Sterilization by Ethylene Oxide –
(‘EtO’ or ‘EO’)
EtO gas is mixed with an inert gas in a chamber
 Kills all microorganisms chemically
 Used for the majority of bulk-sterilized disposables
 Toxic to liver, causes cataracts
 Used in fewer hospitals today
Chemical Sterilization:
Sterilization by Ozone –
> Kills microorganisms by exposure to ozone (O3)
> Needs only oxygen, water, & electrical power
> Cycle time ~5 hours
> Limited range of items that can be processed
TSO3 Corp, model 125L ozone sterilizer -
Uses the oxidizing properties
of ozone (O3) to kill
microorganisms.
Limited market success.
Verifying sterility Bowie-Dick Test –
(ANSI/AAMI ST66)
Pack of special papers subjected to a cycle in
a steam autoclave, to detect any remaining
pockets of air that were not evacuated.
Black symmetrical patterns will be uneven or
discolored if air is present.
Not a biological performance test - serves only to
warn of inadequate air removal.
Bowie-Dick Test; 3M “Comply” Test Pack
Chemical controls – (before exposure)
Change color when exposed to sterilizing conditions
steam
Sterrad
steam
EtO
ozone
Biological controls –
Verification that a sterilizer is effective
Live bacteria that are difficult to kill are added to the
sterilizer load, and checked to be sure that they are
killed-off. All sterilizer controls are documented.
Biological controls – 3M Attest
Biological Indicator (BI) goes through steam sterilization cycle with
the items being sterilized. (Other BIs are available for other
sterilization processes, including Ethylene Oxide EO)
BI is incubated for 24-48 hours. (“Super Rapid” system for steam
sterilization requires just one hour of incubation.)
Each BI contains > 1,000,000 living spores of a highly resistant
organism. If the spores are inactivated or killed by the sterilization
cycle, you have a direct measure of an effective sterilization process.
“Super Rapid”
G.I. Endoscopy --
Upper G.I.
Lower G.I.
Typical endoscopy scenarios -
Processing of endoscopes:
- #1 in ECRI’s Top Ten Hazards for 2016
- flexible fiberoptic scopes
- endoscopic cameras
- rigid scopes & instruments
Most automated endoscope reprocessors achieve high-level
disinfection, but the trend is to full sterilization.
- Steris ‘System 1e’ achieves sterilization with peracetic acid
The Sterrad (peroxide-plasma) can be used for limited scope
types, with only one channel.
EtO is generally not used due to long process times.
Scope washers in a
G.I. endoscopy clinic
Typical endoscope washers in a G.I. clinic:
autoclaves of the past: