Cleaning, Disinfection, and Sterilization Validations of Reusable Medical Devices

Design Considerations for Engineers

Webinar Overview
o What is a cleaning and disinfection/sterilization validation?
• Types of cleaning, disinfection, and sterilization validations
 Residuals
• Categories of reusable medical devices
• Acceptance criteria
o Case Studies
• Surgical Forceps
• Blood Glucose Meter
• Colonoscope
o Design Considerations
o Questions
Cleaning, Disinfection, and Sterilization Validations: Design Considerations 12/8/2011 2

Today’s Goals
o Develop a more thorough understanding of the cleaning,
disinfection, and sterilization processes
o Learn what to consider when designing a device to increase
suitability for reprocessing for reuse

Poll
What Phase are you at in your design process?
A. Early Stage: designing a device and need more information on how
to make it more friendly for reprocessing.
B. Pre-FDA Submission: Need to validate a reprocessing procedure for
submission
C. Post-FDA Submission: Product is on the market but now need to
perform a reprocessing validation
D. Just looking for more information

What is a cleaning and
disinfection/sterilization validation
o Purpose and need for validating procedure
• Set standards for the reprocessing procedure to render device
safe for patient use.
o What does the FDA say?
• “Cleaning is the physical removal of organic soil from an item to
the extent necessary for further processing or for intended use”
• “Disinfection destroys pathogens and other microorganisms by
physical or chemical means”
• “Sterilization validation renders a product free from viable
microorganisms”

What is a Cleaning Validation?
o Cleaning: Removal of soil residues.

Cleaning Validation Procedure
o Inoculate the device.
• Organic Soils
• Microorganisms
o Subject device to cleaning procedure.
• Usually with use of water and detergents.
o Extract remaining residues.
• Microbial, protein, hemoglobin, carbohydrate, endotoxin

Cleaning Validation Acceptance
Criteria
o Visually Clean
o Microorganisms – minimum of 3-log reduction
o Residual Limits Levels:
• Protein < 6.4μg
• Hemoglobin < 2.2μg
• Carbohydrate < 1.8μg
• Endotoxin < 2.2μg

What is a Disinfection Validation?
Definition: Process that kills pathogenic
and other microorganisms by physical
or chemical means

Disinfection Validation Procedure
o Inoculate device with microbes and organic soil
o Process device with validated cleaning procedure
o Subject device to disinfection procedure:
• Disinfectants
• Thermal applications (under 100°C)
o Perform microbial recovery

Disinfection Validation Acceptance
Criteria
o Visually clean
o Microorganisms: 6-log reduction
o Total Organic Carbon (TOC)
screen for residual disinfectant

What is a Sterilization Validation?
o Definition: A process that renders a product free from viable
microorganisms
o Measured by SAL (sterility assurance level): probability that a
product is non-sterile
• Ex: SAL 106 is a one in one million chance of a non-sterile event

Sterilization Validation Procedure
o Introduce biological indicators to device
• Biological spores
o Subject device to sterilization process
o Retrieve biological indicators and perform
sterility test

Sterilization Validation Acceptance
Criteria
o Non-critical device: SAL 10-3
o Critical device: SAL 10-6

Simply Put…
o We have to contaminate the device, clean it and
disinfect or sterilize the device according to the
procedure being validated.
o Then we have to check the level of
contamination remaining on the device after the
cleaning/disinfection/sterilization procedure.
o If all checks are acceptable, the
procedure will be validated for use.

Types of Cleaning, Disinfection and
Sterilization Processes
Cleaning Disinfection Sterilization
Manual
Cleaning with or without use
of brushes, specialized tools
Automated Cleaning
Ultrasonic
Medical Washers
Low Level
Kills most vegetative bacteria,
some viruses and some fungi.
Intermediate Level
Kills vegetative bacteria,
viruses, fungi and
mycobacterium.
High Level
Kills all microbial organisms –
potential to render device
sterile.
Thermal
Disinfection via thermal
applications under 100°C.
High Temperature
Moist heat/steam
Dry heat
Low Temperature
Ozone
Chemical
Liquid - Steris
Hydrogen peroxide
Gas
Ethylene Oxide
Hydrogen peroxide (gas
plasma) - Sterrad
Radiation-Gamma, E-beam

Reusable Device Classification
Device
Classification
Definition Examples
Critical
•Introduced directly into bloodstream
or other normally sterile areas of the
body
•Surgical instruments, needles,
catheters, Implants, invasive
endoscopes
Semi-Critical
•Intact mucous membranes
•Does not penetrate the bloodstream
or normally sterile areas of the body
•Non-invasive flexible and rigid
fiber optic endoscopes, aspirator
tubes, respiratory therapy
equipment
Non-Critical •Intact skin of patient
•Blood pressure cuffs,
stethoscope, external sensors
*Adapted from AAMI

Acceptance Criteria Summary
Device Classification Treatment Options Criteria
Critical
(Must be Sterile)
Sterilization •Sterilization: SAL – 10-6
Semi-Critical
(Sterile or disinfected)
Sterilization
or
High Level Disinfection
•Sterilization: SAL – 10-6
•Disinfection: 6 log
reduction
Non-Critical
(Does not need to be
sterile)
Simple cleaning
or
Low level disinfection
or
Intermediate level
disinfection
•Sterilization: SAL – 10-3
•Cleaning: Removal of
residuals, visually clean
•Disinfection: 3-log
reduction
*Note: Devices must be cleaned prior to disinfection or sterilization

Case Study #1: Surgical Forceps
o Use: For surgical procedures and may potentially contact
bloodstream
o Device Category: Critical
o Complexity: Simple
o Requirements: Cleaned and Sterilized

Forceps Limitations and Risks
o Limitation: Stainless steel is not compatible with many chemicals
• Risk: Rust and corrosion can occur
o Limitation: Uneven grooves on tip and grip points
• Risk: High levels of residuals may be trapped in grooves

Forceps Cleaning Procedure
o Step 1: Cleaned with sponge and Alconox
Detergent
• Alconox is widely used in hospitals and
will not cause corrosion
• Sponge aids in removing residue from
grooves
o Step 2: Rinsed device under running water
• Rinsing removes residuals and detergent
residues
o Step 3: Screened for total organic carbon
from both soil and detergent
• Screening confirms that levels of
residuals are acceptable

Forceps Sterilization Procedure
o Steam sterilization using an
autoclave was validated
• Autoclaves are readily available
• High heat of an autoclave sterilizes
devices
• No chemicals are involved

Case Study #2: Blood Glucose Meter
o Use: Repeatedly used for blood glucose monitoring. Body of
meter may contact blood
o Category: Semi-critical
o Complexity: Medium complexity. Has electronic parts
o Requirements: Cleaned and disinfected

Glucose Meter Limitations and Risks
o Limitation: Cannot be immersed
• Risk: Difficult to clean and disinfect without immersion, which
could affect electronics
o Limitation: Button and crevices limit cleaning ability
• Risk: Residuals may become trapped if procedure is not effective
o Limitation: Device cannot withstand high heat
• Risk: Steam sterilization of thermal disinfection cannot be used
because they could damage the device

Glucose Meter Cleaning Procedure
o Step 1: Cleaned with Sani-Cloth wipes
• Wipes are widely used in hospitals for quick and thorough
cleaning
o Step 2: Screened for TOC
• Screening will confirm if unacceptable levels of residuals are
present

Glucose Meter Disinfection Procedure
o Disinfected with Sani-Cloth wipes; liquid left on device for 5
minutes
• Wipes are convenient
• Does not use high heat
• Does not require immersion of device

Case Study #3: Colonoscope
o Use: Non-invasive diagnostic device used to examine the colon
o Device Category: Semi-critical (contacts mucosal surfaces)
o Complexity: High complexity
o Requirements: Cleaned and Disinfected

Colonoscope Limitations and Risks
o Limitation: Complex design
• Risk: Difficult to design a
cleaning process that is both
simple and effective
o Limitation: Device composed of
multiple materials including
metals, silicone, and glass
• Risk: Susceptible to scratches
and deformities
o Limitation: Not compatible with
some cleaning agents
• Risk: Corrosion or release of
toxic byproducts
o Limitation: Knobs and screws
• Risk: May retain high
residuals levels
o Limitation: Not all parts are
immersible
• Risk: Immersion could
destroy camera or
electronics
o Limitation: Repeated
reprocessing
• Risk: Reprocessing could
affect device functionality

Colonoscope Cleaning Procedure
o Step 1: Clean with sponge and water
• Initial cleaning removes visible contaminants
• Soft sponge will not scratch device
o Step 2: Device partially immersed in Cidex OPA
• Some parts are immersible; these are best cleaned by soaking
o Step 3: Wipe non-immersed parts with Cidex OPA
o Step 4: Rinse with water
• Removes excess chemicals and soil

Colonoscope Disinfection Procedure
o Step 1: Wiped and disinfected with Cidex
Activated for 12 minutes
• Autoclaving not an option, disinfection
appropriate
• Using same type of reagent is convenient
• Longer time of exposure needed to
achieve disinfection
o Step 2: Rinsed under running water
o Step 3: Screened for residuals with TOC

The Importance of Design
1. Proper design ensures device will perform and function correctly
and safely
2. Good design allows the device to be thoroughly cleaned and
effectively disinfected or sterilized

Design Considerations
o Material Design
o Physical Design
o Total System Design
o Misuse-related Design

Material Design Considerations
o Biocompatibility
• Non-toxic
• Compatible with cleaning/disinfection reagents
o Potential release of toxic byproducts
• Reactivity to reagents
• Leaching of materials
o Capacity to retain residuals
• porous/non-porous
• Scoring by cleaning materials
• Smooth vs. rough surfaces
o Metals vs. polymeric materials
• Polymers may react to chemicals
• Metals are susceptible to corrosion and pitting

Physical Design Considerations
o Size, shape, and configuration
• Long, narrow interior channels/lumens
• Rough or discontinuous surfaces, ridges,
crevices, sharp angles, joints
• Small openings
o Will the device be disassembled and
reassembled?
• Should be easy
• Limit use of adhesives or lubricants
• Small pieces may be lost
o Is there an interior space?
• Consider adding an open port to facilitate
flushing soil fluids

Total System Design Considerations
o Design elements
• All components and subassemblies should handle stress of reprocessing
procedure
• Certain materials don’t mix
 Ex: Stainless steel and aluminum, brass, copper, or chrome plating
o How does cleaning process affect delicate instruments
• Small screws
• Coatings, glues, and amalgam
o Effects of reprocessing
• Will toxic byproducts be released?
• Possibility of corrosion?
• Are there electronics?

Misuse-related Design Considerations
Goal: Identify any potential damage to the device resulting from
improper use or reprocessing
o Effects of improper cleaning
• Device deformities
• Scratches and leaching
o Effects of incorrect sterilization or
disinfection
• Corrosion
• Toxic byproducts
• Rust or discoloration
o Consequences of improper
reassembly
• Broken devices
• Lose parts
• Damage equipment
• Loss of time
Note: Manufacturer should
attach warning to instructions
for use (IFU) if serious damage
could occur

Summary
o Cleaning and Disinfection/Sterilization Validation is a major factor
in achieving FDA approval
o Many design factors can positively or negatively impact validation
o An understanding of cleaning, disinfection, and sterilization
processes will aid in designing a more easily validated and
reprocessed device.
Thank you!

Cleaning, Disinfection, and Sterilization Validations of Reusable Medical Devices

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