Cleaning, Disinfection, and Sterilization Validations of Reusable Medical Devices

Cleaning, Disinfection, and Sterilization Validations:

Design Considerations for Engineers

Webinar Overviewo 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 Considerationso Questions

12/8/2011 2Cleaning, Disinfection, and Sterilization Validations: Design Considerations

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

12/8/2011Cleaning, Disinfection, and Sterilization Validations: Design Considerations 3

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 Procedureo 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 Cleano Microorganisms – minimum of 3-log reductiono 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

Cleaning, Disinfection, and Sterilization Validations: Design Considerations 912/8/2011 9Cleaning, Disinfection, and Sterilization Validations: Design Considerations

Disinfection Validation Procedureo Inoculate device with microbes and organic soilo Process device with validated cleaning procedureo 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 SterilizationManualCleaning with or without use of brushes, specialized tools

Automated CleaningUltrasonicMedical Washers

Low LevelKills most vegetative bacteria, some viruses and some fungi.

Intermediate LevelKills vegetative bacteria, viruses, fungi and mycobacterium.

High LevelKills all microbial organisms – potential to render device sterile.

ThermalDisinfection via thermal applications under 100°C.

High TemperatureMoist heat/steamDry heat

Low TemperatureOzone

ChemicalLiquid - SterisHydrogen peroxide

GasEthylene OxideHydrogen 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 SummaryDevice Classification Treatment Options Criteria

Critical(Must be Sterile) Sterilization •Sterilization: SAL – 10-6

Semi-Critical(Sterile or disinfected)

Sterilizationor

High Level Disinfection

•Sterilization: SAL – 10-6

•Disinfection: 6 log reduction

Non-Critical(Does not need to be

sterile)

Simple cleaningor

Low level disinfectionor

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 Forcepso Use: For surgical procedures and may potentially contact

bloodstreamo Device Category: Criticalo Complexity: Simpleo 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 Procedureo 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

grooveso 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-criticalo Complexity: Medium complexity. Has electronic partso 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 Procedureo 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 colono Device Category: Semi-critical (contacts mucosal surfaces)o Complexity: High complexityo Requirements: Cleaned and Disinfected


Colonoscope Limitations and Riskso 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 deformitieso Limitation: Not compatible with

some cleaning agents• Risk: Corrosion or release of

toxic byproducts


o Limitation: Knobs and screws• Risk: May retain high

residuals levelso Limitation: Not all parts are

immersible• Risk: Immersion could

destroy camera or electronicso Limitation: Repeated

reprocessing• Risk: Reprocessing could

affect device functionality

Colonoscope Cleaning Procedureo 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 OPAo 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 disinfectiono Step 2: Rinsed under running watero 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 Considerationso Material Design

o Physical Design

o Total System Design

o Misuse-related Design


Material Design Considerationso 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 Considerationso 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 platingo 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

o Effects of improper cleaning• Device deformities• Scratches and leaching

o Effects of incorrect sterilization or disinfection• Corrosion• Toxic byproducts• Rust or discoloration


Goal: Identify any potential damage to the device resulting from improper use or reprocessing

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

Summaryo 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!


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Cleaning, Disinfection, and Sterilization Validations of Reusable Medical Devices