Guarantee of the Steam Sterilization Process: Practice Based on CDC Evidence William A. Rutala, PhD, MPH Director, Hospital Epidemiology, Occupational Health and Safety; Professor of Medicine and Director, Statewide Program for Infection Control and Epidemiology; University of North Carolina at Chapel Hill, NC, USA

Guarantee of the Steam Sterilization Process l Steam Sterilization: Advantages and disadvantages l Functional workflow l Cleaning and decontamination l Preparation and Packaging l Monitoring

Disinfection and Sterilization Rutala, Weber. EH Spaulding believed that how an object will be disinfected depended on the object’s intended use. CRITICAL - objects which enter normally sterile tissue or the vascular system or through which blood flows should be sterile. SEMICRITICAL - objects that touch mucous membranes or skin that is not intact require a disinfection process (high- level disinfection [HLD]) that kills all microorganisms but high numbers of bacterial spores. NONCRITICAL -objects that touch only intact skin require low- level disinfection.

Processing “Critical” Patient Care Objects Classification: Critical objects enter normally sterile tissue or vascular system, or through which blood flows. Object:Sterility. Level germicidal action: Kill all microorganisms, including bacterial spores. Examples:Surgical instruments and devices; cardiac catheters; implants; etc. Method: Steam, gas, hydrogen peroxide gas plasma, vaporized hydrogen peroxide, ozone or chemical sterilization.

Sterilization of “Critical Objects” Steam sterilization Hydrogen peroxide gas plasma Ethylene oxide Vaporized hydrogen peroxide

Guarantee of the Steam Sterilization Process l Steam Sterilization: Advantages and disadvantages l Functional workflow l Cleaning and decontamination l Preparation and Packaging l Monitoring

Steam Sterilization l Advantages Non-toxic Cycle easy to control and monitor Inexpensive Rapidly microbicidal Least affected by organic/inorganic soils Rapid cycle time Penetrates medical packing, device lumens l Disadvantages Deleterious for heat labile instruments Potential for burns

Minimum Steam Sterilization Times Time at 132 o C in Prevacuum Sterilizer ItemMinimum exposureMinimum drying time Wrapped instruments4 min30 min Textile packs4 min5 min

Steam Sterilization Saturated steam is used to sterilize % of reusable medical devices in healthcare facilities. “ Steam is the preferred method for sterilizing critical medical and surgical instruments that are not damaged by heat, steam, pressure, or moisture. ” * *Rutala, Weber. CDC Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008

Guarantee of the Steam Sterilization Process l Steam Sterilization: Advantages and disadvantages l Functional workflow l Cleaning and decontamination l Preparation and Packaging l Monitoring

Central Processing Physical Facilities l Facility ideally divided into three areas: Decontamination -reusable items are received, sorted, and decontaminated; negative pressure; 6AC/hr. Personnel wear gloves when handling contaminated instruments; face masks, eye protection, and gowns/aprons when splashing may occur. Packaging -used for inspecting, assembling, and packaging clean, but not sterile, material. Sterilization and storage -limited access area with a controlled temperature and relative humidity.

Staging/Preparation

Preparation

Sterilization

Storage of Sterile Surgical Instruments

Guarantee of the Steam Sterilization Process l Steam Sterilization: Advantages and disadvantages l Functional workflow l Cleaning and decontamination l Preparation and Packaging l Monitoring

Cleaning l Mechanical cleaning machines-automated equipment may increase productivity, improve cleaning effectiveness, and decrease worker exposure Utensil washer-sanitizer Ultrasonic cleaner Washer sterilizer Dishwasher Washer disinfector l Manual

Cleaning l Items must be cleaned using water with detergents or enzymatic cleaners before processing. l Cleaning reduces the bioburden and removes foreign material (organic residue and inorganic salts) that interferes with the sterilization process. l Cleaning and decontamination should be done as soon as possible after the items have been used as soiled materials become dried onto the instruments.

Cleaning l Purpose: remove all adherent debris from an item and to reduce the number of particulates, microorganisms, and pyrogens. Removes debris such as blood, mucus, oil, salts or other foreign matter interferes with the sterilization process Reduces the bioburden and enhances the probability of sterilization

Bioburden on Surgical Devices l Bioburden on instruments used in surgery (Nystrom, 1981) 62% contaminated with < % contaminated with < % contaminated with <10 3 l Bioburden on surgical instruments (Rutala, 1997) 72% contained < % contained <10 2 l Bioburden on surgical instruments (50)submitted to CP (Rutala, 2014) 58% contained <10 20% contained < % contained <5x10 2 6% contained <10 3

Washer/Disinfector Rutala WA, Gergen MF, Weber DJ, ICHE. In press l Five Chambers Pre-wash: water/enzymatic is circulated over the load for 1 min Wash: detergent wash solution (150 o F) is sprayed over load for 4 min Ultrasonic cleaning: basket is lowered into ultrasonic cleaning tank with detergent for 4 min Thermal and lubricant rinse: hot water (180 o F) is sprayed over load for 1 min; instrument milk lubricant is added to the water and is sprayed over the load Drying: blower starts for 4 min and temperature in drying chamber 180F

Washer/Disinfector Removal/Inactivation of Inoculum (Exposed) on Instruments WD Conditions OrganismInoculum Log Reduction Positives RoutineMRSA2.6x10 7 Complete 0/8 RoutineVRE2.6x10 7 Complete 0/8 Routine P aeruginosa 2.1x10 7 Complete 0/8 Routine M terrae 1.4x /8 RoutineGS spores5.3x /14 No Enz/DetVRE2.5x10 7 Complete 0/10 No Enz/DetGS spores8.3x /10

Washer/disinfectors are very effective (>5 log 10 reduction) in removing/inactivating microorganisms from instruments

IS THERE A STANDARD TO DEFINE WHEN A DEVICE IS CLEAN? l There is currently no standard to define when a device is “clean”, cleanliness controlled by visual l Potential methods: level of detectable bacteria; protein (6µg/cm 2 ); endotoxin; ATP; lipid l This is due in part to the fact that no universally accepted test soils to evaluate cleaning efficiency and no standard procedure for measuring cleaning efficiency l At a minimum, a cleaning process should: reduce the natural bioburden; remove organic/inorganic contaminants; provide devices that when sterilized have a SAL 10 -6

Cleaning Indicators for Washer Disinfector l Monitor the automated washer and instrument cleaning chemistry functionaiity l Indicator includes proteins, lipids, and polysaccharides to mimic common challenging test soils

Guarantee of the Steam Sterilization Process l Steam Sterilization: Advantages and disadvantages l Cleaning and decontamination l Functional workflow l Preparation and Packaging l Monitoring

Packaging l Once items are cleaned, dried, and inspected, items are wrapped or placed in a rigid container l Arranged in tray/basket according to guidelines Hinged instruments opened Items with removable parts should be disassembled Heavy items positioned not to damage delicate items l Several choices to maintain sterility of instruments: rigid containers, peel pouched; sterilization wraps

Packaging Sterilization Wraps l An effective sterilization wrap would: Allow penetration of the sterilant Provide an effective barrier to microbial penetration Maintain the sterility of the processed item after sterilization Puncture resistant and flexible Drapeable and easy to use l Multiple layers are still common practice due to the rigors of handling

Loading l All items to be sterilized should be arranged so all surfaces will be directly exposed to the sterilizing agent l Other basic principles: Allow for proper steam/gas circulation Nonperforated containers should be placed on their edge Peel packs should be placed on edge

Packaging/Load Configuration l Packaging materials should be compatible with the sterilization process l Packaging (rigid containers, peel pouches, wraps) should provide a barrier to microorganisms and moisture and should be sufficiently strong to resist punctures and tears. l Items should be placed loosely into the basket, shelf, or cart so as not to impede contact between the sterilant and the microorganism.

Objectives of Monitoring the Sterilization Process l Assures probability of absence of all living organisms on medical devices being processed l Detect failures as soon as possible l Removes medical device involved in failures before patient use

Guarantee of the Steam Sterilization Process l Steam Sterilization: Advantages and disadvantages l Cleaning and decontamination l Functional workflow l Preparation and Packaging l Monitoring

Sterilization Process Monitoring Monitoring Tools Physical monitors Chemical indicators Biological indicators Process challenge devices (PCDs) test packs or challenge packs

Sterilization Monitoring Sterilization monitored routinely by combination of mechanical, chemical, and biological parameters l Physical - cycle time, temperature, pressure. Monitors one location in the sterilizer. l Chemical - heat or chemical sensitive inks that change color when germicidal-related parameters present. Identifies processed from unprocessed medical devices. l Biological - Bacillus spores that directly measure sterilization. Integrates all parameters of the process.

ANSI/AAMI ST79:2010 & A1:2010 & A2:2011 & A3:2012 & A4:2013, Section Physical Monitors Marked with correct date and sterilizer identification at beginning of cycle Read & verified by initialing at end of cycle If not correct, do not release load

Chemical Indicators ANSI/AAMI/ISO :2005 /(R)2010 (Mfrs. Standard) ANSI/AAMI ST79:2010 & A1:2010 & A2:2011 & A3:2012 & A4:2013, Section Class 1 Process Indicators Class 2 Indicators for use in Specific Tests Class 3 Single Variable Indicators Class 4 Multi-variable Indicators Class 5 Integrating Indicators Class 6 Emulating Indicators

Class 1 Chemical Indicators ANSI/AAMI/ISO :2005 /(R)2010 (Mfrs. Standard) ANSI/AAMI ST79:2010 & A1:2010 & A2:2011 & A3:2012 & A4:2013, Section Process Indicators Use with individual units to indicate that the unit has been directly exposed to the sterilization process Exposure Control/External CIs Distinguish between processed and unprocessed units Designed to react to one or more of the critical process variables

Class 2 Chemical Indicators Indicators for Specific Tests Equipment Control Testing sterilizer performance Bowie-Dick Test monitors efficacy of air removal and steam penetration in ºF ( º C) dynamic-air removal sterilizers (i.e., vacuum-assisted sterilizers) ANSI/AAMI ST79:2010 & A1:2010 & A2:2011 & A3:2012 & A4:2013, Section ,10.7.6

Class 2 Chemical Indicators ANSI/AAMI ST79:2010 & A1:2010 & A2:2011 & A3:2012 & A4:2013, Section Bowie-Dick tests can detect: Air leaks Inadequate air removal Inadequate steam penetration Presence of non-condensable gases: air or gases from boiler additives Used for routine daily testing and qualification testing

ANSI/AAMI ST79:2010 & A1:2010 & A2:2011 & A3:2012 & A4:2013, Sections and Uniform color change If not uniform, shut down and report to supervisor Remain in use Retest Call for repair Re-qualify if major repair Class 2 Chemical Indicators Bowie-Dick Test

Class 5 Chemical Indicators Integrating Indicators (Internal CIs, Load Control) Designed to react to all critical variables Stated values equivalent to the performance requirements for BIs (ISO series) ANSI/AAMI ST79:2010 & A1:2010 & A2:2011 & A3:2012 & A4:2013, Section

Monitoring of Sterilizers l Use physical, chemical and biological monitors to ensure the effectiveness of the sterilization process l Each load should be monitored with physical and chemical indicators. If the physical, chemical or biological indicators suggest inadequate processing, the items should not be used l Biological indicators should be used at least weekly (in CP at least daily, sometimes every load) with spores intended specifically for the type of sterilizer

Monitoring of Sterilizers l Internal Chemical Indicator Validates the sterilant penetrated the pack or tray Advantage of the pack control monitor is that it is inside each pack in multiple locations Detect local problem

Biological Monitors l Steam - Bacillus stearothermophilus l Dry heat - B. subtilis l ETO - B. subtilis l New low temperature sterilization technologies Plasma sterilization (Sterrad) - B. stearothermophilus Peracetic acid - B. stearothermophilus

Process Challenge Device (PCD) “ A PCD is a device used to assess the effective performance of a sterilization process by providing a challenge to the process that is equal or greater than the challenge posed by the most difficult item routinely processed. ” PCD may be: User-assembled test pack Commercially available, FDA cleared preassembled test pack ST41 describes two types of PCDs Routine BI test pack Challenge BI test pack

Rapid Readout BIs for Steam Now Require a 1- 3h Readout Compared to 24-48h

Super Rapid Readout Biological Indicators Commercially available in early BI (blue cap) Monitors 270°F and 275°F gravity –displacement steam sterilization cycles 30 minute result (from 1 hour) 1492V BI (brown cap) Monitors 270°F and 275°F dynamic- air-removal (pre-vacuum) steam sterilization cycles 1 hour result (from 3 hours)

Recommendations Monitoring of Sterilizers l Following a single positive biological indicator used with a method other than steam, treat as non-sterile all items that have been processed in that sterilizer, dating back to last negative biological indicator. These non-sterile items should be retrieved, if possible, and reprocessed.

Storage l Time-related shelf life-safe storage times for sterile packs vary with the porosity of the wrapper and storage conditions (e.g., 1 year, plastic wrapped pack) l Event-related shelf life-product remains sterile until some event causes the item to become contaminated (e.g., tear in packaging, packaging become wet) l Closed or covered cabinets are ideal but open shelving may be used for storage

Storage of Sterile Items l Event-related shelf life recognizes that the product remains sterile until an event causes it to become contaminated (e.g., tear, wetness). Packages should be evaluated before use for lose of integrity. l Time-related shelf life (less common) considers items remain sterile for varying periods depending on the type of material used to wrap the item/tray. Once the expiration date is exceeded the pack should be reprocessed.

Storage of Sterile Items l Sterile storage area should be well-ventilated area that provides protection against dust, moisture, and temperature and humidity extremes. l Sterile items should be stored so that packaging is not compromised l Sterilized items should be labeled with a load number that indicates the sterilizer used, the cycle or load number, the date of sterilization, and the expiration date (if applicable)

Quality Control l Provide comprehensive and intensive training for all staff assigned to reprocess medical/surgical instruments l To achieve and maintain competency, staff should: hands-on training all work supervised until competency is documented competency testing should be conducted at commencement of employment and regularly review written reprocessing instructions to ensure compliance

Immediate Use Steam Sterilization Issues Over-used…intended for immediate use only

Immediate Use Steam Sterilization l “Flash” originally defined as sterilization of an unwrapped object at 132 o C for 3 min at lbs pressure in gravity l “Flash” used for items that must be used immediately and cannot be packaged, sterilized and stored before use l “Flash” is an antiquated term and replaced by “immediate use steam sterilization” l The same critical reprocessing steps (such as cleaning, decontaminating, and transporting) must be followed

Immediate Use Steam Sterilization l “Immediate Use” is defined as the shortest possible time between a sterilized item’s removal from sterilizer and aseptic transfer to sterile field l A sterilized item intended for immediate use is not stored for future use. l Sterilization process monitoring is essential l Instruments inventories should be adequate to meet surgical volumes and permit the time to complete all critical elements of reprocessing

Sterilization Practices in Healthcare Facilities l Overview l Physical facilities l Cleaning, Packaging, Loading, Storage l Monitoring

Conclusions l All sterilization processes effective in killing spores l Cleaning removes salts and proteins and must precede sterilization l Delivery of sterile products for use in patient care depends not only on the effectiveness of the sterilization process but also on cleaning, disassembling and packaging of the device, loading the sterilizer, and monitoring