There are many steps involved with the preparation of sterile surgical instruments. All of these steps must be performed correctly to ensure a safe product for the patient. When shortcuts are taken, a failure in the process can result. Moreover, this failure may not be identified by a biological indicator, chemical indicator or sterilizer printout. To truly understand the ramifications of the entire process, this paper will address the major factors of cleaning, packaging and sterilizing surgical instruments.
One of the complications of inadequate or improper processing of instruments is Toxic Anterior Segment Syndrome (TASS). TASS is a rare complication of eye surgery which can have devastating effects.1 It occurs when a non-infectious agent enters the anterior chamber of the eye and causes an inflammatory reaction. This inflammatory response may lead to severe visual impairment if it is not recognized and treated in a timely manner. While usually associated with cataract surgery, TASS can occur after any type of anterior segment surgery.
There are many causes of TASS. Cleaning agent residues, endotoxins, denatured ophthalmic viscoelastic devices (OVDs), preservatives, and residues from sterilization processing can all induce TASS and cause severe damage to ocular tissue.2 Particular care must be taken in the processing of intraocular surgical instruments to help ensure that foreign substances or materials associated with the instruments will not be introduced into the anterior chamber of the eye during surgery.
Outbreaks of TASS have been linked to the failure to follow the processing procedures recommended by the instrument manufacturer. Specific instrument cleaning and sterilization recommendations intended to diminish the risk of TASS associated with intraocular surgical instruments have been compiled by a multidisciplinary panel including healthcare professionals and representatives of various professional societies and regulatory agencies and published by the American Society of Cataract and Refractive Surgery (ASCRS, 2006).3 These recommendations include:
An adequate inventory of the necessary intraocular surgical instruments should be maintained in order to allow for the timely processing of instruments between cases.
Adequate time must be allowed for processing instruments according to the manufacturer’s instructions; otherwise, the cleaning and sterilization of the instruments will be ineffective.
A designated cleaning area and equipment specific to the cleaning of intraocular surgical instruments should be identified.
Whenever possible, intraocular surgical instruments should be processed separately from general surgical instruments and equipment in order to reduce the potential for cross-contamination by material or residue from the general surgical instruments.
Instruments should be pre-cleaned immediately following use.
Gross debris should be removed, and instrument lumens should be flushed with sterile distilled water or another suitable agent as recommended by the manufacturer.
Use only those cleaning agents that have been recommended by the manufacturer.
Particular attention should be paid to the specified concentration of cleaning agent and to the recommended water quality.
Final rinsing of the instrument should be performed with sterile, distilled, or deionized water, unless otherwise specified by the manufacturer.
The water used to clean or rinse instruments should be discarded after each use.
If an ultrasonic cleaner is used to process the instruments, it should be emptied, cleaned, rinsed, and dried at least daily or, preferably, after each use.
Brushes and other cleaning tools should be cleaned and sterilized as recommended by the manufacturer at least daily or, preferably, after each use.
Cleaning and sterilization equipment should be properly maintained. Otherwise, foreign materials such as endotoxins or heavy metals may be deposited onto the instruments during processing and induce TASS.
The Association for the Advancement of Medical Instrumentation (AAMI) develops consensus documents regarding the cleaning, disinfection and sterilization procedures of surgical instruments employed in healthcare facilities. There are several AAMI standards that are relevant:
ST-79, comprehensive guide to steam sterilization and sterility assurance in health care facilities (2006).
ST-58, chemical sterilization and high level disinfection in healthcare facilities (2005).
ST81, sterilization of medical devices. (Information to be provided by the manufacturer for the processing of resterilizable medical devices).
AAMI is also developing a guidance document regarding the quality of water for cleaning, rinsing and steam sterilization.
As consensus documents, AAMI documents are based on input from governmental agencies such as the Food and Drug Administration (FDA), Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) as well as professional organizations including the Association of periOperative Registered Nurses (AORN) and the Association for Professionals in Infection Control and Epidemiology (APIC), plus manufacturers and practitioners. AORN publishes recommended practices for decontamination, packaging and sterilization, among other topics.
Training and Policies
It is recommended that policies and procedures be developed, in-serviced and implemented for all cleaning, packaging and sterilization processes. The policies and procedures should be based upon accepted standards of practice established by AAMI, AORN and ASCRS.
All personnel performing cleaning, disinfection or sterilization activities should be trained and their competency verified. Training should be documented. All processing personnel should be certified in sterile processing within two years of employment.4 The training should focus on core competencies with return demonstrations for all activities. Unfortunately, training frequently is allowed to lapse due to time and resource constraints.
Cleaning is the removal—usually with cleaning agent and water—of adherent visible soil (i.e., blood, pus, tissue, etc.) from the surfaces, crevices, serrations, jaws and lumens of instruments, devices and equipment, by a manual or mechanical process that prepares the items for safe handling and/or further decontamination.5
The Occupational Health and Safety Administration (OSHA) defines decontamination as the "act or process by which contaminated items are rendered safe for handling by personnel who are not wearing protective attire." Decontamination is the first and most critical step in breaking the chain of disease transmission and cleaning is the first step in the decontamination process.6
Why is cleaning important? The process of disinfection or sterilization is dependent upon direct contact of the sterilant or disinfectant with the surface of the items to be sterilized. Soils (e.g., blood, mucous, tissue) left on items can be "baked on" during sterilization. Sterilization is a multi-step process and proper cleaning is the first step in that process.
Ineffective cleaning may result in endotoxin accumulation. Endotoxins are potentially toxic, natural compounds commonly associated with pathogens such as bacteria. Classically, an endotoxin is a structural component of the bacteria which is released mainly when bacteria are lysed. Endotoxins are part of the outer membrane of the cell wall of gram-negative bacteria. Although the term "endotoxin" is occasionally used to refer to any cell-associated bacterial toxin, it is usually associated with the outer membrane of gram-negative bacteria such as E. coli, Salmonella, Shigella, Pseudomonas, Neisseria, Haemophilus, and other significant pathogens. Endotoxins account for an estimated 99 percent of the pyrogens found on the surface of medical devices; they are not completely destroyed with sterilization.
All instrument and device manufacturers are required to provide end users with written instructions for cleaning and sterilization based upon their testing and validated cleaning and sterilization methods (AAMI ST81).9-10 It is incumbent upon the end user to follow these instructions each and every time. This is especially relevant in specialty devices which, due to material composition or design of the device, may require a particular water quality (e.g., distilled) cleaning chemicals, cleaning implements, preparation (e.g., lubrication, disassembly) and special sterilization cycles. It is vital to patient safety that this information is obtained and the manufacturer’s instructions for cleaning and sterilization followed.
Biofilms are produced by microorganisms and consist of a sticky structure of organic contaminants. They create a slime layer which can be anchored firmly to a surface and provides a protective environment for microorganisms to grow. Generally biofilms form on any surface that is exposed to non-sterile water or other liquids and is consistently found in many environments including industrial and medical systems. AAMI recommends the use of a towel moistened with water or foam, spray or gel product specifically intended for this use when instruments need to be soaked for a prolonged period of time.11
Prions are the infectious agent that causes Creutzfeldt-Jakob disease (CJD). CJD is a progressive neurological disease with a very low incidence (1 in 1 million). However, prions are difficult to kill and are resistant to virtually every known disinfection and sterilization method.12 The World Health Organization (WHO) has identified eye tissue as high risk tissue for contamination with prions from individuals infected with the disease. Identification of high risk patients is difficult because of the long incubation period associated with CJD. Furthermore, flash sterilization is contraindicated for decontamination or sterilization of prion-contaminated devices.13 Where instruments are suspected of being contaminated with prions they should be quarantined and the procedures recommended by the AAMI (ST79), the CDC, WHO, and your institution’s policies followed as appropriate.
All used supplies and equipment are considered contaminated. The soiled instruments and devices should be collected and transported to the soiled utility or decontamination area in a manner that minimizes potential contamination of staff, patients or the environment.
The area in which soiled instruments are cleaned should be physically separated from other areas in the facility. It should be an enclosed area and accessible from an outside corridor if applicable. The room requires negative air pressure with 10 air exchanges per hour, per AAMI. The floors, walls and worktables should have washable surfaces. The recommended temperature is 60 degrees Fahrenheit to 65 degrees Fahrenheit (15 degrees Celsius to 18 degrees Celsius) according to AAMI.14
Steps in the Cleaning Process
The following steps are recommended:
Pre-clean devices by flushing lumens and immersing instruments in sterile distilled water immediately following use.
Contain contaminated items at the point of use
Transport to the decontamination area
It is recommended to wipe gross soil and debris from instruments throughout the surgical procedure. This will facilitate cleaning. All items should be contained for transportation to the decontamination area to ensure protection of patients and personnel
When decontamination activities are performed personnel must don personal protective equipment (PPE) to include:
Impervious gown with sleeves
Shoe covers (if shoes will be exposed to fluids containing body fluids)
High-filtration mask (needed when lumened devices are being cleaned)
The Cleaning Process
Soaking is important to loosen adherent soils. The use of cleaning agents may assist in the loosening of soils to facilitate removal.
Water quality can affect the efficacy of the cleaning process. Water used for cleaning can contain rust, minerals and other components which can interfere with the action of cleaning agents. It is important to have your water tested at least annually. This service may be provided as a value-added service by the cleaning agent or washing equipment manufacturer.
Cleaning Agent Selection
Follow the recommendation of the instrument manufacturer regarding the appropriate use of cleaning agents. No single cleaning agent will remove all types of soil, or is safe to use with all types of reusable devices. Many facilities use a neutral-pH cleaning agent for cleaning and soaking surgical instruments. Liquids are preferred since they mix easier than powders. However, it is essential that cleaning agents be used according to the cleaning agent manufacturer’s instructions for use including:
Maximum water temperature
The recommendations of the instrument manufacturer should also be consulted regarding the use of enzymatic cleaning agents. It is important to measure the quantity of the cleaning agent as well as the water it will be placed into so the concentration is correct. Too little or too much cleaning agent can impact effective cleaning. Each cleaning agent has its own recommended soak time, from seconds to minutes. Read the label for proper use. Some cleaning agents are inactivated by temperatures above 140 degrees Fahrenheit (60 degrees Celsius). Therefore it is important to monitor the water temperature to make sure the water temperature does not exceed the range recommended by the cleaning agent manufacturer.
Principles of Cleaning
To ensure effective cleaning, all items must be in the open position. If possible, multi-part items should be disassembled. Handle all instruments carefully to prevent damage. When using an ultrasonic cleaner it is important to keep different metal types separated (i.e., stainless steel with non-anodized aluminum, brass, copper, chrome plating). Electrolysis can occur in wet, hot chambers of ultrasonic cleaners which can cause one metal plating to transfer to another metal.
Many manufacturers of eye instruments recommend manual cleaning. The instruments should be submerged and disassembled. It is preferable to use a three-sink (or three-basin) method: wash, rinse, final rinse. If basins are used, they should be drained and cleaned on a frequent basis according to the instrument manufacturer’s directions.
Manual Cleaning Implements
A variety of soft bristle brushes, various sizes and lengths dedicated for use in cleaning surgical ophthalmic instruments only are needed. It may also be permissible to use soft cloths depending on the instrument manufacturer’s instructions for cleaning. However, abrasive items (e.g., wire brushes) sponges/surgeons scrub brushes or materials which are permeable—such as wood—should not be used.
Ultrasonic cleaning is an effective cleaning process. Ultrasonic machines use sound waves transmitted through a solution. The sound waves produce tiny bubbles which implode, resulting in a scouring action that cleans; this mechanical process is called cavitation. Ultrasonic cleaning is effective to remove soils in hard-to-reach areas (box locks, mouth teeth, etc.) All gross soil should be removed from instruments prior to placing in the ultrasonic cleaner. Generally, it is recommended to use cleaning agents specifically formulated for ultrasonic cleaners which are low foaming. The water temperature inside the chamber may reach as high as 100 degrees Fahrenheit to 140 degrees Fahrenheit (37.8 degrees Celsius to 60 degrees Celsius) depending on the model of ultrasonic cleaner used. The solution should be changed frequently (e.g. every two hours) based upon the volume of instruments being cleaned. The unit should be emptied, cleaned, rinsed, and dried on at least a daily basis. At least one reported TASS incident was related to Klebsiella contamination of an ultrasonic cleaner. "The bacteria were killed during the sterilization process but a heat-stable endotoxin remained on the instruments causing the outbreak."15
The ultrasonic cleaning unit should have a cover to contain aerosols. Instrument sets should not be stacked. Each time the water is changed in the unit, the water needs to be "de-gassed." This requires running a cycle with just the metal basket (no instruments) inside.
Sonic cleaners should be routinely tested for efficacy. This can be performed using a piece of heavy-duty household aluminum foil which is placed in the metal basket and run through a cycle. The size of the piece of foil should be equal to the length and width of the chamber (e.g., 9 inches by 5 inches). At the end of the cycle, remove and inspect the foil. There should be large holes and numerous creases in the foil. There are also commercial products on the market to test the efficacy of the sonic cleaner. All testing should be documented. If the unit fails the test, the unit requires service. Following testing the unit should be emptied, cleaned, rinsed, and dried before refilling the unit and processing instruments.
Rinsing is the most important part of the cleaning process. Rinsing removes the debris loosened with manual and/or ultrasonic cleaning and residual cleaning agent. Sterile deionized/distilled water is preferred for the final rinse to prevent mineral deposits and reduce the potential for pyrogens. The water should not be reused. Follow the instrument manufacturer’s recommendations regarding the volume and quality of rinse water, water temperature, and number of rinses.
Items with Lumens
Items with internal passageways require special cleaning. The instrument manufacturer’s recommendations must be closely followed with regard to the cleaning of lumens and internal passageways. It is essential to have the proper size brushes to create friction inside the lumen for cleaning. Rinse thoroughly after cleaning.
Preparation of Devices for Sterilization
There are many choices in packaging materials today. The following packaging materials are available today for steam sterilization:
Cloth: minimum 140 threads per square inch (may not be suitable for all applications)
Polyolefin (plastic based)
When evaluating packaging materials, obtain the packaging manufacturer’s technical data verifying the material has been tested and validated for the sterilization methodology being used. Always follow the packaging manufacturer’s written instructions for use.
Single-ply or double-ply non-woven disposable wrapping material is preferred. Woven textiles generate lint and require ongoing maintenance (inspection, delinting, patching of defects, etc.). Since most eye instrument sets are small and relatively light weight, heavier weights of wrappers are not needed. Some wraps, (e.g., crepe paper) are more difficult to dry. An evaluation of the packaging material is recommended to determine the best result for your facility.
Paper/plastic pouches are often used for packaging. They should only be used for single, light-weight items17 to prevent damage to the seals during the sterilization process. They are not intended for trays or heavy items. Use the correct size pouch; there should be approximately one inch of space around the device. Paper/plastic pouches should not be placed inside wrapped sets or rigid containers.18 The use of tip protectors is recommended to protect instruments and prevent damage to the packaging materials. If tip protectors are used, obtain the manufacturer’s technical data verifying sterilant penetration in the selected sterilization methodology.
All items should be prepared according to the device manufacturer’s written instructions. Instruments and devices must be checked for cleanliness, functionality and completeness.19 All instruments should be in the open position. Stringers should be used to keep ring handles instruments in the open position so that the steam can make full contact with the jaws or blades of the instrument. Use perforated or mesh-bottom trays to facilitate condensate removal. It is permissible to use an absorbent, non-linting towel in bottom of tray to facilitate drying. Lumened items should be flushed with sterile distilled water immediately before steam sterilization.20
The use of silicone mats to protect or separate instruments may increase moisture inside the set and require extended drying times.21
When labeling packages, only indelible non-toxic markers should be used.22 Writing should not be performed on the packaging material; only on autoclave tape or on the clear side of paper/plastic pouches. 23
The usual method of sterilization for eye instruments is steam under pressure. It is inexpensive, convenient, non-toxic and easy to use. Tabletop steam sterilizers with chambers less than 2 cubic feet capacity are used in smaller facilities where the volume of processing is lower. Larger steam sterilizers are usually found in larger or multi-specialty facilities where the demand is higher.
When selecting a sterilizer, evaluate the chamber capacity. How many sets or packages can be sterilized in one cycle? Many chambers only permit sterilization of one set at a time. The type and chamber size of the sterilizer will also impact on the tray or basket used for the set. Since solid bottom trays must be tilted on their side24 for sterilization (to permit condensate removal), the dimensions of the tray may not permit this, which can result in wet sets. Review the user’s manual to identify the various validated cycles for the sterilizer. Can you process all the devices/instruments within those specified parameters? Make certain the manufacturer’s instructions for loading the sterilizer are carefully followed. Overloading a sterilizer can result in a sterilization failure.
Drying can be affected by the configuration of the set, how the sterilizer is loaded, and the packaging materials. Most tabletop sterilizers require that the door to the sterilizer be opened at the end of the cycle, when the drying phase is initiated. Follow the sterilizer manufacturers’ instructions carefully.
AAMI and AORN recommend that all sterilization cycles be monitored:
Mechanically: by reviewing the printout or chart at the end of each cycle.
Chemically: by placing a chemical indicator inside and outside each package to be sterilized.
Biologically: using biological indicators (spore tests) at least weekly.
Many tabletop sterilizers do not come equipped with a printout, however, this can be added as an additional feature. It is recommended to have a printout to verify that all cycle parameters were met for each cycle processed.
All items processed in each load should be documented on a log form. Each item processed in each load/cycle should be identified with a lot control number consisting of the date of sterilization, sterilizer number and cycle number. This information would then be used to track devices in the event of a sterilizer malfunction. Sterilization records should be retained for a period as recommended by the facility’s legal advisor but no less than one year.
Wrapped vs. Flash
AORN does not support flash sterilization as a substitute for sufficient instrument inventory.25 Wrapped sterilization provides sterility protection for the instruments until the instruments are used. It is the preferred method for sterile devices.
Unwrapped (flash) sterilization is performed without packaging. At the end of the cycle the instruments are still wet. Moisture acts as a vehicle to attract contaminates in the air onto the device. The two major issues with flash sterilization are sufficient time to perform the recommended cleaning and transfer of the device after sterilization to prevent re-contamination. While there are flash sterilization containers which protect the instruments from the flash sterilizer to the point of use, the issue of proper cleaning is still problematic. When an item is needed quickly and flash sterilization is performed, the part of the process that usually suffers is the cleaning. This can lead to complications, as noted previously.
In some facilities, the first patient of the day receives a terminally sterilized (wrapped) set of instruments and all other patients thereafter receive flash sterilized instruments. This is not providing the same standard of care to all patients. Unless there was a documented emergency requiring flash sterilization for the to-follow patients, there is no justification for routine flash sterilization of instrumentation.26 Regulatory and accrediting organizations are focusing on flash sterilization because of its implications for patient safety. It is recommended that a flash log form be used and all flash cycles be documented along with the reason for the flash cycle. This information will facilitate identification of needed additional instrumentation.
Audits and monitoring of all phases of the sterilization process should be routinely performed. Any non-compliance with stated policies should be documented with the corrective action taken. Corrective action may include re-training or rein-servicing.
Patient safety in surgical instrument processing is an essential component of the process. Every procedure should be developed with patient safety in mind. There are many steps in the sterilization process and all must be followed in order for successful sterilization to be accomplished. Shortcuts or deviations from stated policies can not only impact patient safety but also be a liability for the facility. All patients deserve quality medical care with correctly processed devices. It is the responsibility of each facility performing these functions to develop policies and procedures to ensure successful patient outcomes and to monitor compliance with stated protocols.
Nancy Chobin, RN, AAS, ACSP, CSPDM is the corporate consultant/educator for the Saint Barnabas Health Care System in West Orange, N.J. She is a member of AAMI, AORN and IASHCMM. She also serves as the volunteer executive director of the Certification Board for Sterile Processing & Distribution, Inc. of Alpha, N.J.
1. Johnston J. Toxic anterior segment syndrome—more than sterility meets the eye. AORN J. December 2006.
2. American Society of Cataract and Refractive Surgeons. TASS Outbreak—Final Report. Sept. 22, 2006.
3. American Society of Cataract and Refractive Surgery. Recommended Practices for Cleaning and Sterilizing Intraocular Surgical Instruments. February 2007.
4. Association for the Advancement of Medical Instrumentation. Comprehensive Guide to Steam Sterilization and Sterility Assurance in Health Care Facilities, ST-79, 2006.
5. Sterile Processing University, LLC. The Basics of Sterile Processing. First Edition. Chapter 5. 2006.
6. Sterile Processing University, LLC. The Basics of Sterile Processing. First Edition. Chapter 5. 2006.
7. Wikipedia accessed via Internet Aug. 6, 2007.
8. Davis BL and Mamalis N. Averting TASS. Cataract & Refractive Surgery Today. www.crstodayarchive.com. Accessed Aug. 4, 2007.
9. Association of periOperative Registered Nurses. Recommended practices for sterilization in the perioperative setting. In: Association of periOperative Registered Nurses. Standards, Recommended Practices and Guidelines, Denver. AORN, 2007: 637-687.
10. Association of periOperative Registered Nurses. Recommended practice cleaning and caring for surgical instrumentation and powered equipment. In: Association of periOperative Registered Nurses. Standards, Recommended Practices and Guidelines. Denver. AORN, 2006: 555-563.
11. Sterile Processing University, LLC. The Basics of Sterile Processing. First Edition. Chapter 5. 2006.
12. Sterile Processing University, LLC. The Basics of Sterile Processing. Chapters 3, 5, 8. First Edition. 2006.
13. Rutula W. and Weber D. CJD — Recommendations for Disinfection and Sterilization. Clin Infect Diseases. Vol. 32, 2001, pgs. 1348-1356.
14. Association for the Advancement of Medical Instrumentation. Comprehensive Guide to Steam Sterilization and Sterility Assurance in Health Care Facilities, ST-79, 2006.
15. Davis BL and Mamalis N. Averting TASS. Cataract & Refractive Surgery Today. www.crstodayarchive.com. Accessed August 4, 2007.
16. Eames, WB, Byrington, SQ and Sunway, NB. A Comparison of Eight US Cleaners of Dental Instruments. American Journal of Dentistry, 1995, June 8 (3), 152-6. Also see: Australian Standards (AS2773). Ultrasonic Cleaners for Health Care Facilities, Standards Association of Australia, 1999.
17. Sterile Processing University, LLC. The Basics of Sterile Processing. Chapter 7. First Edition. 2006. Also see: Association for the Advancement of Medical Instrumentation. Comprehensive Guide to Steam Sterilization and Sterility Assurance in Health Care Facilities, ST-79, 2006.
18. Association of periOperative Registered Nurses. Recommended Practices for Packaging. In: Association of periOperative Registered Nurses. Standards, Recommended Practices and Guidelines, Denver. AORN, 2007.
19. Sterile Processing University, LLC. The Basics of Sterile Processing. Chapter 7. First Edition. 2006.
20. Association for the Advancement of Medical Instrumentation. Comprehensive Guide to Steam Sterilization and Sterility Assurance in Health Care Facilities, ST-79, 2006.
21. Association of periOperative Registered Nurses. Recommended Practices for Packaging. In. Association of periOperative Registered Nurses. Standards, Recommended Practices and Guidelines, Denver. AORN, 2007.
22. Sterile Processing University, LLC. The Basics of Sterile Processing. Chapter 7. First Edition. 2006. See also: Association for the Advancement of Medical Instrumentation. Comprehensive Guide to Steam Sterilization and Sterility Assurance in Health Care Facilities, ST-79, 2006.
23. Sterile Processing University, LLC. The Basics of Sterile Processing. Chapter 7. First Edition. 2006.
24. Sterile Processing University, LLC. The Basics of Sterile Processing. Chapter 7. First Edition. 2006. Association for the Advancement of Medical Instrumentation. Comprehensive Guide to Steam Sterilization and Sterility Assurance in Health Care Facilities, ST-79, 2006. See also: Association of periOperative Registered Nurses. Recommended Practices for Packaging. In: Association of periOperative Registered Nurses. Standards, Recommended Practices and Guidelines, Denver. AORN, 2007.
25. Association of periOperative Registered Nurses. Recommended Practices for Sterilization in the perioperative setting. In: Association of periOperative Registered Nurses. Standards, Recommended Practices and Guidelines, Denver. AORN, 2007: 637-687.
26. Chobin N and Trattler B. Is routine flash sterilization best practices?" Manag Infect Control. August 2003.