UNIT Two. Lesson 1C Sterilization

Transcription

1 _ Introduction UNIT Two Lesson 1C Sterilization Pathogenic microorganisms are capable of causing disease when they invade human tissue. Every effort must be made to remove microorganisms from equipment and instruments that contact human tissue during surgical intervention. Sterilization and disinfection, the cornerstones of infection control, are two processes used to destroy microorganisms. Therefore, the perioperative nurse must have an in-depth understanding of the principles and practices of sterilization and disinfection to prevent the transmission of infection. Learning Outcomes 1. Identify the key terms used in disinfection and sterilization. 2. Identify the classification categories that determine whether an item will be sterilized or disinfected. 3. Outline the four steps to cleaning that occur during the decontamination process. 4. Describe the methods used to accomplish disinfection, specifically high-level, intermediate-level, and low-level disinfection. 5. Describe the methods used to accomplish sterilization, specifically thermal and chemical sterilization. 6. Identify the hazards associated with sterilization and disinfection processes. 7. Outline appropriate uses of immediate-use steam sterilization. 8. Compare and contrast gravity and high-vacuum sterilizers. 9. Identify the methods commonly used for monitoring sterilization processes. 10. Identify the factors which determine event-related sterility. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 1

2 _ Required Readings Operating Room Nurses Association of Canada. (2013). ORNAC Standards for Perioperative Registered Nurses (11th ed.). Canada: Author. Instrument Management and Reprocessing, Section 2, Rothrock, J. C. (Ed.). (2015). Alexander's care of the patient in surgery (15th ed.). Toronto: Mosby. Sterilization, page Required Video AORN (2010). Sterilization in the Perioperative Setting [31 min]. AORN: Copyright: Cine - Med Inc. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 2

3 _ Definitions Decontamination literally means to remove contamination. It is any physical or chemical process that removes or reduces the number of microorganisms or infectious agents. In the perioperative setting it has two meanings: o to render an object safe for handling by removing infectious material by using a chemical or physical agent, and o to clean an object as the first step leading to disinfection or sterilization (Phillips, 2013). Failure to remove foreign matter (e.g. blood, soils, lubricants, etc.) from an object before a disinfection or sterilization process is likely to render the process ineffective. Disinfection is a process that kills many or all living microorganisms, with the exception of bacterial spores from inanimate objects (Rothrock, 2015). This is generally accomplished by the use of chemicals or physical process. High-level disinfection can be expected to destroy all microorganisms (bacteria, viruses, and fungi), except high numbers of bacterial spores (Phillips, 2013). Intermediate disinfection inactivates vegetative bacteria, including m. tuberculosis, including most fungi and viruses but does not kill bacterial spores (Phillips, 2013). Low-level disinfection can kill most bacteria, some viruses, and some fungi, but it cannot be relied on to kill resistant microorganisms such as m. tuberculosis or bacterial spores (Phillips, 2013). A germicide is an agent that destroys microorganisms, particularly pathogenic organisms. Other agents designated by words with the suffix cide (e.g. virucide, fungicide, bactericide, sporicide, tuberculocide) destroy the microorganisms identified by the prefix. For example, a bactericide is an agent that kills bacteria. Chemicals used for the purpose of destroying all forms of microbial life, including fungal and bacterial spores, are called chemical sterilants. A microorganism is a living organism so small in size that they are only visible by aid of a microscope i.e. bacteria, virus, yeast, fungi, etc. A spore is the inactive or dormant viable state of a microorganism. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 3

4 _ Sterilization is a process that kills all living microorganisms including spores. It is accomplished by either a physical or chemical process. Some examples of sterilizing agents are steam, ethylene oxide, etc. Categories of Items Relevant to Risk of Infection Categories of Items Relevant to Risk of Infection may also be referred to as Spaulding s Classification of Patient Care Items. Spaulding s system was developed more than 30 years ago and was later adopted and modified by the CDC to determine whether an item must be sterilized or disinfected. This classification divides instruments and items for client care into three categories according to the degree of risk of infection involved in the use of the items (Phillips, 2013). The three categories of items are critical, semi-critical, and non-critical (Rothrock, 2015). Items in the critical category present a high risk of infection if contaminated with any microorganism. It is crucial the items entering sterile tissue or the vascular system be sterile. This category includes surgical instruments, cardiac and urinary catheters, implants, and needles. Most of the items in this category should be purchased sterile or be sterilized by steam if possible. If heat labile, the item may be treated with ethylene oxide (EO) or sterilization processes such as 2% glutaraldehyde-based formulations and peracetic acid. Semi-critical items are those items that come in contact with mucous membranes or broken skin. These items must be free of all microorganisms, with the exception of high numbers of bacterial spores. Intact mucous membranes are generally resistant to infection by common bacterial spores but are susceptible to other organisms, such as tubercle bacilli and viruses. Respiratory therapy, anesthesia equipment, and endoscopes are included in this category. These items generally require high-level disinfectant (AORN, 2013). Non-critical items come in contact with intact skin or mucous membranes (ORNAC, 2013). Intact skin acts as an effective barrier to most microorganisms, and sterility is not critical. Examples of non-critical items include bedpans, blood pressure cuffs, bed rails, linens, food utensils, and client furniture. Most non-critical reusable items may be disinfected where they are used and do not need to be transported to a central processing area. There is generally little risk of transmitting infectious agents to patients by means of non-critical items; however, these items could potentially contribute to secondary transmission by contaminating medical equipment that comes in contact with clients. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 4

5 _ Decontamination Decontamination is the process by which chemical or physical agents are used to clean inanimate objects to a level that is safe for handling (Phillips, 2013). This is achieved by two steps: cleaning and disinfection. 1. Cleaning is the first and most important step. If an item is not cleaned properly, it cannot be disinfected or sterilized. There are four steps to cleaning: a. sorting: disposables and sharps are sorted appropriately before entering decontamination. All instruments are opened and taken apart, then sorted according to washing methods. b. soaking: immediately after use, the instruments are soaked in a cleaning agent (e.g., enzymatic foam or solution) or rinsed with water to prevent debris from drying during transport to the decontamination area. c. washing: the mechanical removal of soil which is achieved by hand washing (e.g., power equipment, delicate, etc.) or machine washing (e.g., hemostats) with the aid of chemical agents to render the instruments safe for handling by the SPD personnel. d. rinsing: following washing and before disinfection, the item must be rinsed so any residue or film from detergent is removed. Residue or film can decrease the effectiveness of the disinfectant (Phillips, 2013). Rinsing also removes and soil or debris loosened by the cleaning process. Instruments can be cleaned manually (by hand), ultrasonic cleaner (uses high frequency sound waves), or by washer-sterilizer/washer-decontaminator (water turbulence and high pressure steam). 2. Disinfection is the next step in removing or reducing contamination of a device to a level that is safe to handle. Disinfection is the process of eliminating many or all pathogenic organisms from inanimate objects (Rothrock, 2015). It is not as lethal a process as sterilization because of its inability to kill large populations of microbial spores. Although a large number of disinfectants are used in the heath care setting, only the most common used in the perioperative setting are reviewed in the lesson. Staff that is responsible for cleaning and disinfecting surgical instruments should check the manufacturer s instructions regarding specific concentration, exposure times and indications for use (Rothrock, 2015). These chemicals can only be relied on to produce sterility if adequate cleaning and proper guidelines with regard to organic load, contact time, temperature, and ph are met. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 5

6 _ High Level Disinfectants A. Glutaraldehyde Glutaraldehyde is a high-level chemical disinfectant that is also capable of sterilization (Goodman & Spry, 2014). o High level disinfectant: Glutaraldehyde is an aqueous solution that is acidic and in this state, it is not sporicidal (no ability to kill spores). When the solution is activated by adding alkalizing agents, the solution becomes a high level disinfectant. o Sterilant: If glutaraldehyde (e.g., 2%) is immersed for a period of greater than 10 hours, it becomes a chemical sterilant. However, because of this lengthy immersion time required for sterilization, glutaraldehyde is rarely used as a sterilizing agent (Goodman & Spry, 2014) Used on semi-critical items such as endoscopic equipment, thermometers, and rubber/plastic equipment. Irritating to the eyes, nose and throat when used in poorly ventilated rooms. The solution should be kept covered and used in a well ventilated area (Rothrock, 2015). B. Peracetic Acid (or peroxyacetic acid) Peracetic acid is a high-level chemical disinfectant that is also capable of sterilization. Even in low concentrations (0.001% to 0.2%) it is characterized by a very rapid action against all microorganisms, including bacterial spores (even at low temperatures). Its decomposition products (acetic acid, water, oxygen, hydrogen peroxide) are not harmful to persons or the environment, and leave no residue. It is effective in the presence of organic matter. It is used primarily for flexible endoscopes and their accessories (Goodman & Spry, 2014). Liquid peracetic acid sterilizers are tabletop units (e.g., Steris) that are used to process endoscopes. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 6

7 _ Critical Item: The items to be sterilized are placed in the accompanying tray and the peracetic acid (e.g., 0.2%) circulates throughout the tray to all surfaces, including internal lumens through irrigator adaptors. Once the cycle is complete, the circulator transports the tray to the scrub nurse who removes the items, which are wet, for placement on the sterile field. The cycle usually takes thirty minutes (Goodman & Goodman & Spry, 2014). Sterilized items must be used immediately. The nature of the process permits point-of-use sterilization, but not sterile storage (Goodman & Spry, 2014). Semi Critical Item: If the required item (e.g., endoscope) is not required as a critical item, but rather a semi critical item, after disinfection, the endoscope should be rinsed with sterile water. Tap water should not be used as it may contain organisms such as nontuberculous mycobacteria and legionella. However, in circumstances where use of sterile water is not feasible, a tap water rinse should be followed by an alcohol rinse and forced-air drying (Goodman & Spry, 2014). Forced-air drying significantly reduces bacterial contamination of stored endoscopes. Review: Chemical disinfectants, such as glutaraldehyde and peracetic acid, are dependable high-level disinfectants, but can also be chemical sterilants as well. Thus, high level disinfectants and sterilants are frequently the same material; however, the difference between the two depends on their use. Gluteraldehyde has the ability to kill all classes of microorganisms only with extended exposure times (e.g., greater than 10 hours). Peracetic Acid has the ability to kill all classes of microorganisms within minutes (Phillips, 2013). September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 7

8 _ C. Pasteurization The process of heating a device in water (may or may not contain detergents) to temperatures at ºC and holding the device there for a period of time (usually 30 minutes), depending on the temperature (Phillips, 2013). This pasteurization process is suitable for semi critical items - respiratory therapy devices, anesthesia masks, and tubing that do not directly penetrate deep into the airway. Since the process involves nothing but heated water, no rinsing is necessary. Items must be dried before storage in a manner that will not contaminate them. Forced-air-heated cabinets are available for this purpose (AORN, 2013). Intermediate-level Disinfectants Alcohol % Bactericidal, pseudomonacidal, and fungicidal in 10 min. total immersion. 15 min. exposure for HIV and HBV and requires 15 min. immersion time to be tuberculocide Virucide, good for housekeeping Not sporicidal Can disinfect semi critical instruments (e.g., thermometer) Flammable Low-level Disinfectants Quaternary Ammonium Compounds or QUATS Disinfecting of non-critical patient care equipment and environmental decontamination. Chlorine An inorganic chlorine solution is used for spot disinfection of countertops and floors. Virucide Example - bleach September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 8

9 _ Safety Alert! Safety is of the utmost importance and consistent practice must be maintained to protect you and others from the dangers of the chemicals used in the cleaning, disinfection, and sterilization processes. Routine Practices must be practiced at all times. Eye protection, gowns, protective gloves and/or moisture resistant masks/face shields should be worn to prevent contact with splashes during the cleaning procedure and disinfection/sterilization process. All manufacturers instructions and WHMIS guidelines must be followed. Inspection and Assembly of Instruments Once the instruments are rendered safe for handling by health care staff (e.g., SPD staff), they are inspected for soil, stains, corrosion, proper function, and structural soundness (Fuller, 2013). Instruments are inspected carefully for precision (e.g., tips are meeting properly), sharpness, and functionality (Fuller, 2013). Once the instruments have passed inspection they are ready for assembly. Usually the instruments are compared with computerized lists which maintain correct manufacturers number, number of particular instrument on set, arrangement, instructions for sterilization, etc. Assembly may include any of the following: Wrapper(s) (e.g., fabric or nonwoven) Peel pouch/pack wrapper (usually lightweight or single items) Rigid closed container (e.g., Genesis container) September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 9

10 _ Sterilization Once the item is wrapped (according to manufacturer s instructions), a sterilization method is chosen depending on the nature of the item to be sterilized. The enormous variety and amount of instruments used in the perioperative environment does not easily fit into a generalized protocol for a single sterilization method. Therefore, there are a number of methods of sterilization. They generally include: 1. Thermal sterilization 2. Chemical sterilization 3. Radiation 4. Dry Heat 5. Ozone The complexity of sterilization methods means that the manufacturer s recommendations must be followed carefully (Rothrock, 2015). The focus of this program will be on thermal and chemical sterilization. 1. Thermal Sterilization A. Steam sterilization- Steam under pressure (moist heat) Most common and reliable sterilization method used within healthcare facilities. It is the most economical, safest, and effective method of sterilization (Goodman & Spry, 2014). Advantages: o It does not produce harmful by-products o Readily available o Economical o Suitable for a wide range of instrumentation o It is fast-destruction of resistant spores occurs quickly (Goodman & Spry, 2014) The three factors necessary to achieve steam sterilization are temperature, time and moisture (saturated steam). Steam must reach a temperature of at least 250 F (121 C) to kill microorganisms and spores. This can only be accomplished if steam is placed under greater than atmospheric pressure in autoclaves. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 10

11 _ Typically a temperature of 270 F (132 C) is used in health care facilities. The time or length of exposure required for steam sterilization is influenced by the type of sterilizer and items to be sterilized (e.g., power equipment is sterilized via a low temperature setting). Generally a steam sterilizing cycle, which includes the conditioning, exposure and exhaust phase takes approximately minutes. Refer to Rothrock (2015) page 95 for information on types of sterilizers used. For example: gravity displacement or prevacuum. Steam sterilization is NOT suitable for all instruments (e.g., endoscopes, some plastic material, etc.). A written record of the sterilizing cycles is kept for quality assurance. Depending on where you work, a chemical indicator or integrator will be used in the instrument trays or other sterilized packages to monitor the parameters for sterilization. These sterilization monitoring devices will be discussed later in the lesson. The steam sterilization process is the function of 3 basic parameters: time, temperature, and the presence of saturated steam. All three are critical for effective steam sterilization. B. Immediate-Use Steam Sterilization (used to be called Flash Steam) Immediate use steam sterilization (IUSS) is a process for sterilizing items that are needed immediately (Goodman & Spry, 2014). Certain conditions must be present before decisions to flash sterilize an item. These include: an urgent need for the item no other sterilization alternative there is no replacement instrument available Work place practices ensure proper decontamination and preparation of the item prior to sterilization. Cleaning is absolutely critical to proper instrument processing. Inadequate cleaning will compromise the sterilization process. Therefore, all staff must be trained properly if attempting to flash sterilize (ORNAC, 2013). The physical layout of the area ensures safe transfer of the item to the sterile field. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 11

12 _ Items that are IUSS should be prepared to allow steam to contact all of the surfaces. A closed container system should be used in IUSS to protect items in transfer (ORNAC, 2013). The item is exposed to the same temperature of 270 F (132 C) at a PSI of 27 for 3-10 minutes depending on the sterilizer. The item will be wet and hot coming out of flash sterilization because there is no drying time (Goodman & Spry, 2014). A record of the sterilization will need to be checked for correct sterilization parameters prior to instrument use and the record needs to be kept for quality assurance. Depending on where you work, a chemical indicator or integrator will be used in the flash pan or tray to monitor the parameters for sterilization. Note: IUSS should not be used for: Routine sterilization of instruments Sterilization of any kind of implant Compensate for inadequate inventory or scheduling problems Complete sets or trays of instruments (ORNAC, 2013). Safety Alert! Advances in technology have led to new materials being used with complex surgical instrumentation which has led to equally complex guidelines/standards to ensure patient safety for immediate use sterilization. Hence, this complexity has required that only appropriately trained personnel shall perform immediate-use steam sterilization (ORNAC, 2013). 2. Chemical Sterilization A. Ethylene Oxide (EO) Gas EO is a toxic gas used to sterilize items that cannot tolerate the temperature and moisture of steam sterilization, such as rigid endoscopes, plastic goods, etc. (Goodman & Spry, 2014). It is dependent on the following parameters: gas concentration, temperature, humidity, and time. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 12

13 _ Advantages of EO: effective against all types of microorganisms non-corrosive (Goodman & Spry, 2014) Disadvantages of EO: lengthy sterilization cycle and lengthy aeration time more expensive than steam sterilization; highly flammable; produces toxic by-products; and vesicant (blistering agent) when it comes in contact with skin and mucous membranes (Phillips, 20013). Personal protection (goggles and specialty gloves) should be used by those coming into contact with EO. Also, proper aeration standards should be followed according to the hospital s policy. B. Liquid Peracetic Acid As discussed in previous section. Peracetic acid circulates through the Steris machine. Results in a just in time sterilized item for immediate use on sterile field. If not for immediate use, then stored unsterile in forced-air drying cabinet (Rothrock, 2015). C. Glutaraldehyde (2% aqueous solution) As discussed in previous section. Sterilization for critical items can be achieved if left immersed in solution for greater than 10 hrs (Goodman & Spry, 2014). D. Hydrogen Peroxide Gas Plasma (aka Sterrad) Suitable for moisture and heat sensitive items (e.g., cameras, endoscopes, etc.) and can be used with most metals and plastics. Quick and safe alternative to ethylene oxide sterilization. Uses a specific concentration of hydrogen peroxide combined with water that is vaporized to produce a reactive gas Total cycle time is 55 minutes and no aeration is needed. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 13

14 _ 3. Radiation (physical) Microwave or X-ray. The choice of method is dependent on the compatibility of the item to be sterilized with the sterilization process, the configuration of the item, the required equipment, the cost, the availability, the safety factors, the packaging of the item, and the length of time of the sterilization process. 4. Dry Heat Dry heat is a form of hot air that is used primarily for powders, oils, and petroleum products that cannot be penetrated by steam or ethylene oxide or other sterilizing agents. Most of these products are supplied sterile from the manufacturer; therefore, dry heat sterilization is rarely used in hospitals today (Goodman & Spry, 2014). September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 14

15 _ Summary Diagram: DISINFECTION 1. High Glutaraldehyde Peracetic Acid Pasteurization 2. Intermediate Alcohol 3. Low QUATS chlorine CATEGORIES OF ITEMS Critical Semi-Critical Non-Critical STERILIZATION 1. Thermal Steam/IUSS 2. Chemical EO Peracetic Acid Glutaraldehyde Hydrogen Peroxide Gas Plasma 3. Radiation 4. Dry Heat STERILIZATION VALIDATION PARAMETERS 1. Physical Indicators 2. Chemical Indicators 3. Biological Indicators September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 15

16 _ Case Study In returning to our case study from the previous lesson, Mrs. Black is having an emergency open appendectomy for a ruptured appendix. Lucy (RN) the circulating nurse is opening sterile supplies to the scrub nurse Matt (LPN) while the patient is still in the ER department. Lucy opens up the genesis rigid container by removing two tamperproof arrows from each end of the container. Lucy then proceeds to remove the cover and steps back from the open sterile contents. Matt comes to the rigid container, and locates and checks the processed chemical indicator inside. Matt then takes the instruments and places them on his back sterile table. Case Analysis Perioperative nurses must be familiar with the various methods for monitoring the sterilization parameters/indicators of the surgical supplies will use. Let s now explore some these indicators commonly seen in the OR. Monitoring Sterilization: Validation Parameters Before an item can be considered sterilized, parameters of time, humidity, pressure, and temperature have to be met (Goodman & Spry, 2014). The following indicators are used to monitor these parameters: Physical Indicators Chemical Indicators Biological Indicators 1. Physical Indicators (also called Mechanical Indicators) are graphs, thermometers, printouts, and gauges that record activities within the chamber during the sterilization cycle (Goodman & Spry, 2014). The physical monitors should be monitored to verify that the intended parameters of time, temperature, and exposure have been met. These are verified by the operator of the equipment and become a permanent record of the sterilization. Below is an example of a physical indicator sterilizer printout. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 16

17 _ 2. Chemical indicators, internal and external, use sensitive chemicals to assess physical conditions, such as temperature, during the sterilization process, resulting in a visual or physical change (Goodman & Spry, 2014) Indicators do not establish the sterility of an item; they indicate only that the process parameters have been met (e.g., exposed to a certain temperature) (Phillips, 2013). An example would be an indicator tape on the outside of an item which will change color rapidly when exposed to a certain temperature. There are six classes of chemical indicators: Class 1 Process indicator: used to demonstrate that the product has been exposed to the sterilization process. Class 1 process indicator is an external indictor (usually in the form of a tape or label) and should be present on the outside of every package/rigid container intended for sterilization (Goodman & Spry, 2014). September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 17

18 _ Note: Process indicators distinguishes between processed and unprocessed packages (ORNAC, 2013) Tape Arrows (tamper proof) Dot Class 2 Indicators for Use in Specific Tests: Class 2 indicators are used for testing the sterilizers for air leaks, inadequate air removal, and inadequate steam penetration (Goodman & Spry, 2014). Class 2 indicators are used daily in each pre-vacuum sterilizer before the sterilizer is placed into routine use. An example would be a DART test (dynamic-air-removal test) which is used to test the ability of the sterilizer to adequately remove air and to achieve an adequate vacuum. A Bowie Dick is an example of a specific dynamic air removal test. Note: Dynamic-air-removal tests are not a test for sterilization. Class 3 Single-parameter indicator: internal indicator designed to react to one of the critical parameters (i.e. temperature) of sterilization and to indicate exposure to a sterilization cycle at a stated value of the chosen parameter (Goodman & Spry, 2014). September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 18

19 _ Class 4 Multi-parameter indicator: designed to react to two or more of the critical parameters of such as time and temperature. An example is a strip (internal indicator) that contains ink which turns color when exposed to the correct combination of sterilization parameters. Class 5 Integrating indicator (aka integrator): internal indicator designed to react to all critical parameters of sterilization. Hence, the integrator integrates the 3 critical variables of time, temperature, and saturated steam and then indicates if these have been met. It does not prove sterility but demonstrates process completion and penetration of the sterilant into the package/rigid container. Integrators should be used in every load. Class 5 is one of the most common chemical indicators used. There are different integrators used for the different forms of sterilization (e.g., steam or EO). Steam EO Class 6 Emulating indicator: Relatively new to the market, these cycle verification internal indicators confirm the presence or absence of specific time and temperature parameters during a cycle and integrates all the critical parameters (Goodman & Spry, 2014). Hence, these internal indicators react to a single set of predetermined values (Goodman & Spry, 2014). For example, a class 6 emulating CI may be designed to react at 18 minutes at 273 F. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 19

20 _ This indicator is used typically for instruments requiring extended cycles (e.g., large ortho trays) or for instruments that were in contact with prion-contaminated tissue (Goodman & Spry, 2014). These indicators are fairly new so their use is not wide spread. Review: Chemical indicators are used to verify whether items have been exposed to one or more critical parameters necessary for sterilization; they are not used to verify that sterilization has been met. A visual change, usually in color, indicates a defined level of exposure based on the classification of the chemical indicator used. The use of the chemical indicator by itself does not prove that the item is sterile. Chemical indicators should be used in conjunction with physical and biological indicators to document the effectiveness of the sterilization process. Applicability of Chemical Indicators to Operating Room Class 1 indicator provides assurance that the package was put through a sterilization process. Sterile processing personnel check the Class 1 indicator (tape or label) before releasing sterilized instruments for use. Operating room personnel then check the Class 1 indicator (external) before opening the package (e.g., tamper proof arrow, or tape) to the sterile field. When the perioperative nurse is checking packages for sterility, there are a few other things that he/she must check in addition to the presence of external indicators. According to ORNAC (2013), all items added to the sterile field shall be assessed prior to opening for sterility by checking for: o Visible signs of moisture (e.g., using a rigid container); and o Wrapper integrity if using instrument wrap (e.g., assess for holes and tears). September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 20

21 _ As these things are checked for sterility, the scrub nurse is also then checking the Class 5 indicator (internal) when opening the package (e.g., integrating indicator or integrator). For cost purposes many facilities opt to use a lower class internal indicator. It is recommended the use of a Class 5 Integrating Indicator because it monitors all the parameters of the sterilization cycle rather than just one or two. Note: Indicator test results are shown immediately after the sterilization cycle is complete and could provide an early indication of a problem and where the problem occurred in the process. If the internal or external indicator suggests inadequate processing, the item that has been processed should not be used. Case Analysis In returning to our case study, Lucy was correct in checking the external indicators (e.g., tamperproof arrows) when opening the sterile instruments. As Matt proceeded to take the instruments and place them on his back sterile table, he did assess for a chemical indicator before removing. However, Matt did not assess whether the rigid container had moisture in it. Moisture can be visible and if present, must be considered compromised (ORNAC, 2013). The scrub nurse can also assess for moisture by lifting out the mesh pan and holding the pan while the circulating nurse can feel for any moisture in the bottom of the pan. If no moisture is found, then the instruments are considered sterile and can be placed on the sterile field. 3. Biological Indicators are strips, ampules, and capsules that contain a known, living, and highly resistant spore population. Biological indicators (BIs) are the most accepted means of monitoring the sterilization process because they directly determine whether the most resistant microorganisms (e.g., geobacillus or bacillus species) are present, rather than merely determine whether the physical and chemical conditions necessary for sterilization are met. BI ampules, strips, or capsules are placed in the sterilizer. Following sterilization, the BI ampules, strips, or capsules are placed in a growth medium and incubated. If no bacterial growth, it is assumed that all spores have been killed and sterilization has been achieved. If bacterial growth, there will be a color change and an indication that sterilization has failed (Goodman & Spry, 2014). September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 21

22 _ For example, bacillus stearothermophilus, a spore, is used to test steam sterilizers. Another spore, bacillus subtilis is used to test ethylene oxide (EO) sterilizers. Biological monitors are done with all implants and on a regular schedule (e.g., daily, weekly).they are also used when maintenance is done to any sterilizer. It is strongly recommended that loads with implants are quarantined until the BI results are available. However, when medical situations dictate that an implant be released before results are known, the early release should be documented. Conventional BIs must be incubated for the specified amount of time (usually 48 hrs for wrapped items and 24 for flash cycles). However, rapid result BIs permit the release of an implant with a 3 hour reading for wrapped and 1 hour for a flash sterilization cycle (Goodman & Spry, 2014). No indicators, chemical or biological, can tell you with certainty that the product is sterile. That determination comes only from careful control of the whole process, from cleaning through sterilization, storage, and handling until the moment of use. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 22

23 _ Summary: Sterilization Performance Monitoring Biological Indicator A biological indicator is a standardized viable population of microorganisms (usually bacterial spores) known to be resistant to the mode of sterilization. BEST Chemical Integrator Integrates the 3 critical variables of time, temperature, and saturated steam and then indicates if these have been met. Integrator should be used in every load (i.e. Sterigage). Multi- Parameter Chemical Indicators Measures two to three parameters Process Indicators Autoclave tape, dots, and arrows: Identifies that the object has been exposed to the sterilization process - not that any parameters were met (changes color) Physical Indicators Examples include printed records, graphs, etc. LEAST September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 23

24 _ Load Control Number Every package intended for sterilization should be labeled with a load control number that indicates the following information: 1. sterilization date 2. number of sterilizer used 3. cycle (of sterilizer) 4. expiration date The load control number facilitates identification and retrieval of supplies, in case of a recall due to sterilization failure. This number is printed out by a label gun that correlates the same number for every package put in the load. The following print out illustrates the four components of the load control number. Sterilizer Used Sterilization Date Cycle /Load Expiration Date To avoid confusion, the sterilization date is recorded as a Julian date (day 1 through 365) and the expiration date as a Georgian date (month, day, year). September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 24

25 _ Event Related Sterility The practice of sterilization of instruments and linens in the hospital setting was always based on a system where by sterility was only guaranteed for an item processed "inhouse" until a specific date. This was one month for linen-wrapped goods and six months for items in a rigid container. This was indicated on the package stickers just illustrated. This system seemed quite arbitrary and resulted in re-wrapping and resterilizing any item which had not been used within its time limit. Recently this practice is changing, based on research, to an event-related process. According to AORN (2013), factors that determine the length of time an item is considered sterile include: The type and number of layers of wrappers used. The number of times a package is handled before its use, and who is handling the package. The conditions under which the package is stored, including shelf style/ construction, temperature, humidity, and use of a dust cover. The probability that an event would occur that could compromise sterility, increases over time. That is, the longer something is stored/handled/transported the higher the risk of having a contaminated item. Rotation of items in storage is essential to the success of this system. The scrub nurse and circulating nurse question the sterility of an item. The two factors that influence their decision are: 1. Sterility is Event Related NOT, Time Related 2. IF IN DOUBT CONSIDER IT UNSTERILE, STERILE September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 25

26 _ Learning Check 1. Sterile means a. free of all living microorganisms b. free of all bacteria c. free of all living microorganisms and spores 2. Disinfection means a. the destruction of all gram-negative bacteria b. the destruction of all pathogenic microorganisms except spores c. the process used to make skin as clean as possible 3. Items that can tolerate moisture and high temperatures are generally sterilized using: 4. Steam at atmospheric pressure can achieve sterilization if exposure time is greatly increased. TRUE FALSE 5. Steam sterilization is a function of time, temperature, and moisture. TRUE FALSE 6. List four advantages of steam sterilization: September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 26

27 _ 7. Sterilization in a gravity displacement autoclave may be accomplished at a temperature of 270 o F (132 o C). TRUE FALSE 8. Wrapped items require a longer exposure time than unwrapped items in a gravity displacement sterilizer. TRUE FALSE 9. In immediate use steam sterilization, items are not wrapped and are placed in a container that will allow sufficient steam contact. Because there is little or no drying time in the flash cycle, the item is wet after processing. TRUE FALSE 10. When should immediate use steam sterilization be used? 11. Exposure times in all steam sterilizers should (Circle all of the correct answers): a. be identical for all sterilizers b. be identical for all items c. be determined by the type of sterilizer d. be determined by the item being sterilized e. be determined according to manufacturer guidelines f. be determined by the skill of the sterilizer operator 12. Explain when ethylene oxide sterilization is appropriate. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 27

28 _ 13. Ethylene oxide is a known carcinogen. List three other disadvantages of ethylene oxide Liquid peracetic acid sterilization: (Circle all appropriate answers) a. is appropriate for flexible endoscopes b. results in an unwrapped wet item c. results in a wrapped dry item d. can only be used for items that are immersible 15. Disinfectants are used on a. inanimate surfaces b. body surfaces 16. The high-level disinfectant, glutaraldehyde, is appropriate for use on a. table tops b. surgical instruments c. floors 17. All disinfectants can be used for sterilization purposes provided immersion time is sufficient. TRUE FALSE 18. Explain the difference between a gravity displacement autoclave and a prevacuum autoclave. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 28

29 _ Learning Check Answers 1. C 2. B 3. Steam (Thermal) Sterilization 4. False 5. True 6. Most economical Safest and fastest Best understood/most reliable No harmful by-products 7. True 8. True 9. True 10. immediate use steam sterilization should be utilized when there is an urgent need for an instrument, no other sterilization alternative, there is no replacement instrument available, where proper decontamination and preparation are possible and where the physical layout allows direct and aseptic delivery of the processed items to the scrub. Implants should never be flashed. 11. C, D, E 12. ETO Sterilization is appropriate for items that are heat labile and moisture sensitive, plastic or porous, electrical, intricate/delicate (e.g., where other processes of sterilization are inappropriate, may cause damage to items or improper sterilization) 13. Highly explosive and flammable Very expensive Very long processing and aeration time 14. A,B,D 15. A 16. B 17. False 18. How the air is removed from the system prior to steam penetration. There is a passive removal of air by gravity in the gravity displacement system, whereas the addition of a prevacuum rapidly removes air. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 29

30 _ References AORN (2013). Perioperative standards and recommended practices. Denver: AORN, Inc. Fuller, J. (2013). Surgical technology. (6th ed.). Toronto: Mosby. Goodman, T. & Spry, C. (2014). Essentials of Perioperative Nursing (5 th ed.) Toronto: Jones and Bartlett Publishing. Operating Room Nurses Association of Canada (ORNAC) (2013). ORNAC Standards for Perioperative Registered Nurses (11th ed.). Canada: Author. Phillips, N. (2013). Berry & Kohn s Operating Room Technique. (12th ed.). Toronto: Mosby. Rothrock, J.C. (2015). Alexander s Care of the Patient in Surgery (15th ed.). Toronto: Mosby. September 2014 RN Professional Development Centre & Nova Scotia DOH, Halifax, NS 30