Preventing infection in surgical patients begins with cleaning, disinfecting, and sterilizing the medical instruments used during surgical and nonsurgical procedures. An estimated 71.9 million procedures are performed each year in the United States, so processing the instruments correctly is essential to minimize infection risk.1 The Joint Commission considers the following as infection prevention and control activities: Cleaning and performing low-level disinfection of medical supplies and devices and performing intermediate- and high-level disinfection and sterilization of medical equipment, devices, and supplies.2 Ongoing education about disinfection and sterilization techniques will improve your understanding of the implications of improper instrument handling. This article reviews the AORN practice recommendations for disinfection and sterilization so that you can better care for your patients during the perioperative and intraoperative periods.
Preventing infection
Many recognized processes are in place to prevent surgical infections, and most include checklists to ensure compliance. The Surgical Care Improvement Project (SCIP), formed in 2004 by the Centers for Medicare and Medicaid Services (CMS) and the CDC, aimed to reduce preventable surgical morbidity and mortality by 25%.3 The SCIP process and outcome measures include specific quality measures that are recognized as evidence-based best practice standards and include antibiotic selection, timing of antibiotic administration, and timing of antibiotic discontinuation.
Other best practice standards on hand hygiene, sterile technique, surgical technique, and postoperative dressings can help reduce infection. Although these practices address patient-specific interventions, they don't address OR preparation, including instrument disinfection and sterilization. A partnership must be formed between the perioperative nurse and the sterile processing department to ensure that surgical items are free from contamination at the time of use.4,5
The CDC's 2008 Guideline for Disinfection and Sterilization in Healthcare Facilities outlines evidence-based recommendations for cleaning, disinfecting, and sterilizing patient-care medical devices.6 (See The Spaulding classification system.) This guideline also addresses cleaning and disinfecting the healthcare environment, including ambulatory care settings, and the types of disinfectants and recommendations for using them. (Healthcare providers also should follow the directions on the product labels.)
Disinfection and sterilization guidelines are also provided by the AORN and the Association for the Advancement of Medical Instrumentation (AAMI).
What can affect the process?
A number of factors can affect the disinfection and sterilization process:
Microbial burden. The more microbes present on the instrument, the longer it takes to inactivate the organisms. The location of the microbes also is a factor-hinged parts, portals, bends, and crevices are more difficult for the disinfectant to reach than flat surfaces on instruments. The disinfectant being used may be the recommended product, but will be ineffective if there are air pockets or pieces that can't be penetrated. Air pockets can be created in equipment such as endoscopes, in which channels, crevices, and joints impede the disinfectant's ability to fully penetrate. Equipment that's easier to clean and disinfect is needed.
Microbial resistance. Spores have a coat that forms a barrier to disinfectants; Mycobacterial cell walls are waxy and can resist penetration by the disinfectant. Gram-negative organisms such as Acinetobacter baumannii are encapsulated, and use this as a barrier to surface disinfection. The concentration, exposure, and contact time of the disinfectant are crucial in inactivating resistant organisms.
Temperature, pH, relative humidity, and water hardness can also affect disinfection effectiveness. In most cases, disinfectant effectiveness increases with a temperature increase, but there are exceptions: An extreme temperature may cause the disinfectant to break down and weaken. Water hardness can reduce the effectiveness of some disinfectants, as magnesium and calcium (which are divalent cations) interact with the disinfectant, creating insoluble precipitates.
Cleaning
Before an item can be disinfected or sterilized, it must be cleaned and decontaminated to remove the bioburden (microbial contaminants including bacteria, yeast, and mold) and other debris or organic material such as blood, mucus, fat, or tissue that may interfere with or react to the sterilization or disinfection process.7 Organic and inorganic materials typically are removed with water and detergent or an enzymatic product.
Load instruments properly into the washer-disinfector or ultrasonic cleaner. Fully open hinged items and avoid stacking instruments so the cleaning solution will contact all surfaces of the instruments. If a mechanical unit such as an ultrasonic cleaner, washer-disinfector, or washer-sterilizer isn't available, perform cleaning manually, using friction to remove bioburden and debris.
Removal of bloodborne pathogens begins in the OR during surgery. Some surgical instruments may be soaked to remove blood. Keep instruments free from gross contaminant during procedures by moistening instruments with sterile water and placing smaller instruments in a basin of sterile water. Take care not to contaminate the sterile field by placing the basin in a ring stand.
After surgery, take the items to a decontamination area that's monitored and is equipped with negative air pressure. If negative pressure isn't available, the area should be as far from the patient-care area as possible.
Disinfection
Disinfection eliminates pathogens on inanimate objects, but won't eliminate bacterial spores.8 This is one distinguishing factor between disinfection and sterilization (which does kill spores). Liquid chemicals (alone or in combination) or wet pasteurization are used in disinfection. Disinfectants must be FDA-approved or registered with the Environmental Protection Agency (EPA).
Manufacturer recommendations for equipment define how the disinfectants are to be used and on what equipment. Substitutions aren't acceptable and may compromise the entire process. Disinfectants, like many other chemicals, should be used with caution-you need to wear personal protective equipment (PPE) and work in a room with special ventilation.
High-level disinfectants include glutaraldehyde, hydrogen peroxide, ortho-phthalaldehyde, and peracetic acid and hydrogen peroxide. Germicidals that aren't FDA-approved and alternative processes aren't recommended for use in healthcare facilities.5
Sterilization
Done properly, sterilization destroys all surface microorganisms (pathogenic, nonpathogenic, and spores) on an item. The sterility assurance level of an item is the probability of a single viable microorganism remaining after sterilization. Items that require sterilization are those that are referred to as critical because they've come in contact with sterile body tissues or sterile body fluids. Items that are deemed heat-resistant should be steam-sterilized. Devices that are heat-sensitive require an alternate method of sterilization.
Steam sterilization uses moist heat to quickly sterilize instruments, provided the correct temperature is reached, pressure is maintained, and contact time is sufficient. The two most common types of steam sterilizers are gravity displacement sterilizers and high-speed prevacuum sterilizers. All sterilizers must have controls in place to monitor effectiveness and ensure that no processes are compromised. Chemical and biological indicators are used to monitor the efficiency of the sterilizer as well as a test to check for air leaks. The air leak test determines the steam sterilizer's ability to remove air from the chamber.
Ethylene oxide is a low-temperature process used with instruments that are heat- and moisture-sensitive. Risks of this process include the creation of hazardous byproducts from inadequately aerated items.
Hydrogen peroxide gas plasma uses radiofrequency or microwave energy as the mechanism for sterilization.
Peracetic acid sterilization is an oxidizer and is commonly used. The container should be punctured just before use and before closing the sterilizer lid. Endoscopes and endoscope accessories with lumens are processed using this method.
Flash sterilization is an abbreviated cycle that should never be used for convenience. Monitoring flash sterilization use is crucial to determine how often it's used, which items are sterilized, and the parameters and process for each item sterilized. Documentation should include the item that was flashed sterilized, the cycle of sterilization, and the reason. This information is used to determine equipment needs and to assist in identifying unsafe practices.
The Joint Commission states that items that aren't processed using a full cycle can be transported in flash pans or other containers specifically structured to prevent contamination of sterilized items during transport. The CMS refers to items being wrapped and contained in special metal containers.9 Questions to keep in mind when an item is flash sterilized include:
* What is the sterilizer manufacturer's recommended load for the cycle?
* Is the appropriate containment device being used for the load?
* Is the chemical indicator recommended for the load by the manufacturer?
* Is the cycle checked regularly with a biological indicator?
AORN recommends flash sterilization be restricted and items disassembled, decontaminated, and cleaned before flash sterilization. Follow the manufacturer's recommendations, use closed rigid containers, and use the item immediately after flash sterilization.
What does this mean to the perioperative nurse?
AORN's latest perioperative standards and recommended practices include recommendations for sterilization in the perioperative practice setting. Let's look at these recommendations and their infection prevention implications and rationales.
* Recommendation I refers to cleaning and decontamination before sterilization and storage, and includes guidance on use of PPE, workflow patterns, room temperature, humidity, and ventilation. Appropriate removal of bioburden and debris before sterilization is important to ensure the integrity of the entire process. Workflow patterns help maintain the sterile field and reduce the risk of contamination of processed sterile instruments. OR staff should follow standard precautions and wear appropriate PPE when cleaning surgical instruments to reduce the risk unintentional exposure to bloodborne pathogens. Room temperature and humidity are controlled to provide an environment that's conducive to the work and inhibits bacterial growth.
* Recommendation II addresses packaging to ensure that sterility is maintained until the instrument is used. This recommendation focuses on packaging systems, weight of an instrument set, and correct use of paper pouches. Weight can be an issue in maintaining sterility because of the potentially increased drying time of instruments. Proper package size will allow for adequate air removal, steam contact, and drying.10
* Recommendation III is specific to the use of saturated steam. This is the preferred sterilization method because it's inexpensive, effective, and fairly rapid. Items must be sterilized for the entire cycle and not compromised by leaving the sterilizer door open for cooling, which could interrupt the cycle and contaminate the load.
* Recommendation IV is a comprehensive review of flash sterilization, which should only be used in clinical situations and in a controlled manner. The recommendation contains numerous specifics and mandates that flash sterilization should only be performed if certain conditions can be met including manufacturer recommendations for cycle type, cleaning and decontamination, use of closed containers, and use of process challenge devices.
* Recommendation V describes ethylene oxide sterilization. The authors of one study reviewed more than 200 cases requiring cranial explants and re-implantation following traumatic injury or other conditions that required cranial reconstruction. They determined that ethylene oxide was the preferred method for sterilizing bone explants, but due to concerns about hazardous material exposure to employees, this method is increasingly less available.11
* Recommendation VI covers the use of low-temperature hydrogen peroxide gas plasma sterilization methods for heat- and moisture-sensitive items, if directed by the manufacturer. Because the byproducts of this process are oxygen and water, aeration (the process of circulating warm air in the enclosed cabinet) isn't needed.
* Recommendation VII discusses the use of peracetic acid as a low-temperature liquid sterilant appropriate for heat-sensitive surgical items that can be immersed. This process can be used for critical items that can't be steam sterilized at high temperatures.
* Recommendation VIII calls for ozone to be used for heat- and moisture-sensitive items as recommended by the manufacturer. The FDA has cleared ozone for sterilizing metal and plastic surgical items and for some instruments with lumens. Follow the manufacturer's recommendations to ensure appropriate management of the item.
* Recommendation IX suggests that dry heat sterilization be used to sterilize items that can withstand high temperatures. Dry heat sterilizers aren't readily available in sterile processing departments. Heat sterilization, however, is the highest level of sterilization, and is designed to eliminate all microorganisms from the item. This process is preferred to reduce the risk of transmitting infectious organisms.
* Recommendation X calls for establishing a formalized program between healthcare organizations and industry representatives for the receipt and use of loaner instruments. Loaner instruments reduce equipment costs to the healthcare facility, but can compromise patient safety if they aren't processed properly (for example, if flash sterilization is used). Having every available instrument in stock isn't practical, but administrative controls should be in place to minimize the use of loaner instruments.
* Recommendation XI states that sterilized materials should be packaged, labeled (including with the date), and stored to make sure items are sterile. Proper packaging maintains the sterility of the instrument. Labeling notifies the healthcare provider that the item has been sterilized and provides a visual that the item hasn't been compromised. The date provides a time frame in which the item is verified sterile.
* Recommendation XII states that the process of transporting items should be controlled. Rigid containers decrease healthcare providers' risk of injury from contact with sharps, and prevent the instrument from being damaged or contaminated. A towel-wrapped item is never acceptable, nor is a partially covered rigid container.
* Recommendation XIII recommends that personnel should be oriented to the sterile processing of surgical instruments in the perioperative setting and should have continuing education. Orientation to the proper cleaning, decontamination, disinfection, and sterilization processes provides healthcare providers with the underlying concepts behind the processes. Continuing education ensures that staff members are up to date with changes in the field.
* Recommendation XIV covers maintenance of sterilization process records as indicated by the organization and in accordance with local, state, and federal regulations. A record of the method, cycle, and reason for flash sterilization is important to review potential areas of improvement. All records should be maintained per facility protocol and should be available for recall by local, state, and federal agencies.
* Recommendation XV states that policies and procedures for sterilization processes should be developed and made available. These policies and procedures should follow the CDC, AORN, and AAMI recommendations and evidence-based practice, and should be accessible by staff.
* Recommendation XVI states that facilities should develop and monitor a quality control program. Quality control is important to monitor processes, verify best practice, validate controls, and implement interventions for safe practice.
Maintaining best practices
Perioperative nurses play an important role in managing medical instrumentation. By staying up to date on the AORN recommendations for disinfection and sterilization, you'll be able to provide best-practice patient care.
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