Getinge 700HC

What’s the difference?
The difference between high-level disinfection (HLD) and sterilization is sometimes misunderstood by healthcare personnel, and that can result in disastrous consequences for patients. Arthur Trapotsis, vice-president, research and development, Consolidated Stills and Sterilizers, Boston, and chief technology officer, William Barnstead Engineering Corp, Boston, finds confusion between the two terms alarming: "I often hear the terms disinfection and sterilization used interchangeably. This is incorrect and very misleading. It scares me when I hear healthcare professionals mixing up the terminology. In basic terms, sterilization is the destruction of all microorganisms, including spores, and HLD could be anything less than that."

Besides HLD, there are two other categories of disinfection. Chuck Fishelson, vice president, Alfa Medical Equipment Inc, Hempstead, NY, described them: "There are three levels of disinfection: High, intermediate, and low. High-level disinfection kills all organisms, except high levels of bacterial spores, and is effected with a chemical germicide cleared for marketing as a sterilant by the Food and Drug Administration. Intermediate-level disinfection kills mycobacteria, most viruses, and bacteria with a chemical germicide registered as a tuberculocide by the Environmental Protection Agency (EPA). Low-level disinfection kills some viruses and bacteria with a chemical germicide registered as a hospital disinfectant by the EPA."

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Todd Nielsen, national director of sales and marketing, infection control, Getinge USA, Rochester, NY, illustrated the difference between disinfection and sterilization: "The levels of disinfection and sterilization are points along the same continuum of risk. HLD is at a point on the continuum indicating a greater risk of contamination than sterilization. Sterilization is the terminus of the continuum where risk is, effectively, reduced to the lowest practical point. As an alternative to the continuum construct, think in terms of concentric circles: Low-level disinfection is a sub-set of high-level disinfection, which in turn is a sub-set of sterilization."

Basically, the difference between HLD and sterilization is that only sterilization can kill high numbers of bacterial spores. However, in recent years, a new challenge to sterilization has stolen some of spores’ significant thunder. Fishelson indicated that prions are now at the top of the microbial totem pole, requiring even more sterilization exposure time than highly resistant bacterial endospores.

The threat of infection by spores or prions doesn’t exist in all circumstances so sterilization of all items used on or by patients is unnecessary. Rutala and Weber noted, "Because sterilizing all such items is unnecessary, hospital policies need to identify whether cleaning, disinfection, or sterilization is indicated based primarily on an item’s intended use but considering other factors including cost."1

Spaulding classification of medical devices
The system used to determine whether items should be cleaned, disinfected, or sterilized was proposed in 1968 by Earl Spaulding.3-8 Cynthia Spry, RN, MSN, CNOR, international clinical consultant for Advanced Sterilization Products (a Johnson & Johnson company), Irvine, CA, told Healthcare Purchasing News, "The classification of a device provides guidance as to how a device should be processed. If the person responsible for instrument processing knows how the device is used or classified, then it is possible to determine whether sterilization is required or whether HLD is appropriate."

Spaulding’s classification of medical devices divides items into three categories — critical, semicritical, and noncritical— based on how the object is intended to be used.2-8 Rutala and Weber explained how the system works in their special report for "Emerging Infectious Diseases"1:

• "Critical objects (those that enter sterile tissues or the vascular system or through which blood flows, such as implanted medical devices) should be sterile when used."

• "Semicritical items (that touch mucous membranes or nonintact skin, e.g., endoscopes, respiratory therapy equipment, and diaphragms) require high-level disinfection (i.e., elimination of all microorganisms except high numbers of bacterial spores)."

• "Noncritical items (bedpans, blood pressure cuffs, and bedside tables) require only low-level disinfection."

In their report, Rutala and Weber noted, "Adherence to these recommendations should improve disinfection and sterilization practices in health care facilities, thereby reducing infections associated with contaminated patient-care items."1

More on sterilization and critical devices
"Nielsen stated, "The minimum acceptable standards for reducing the risk of infection will vary, dependent upon the type of device. Critical devices used for invasive procedures require terminal sterilization, or the highest level of cleanliness. Otherwise put, critical devices demand the most reduction of infection risk. Noninvasive devices require less rigorous protocols, because the nature of their use poses less threat of infection. It is critical to understand this continuum, as well as the nature of devices, and the processing guidelines set forth by the device manufacturer."

Noting that "the physical, emotional, and economic cost of a surgical-site infection is high," Spry emphasized the importance of sterilization for surgical instruments: "One should always sterilize devices categorized as critical. These are the devices used in surgery. Sterilization is the standard for surgical instruments. It is inappropriate to use HLD in its place.

"There was a time when devices, such as laparoscopes, which required low-temperature sterilization and which are used in minimally invasive surgeries, could only be sterilized in a technology method that required many hours," Spry continued. "As the number of minimally invasive procedures increased, hospitals did not have enough laparoscopes to meet the demand for a sterile scope for every procedure or patient. As a result, scopes that were sterilized at the end of the day were only high-level disinfected between patients because the time required for HLD was 10 to 45 minutes. HLD is rapid, but it is not appropriate for critical devices. HLD is only appropriate for semicritical devices such as endoscopes. Processing personnel may choose to sterilize a semicritical device, although this is not necessary. While it is acceptable to sterilize a semicritical device, it is not appropriate to high-level disinfect a critical device."

Newer technology is making it easier to be more thorough, according to Spry. "Fortunately it is now possible to sterilize laparoscopes and other devices that require low temperature using newer technology that is both rapid and low-temperature," Spry noted. "Sterilization may be accomplished with steam under pressure, ethylene oxide, hydrogen peroxide gas plasma, or liquid peracetic acid. HLD is accomplished with liquid chemical germicides such as glutaraldehyde and ortho-phthalaldehyde. Some chemical germicides that are used to achieve HLD are capable of sterilization as well. However, because of the time required to achieve sterilization, they are seldom used for this purpose. For example, HLD, depending upon the chemical composition and temperature of the solution, requires an immersion time of anywhere from 5 minutes to 45 minutes. Sterilization with the same chemicals can take anywhere from 6 to more than 10 hours. For this reason, it is completely impractical to use liquid chemical germicides sold for HLD purposes as sterilizing agents. In some very poor countries where there is no sterilization technology, it is common practice to leave surgical instruments immersed overnight in a high-level disinfectant as a means to sterilize them. Fortunately this is not the case in developed countries."

Looking forward
Because central sterile supply departments are constantly under pressure to turn around instruments and equipment quickly, the future for sterilizing equipment and products will continue to bring improved efficiency and faster cycles. An understanding of the value of education will continue to grow as well, because training personnel is a way to get the most out of the facility’s investment in expensive equipment.

Trapotsis observed: "In general, education is the future product. Specifically, there is a tremendous need for a low-temperature sterilization process that has superior material compatibility and that can adequately penetrate a long lumen in a timely fashion. By creating a more robust product, endoscope manufacturers could greatly assist in the quest for such a process."

REFERENCES

1.Rutala WA, Weber DJ. New disinfection and sterilization methods. Emerg Infect Dis. Last reviewed December 8, 2001. www.cdc.gov/ncidod/eid/vol7/no2/rutala.htm.

2.Rutala WA, Weber DJ. Disinfection and sterilization in health care facilities: what clinicians need to know. Clin Infect Dis 2004;39:702-709.

3.Rutala WA. Selection and use of disinfectants in health care. In: Mayhall CG. Hospital Epidemiology and Infection Control. 1st ed. Baltimore, MD: Williams & Wilkins;1996:913-936.

4.Rutala WA. Disinfection and sterilization of patient care items. In: Herwaldt LA, Decker MD. A Practical Handbook for Hospital Epidemiologists. Thorofare, NJ: SLACK Inc; 1998:271-280

5.Sehulster LM, Chinn RYW, Arduino MJ, Carpenter J, Donlan R, Ashford D, et al. Guidelines for environmental infection control in health-care facilities. Recommendations from CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC). November 2003. www.cdc.gov/ncidod/hip/enviro/guide.htm. Last updated February 2004.

6.Spaulding EH. Role of chemical disinfection in the prevention of nosocomial infections. In: Brachman PS, Eickhoff TC, eds. Proceedings for the International Conference on Nosocomial Infections, 1970. Chicago, IL: American Hospital Association; 1971:247-254.

7.Spaulding EH. Chemical disinfection and antisepsis in the hospital. J Hosp Res 1972;9:5-31.

8.Spaulding EH. Chemical disinfection of medical and surgical instruments. In: Lawrence CA, Block SS, eds. Disinfection, Sterilization, and Preservation. Philadelphia, PA: Lea & Febiger; 1968.