infection control and hospital epidemiology february 2007, vol. 28, no. 2 original article How to Assess Risk of Disease Transmission to Patients When There Is a Failure to Follow Recommended Disinfection and Sterilization Guidelines William A. Rutala, PhD, MPH; David J. Weber, MD, MPH background. Disinfection and sterilization are critical components of infection control. Unfortunately, breaches of disinfection and sterilization guidelines are not uncommon. objective. To describe a method for evaluating a potential breach of guidelines for high-level disinfection and sterilization of medical devices. methods. The appropriate scientific literature was reviewed to determine the frequency of failures of compliance. A risk assessment model was constructed. results. A 14-step protocol was constructed to aid infection control professionals in the evaluation of potential disinfection and sterilization failures. In addition, a model is presented for aiding in determining how patients should be notified of the potential adverse event. Sample statements and letters are provided for communicating with the public and individual patients. conclusion. Use of a protocol can guide an institution in managing potential disinfection and sterilization failures. Infect Control Hosp Epidemiol 2007; 28:146-155 In the United States in 1996, there were approximately infection failure on record involved the distribution of an 46,500,000 surgical procedures and a much larger number of inactive lot of glutaraldehyde disinfectant solution that had invasive medical procedures.1 For example, there are about been used by 60 hospitals in Belgium and involved 34,879 5 million gastrointestinal endoscopies per year. Each of these patients. In this incident, 25,589 patients were screened for procedures involves contact between a medical device or sur- infection with hepatitis B virus (HBV) and hepatitis C virus gical instrument and a patient’s sterile tissue or mucous mem- (HCV), and no acute infections were observed.8 It is our branes. A major risk of all such procedures is the introduction experience that the number of incidents that are published of pathogenic microbes, which can lead to infection. Failure or reported in the press represent a small fraction of the to properly disinfect or sterilize equipment has led to person- disinfection and sterilization instrument reprocessing failure to-person transmission via contaminated devices (eg, My- incidents that result in patient notification. These failures cobacterium tuberculosis transmitted via contaminated bron- may result from human error (eg, incorrect setting of the choscopes). Thus, achieving disinfection and sterilization temperature on a steam sterilizer or failure to clean items through the use of disinfectants and sterilization practices is before disinfection),4 equipment or product failure,8-10 or essential for ensuring that medical and surgical instruments systemic problems (ie, an organizational, procedural, or en- do not transmit infectious pathogens to patients. vironmental factor that facilitates the failure, such as the Deficiencies in disinfection and sterilization leading to use of incorrect channel connectors). Equipment failure in- infection have resulted either from failure to adhere to sci- cidents may stem from problems with design, manufacture, entifically based guidelines 2-4 or failures in the disinfection maintenance, or storage, as well as from a lack of user com- or sterilization processes.5 Patient notifications due to im- petence.11 This article presents a scheme for performing an proper reprocessing of semicritical (eg, endoscopes) and evaluation of possible failures of high-level disinfection or critical medical instruments have occurred regularly; these sterilization of patient care items. It will also provide a incidents generally involve single institutions, but may also method for assessing patient risk for adverse events, espe- involve multiple institutions (Table 1).6,7 The largest dis- cially infection. From the Department of Hospital Epidemiology, University of North Carolina Health Care System, and the Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill (both authors). Received July 21, 2006; accepted November 3, 2006; electronically published January 24, 2007. ᭧ 2007 by The Society for Healthcare Epidemiology of America. All rights reserved. 0899-823X/2007/2802-0006$15.00. assessing risk to patients from disinfection and sterilization failures 147 disinfection and sterilization are those that enter sterile tissue or the vascular system and guidelines must be sterile because any microbial contamination could result in disease transmission. This category includes surgical Sterilization describes a process that destroys or eliminates instruments, cardiac and urinary catheters, implants, and ul- all forms of microbial life and is carried out in healthcare trasound probes used in sterile body cavities. facilities by either physical or chemical methods. Steam under Semicritical items are those that come in contact with mu- pressure, dry heat, ethylene oxide gas, hydrogen peroxide gas cous membranes or nonintact skin. Respiratory therapy and plasma, and liquid chemicals are the principle sterilizing anesthesia equipment, some endoscopes, laryngoscope blades, agents used in healthcare facilities in the United States. When esophageal manometry probes, anorectal manometry cathe- chemicals are used for the purposes of destroying all forms ters, and diaphragm fitting rings are included in this category. of microbiological life, including fungal and bacterial spores, Thus, these medical devices should be free of all microor- they may be called chemical sterilants. These same germicides ganisms (ie, mycobacteria, fungi, viruses, and bacteria), al- used for shorter exposure periods may also be part of the though small numbers of bacterial spores may be present. disinfection process (ie, for high-level disinfection). Intact mucous membranes, such as those of the respiratory Disinfection describes a process that eliminates many or tract or the gastrointestinal tract, generally are resistant to all pathogenic microorganisms, with the exception of bacterial infection by common bacterial spores but susceptible to other spores, on inanimate objects. Disinfection is usually accom- organisms, such as bacteria, mycobacteria, and viruses. Semi- plished by the use of liquid chemicals or wet pasteurization critical items minimally require high-level disinfection using in healthcare settings. The efficacy of disinfection is affected chemical disinfectants (eg, glutaraldehyde, hydrogen perox- by a number of factors, each of which may nullify or limit ide, ortho-phthalaldehyde, peracetic acid with hydrogen per- the efficacy of the process. Some of the factors that affect oxide, or chlorine). both disinfection and sterilization efficacy are prior cleaning Noncritical items are those that come in contact with intact of the object, the organic and inorganic load present, the type skin but not mucous membranes. Intact skin acts as an ef- and level of microbial contamination, the concentration and fective barrier to most microorganisms; therefore, the sterility duration of exposure to the germicide, the nature of the object of items coming in contact with intact skin is not critical. (eg, presence of crevices, hinges, or lumens), the presence of Examples of noncritical items are bedpans, blood pressure biofilms, the temperature and pH of the disinfection process, cuffs, crutches, bed rails, linens, bedside tables, patient fur- and, in some instances, the relative humidity of the sterili- niture, and floors. In contrast to critical and some semicritical zation process (eg, for ethylene oxide disinfection). items, most noncritical reusable items may be decontami- Cleaning, on the other hand, is the removal of visible soil nated where they are used and do not need to be transported (eg, organic and inorganic material) from objects and sur- to a central processing area. There is virtually no documented faces, and it normally is accomplished by manual or me- risk of transmitting infectious agents to patients via non- chanical means using water and detergents or enzymatic 20 critical items when they are used as noncritical items and products. Thorough cleaning is essential before high-level dis- infection and sterilization, because inorganic and organic ma- terials that remain on the surfaces of instruments interfere table 1. Reprocessing Failures of Semicritical or Critical Medical with the effectiveness of these processes. Instruments Resulting in Patient Notification Over 35 years ago, Earle H. Spaulding12 devised a rational No. of approach for disinfection and sterilization of patient care persons items and equipment. This classification scheme is so clear Location or institution, year Instrument involved exposed and logical that it has been retained, refined, and successfully Sacramento, CA, 2002 Endoscope 750 used by infection control professionals and others when plan- Toronto, ON, 2003 Endoscope 146 ning methods for disinfection or sterilization.13-18 Spaulding12 Seattle, WA, 2004 Endoscope 600 believed that the nature of disinfection could be understood Sacramento, CA, 2004 Endoscope 1,331 more readily if instruments and items for patient care were San Francisco, CA, 2004 Endoscope 2,000 Long Island, NY, 2004 Endoscope 177 divided into 3 categories on the basis of the degree of risk Charleston, NC, 2004 Endoscope 1,383 of infection involved in the use of the items.