Infection control is an important health care issue that affects many facets of clinical practice. Audiologists must be diligent in their effort to control the spread of infectious disease within the context of the clinical setting.
Audiology involves and requires a notable degree of direct and indirect patient contact (Kemp & Bankaitis, 2000a; Kemp & Bankaitis, 2000b). The profession relies on the use of probes, specula, curettes and other instrumentation which are inserted in the ear. Additionally, audiologists typically handle several different earmolds and hearing aids throughout their day. The practice of audiology creates an environment in which various objects come into direct or indirect contact with multiple patients and the importance of infection control is paramount.
The scope of audiology practice has expanded over the last few years placing clinicians at greater risk for potential exposure to blood and other bodily fluids. For example, intraoperative monitoring not only places the audiologist in the operating room, but requires the handling, insertion, and removal of needle electrodes. Many audiologists are involved in the administration of balance tests which, on occasion, cause patients to become nauseous and sick. Cerumen management, hearing aids, immittance measures, otoacoustic emission probes and the like involve direct or indirect contact with cerumen.
Cerumen, a bodily substance, is not considered an infectious agent per se until it becomes contaminated with blood or mucus (Kemp, Roeser, Pearson, & Ballachandra, 1996). The color and viscosity of cerumen, however, makes it difficult to detect the presence of such bodily fluids, particularly if the material is clear like mucus or dark-colored like dried blood (Kemp & Bankaitis, 2000a; Kemp & Bankaitis, 2000b). Due to the potential for contamination, cerumen should always be treated as an infectious substance because the clinician is not in the position to determine the content of cerumen through visual inspection (Kemp et al., 1996).
Most importantly, audiological services are sought by a wide range of patients who vary across several factors such as age, underlying disease, nutritional status, exposure to past and current pharmacological interventions and socioeconomic status. As such, audiologists often provide services to individuals with compromised immune systems (Bankaitis, 1996, 1998, 1999). For example, patients with varying degrees of HIV-infection have been identified as at-risk for developing hearing loss as a direct or indirect consequence of the virus (Bankaitis, 1996; Bankaitis, Christensen, Murphy, & Morehouse, 1998; Bankaitis & Schountz, 1998, Bankaitis, 1999). With the life advantage of retro-viral pharmacological agents, many HIV/AIDS patients are able to return to work (Johnsen, 1998) and therefore, seek audiological services, particularly from the standpoint of improving quality of life (Bankaitis, 1996; Friedman & Noffsinger, 1998; Johnsen, 1998). Although the risk of transmitting HIV during the provision of audiology services is remote, HIV-status and other degrees of immunocompromise influence the overall efficacy of the immune system (Schountz & Bankaitis, 1998).
Geriatric, diabetic, HIV-positive, pediatric and other patient populations with compromised immune systems are at considerable risk of developing serious, life-threatening opportunistic infections as a result of exposure to ubiquitous microbes. In other words, when reduced resistance occurs in an individual, otherwise non-pathogenic organisms may gain access to an immunocompromised system, resulting in the development of serious infections. As such, great care must be taken to protect all patients and clinicians from potential sources of infection in the audiology office.
Infection Control can be defined as an organized effort to manage one's environment in order to minimize exposure to micro-organisms which may make you or your patients sick (Kemp & Roeser 1998). Regardless of whether the organism is a bacteria, fungus, or virus, the goal of infection control is to reduce or eliminate opportunities for direct or indirect transmission of microorganisms from person to person (Kemp & Bankaitis, 2000a; Kemp & Bankaitis, 2000b). This process not only involves controlling exposure between people, but between people and work environment. To optimally achieve infection control, hearing health care settings must rely on the guidance of infection control guidelines that specifically outline procedures that, when followed, reduce the potential for cross-contamination and cross-infection (Kemp & Bankaitis, 2000a). Prior to incorporating audiology specific infection control guidelines, an understanding of disease transmission is needed.
MODES AND ROUTES OF DISEASE TRANSMISSION
In general, microorganisms may be transmitted via four principle modes: contact, vehicle, airborne, and vectorborne. With regard to audiology settings, contact transmission represents the most frequent means of disease transmission (Kemp & Bankaitis, 2000b). Contact transmission may occur directly or indirectly. Direct contact transmission may occur when the hearing health care profession touches the patient's ear with an unwashed hand whereas indirect contact transmission may occur when a clinician handles a hearing aid with bare hands which the patient placed in the hands of the clinician. Vehicle transmission applies to diseases transmitted by contaminated items including food (i.e. salmonellosis) or water (i.e. legionellosis) whereas airborne transmission refers to the dissemination of infectious agents by air. Lastly, vectorborne transmission occurs when an animal or insect carries the pathogen, infecting the susceptible host (mosquitoes transmitting Malaria). Regardless of the mode of disease transmission, once a transmission mode is established, microbes seek an entry into the body, usually by natural orifices such as the nose, eyes, and ears, or via the epithelial layer of the skin.
BASIC INFECTION CONTROL GUIDELINES FOR AUDIOLOGY
Infection control programs are designed to reduce the number of germs in the working environment and eliminate cross-contamination. The effectiveness of the program begins with a mindset which assumes all patients are possible carriers or potential hosts of an infectious disease. In addition, the Occupational Health and Safety Administration (OSHA), the regulatory body responsible for overseeing the implementation of safety procedures in the workplace, requires that each facility have a written infection control plan. The plan is to be made available to all workers and is to provide protocols to be used in the office for infection control. The written plan requires the following to be included:
- Exposure classification:Each employee is classified on the basis of potential exposure to blood and other infectious substances
- Record of Hepatitis B vaccination and records of vaccination
- Plan for annual infection control training and records of training
- Implementation protocols: Actual steps that will be taken in your office to observe universal precautions
- Postexposure plan and records
- AUDIOLOGY INFECTION CONTROL BASICS
The Centers for Disease Control and Prevention (CDC) has recognized handwashing as the single most important method in reducing the spread of disease, particularly in the health care setting (Freyer, 1998). It is critical to any infection control program. Hands should be washed with hospital grade antibacterial soap and water immediately before AND after each patient. The skin must be washed by rubbing vigorously to clean hands, wrists, and lower forearms. Bar soap should not be used as it is a breeding ground for germs. In the absence of access to a sink and running water, antimicrobial 'no rinse' hand degermers are effective if used according to directions.
Gloves should be worn prophylactically when the risk of exposure to cerumen or other bodily fluids exists. In audiology practice, gloves should be used during cerumen management, when pulling out earmold impressions, handling needle electrodes for intraoperative monitoring procedures, handling used immittance or otoacoustic emission probe tips, when handling hearing aids, and the like. Gloves should also be worn when cleaning up spills of infectious waste and while disinfecting a contaminated area. After use, gloves should be properly disposed of and hands should be washed immediately after removing gloves. Unless grossly contaminated with blood or other bodily fluids, gloves may be disposed of in the regular trash.
Safety glasses and disposable masks are necessary when there is risk of splash or splatter of potentially infectious material, or when the clinician/patient is at risk of airborne contamination. Cerumen removal by irrigation may require safety glasses or masks if the splash of the irrigation is significant. Also, safety glasses and a mask should be worn when working with a grinding or buffing wheel to reduce the chance of microorganisms and particles of plastic from being inhaled or landing in eyes.
Waste (gloves, wipes, paper towels etc.) contaminated with blood or ear drainage or cerumen containing blood or ear drainage can be placed in the regular trash unless the blood or mucous is significant in amount. Waste contaminated with blood, ear drainage, or cerumen should be separated from the rest of the trash to minimize the chance of clean up personnel making casual contact with it. This can be accomplished by placing such waste in small plastic bags or wrapping it in paper. Materials containing significant amounts of blood should be disposed of in impermeable bags labeled with the biohazard symbol.
Sharp instruments such as needles, scalpel blades, and the like must be disposed of in a sharps box. The sharps box is a plastic container that can not be easily penetrated and is, therefore, designed to minimize contact with sharp objects. Sharp boxes should be labeled as a biohazard. These containers are to be handled by a licensed waste disposal company.
When to clean, disinfect, versus sterilize
Cleaning means that gross contamination is removed but germs are not necessarily killed. It is an important precursor to disinfecting or sterilizing because gross contamination must first be removed before these procedures will be effective. Disinfection means killing germs. There are various levels of disinfection depending on how many and which germs are killed. For example, household disinfectants kill a very limited number of germs whereas hospital grade disinfectants kill a much wider variety of microbes. For audiology purposes, hospital grade disinfectants should be used.
In contrast to disinfection, sterilization means killing 100 percent of the vegetative microorganisms and their endospores 100 percent of the time. When microbes are challenged, they revert to a spore form of life which is much more resistant to outside forces. If the spore is not eliminated, it may become vegetative again and cause disease. The preferred sterilization technique is heat under pressure in an autoclave. Unfortunately, most implements used by audiologists would melt in these sterilizers. Consequently, 'cold sterilization' with chemicals may work best for audiologists. This is accomplished by soaking instruments in 2% glutaraldehyde for ten hours, or in 7.5% hydrogen peroxide (Sporox) for 6 hours. Glutaraldehyde in a concentration of 2% or higher and hydrogen peroxide in a 7.5% solution are currently the only chemicals approved by EPA for sterilization. Contrary to popular belief, a 10:1 solution of water and bleach is not a sterilant.
When to Disinfect
Disinfection is acceptable for those items that do not touch blood or other infectious substances ('non-critical' items). Always clean first, then disinfect. Non-critical items in an audiology setting include earmolds, headphones, specula or any object or surface that is not contaminated with visible blood, ear drainage or cerumen that contains such bodily fluids. All of these items should be disinfected before handling or re-use. Hearing aids should not be handled with bare hands until the item has been completely cleaned and disinfected with a disinfectant towelette. The audiologist may need to receive the hearing aid(s) with a gloved hand or ask the patient to place the instrument on a tissue or in a container until it can be cleaned and disinfected. Gloves should be worn while disinfecting the appliance or a disinfectant towelette used to hold, clean and disinfect the appliance,
Surfaces in work areas should be disinfected regularly. Routine disinfection should be performed on tables, countertops, or repair benches where earmolds and hearing aids are cleaned. Patient 'touch' surfaces like the examination chair arm rests, and the reception counter should also be routinely disinfected.
Waiting room toys and motivation devices must be disinfected frequently. Toys should be nonporous. Children invariably place toys in their mouths and therefore great care should be taken when selecting, handling and cleaning objects which may potentially contain saliva. Always thoroughly wash hands after contacting a potentially infectious item or wear gloves while cleaning up.
When to Sterilize
Critical items, those that may contact blood or mucus, require sterilization. Cerumen is not an infectious substance per se, but often contains dried blood or mucus. If there is visible blood in or on cerumen, then that cerumen specimen is a potentially infectious substance and the instruments contacting it must be precleaned and then sterilized. The color and viscosity of cerumen make it very difficult for the clinician to determine whether blood, particularly dried blood, is present. For this reason, instruments like curettes used in cerumen removal, impedance probe tips, and otoscopic specula, etc. should be sterilized after use. The process requires cleaning first, then sterilizing the instruments in an autoclave or 2% glutaraldehyde or Sporox (7.5% hydrogen peroxide).
CURRENT STATUS OF INFECTION CONTROL IN THE AUDIOLOGY CLINIC
Only a few survey studies have attempted to assess general infection control practices in the audiology literature. Based on the results of a randomly distributed infection control survey, Hudson and Ballachandra (1996) summarized that audiologists were unaware of the potential sources of cross infection in the clinic, thereby creating an environment of increased risk in the spread of infection and disease. The majority of surveyed audiologists were unaware of the potential for cross-infection by way of virulent pathogens located on standard audiological equipment including headphones, otoscope specula inserted in the ear canal during ear canal inspection, and probe tips inserted in the ear to assess ear drum mobility.
Most recently, Amlani (1999) reported findings of an infection control survey that was randomly distributed to 640 practicing audiologists. Based on responses from 311 audiologists (49% response rate), 70% of surveyed audiologists believed that audiology setting is not associated with high exposure to communicable diseases. In addition, only 26% (81/311) reported washing hands after each patient although the percentages improved based on the type of services provided. Hand washing increased to 63% (188/311) when earmold impressions were removed from patient's ears. However, it was unclear as to whether or not hands were washed immediately after the handling of an earmold impression or only at the end of the appointment time. None of the respondents (311/311) used latex gloves when handling earmold impressions. Over one-third of the audiologists (36%) not only handled earmold impressions with bare hands, but reportedly did not wash hands after the patient appointment. Since the outer surface of an impression removed from the ear is contaminated with substances lining the ear canal (i.e. cerumen, mucous, blood etc.), handling of the earmold impression without gloves or without immediately washing hands poses a risk in cross-contamination to any person or surface in which the clinician subsequently comes in contact with.
Protection against inadvertent transmission of disease from patient to patient, clinician to patient, and patient to clinician must be approached from a preventative standpoint. It has been documented that infection rates in clinics and other treatment facilities have been reduced or eliminated with the implementation of appropriate infection control measures (Wenzel, Nettleman, Joanes, & Pfaller, 1991). As the scope of audiology practice exposes clinicians and patients to potentially infectious organisms, the importance of an audiology-specific infection control can not be overlooked.
For more information on this topic, please refer to Infection Control for the Professions of Audiology and Speech-Language Pathology available by calling 1-800-347-1960 or contact Bob Kemp of Oaktree Products at (636) 530-1664 or 'A.U.' Bankaitis of St. Louis University Medical Center at (314) 577-6110.
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Schountz, T. & Bankaitis, A.E. (1998). Basic Anatomy and Physiology of the Immune System. Seminars in Hearing, 19(2): pp. 131-142.
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