Besides obtaining reliable audiometric test data, Occupational Hearing Conservationists (OHCs) have other elements of the hearing conservation program that must receive consistent attention. Federal regulations and health-care accreditation programs require awareness of infection risk, and cleaning common headsets can introduce risks of its own.
With regard to infection control standards, direct contact of the pinnae (outer ears) with the headset ear cushions is of particular concern. Since the cushions are placed over the ear, they may serve as potential carriers of microorganisms (from the air, skin contact, draining ears, etc.) when in contact with the pinnae and the ear canal opening (Bankaitis, 2012).
Most hearing conservation programs use Telephonics TDH39P transducers in the audiometric headsets. TDH-style headsets are comprised of a headband, two transducers with plastic cushions, and a cable to connect to the audiometer. While the headsets have advantages in low cost and ease of use, they can present challenges when cleaning and disinfection is necessary. At Benson Medical Instruments alone, we have seen several facilities inadvertently damage their headset transducers due to improper cleaning of the earphone/transducer filter.
A common cause of transducer failure occurs when OHCs disinfect ear cushions and accidentally introduce cleaning liquid onto the earphone. Transducers and their filters make up the earphone, which is very close to the ear cushions and should not come into contact with liquid of any kind. Kathy Parks from Telephonics, a manufacturer of transducers, indicated that attempting to clean or disinfect the transducer itself (as opposed to the ear cushion) can "damage the filter cloth" and "force the patient's" skin oils into the filter, thus breaking down the adhesives in the transducer (Parks, 2010).
This leaves a few options open when dealing with earphone cushions:
If an OHC decides not to use earphone covers and goes with options 2 and 3 above, there are three strategies that have been used in the past to try to disinfect ear cushions:
First, we have the option of alcohol wipes. Alcohol wipes are recommended by Lee Grason of Grason & Associates, a manufacturer of ear cushions used with TDH-style headsets. Grason recommended the use of medical-grade alcohol wipes because this solution was tested on the earphone cushions with virtually no degradation until one to two (and sometimes even three) years later. According to Grason, alcohol kills most pathogens (Grason, 2012).
Next is the troublesome utilization of baby wipes. Use of baby wipes has been shown to be detrimental to ear cushions' lifetime. Grason also stated operators should never use baby wipes to clean the earphone cushions. Some baby wipes contain scents, oils (where the active ingredient is usually chloride), lanolin, or disodium EDTA (an oxidizer also used in gasoline), and when these ingredients are used the outer surface of the cushion will prematurely age and harden as a result. Those doing mobile testing in hot climates will find that heat plus baby wipes equals disaster, because usage leads to a hardened outer surface and cracking after prolonged use. In any case, baby wipes are not designed to disinfect surfaces, including audiometric headsets.
The third option involves using a non-alcohol disinfectant. A.U. Bankaitis, vice president of Oaktree Products, Inc., a company which manufactures hearing health-care products, indicated that while alcohol is a disinfectant, it "chemically denatures acrylic, rubber, silicone and plastic." Bankaitis recommends a non-alcohol-based disinfectant, such as one with the active ingredient quaternary ammonium, because it doesn't have the drawbacks of alcohol but retains the benefit of being a wide-range disinfectant.
So where do governmental and non-governmental regulatory agencies stand regarding the cleaning of headsets?
The Occupational Safety & Health Administration (OSHA) does not have any specific standards for cleaning audiometric equipment, but a representative stated unofficially in an e-mail message that any employee who has contact with potentially infectious material should be covered under OSHA's Bloodborne Pathogen standard—1910.1030.
Since an OHC cannot tell from a visual inspection of cerumen whether it contains blood or other pathogens, the OSHA standard of 1910.1030(d)(1) would apply in taking precautionary measures. The standard states:
"Universal precautions shall be observed to prevent contact with blood or other potentially infectious materials. Under circumstances in which differentiation between body fluid types is difficult or impossible, all body fluids shall be considered potentially infectious materials."
Cerumen tends to reside in the ear canal and it is highly unlikely that an over-the-head ear cushion will come in contact with cerumen (although it can), but most experts agree that precautionary measures should be taken.
Another relevant consideration is noted in 1910.1030(d)(4)(ii):
"All equipment and environmental and working surfaces shall be cleaned and decontaminated after contact with blood or other potentially infectious materials."
A representative of the Joint Commission (formerly the Joint Commission on Accreditation of Healthcare Organizations) stated that the Joint Commission does not provide any specific guidelines, but, instead, defers to the Center for Disease Control's (CDC) standards of infection control. The CDC recommendation directive is titled the "Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008," where headsets fall under the noncritical items list, since they are placed over the pinnae on presumably intact skin (i.e., not broken or open).
Additionally, the "CDC Isolation guideline recommends that noncritical equipment contaminated with blood, body fluids, secretions, or excretions be cleaned and disinfected after use." One reason it is necessary to clean the noncritical environmental surfaces is that "surfaces may contribute to transmission of epidemiologically-important microbes (e.g., vancomycin-resistant Enterococci, methicillin-resistant S. aureus, viruses)." (CDC, 2008)
More specifically, the operator should "ensure that, at a minimum, noncritical patient-care devices are disinfected when visibly soiled and on a regular basis (such as after use on each patient or once daily or once weekly)." (CDC, 2008) The CDC advises as well that disinfectants should be nontoxic, fast-acting, and environmentally-friendly (meaning that the product shouldn't damage the environment on disposal) (CDC, 2008).
But while the CDC recommends that equipment be cleaned on-site with such low-level disinfectants as ethyl or isopropyl alcohol (CDC, 2008), elsewhere, the guideline contradicts the aforementioned statement by stating that an ideal disinfectant should have surface compatibility, that is, the substance shouldn't cause the deterioration of "…rubber, plastics, and other materials." (CDC, 2008) Since there is concern that alcohol can dry out the cushion, thus causing deterioration, one is left to wonder what can be used to sufficiently disinfect the cushion.
From a nongovernmental standpoint, the Hearing Conservation Manual published by the Council for Accreditation on Occupational Hearing Conservation states that handwashing before and after examining someone's ears is the "most important" way to reduce the risk of contamination (CAOHC, 2010). Earphone cushions should also be cleaned before handling or re-use, according to both the American Academy of Audiology and the Navy and Marine Corps Public Health Center, with disinfectant towelettes (not full-strength pharmaceutical-grade "rubbing" alcohol) so as to avoid cross-contamination among patients (CAOHC, 2010).
So after seeing what the relevant authorities have to say about infection control, some may wonder: how exactly are OHCs supposed to clean their headsets?
Because of the aforementioned varying guidelines, there are unfortunately no hard and fast rules on how to clean or protect ear cushions from possible contamination. An OHC's best method for compliance would be to consider the following suggestions when thinking about cleaning headsets to ensure a long life.
By following the above guidelines, OHCs can feel secure knowing they've done their part to curb the risk of infection among their patients.
"Academy of Audiology Guideline". Infection Control in Audiological Practice. Audiology Today. Vol. 15:5, p. 17.
Bankaitis, AU (2005). "Hearing Aids: Lick ‘Em and Stick ‘Em?" Audiology Today 17 (6): 2.
CDC (2008). "Guideline For Disinfection and Sterilization in Healthcare Facilities", pp. 30, 84, 104-5, 106, 107.
Hawke, M (2002). "Update on Cerumen and Ceruminolytics." Ear Nose Throat J. Aug;81(8 Suppl 1):23-4.
MedlinePlus (2012): Ear infection-Acute. Retrieved from http://www.nlm.nih.gov/medlineplus/ency/article/000638.htm.
Navy and Marine Corps Public Health Center (2012). "The Audiometer & Test Environment" Power Point presentation. Retrieved from http://www.nehc.med.navy.mil/.../audiometerandthetestenvironment.ppt.
Suter, Alice H. Hearing Conservation Manual, CAOHC, 4th ed., 2010, pp. 19, 24, 66, 69.
Kimberly Fortin recently joined Benson Medical Instruments, a manufacturer of audiometers and software for hearing conservation in Minneapolis, MN.