A Practical Guide To Using Glutaraldehyde and Other High-Level Disinfectants
By Phillip Coles
All high-level disinfectants, including glutaraldehyde, OPA, peracetic acid, and hydrogen peroxide, are designed to kill microorganisms and have the potential to be irritants and possibly sensitizers. Glutaraldehyde has been the high-level disinfectant of choice for more than 30 years. Yet it is only in the last ten years that its use has become regulated. This has prompted a gradual move away from glutaraldehyde to other disinfectants. With virtually no odor, other disinfectants are often perceived as harmless, which results in healthcare workers not taking proper precautions when handling and working with them.
A new BIOSHARE Focus Sheet will soon be published by the Dow Chemical Company (now merged with Union Carbide, the supplier of raw glutaraldehyde and OPA), titled "Health Effects of and Handling Precautions for o-Phthalaldehyde (OPA)." It states, "these solutions (OPA) should be used in well-ventilated rooms (i.e., ten air exchanges per hour) or in a hood, and personnel using the solutions should wear appropriate personal protective equipment (PPE) to prevent eye and skin exposure to either the vapor or the liquid." BIOSHARE literature is also available for glutaraldehyde and makes similar recommendations.
The American National Standard1
Regardless of which high-level disinfectant you choose, the basic safety protocol is essentially the same. Although originally written for glutaraldehyde, the engineering controls and personal protection requirements in the American National Standard Institute (ANSI) are the standard for healthcare facilities. They form the basis of the standards used by OSHA and JCAHO. The object of this article is to review and simplify the key issues of the ANSI standard and to offer some practical and inexpensive solutions for working with high-level disinfectants.
Three Key Issues of the ANSI Standard
Wading through the ANSI standard can be a daunting task and often results in inaction. It can be broken down into three key areas: ventilation, PPE, and training/continuing education.
Ventilation: Section 3.4.2 of the ANSI standard states that "rooms in which glutaraldehyde disinfection/sterilization is performed should be large enough to ensure adequate dilution of vapor and should have a minimum air exchange rate of ten air exchanges per hour." This is the same recommendation that the Dow Chemical Company gives for OPA and glutaraldehyde.
Typically the only rooms in a healthcare facility having ten or more air exchanges would be the OR or isolation rooms. Even with ten air exchanges per hour, healthcare workers may still have a problem if the supply and return air vents are all in the ceiling. Fresh air can simply short circuit over to the return vent without mixing with the air in the lower part of the room. Fumes from the disinfectant can actually be drawn upward across the worker's face, exacerbating the problem.
Section 3.4.3 goes on to say that where ventilation is not adequate (less than ten air exchanges), "a local exhaust hood should be installed for the containment of glutaraldehyde vapor." The exhaust hood can either be ducted to the outside or a ductless fume hood that uses a carbon filter can be used. This again is the same recommendation that Dow Chemical gives for OPA and glutaraldehyde.
A fully enclosed hood either vented to the outside or passing through a carbon filter (ductless fume hood) not only gives protection from fumes, but also contains splashes and spills that are a major source of fumes.
Unless a hospital has fully enclosed automated washers or ten air exchanges per hour, a ducted or ductless hood should be used when using glutaraldehyde or OPA.
Personal Protective Equipment (PPE): Section 4.2.2 of the ANSI standard reviews this in depth. This is perhaps the most commonly neglected area simply because it is inconvenient! The model in Figure 1 is shown wearing the correct apparel. The following recommendations are for all high-level disinfectants:
- Wear gloves that are long enough to extend up the arm to protect the forearm or clothing from splashes or seepage. For glutaraldehyde, nitrile gloves are preferred. For OPA, butyl rubber or PVC gloves are best. For incidental contact, latex gloves can be used with both chemicals; however, OPA solutions can penetrate certain types of latex gloves in less than 15 minutes.
- Always wear splash-proof monogoggles, or both safety glasses with side shields and a wraparound full-face shield, when working around OPA solutions. Many face shields alone may not offer total protection against eye contamination and should be used as an adjunct to protect facial skin.
- Wear an impervious gown. Splashes from OPA will leave a permanent black stain on clothing.
- An emergency eyewash unit should be located within ten seconds travel time or 100-foot travel distance. One easy, inexpensive way to comply with this requirement is to mount a small eye wash that fits directly on a water faucet.
All four of the above recommendations should be in place; however, healthcare workers should ensure that a face shield and gloves are worn.
Although not strictly part of PPE, a neutralizer for glutaraldehyde and OPA is an important tool in worker safety. These chemicals retain their antimicrobial activity and their potential as irritants and sensitizers after their re-use date has expired. The worker who is disposing of it, is at risk from elevated exposure levels, splashes and spills, or worse, dropping the bowl. Adding glycine can safely and quickly deactivate both glutaraldehyde and OPA. Glycine also can be used to deactivate spills.
Training and Continuing Education: Section 5 of the ANSI standard deals with personnel considerations. With the high turnover in staff and increased patient load, adequate training on the use of disinfectants often is forgotten. Even long-time staff need to be updated on the proper procedures. This is important for both patient and worker safety, and include the following:
- Personnel safety including means of avoiding exposure to glutaraldehyde and other liquid chemical sterilants.
- Safe use of liquid sterilants, including applicable regulations and label directions. This includes checking the efficacy of the sterilants at least once a day by using the appropriate test strip.
- Keeping proper records by logging the expiration date of the disinfectant. It is good practice to write the date on a piece of tape and attach it to the soak container.
- Ensuring your staff has read and understands the instruction manual of the specific instruments being disinfected.
- Understanding the proper soaking time. Most glutaraldehyde labels require a 45-minute soak time at 77°F AORN, APIC, SGNA, and ASGE in a joint position paper recommend a 20-minute soak time at room temperature.2 This is the accepted norm across the country.
Exposure levels for glutaraldehyde: There is confusion on what the allowable exposure levels are and how they are enforced. OSHA limit is 0.2 parts per million (ppm), which is enforced under their General Duty Clause. In 1995, Union Carbide lowered its recommended exposure level to 0.1 ppm. ACGIH has recommended a much lower level of 0.05 ppm. It is important to remember that these are instantaneous exposure levels, and should not be exceeded for a single moment. The act of pouring fresh glutaraldehyde, removing instruments, and disposing of used glutaraldehyde, will typically create levels in excess of the OSHA requirement for short periods.
Monitoring glutaraldehyde: There are four primary methods for measuring glutaraldehyde exposure. The badge, silica gel tube, and filter cassette method provide a 15-minute integrated time-weighted sample. The problem with these methods is they are unlikely to pick up momentary spikes in exposure level and lead to a false sense of security that glutaraldehyde exposure levels are acceptable.4 The fourth method is a hand-held meter, which has the advantage of being able to measure instantaneous levels. However, its limitation is detecting amounts lower than 0.05 ppm.
Effects of exposure to glutaraldehyde: Some of the adverse effects from exposure include skin, eye and nasal irritation, headaches, cough, and occupational asthma. In more serious cases, workers have attributed glutaraldehyde use to multiple chemical sensitivity/idiopathic environmental intolerance, resulting in litigation being brought against some healthcare facilities. Contrary to popular belief, there is no evidence that glutaraldehyde exposure is carcinogenic.5
Fume Hoods: A Simple Solution: Most hospitals have installed enclosed automated washers in their CS and OR departments. This greatly reduces the potential for exposure and eliminates splashes and spills. However, smaller departments and offices, for the large part, manually disinfect their instruments in conventional soak trays with little or no fume and splash protection.
Fume hoods, as required by the ANSI standard and recommended by Dow Chemical for OPA and glutaraldehyde, are a simple and affordable solution to this problem. Fume hoods are typically enclosed to capture the fumes during reprocessing before they can disperse into the room. A blower draws the fumes away from the worker. The soak and rinse trays should be placed side by side in the hood to prevent drips and exposure when transferring the instrument from soak to rinse. There are two types of hoods:
- Ducted fume hoods that vent directly to the outside or to a non-recirculating exhaust system at a location away from people and air intake ducts.
- Ductless fume hoods deliver vapor to a filter that chemically inactivates the fumes and returns clean filtered air to the room. They have the advantage of not requiring expensive ductwork or structural changes. Ductless fume hoods do not negate negative and positive airflow requirements or add to the heat/cooling requirements of the room.
Typical fume hoods are bulky and are not practical for the often cramped work areas found in most offices. One manufacturer of ductless fume hoods working directly with instrument manufacturers and hospitals has developed a large range of compact, instrument-specific, ductless fume hoods. They range from small countertop systems for soaking transvaginal ultrasound probes to large mobile workstations for flexible sigmoidoscopes and colonoscopes (Figure 1). Special molded trays have also been developed for soaking both small and large endoscopes and ultrasound probes, thereby dramatically reducing the amount of disinfectant used. The resulting cost savings justifies the cost of the fume hood, while providing protection for the worker and meeting OSHA and JCAHO requirements.
Ensuring that your staff is properly protected while working with high-level disinfectants does not need to be a complicated process. Regardless of which high-level disinfectant you use, make sure that:
- hospital staff is using proper PPE.
- A fume hood is being used if there are not ten or more air exchanges.
- Staff are properly trained in the use of the high-level disinfectant and fully understand the reprocessing procedure for the instrument being disinfected.
Phillip Coles is the president of PCI Medical in Deep River, Conn.
For a complete list of references, visit www.infectioncontroltoday.com