Infection control professionals have long considered glutaraldehyde to be an effective high-level disinfectant. Here are five tips to make it a safe one as well.
1. Clean before you disinfect. As with all sterilization and disinfection processes, the first critical step is to thoroughly clean the items. Glutaraldehyde is a tissue fixative - in fact, one of its industrial uses is in leather tanning. Using this chemical without cleaning first could cause proteinaceous material to adhere to instrumentation, shielding microorganisms from chemical contact. Once you've cleaned the items, rinse them to remove detergents and other surfactants that could alter the action of the liquid chemical disinfection solution. One more thing: Let items dry before high-level disinfection to minimize the dilution of the glutaraldehyde solution.
2. Consider time and temperature. The FDA has cleared 14 brands of solutions containing glutaraldehyde. Concentrations of glutaraldehyde vary from a low of 1.12% when combined with 1.93% phenol/phenate to several 3.4% aqueous solutions. Each product makes a label claim of how long contact must be maintained at a specified temperature to satisfy the FDA required testing of tuberculocidal activity. You can access the most current listing of cleared liquid chemical sterilants and view the time/temperature claims for sterilization and high-level disinfection at
www.fda.gov/cdrh/ode/germlab.html.
This time-temperature relationship has been the source of much controversy in recent years. The FDA-required tests for tuberculocidal activity are very strenuous, involving much greater contamination than would be found on a cleaned endoscope. Thus,experts have argued that shorter contact times are adequate in actual practice when devices are properly cleaned. According to these experts, a 20-minute immersion in at least a 2% solution of glutaraldehyde at room temperature is adequate.
Quick Tips for Safe Use of Glutaraldehyde | | |
3. Rinse thoroughly. Glutaraldehyde that is not removed at the end of the immersion time can injure tissue in patients. It can also be a sensitizing agent even at low concentrations when in contact with tissue. Therefore, rinse items thoroughly after you soak them. In general, the rinse water should be sterile so as not to introduce any waterborne contamination. Some automated endoscope reprocessors use filters to produce bacteria-free water that is technically not sterile, although it is safe for use on semi-critical devices that contact intact mucous membrane. While controversial, the FDA allows the use of filtered water for rinsing critical items intended for contact with the bloodstream, normally sterile body areas or compromised tissue.Consult device manufacturers' written recommendations on processing, including the amount of water needed to provide adequate rinsing. Merely dipping the device in a container filled with water for rinsing is not adequate. There must be flow-through of rinse water in lumens, which will require some agitation or irrigation. For flexible endoscopes, manufacturers recommend following water rinses with an alcohol rinse to aid in drying. Residual water in a sterile or high-level disinfected scope that is exposed to the air and handling can serve as a reservoir for bacteria.
4. Monitor the solution. Glutaraldehyde solutions are generally labeled for reuse for a specific maximum period of time ranging from 14 to 28 days, depending on brand. However, dilution from water remaining in or on devices can shorten the reuse time. At least once every day, monitor the solution concentration using chemical indicator strips. Keep a log of each test.
5. Use caution. While glutaraldehyde is a very effective disinfectant, it has some drawbacks. Its vapor is a respiratory irritant that can cause coughing and bronchial irritation, especially for asthma sufferers.
There is no official federal OSHA ceiling limit value for glutaraldehyde. However, the American Conference of Governmental Industrial Hygienists (ACGIH) currently recommends a ceiling limit of 0.01 parts per million for occupational exposure. Under OSHA's authority to require that employers provide a safe work environment, that agency will use the ACGIH limit for assessing worker safety. To achieve this level, only use glutaraldehyde in well-ventilated areas with containers that have lids that are kept in place. You may need to invest in freestanding or vented chemical fume hoods. Do not use open boats or containers for soaking devices. Also, have a plan in place to deal with any spills of glutaraldehyde solutions.
When working with any liquid chemical sterilant, wear eye goggles or a shield. Eye contact with 2% or higher concentrations of glutaraldehyde can result in severe irritation and damage.
There is no evidence that glutaraldehyde is implicated as a mutagen, teratogen or a carcinogen. Some have confused data and warnings about ethylene oxide and formaldehyde with glutaraldehyde. These are all very distinct chemicals with their own unique properties. One should not generalize from one to another.
Janet K. Shultz (jsassoc@msn.com) is a consultant on aseptic practice and instrument processing in the perioperative care setting.
