Anesthesia component cleaning considerations: Soak, hang, swing, toss

Among the questions commonly asked in the AAHA Community (open to all AAHA members) is this one: “How should we clean our breathing circuits and reservoir bags after using them?” 

The answers given range from “use a mild detergent” to “use a disinfectant” to “throw away after each use” to “spot clean only.” If one thing is clear from these varying comments, it’s that there is no clear consensus. 

A lack of standards

According to Darci Palmer, BS, LVT, VTS (Anesthesia and Analgesia), Executive Director of the Academy of Veterinary Technicians in Anesthesia and Analgesia and Veterinary Anesthesia Nerds Administrator, the reason that there are not more definitive standards for cleaning anesthesia machine parts is that most equipment was originally designed to be single-use only (as it is still used in human medicine). “Because of the high risk of cross contamination with human diseases, many items used during anesthesia are deemed disposable or single use only,” she explained.   

In human medicine, she said, “the number one reason items like endotracheal tubes, breathing circuits and reservoir bags are not reused is liability.” In veterinary medicine, where we are decidedly more cost-conscious and less concerned with the liability associated with cross-contamination between patients, many items that would be single-use only on the human side get disinfected and reused as much as possible.  

According to Palmer, “No organization in veterinary medicine has taken the initiative to develop cleaning protocols associated with anesthesia equipment.” As a result, different practices use different methods to clean (or not clean) their anesthesia components. Palmer has utilized many of them herself over the years, and she reported in a recent blog article that based on available research citing a “very low to almost non-existent” rate of cross contamination of breathing circuits, her team discontinued their practice of cleaning anesthesia tubing and rebreathing bags. Instead, they would hang them to dry after each use and replace the tubing every 4 to 6 months barring damage, gross contamination, or exposure to a known infectious patient.     

In the absence of robust research on the topic and well-defined protocols, it’s understandable that not all practices have come to the same conclusions when it comes to anesthesia component cleaning. Here, Palmer shares expert insight from her years of experience and the available literature to give veterinary professionals some points to consider when they create their own protocol.  

Disinfection and sterilization methods 

Breathing circuits 

For practices that choose to clean their breathing circuit tubing, soaking in the tubing in disinfectant is a common cleaning method. Disinfectants generally do a very good job of killing pathogens of concern, but there are many factors to consider when cleaning anesthesia machine parts.  

The first is that not all tubing types can be soaked. “The ONLY breathing circuits that are appropriate to soak in disinfectants are the single hoses (e.g. dual wye rebreathing or Jackson Rees non-rebreathing),” Palmer said. Coaxial circuits should not be soaked because they cannot be submerged in water.   

Apart from tubing selection, successful soaking requires proper disinfectant dilution and soaking timing. “The use of too concentrated solutions or soaking them too long in the solution allows certain disinfectants such as chlorhexidine to leech into the plastic,” Palmer said. The tubing must be thoroughly rinsed as well to remove any disinfectant residue prior to patient use. She explained that exposure to chlorhexidine via the breathing circuit can result in tracheal irritation and, in some cases, necrosis.  

What about other methods of sterilization? Components made of plastic and rubber cannot be autoclaved without being destroyed. Ethylene oxide (ETO) could be used instead, but Palmer said that the cost of this method is often higher than the cost of purchasing new breathing circuits.  Also, she added, plastic components need to be aerated after ETO use, extending the time during which they cannot be used.  

Rebreathing bags 

Just as with tubing, many—but not all—rebreathing bags are also meant to be single use in human medicine as well. “The material used to make the reservoir bag will determine if it is reusable in human medicine,” Palmer explained. Reuse of a bag in human medicine would require autoclave sterilization, something that can only be accomplished with a silicone reservoir bag that is much more costly than the rubber bags most often used in veterinary medicine. 

In her blog, Palmer explained that rebreathing bags can be cleaned with a soapy solution or dilute chlorhexidine and then rinsed thoroughly with water. A note of caution, however: some reservoir bags are lined with a surfactant to prevent the inner surfaces from sticking to each other. Cleaning with soap or disinfectant may disrupt this layer, leading to decreased functionality and shortened lifespan of the bag.  

Drying methods 

Hanging is a commonly used drying method that allows for air drying of the tubing and reservoir bag after use. This is not a fast process, however. Palmer said that circuits should be hung to dry for at least a few weeks in a cool area of the hospital with low humidity. Reservoir bags should be hung upside down, not laid flat on a surface.  

Swinging can help to accelerate the breathing circuit drying process by forcing more of the water droplets out of the tubing, but it is not always an appropriate step. Coaxial breathing circuits (such as Universal F rebreathing circuits and Bain coaxial non-rebreathing circuits) should never be swung, Palmer said, because swinging can cause the inner hose to detach from the outer hose at one or both ends. If this damaged tubing were to be connected to a patient, it would effectively be mechanical dead space and cause significant hypercapnia, Palmer explained.  

Even when swinging is not contraindicated, it may not remove all the moisture in the tubing.  Dual wye rebreathing hoses, Palmer explained, are corrugated and will not be completely dried by swinging.  

To achieve better, faster drying, Palmer said that some practices will use forced air (such as from a Bair Hugger) to dry their breathing circuits. This requires the purchase of an attachment to connect the Bair Hugger to the tubing.  While in theory this is an effective practice, Palmer said it may not be practical if a patient needs thermal support. “The use of a Bair Hugger is nice, but if the practice only has one then priority should go to the patients,” she said.  

 

 

 

Making a decision for your practice 

With differing opinions and a lack of defined protocols, it can be difficult to determine the best course of action for preventing cross contamination when it comes to anesthesia component cleaning. Palmer recommended that no matter how a practice decides to approach cleaning and drying of these components, they plan to regularly inspect and replace all components. This is particularly important for coaxial circuits, she said, which need to be replaced more often than other types.   

Palmer said it’s also essential for practices to evaluate the available evidence surrounding the efficacy of cleaning protocols and determine if they are feasible for their team. “If a clinic is going to invest staff time and products to clean breathing circuits, then the process must be done correctly to ensure that the circuits are in fact being disinfected,” she said. “Otherwise, the clinic is just wasting money without any gain in patient care or safety.”   

As a member of the AAHA Community, you can also learn more from your colleagues on this topic on these threads:

Washing anesthesia circuits

Is there a protocol for cleaning tubing and bags?

Further reading: 

Veterinary Nerds Breathing Circuit Classification 

Veterinary Nerds Cleaning Breathing Circuits and Reservoir Bags 

An investigation of the bacterial contamination of small animal breathing systems during routine use 

Anesthesia Best Practices: Anesthetic Equipment Checklist

Photo credit: Manu Reyes/iStock via Getty Images 

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