October 2024

In this VETgirl online veterinary continuing education blog, we review the importance of cleaning, sterilizing and proper storage of endotracheal tubes (ETT) between patient use. Often much debated in veterinary medicine, how should we be cleaning our ETTs? Should they be single use like they are in human medicine? (Not typical for the vet space due to cost). Is there an established standard of practice for ETT maintenance in veterinary medicine?

The American Animal Hospital Association standards of accreditation require that:

“Endotracheal tubes are sterile or thoroughly cleaned and disinfected with a non-irritating solution prior to use.

Endotracheal tubes are disposable and single use, autoclaved or gas sterilized between each use.

Endotracheal tubes are dried and stored in a manner that prevents contamination prior to use. (i.e., an open rack near a dental area is not acceptable; however, a clean, dry drawer or enclosed case near the induction area is acceptable).”1

The take home message is that the ETT can be a vector for transmission of pathogens from patient to patient or environment to patient. ETTs have been identified as a one of the target vectors for hospital-acquired or nosocomial infections.2 As such, establishing a thorough cleaning and storage plan for reused ETTs is essential to maintaining best practice.

While there are no established evidence-based cleaning protocols for ETT decontamination between patients in veterinary literature, comparative studies on cleaning methods have been performed. Perhaps, the most common ETT disinfectant practice in veterinary facilities includes using a diluted chlorhexidine soak. Marquis et al compared four cleaning practices:

(1) a 1-hour soak in 0.04% dilution of chlorhexidine (2% Nolvasan Solution); note, this is the manufacturer’s lowest effective concentration, with lukewarm tap water

(2) lukewarm tap water with 1 teaspoon of liquid dish detergent

(3) lukewarm tap water with no detergent or disinfectant

(4) a 1-hour, 300-ppm bleach solution in lukewarm tap water

Surprisingly, and perhaps alarmingly, they found that all four protocols still produced significant bacterial growth on culture, with no one protocol being significantly better than another at producing improved sterilization of the ETT tubes!3 These findings perhaps suggest to us in veterinary medicine (where we are more likely to reuse ETT tubes between patients), that we should be going above and beyond traditional soapy, soak and scrub techniques and consider a glutaraldehyde or ethylene oxide (ETO) sterilization technique between patients.4

Of course, before placing ETTs through a glutaraldehyde or ETO sterilization process, they must first be clean of organic debris. A glutaraldehyde sterilization process may sound appealing since it has broad spectrum activity against bacteria, fungi, and viruses (but notably not against coccidia and prions).2 It is a common disinfecting solution used with endoscopy equipment, but is caustic to mucous membranes including the airway.5 Following glutaraldehyde sterilization, endotracheal tubes need to be thoroughly rinsed and dried before use. Alternatively, ETO is used in gas sterilization technique and is effective at inactivating anything with DNA and RNA so is highly preferred for sterilizing medical equipment without causing harm to the medical equipment. The downside to ETO sterilization is the requirement of specialized equipment, ventilation and cost. Other considerations with ETO sterilization are that the turnover time for equipment sterilized by ETO is often 24 hours and ETTs must first be free of organic and inorganic debris and completely dry before ETO sterilization.

Cleaning and sterilization of the ETTs aren’t our only concerns with repeat use. Between uses, the integrity of the ETT cuff can be damaged and so should be confirmed prior to each use. Once inflated, the cuff should remain inflated. If the cuff deflates slowly over time or under pressure, the ETT should be disposed of as the integrity of the cuff is compromised which could result in a under protected airway when in use. Then finally, there is the consideration for storage between use. Once sterilized and dry, ETTs should be placed in a closed cabinet or drawer away from dust and risk of contamination (see Figure 1).

Figure 1. Closed cabinet storage for endotracheal tubes. Photo courtesy of Chris Ralphs, DACVS Ocean State Veterinary Specialists

Both PVC and silicone ETTs are the most commonly used types of ETTs in veterinary medicine today. With the risk for patient-patient and environment-patient contamination, coupled with the risk of ETT cuff integrity, more often than not, manufacturers recommend ETTs be for single patient use. And although we don’t have robust studies yet to better understand the risk level of transmitting infections to patients from reuse of ETTs, with proper cleaning and storage practices, these ETTs can withstand multiple uses in veterinary medicine.

Check out how to check your endotracheal tube cuff for a leak HERE.

Once intubated, make sure you know how to properly inflate your endotracheal tube cuff by watching this video HERE.

References:

  1. American Animal Hospital Association. AAHA Standards of Accreditation. Updated 15MAR2024. https://www.aaha.org/resources/aaha-standards/traditional-standards/
  2. Stull JW, Bjorvik E, Bub J, et al. 2018 AAHA Infection Control, Prevention, and Biosecurity Guidelines. J Am Anim Hosp Assoc. 2018 Nov/Dec;54(6):297-326. doi: 10.5326/JAAHA-MS-6903. PMID: 30376377.
  3. Marquis CR, Gull T, Dodam J, et al. Comparison of four endotracheal tube cleaning protocols in anesthetized dogs. J Am Vet Med Assoc. 2023 Jan 2;261(3):336-341. doi: 10.2460/javma.22.10.0446. PMID: 36595367.
  4. Yoon SZ, Jeon YS, Kim YC, et al. The safety of reused endotracheal tubes sterilized according to Centers for Disease Control and Prevention guidelines. J Clin Anesth. 2007 Aug;19(5):360-4. doi: 10.1016/j.jclinane.2007.02.009. PMID: 17869987.
  5. Sykes JE, Weese JS. Infection Control Programs for Dogs and Cats. Canine and Feline Infectious Diseases. 2014:105–18. doi: 10.1016/B978-1-4377-0795-3.00011-9. Epub 2013 Aug 26. PMCID: PMC7152206.

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