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Microbiology Assignment on Sterilization of Laryngoscopes


Task: Write a report on microbiology assignment critically analyzing the concept of sterilization of laryngoscopes.


A laryngoscope is a piece of equipment commonly used by anesthesiologists in general anesthetic and endotracheal intubation processes. This equipment has been identified as a major cause of cross-infection. According to the Center for Disease Control, these are listed as semi critical items, and this denotes that they must be chemically disinfected before use. Many viruses, including Human Immune-deficiency Virus and Hepatitis B Virus have been found on this equipment, with HPV being known to survive up to six days on surfaces(Chawla et al., 2016). Proper guidelines exist to govern the cleaning and disinfection of clinical equipment. Recent surveys, however, indicate that there is poor adherence to this protocol, making them ineffective in preventing contamination.This report aims to find out why the decontamination protocol is seen as ineffective and what could make it better.

Literature review
Laryngoscopy involves direct contact between the laryngoscope and saliva, the mucous membrane, and blood, and this makes it a major risk for infection among patients it is used on. The article by(Machan, 2012) states that while anesthesia professionals are aware of the risk of cross-infection, the idea of taking precautions has not been embraced. It further states that when patients do not seem to have any infections, only 24 percent of anesthesiologists take the necessary precautions, while a more significant 88% will be cautious when presented with a HIV positive patient(Rutala & Weber, 2016). Research has shown that blood on the equipment cannot always be seen by the naked eye. When a test was done to find hidden blood in the equipment, 86% of the samples showed presence of blood secretions(

Dias & Karnik, 2017). Since then, many tests have been used to find blood in airway equipment.
This contact with the mucous membrane leads to the equipment being termed semi critical, and means that disinfection should be thorough enough to wipe off all microorganisms except bacterial spores. CDC suggests pasteurization in hot water of above 80?C for 30 minutes, or exposure to a sterilizing chemical for an appropriate length of time between 10-45 minutes(Sherman & Hopf, 2018). The best method of decontaminating, however, is autoclaving as it also inhibits bacterial growth. The chemicals recommended by the Food and Drug Administration include glutaraldehyde, hydrogen peroxide, ortho?phthalaldehyde and peracetic acid with hydrogen peroxide(Merry, et al., 2019).

In this report, it is hypothesized that since blood is likely to be found on laryngoscope blades, cleaning it well shall definitely make using it safer for both the patient and the anesthesiologist.

A survey was done in India by Dias and Karnik (2017) in which professional anesthesiologists answered questions about the cleaning procedures performed on laryngoscope before they used them. This survey was issued by way of questionnaires to professionals attending a conference who were willing to answer the questionnaire. 150 anesthesiologists consented to aid in this survey.

The survey by Dias and Karnik(2017) indicates that at least 28% of the anesthesiologists questioned had no idea how used laryngoscope blades were washed. In addition, only 46% of them cleaned the handle after every use, with the rest doing so only regularly and when secretions and blood are visible on it with the naked eye, or not at all. It is also worth noting that only19% of these medical professionals knew that soaking in disinfectants was the way to decontaminate laryngoscope blades after use(Dias & Karnik, 2017). This survey, which was done in India, showed that there was no specific protocol on the cleaning of laryngoscopes. While the general opinion was that these reusable equipment needed to be cleaned and disinfected, actions by professional at health institutions did not reflect this. In another research, Machan (2012) states that most clinicians would prefer to have single-use devices than the reusable ones.This means that an opinion has already been formed against reusable devices by the very people who are to use them in applying treatment. Both the blade and the handle can cause cross-infection and should be disinfected, because when the equipment isfolded and not in use, the contaminated tip is in contact with the handle.The report recommended sterilization of equipment, use of disposable equipment, and creating new designs for the handle to ensure as few contact points as possible. The laryngoscope handle is built to strengthen grip but then favors build-up of dirt. The blade is complex with several removable parts that support dirt accumulation. This design means that pathogens are likely to accumulate on this device and any mishap in handling, cleaning, and storage will allow persistence of these pathogenic microorganisms.

To add to this, improper handling can lead to infection even after disinfection has been done. A clean way to of inducing anesthesia has been created to reduce risk of infection (Machan, 2012). This includes wearing 2 pairs of gloves before inducing, and then removing the gloves carefully such that the laryngoscope remains inside the glove. This process is to ensure the laryngoscope does not get into contact with other equipment or surfaces. Another method is to use a plastic bag securable by tape, in which the blade is placed after use to avoid contamination.

The study by Machan (2012) suggests that the procedure for cleaning and disinfecting the equipment should be revised. For example, the equipment should be cleaned first before being soaked in disinfectant so that the decontamination is more effective, but this is not always done. In fact, the CDC does not have a set procedure for disinfecting these equipment. It issues suggestions but encourages users to follow manufacturer’s directions during decontamination. When this cleaning process is not seen as a requirement, there is little that can be done to curb runaway cross-infection among patients. The current recommended sequence is clean, rinse, disinfect, and rise.

The research done on this topic by Machan (2012) found no evidence of pathogenic substances on the laryngoscope blade and handle. However, since there are pathogens such as viruses that are known to be able to survive on dry surface for more than a week, the risk should be recognized and dealt with. Another research by Sousa, et al.(2013) found pathogens such as Streptococcus pneumoniae in blades that were ready for use and in neonates on whom laryngoscopes had been used and who had died. This research noted that the experts were aware that the cleaning methods being followed were not in tandem with those recommended by representative bodies. The medical personnel, it notes, stated that they would not use the freshly cleaned equipment they used on patients into their own mouths. With this knowledge, it can be assumed that the cleaning is process is ineffective not because the methods recommended are wrong, but because the recommendations are either ignored or not followed to the letter as they should be.As was found by Dias & Karnik (2017), washing with detergent was the most common way that the laryngoscopes were cleaned, instead of the recommendation by CDC of soaking in hot water or disinfectant.

While some articles might argue that cross-infection is much reduced when single-use laryngoscopes are used in anesthesia, other factors like the environment must be considered as well. Contributing to other infections through pollution caused by single-use medical equipment will negate the positive work that they supposedly do. Therefore, it is better to follow the manufacturer’s disinfection recommendations so that the reuse of these equipment does not denote a risk of infection for the patients.The risk of infection due to reusable airway equipment is due to insufficient decontamination. In addition, using the device safely such that no contamination happens will reduce contamination and therefore cross-infection.

Chawla, R., Gupta, A., Gupta, A. and Kumar, M., 2016. Laryngoscope decontamination techniques: A survey. Journal of anaesthesiology, clinical pharmacology, 32(1), p.99.

Dias, R. & Karnik, P., 2017. Disinfection of laryngoscopes: A survey of practice. Indian Journal of Anaesthesia, 61(3), pp. 245-249.

Machan, M., 2012. Infection Control Practices of Laryngoscope Blades: A Review of the Literature. AANA Journal, 80(2), pp. 274-278.

Merry, A. et al., 2019. The SAFE-T Summit and the International Standards for a Safe Practice of Anesthesia Safe Practice of Anesthesia. The official journal of the anesthesia patient safety foundation, 33(3), pp. 69-104.

Rutala, W.A. and Weber, D.J., 2016. Disinfection, sterilization, and antisepsis: An overview. American journal of infection control, 44(5), pp.e1-e6.

Sherman, J.D. and Hopf, H.W., 2018. Balancing infection control and environmental protection as a matter of patient safety: the case of laryngoscope handles. Anesthesia & Analgesia, 127(2), pp.576-579.

Sousa, A. N., Levy, C. & Freitas, M., 2013. Laryngoscope blades and handles as sources of cross-infection: an integrative review. Journal of Hospital Infection , Volume 83, pp. 269-275.

Van Wicklin, S.A., 2019. Contamination and Disinfection of Rigid Laryngoscopes: A Literature Review. AORN journal, 110(1), pp.49-59.

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