Single use airway devices: Harms and solutions

Annually the NHS in England procures and disposes of 32.3 million (m) airway devices purchased for £56.9m. These devices are used for general anaesthesia and includes 18m supraglottic devices (SGDs), 5.3m endotracheal tubes (ETTs), 4.4m tracheostomy tubes and 2.9m laryngoscope blades. Here we discuss the origins of single use airway devices and suggest routes toward responsible and sustainable alternatives.

Most airway devices are made of plastic. Plastic became widely available in the 1960s and as a material offers many advantages: it can be made flexible or rigid, is airtight, waterproof and cheap. However plastic manufacture is characterised by the extraction, refinement, combustion and dispersal of organic hydrocarbons (oil) and their polymers, with the addition of plasticising chemicals (typically phthalates or esteric aromatic compounds) to soften the finished product. The manufacturing process takes refined oil as both substrate and energy source, emitting pollution in the form of carbon dioxide and particulate matter. In the UK airway devices are typically used once and disposed of in energy and carbon-intensive waste streams (typically incineration), emitting further carbon dioxide.

Most disposable laryngoscope blades are manufactured from steel, in northern Pakistan, and aligned with the principle of cost reduction, this includes the use of sweatshops, child labour, and welding equipment with limited personal protection [1].

Single use and the airway

Association of Anaesthetists current guidance states that laryngoscope blades and handles, ETTs, SGDs and oro/ nasopharyngeal airways must be high-level disinfected or sterilised as these devices may become contaminated with blood, occasionally breaching a mucosal barrier [2]. The guidelines encourage the procurement of single use devices (SUDs).

A significant factor in the historical move to single use laryngoscope blades was the identification of variant CreutzfeldJakob disease (vCJD) caused by a prion protein that can reside in oropharyngeal lymphatic tissues of those with end-stage vCJD. Continued use of SUDs has been perpetuated by the fact that the single use approach eliminates other infection risk, including the transmission of respiratory pathogens. SUDs also offer convenience and alleged cost savings compared to reusable devices, especially where the infrastructure to enable devices to be reused is lacking (many hospitals lost sterile services capacity during the vCJD scare).

At present, most airway devices in the UK are single use. A survey of hospitals in the UK showed that 95% (21/22) used single use laryngoscope blades [3]. Most other airway devices are also single use, although reusable SGDs, laryngoscopes and videolaryngoscopes are commercially available. The notion of single use has even extended to flexible bronchoscopes, described as a possibly cost-effective solution: apparently through avoiding costs of repair, reprocessing, maintenance and risk of litigation.

Whilst we agree that it would be unacceptable to compromise safety in favour of an improved environmental profile, we need to re-appraise the belief that single use airway devices are best.

Myth 1: Re-use is an infection risk

A recent review found a lack of evidence to support the argument that SUDs reduce the incidence of nosocomial infections [4]. In the 1970’s there were a few cases of transmission of vCJD between patients linked to neurosurgical equipment and predated sterilisation, but vCJD has never knowingly been transmitted by airway devices. Testing of over 62,000 tonsil specimens in the UK has never found evidence of prion protein [5], and in England and Wales, tonsillectomy has been performed using reusable instruments and steam sterilisation since 2001 [6]. It seems nonsensical to not apply the same approach to airway devices. The UK National Prion Clinic agrees, and they advise: ‘For patients who are not suspected to have prion diseases we don't think there is a requirement for single use anaesthetics equipment’ [7].

Nevertheless, contaminated laryngoscope blades have been linked to the deaths of critically ill patients [8] and a lack of standardised reprocessing procedures was previously a recognised concern [9, 10]. This does not mean that we need SUDs, rather it means that we should explore reliable methods for decontamination and sterilisation. In other settings, steam sterilisation and the reuse of laryngoscope blades are the norm. Contrary to myth, disposable laryngoscopes carry a greater bioburden when compared with reusable sterilised devices.

Disposable laryngoscopes are disinfected rather than sterilised, with thresholds of acceptable bioburden set by manufacturers in accordance with international standards (ISO 11737-1). Importantly however there has been no study comparing infection rates between reusable and disposable laryngoscopes. Airway interventions are inherently non-sterile procedures and involve an anaesthetist in non-decontaminated attire and gloves; the source of infection may be independent of laryngoscope type.

Myth 2: Single use is better for the environment

Multiple studies show the general principle that reuse of medical equipment is better for the planet, the same is true for airway devices. Single use plastic laryngoscope handles represent up to 18 times the carbon footprint compared to reusable steel [11]. Similarly, 40 single use SGDs have a lifecycle carbon footprint of 11.3 KgCO2e, 1.5 times greater than a reusable device used and decontaminated 40 times [12].

Myth 3: Single use is financially cheaper

In one study from Australia, the cost of using 4490 disposable laryngoscope blades each year was estimated to cost £6000 more than using reusable equivalents [13]. A UK analysis suggested reusable laryngoscope blades cost almost half that of single use [14], and by extrapolation, this would save the NHS £4.9m per annum.

The future

In summary, SUDs are costly for the public purse, the environment and global society. Reusable alternatives to some devices exist, with tried and tested reprocessing techniques to ensure safety and reliability. However, there is a need for further industrial and clinical research into reusable device design and novel and reliable decontamination techniques. Alongside this, we must advocate for national and international policy maturity, away from over-zealous precaution and towards an evidencebased assessment of risk, that also considers planetary and societal harm from the single use culture.

James Dalton
Anaesthesia Sustainability Fellow, University Hospitals Sussex NHS Foundation Trust

Richard Newton
Consultant Anaesthetist & Environmental Anaesthesia Lead, University Hospitals Sussex NHS Foundation Trust

Mahmood Bhutta
Chair of Ear, Nose & Throat Surgery & Professor of Sustainable Healthcare, Brighton and Sussex Medical School

References

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2. Association of Anaesthetists. Infection Prevention and Control Guideline, 2020. URL: https://anaesthetists.org/Home/Resourcespublications/Guidelines/Infection-prevention-and-control-2020 (Accessed 06.11.2023) 

3. Ghandi J; Campbell G. Unpublished data. Reusable vs single use infection control policy. Association of Anaesthetists Survey. 2022 

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5. Clewley J P; Kelly C M; Andrew N; et al. Prevalence of disease related prion protein in anonymous tonsil specimens in Britain: cross sectional opportunistic survey. British Medical Journal. 2009; 338: b1442 

6. Clarke M B; Forster P; Cook T M. Airway management for tonsillectomy: a national survey of UK practice. British Journal of Anaesthesia. 2009; 99: 425–428 

7. UK National Prion Clinic (University College London) email to J Gandhi (Association of Anaesthetists) 07 April 2022 

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11. Sherman J D; Raibley 4th L A; Eckelman M J. Lifecycle assessment and costing methods for device procurement: comparing reusable and single-use disposable laryngoscopes. Anaesthesia & Analgesia. 2018; 127: 434-443. 

12. Eckelman M; Mosher M; Gonzalez A; Sherman J. Comparative life cycle assessment of disposable and reusable laryngeal mask airways. Anaesthesia & Analgesia. 2012; 114: 1067–1072. 

13. McGain F; Story D; Lim T; McAlister S. Financial and environmental costs of reusable and single-use anaesthetic equipment. British Journal of Anaesthesia. 2017; 118: 862-869 

14. Unity Insights & Kent Surrey and Sussex Academic Health Sciences Network. Carbon savings laryngeal blades and suture kits, 2022. 

15. URL: https://unityinsights.co.uk/our-insights/carbonsavings/#:~:text=On%20the%20carbon%20emissions%20 front,52%25%20and%2090%25%20respectively (Accessed 06.11.2023)