Introduction
Epistaxis is a common presentation. Prompt treatment is essential to manage this, which commonly involves nasal cautery with silver nitrate. Silver nitrate cautery is regularly carried out by junior or non-ENT clinicians. However, to our knowledge, there is no existing published low-cost training model to aid clinicians to improve their practical NC skills.
We created a low-cost, high-fidelity nasal cautery model, named “CauterClay” to address this gap. We designed an easily recreatable air-dry clay scaffold with simulated nasal mucosal lining and bleeding point. We assessed the model’s fidelity, along with pre- and post-tool confidence in carrying out nasal cautery on a patient using a voluntary, anonymous eight-point survey (Microsoft Forms, Microsoft Corp, Redmond, Washington, US).
Technical report
We designed the air-dry clay scaffold to be simple and easily replicable. Below, we describe our development process and how other users can create their own CauterClay.
Following several model iterations, we created a paper blueprint template (Fig. 1). To create the model, a flat sheet of air–dry clay is rolled to a thickness of 4 mm with a rolling pin or alternative (glass bottle). The blueprint is placed on top and lines are traced onto the clay below. The template is removed, cuts and scores are made as directed to the clay to facilitate folding or attachment. Once assembled, the clay scaffold is dried and will be ready for use (Fig. 2).
A printable template of the air-dry clay scaffold. Freely available to download at https://protect2.fireeye.com/v1/url?k=31323334-501d0a38-31357b2d-454441504e31-83da00886bbea2b2&q=1&e=18effef8-643f-465d-a443-b1f808f0073c&u=http%3A%2F%2Fwkxm.org%2Fcauterclay.
Model in action: being used to train a learner.
In designing this tool, we focussed on recreating the fidelity and tactile experience of carrying out nasal cautery on a patient, which requires a realistic mucosa texture. We tested a variety of materials to identify the best analogue using the following criteria: (i) ability to scar; (ii) time to scar; (iii) general appearancewhen compared to nasal mucosa; (iv) ease of availability.
Figure 3 outlines the materials we tested for simulated nasal mucosa and how they performed. Nasal mucosa is thin, highly moist and vascular.Reference Harkema, Carey and Wagner1 We tested luncheon ham, roasted ham, smoked bacon and thinly-sliced beef “shabu-shabu”. The latter was by far the more-superior material and is readily available from Asian supermarkets. It not only “responded” to silver nitrate quickly, just like human tissue, but also scarred with a local whitening reaction as would be observed when silver nitrate cautery is carried out on a patient. For reasons of possible religious sensitivity, we tested lamb and beef as well as pork.
The materials we tested silver nitrate on: (a) luncheon meat, (b) roast ham, (c) smoked bacon, (d) thinly sliced beef (‘shabu-shabu’).
To simulate a bleeding point and provide a “target” for users to “aim” their nasal cautery we used toy “fake blood”. Alternatively, paint could be used (e.g. acrylic or thick watercolour). Below we summarise the equipment required, and include an estimated cost, itemised to a per-model price based on our experience. We assume that, if this model is used in a setting where nasal cautery will be carried out on patients, users will have access to a head torch, silver nitrate, personal protective equipment (PPE) and paper with printing facilities.
Components required (estimated costs, per model listed below): (1) Air-dry clay, c. 100 g per model (£0.50); (2) Simulated nasal mucosal lining (thinly-sliced meat) (£0.20); (3) Red paint or “fake blood” (£0.05); (4) Silver nitrate applicators (-); (5) Head torch (-); (6) Appropriate PPE; (7) Paper (and printer if using printed template) (-); Total cost per model: £0.75.
Model evaluation
We carried out model evaluation across three dates (2/10/25–3/12/25) with a variety of users (n = 31, foundation doctors, general practice/core trainees and consultants) in the Department of Otolaryngology in the National Health Service (NHS) in Tayside with consultant approval. It was also included in the latest induction session for all foundation doctors covering ENT in NHS Tayside.
Data was collected with an optional, anonymous eight-point online survey (in Microsoft Forms). The majority of users were nasal cautery naive, with no prior experience (n = 20/31; 64.5 per cent).
Users were asked to report their confidence in “carrying out effective nasal cautery on a patient” before and after using the model on a five-point scale, from “very unconfident” to “very confident”. All users excluding consultants reported an increase in self-reported confidence in carrying out nasal cautery on a patient following model use.
Prior to using the training model, the majority of users reported a confidence of “neutral” or below (n = 26/31; 83.9 per cent), this decreased to 16 per cent (n = 5/31) following model use, which was statistically significant (Wilcoxon signed rank test, p < 0.001). Following model use, most users reported they were “confident” or “very confident” (n = 24/31; 77.42 per cent). Users were also asked to rate fidelity of the model, comparing it to their own clinical experience if they had carried out nasal cautery before and the “access” required to do nasal cautery, these are summarised in Figure 4 below.
Pie charts summarising the grade of respondents (Top Left, n=31), user-reported fidelity in nasal cautery experienced users (Top Right, n=11), user-reported fidelity in nasal cautery naive users (Bottom Left, n=20) and simulator fidelity of the access required in nasal cautery rated by all users (Bottom Right, n=31). Pie charts titled by question from online survey. Rating questions all used a 5-point scale, ‘1 star, not at all like real-life, 5 stars, very similar to real-life’.
Figure 4 Long description
Four pie charts are shown. The first chart, titled What grade are you?, shows the distribution of respondents: FY1 35 percent, FY2 45 percent, CST/GPST 10 percent and Consultant 10 percent. The second chart, How did this model compare in your experience of carrying out nasal cautery?, displays ratings: 3 stars 18 percent, 4 stars 55 percent and 5 stars 27 percent. The third chart, Do you feel this model provides a realistic simulation of carrying out cautery?, shows ratings: 3 stars 42 percent, 4 stars 42 percent and 5 stars 17 percent. The fourth chart, How would you rate the model in simulating the access required for carrying out cautery?, presents ratings: 3 stars 26 percent, 4 stars 49 percent and 5 stars 26 percent.
Discussion
Modern medical education is multimodal. Simulation is a key part of teaching not only in procedural skills education but also in clinical decision-making.Reference Mawyin-Muñoz, Salmerón-Escobar, Hidalgo-Acosta and Calderon-León2 The initial focus on fidelity and accurate, whole, realistic recreation of scenarios has shifted. Meta-analyses have shown that fidelity of simulations is not essential for effective education.Reference Yang, Wang, Chou and MH-M3 In fact, whilst high fidelity can be associated with higher learner satisfaction, there is no significant difference in outcome when compared against low-fidelity simulation.Reference Yang, Wang, Chou and MH-M3, Reference Lefor, Harada, Kawahira and Mitsuishi4
Otolaryngology is a procedure-rich speciality with substantial literature evaluating simulation-based training techniques. Previous work developed simulation in ENT induction to introduce new doctors to common tasks such as otoscopy and nasal packing.Reference Bhalla, Beegun, Awad and Tolley5 Published work also describes a nasal model built from plaster of Paris used to aid learner familiarity with nasal anatomyReference Bright, Varghese and Kurien6 and a cortical mastoidectomy model trainer.Reference Jefferies and Lavigne7 There are, however, no published nasal cautery models.
Nose bleeds are extremely common, affecting more than half of American adults in their lifetimeReference Tunkel, Anne, Payne, Ishman, Rosenfeld and Abramson8; however, only a small proportion require medical attention. National consensus guidelines in the United Kingdom (UK) highlight the use of nasal cautery, primarily with silver nitrate as first-line management for epistaxis.9 All treatments carry risk of complications, nasal cautery is no different. Silver nitrate is the mainstay of treatment in our department. Previous work has clarified it has the lowest complication and associated pain of the three main comparable epistaxis interventions (silver nitrate, electrocautery, nasal packing).Reference Kindler, Holzmann, Landis, Ditzen and Soyka10 We focussed on nasal cautery with silver nitrate as opposed to electrocautery as it required the least resources and is most accessible.
In a training environment, it is key to provide support and education to reduce potential harm. Simulation is a key method to reduce complications and increase treatment efficacy.Reference Zendejas, Cook, Bingener, Huebner, Dunn and Sarr11 There is no existing published low-cost training model for nasal cautery. The only existing trainer is by Adam Rouilly and costs c. £739, with further consumable costs for fake blood (£27).
In our design of CauterClay, we focused on using low-cost materials, prioritising accessibility and targeted fidelity. Our model focussed on making the experience of cauterising tissue and accessing a bleeding point realistic. In theory, other nasal pathology, such as a perforation or pyogenic granuloma, could be added by altering the nasal septum during clay scaffold assembly.
• Epistaxis is common and often managed by non-ENT clinicians with silver nitrate cautery
• There is no existing published low-cost high-fidelity nasal cautery model
• We created CauterClay: a low-cost high-fidelty nasal cautery model
• Single-centre evaluation of CauterClay demonstrated a statistically significant increase in self-reported nasal cautery confidence
• Users can recreate their own CauterClay model using our technical report
Limitations
Our model clearly had some limitations. Due to the design of the scaffold and type of material used for simulated mucosa, bleeding points and subsequent nasal cautery could only really be applied to the septum. Whilst the air-dry clay model provided a robust scaffold for the nasal mucosa to hang over, due to its rigidity nasal speculums could not be applied.
Whilst resource costs were low, model construction is time intensive. The clay air-drying necessitated a two-stage approach, firstly creating the scaffold and then waiting for it to dry, before using it. However, compared to other models like a plaster of Paris approach,Reference Bright, Varghese and Kurien6 this is less labour and skill intensive. Lastly, given the simulated mucosa we used was raw meat, we used the models, including clay scaffold, in a single-use fashion, disposing of them after a single session to avoid any contamination.
To combat this in the future, we propose a 3D-printed thermoplastic elastomer (TPE) nasal model, which can have pathology added which could be lined on all internal walls with paper and a paint loaded cotton bud could be used instead to simulate the cautery. This would have multiple benefits: (1) easier to create: most institutes of higher education have 3D printing facilities, it saves on model-creation time by the user; (2) safer: paint loaded buds do not have caustic material and paper is easier to store than meat; (3) reusable: a plastic model would be reusable and washable; (4) a TPE model would have some flexibility possibly allowing use of nasal Thudicums to simulate another aspect of nasal cautery.
Conclusions
Silver nitrate nasal cautery is a key method of managing epistaxis that has failed to respond to conservative first-aid management. We have outlined a simple, re-creatable, low-resource high-fidelity nasal cautery model that can be used to aid nasal cautery training. Our single-centre evaluation of the model demonstrated a statistically significant increase in self-reported nasal cautery confidence. Further work to develop a nasal cautery model that is easier to create and add pathology should be carried out in the future. In the future, we aim to develop a re-usable model that has potential to incorporate additional pathology, while retaining the low-cost nature of CauterClay.
Financial support
This research received no specific grant from any funding agency, commercial or not-for-profit sectors.
Competing interests
Stephen Jones is an editor of the Journal of Laryngology and Otology.
Ethical standards
The authors assert that all procedures contributing to this work comply with the ethical standards of the Helsinki Declaration of 1975, as revised in 2008.
Open access
