In his seminal book Human Error, James Reason presents his ‘Swiss Cheese Model’ – the basic concept being that in order for an error to occur, the holes in multiple slices of cheese need to line up with each other. Each slice of cheese can be thought of as a line of defence and an opportunity to stop the error happening. In this article I will describe five such ‘slices of cheese’. These defence strategies are based on the research and opinion of experts, and Dental Protection have termed them ‘safer and reliable practices’. They are ‘speaking up’, ‘checking’, ‘repeat-back/read-back’, ‘huddles’, and ‘simulation’. Let us now unpack and discuss each one in turn and how they can be employed in the world of dentistry to both prevent and mitigate human error. 

Speaking up 

Speaking up is about ensuring that we always check each other, and welcome being checked. This could be the dental nurse speaking up when the dentist is about to extract the wrong tooth or the pharmacist phoning to double check a patient prescription – even when there turns out to be no validity to their concerns. Having your colleague(s) looking out for you, is a critical element of not only ensuring patient safety, but also your own safety in terms of dentolegal risk. As we have previously discussed, human error is common, and research shows that most errors that we make can go undetected by ourselves, but not necessarily by those around us. We can therefore reduce the chance of patient harm if we can make everyone feel comfortable speaking up about any issues of concern. It is important therefore to flatten any hierarchy around safety and reliability, to ensure everyone feels that they can speak up. Three simple approaches to enable this strategy are: 

• Explicitly tell others that you want them to speak up, and that you will likewise speak up to them. 

• Thank anyone who does speak up (even if they are wrong). If you respond in a positive and thankful way only when your colleague’s concern about error is correct (and negatively when it is incorrect) the research shows that those colleagues are at risk of delaying (or even withholding) the raising of their concerns in future situations, sometimes too late to prevent harm. 

• Engage with those who are reluctant to ‘speak up’ to you. 

Checking 

Checking isn’t a single strategy but is rather a collective term for many techniques and approaches. Healthcare, generally, is a very action-orientated industry and as such has traditionally placed a very high value on action. Similarly, most of the work of a dental healthcare professional involves ‘doing’. We are proceduralists. The research in reliability shows, however, that checking is a high value action that improves safety and reliability. It is as important (if not at times more important) as doing, and it is interesting to note that checking strategies have a high status in industries where safety is critical. It is also important to appreciate that checking involves action now to prevent patient harm, and is not the retrospective reporting of harm. 

A common way of checking is the use of visual prompts and memory aids, such as checklists. The latter are critical to address the limits of human performance. Checklists reduce cognitive burden or workload, which can really help when you are under stress. They can increase the likelihood that you are in control of the situation rather than being controlled by it. Experts in human factor science have found that the cognitive load associated with trying to remember simple, repetitive, yet critical steps, decreases our ability to problem solve and to maintain situational awareness, particularly when under stress. As such, checklists allow you to concentrate on first-order concerns and are critical in preventing never-ever events (things that should never happen). They can also help in changing the culture of a team, by empowering people to speak up, and ensuring that everyone follows the same accepted process. 

Repeat-back/read-back 

Repeat-back/read-back is a critical strategy to help minimise miscommunication, by ensuring that the message sent is the message received. For example, we are all familiar with pilots receiving instructions from air traffic control repeating-back those instructions – as any misunderstandings could have very real safety consequences for all concerned. Similarly, a waiter/waitress in a restaurant, reads-back the order to check that they have understood it correctly, as getting it wrong, would not only risk customer dissatisfaction, but there could also be commercial implications for the business. 

Repeat-back/read-back has many potential uses in the dental context, including checking with patients their understanding of any treatment options you may have discussed with them, or whenever you are communicating with staff, laboratories, or internal/external colleagues. 

Using the repeat-back/read-back strategy strengthens positive communication. It is easy to do, as it can be implemented with no cost and minimal time and effort – yet it can have an amazing capacity to reduce miscommunication. Establishing a process where we always use repeat back for some critical communications is a great, yet simple step to improve reliability. The likelihood of message sent/message received failure occurring increases dramatically with distraction, fatigue, stress, background noise, and so on. When a series of complex instructions are being passed between two individuals, the likelihood of transmission error can be as high as 20 to 30%. This simple strategy also has great value because hearing the verbal repetition of instructions given, allows the person sending them to reflect on the logic, adequacy, and appropriateness of what they’ve said. Finally, the strategy also facilitates ‘safety netting’ – information given to a patient or their carer during a consultation, about actions to take if their condition fails to improve, changes or if they have further concerns about their health in the future. 

Huddles 

Huddles provide an opportunity for the whole team to prepare for what has, will, and could happen. They can be used to plan ahead for what if scenarios and can therefore help build situational awareness – a term commonly used in human factors and in aviation (cockpit safety).

In practical terms, huddles are ten-minute briefings, usually involving all staff, not just clinical staff. It is a meeting held, often standing up and usually at the beginning of a clinical session or before a complex procedure. If you brief well, you can get ahead of problems, communication is better, and performance becomes more reliable. Huddles help facilitate good, effective communication and can be used to reassure the wider team that anyone can speak up if concerned.

In the dental context, a huddle could be as simple as checking: Do we have all staff available today – is anyone absent? They can be used to discuss who will be working with who (perhaps including a visiting specialist), vis-à-vis experience, and can be an opportune time to talk through a day list and check: Is the laboratory work back for x? Y is, for example, a diabetic…have we in-date glucose tablets available and close at hand in the case of a medical emergency? Huddles can also be used to plan regular breaks and discuss minimising distractions at critical times during an appointment or a procedure. 

Simulation 

The general concept of simulation is something that all clinicians will be very familiar with... think cardiopulmonary resuscitation (CPR) training. In the dental context, many operative skills are initially taught in simulation facilities using phantom heads. Increasingly, virtual and augmented reality technologies are being used as an important teaching tool for students, who practise with 3D headsets before working on real-life patients – for instance in practising local anaesthetic delivery techniques.

In terms of a strategy to prevent and mitigate human error in dentistry, simulation can be used to check that we know how to work together. The research shows that simulation improves team performance and reliability. Simulating or dress rehearsing a scenario (such as a medical emergency), can reveal unrecognised people, process and system deficits or show up where any gaps are. Simulation can also encourage people to speak up. It is also well recognised that when we have had time to rehearse and practise procedures, we perform better under stress. Finally, simulation can save time and decrease your cognitive burden, especially in an emergency. 

Summary 

In conclusion, the five safer and reliable practices that we have discussed in this article as strategies to prevent and mitigate human error in dentistry are:

1. Speaking up -We always check each other, and welcome being checked. 

2. Checking - We use a range of techniques to continually check. 

3. Repeat-back/Read-back - We always check that the message sent is the message received. 

4. Huddles - We prepare for what has, will, and could happen. 

5. Simulation - We always check we know how to work together.