Working out wrong‐side blocks

The problem of doctors performing procedures on the wrong side or site refuses to go away. Headlines decry the failure of healthcare to prevent so-called Never Events. The newly formed UK Healthcare Safety Investigation Branch has decided that its first investigation will be into wrong site interventions 1. Patients and politicians cannot understand how a system delivered by intelligent, well-meaning professionals can get something so basic as undertaking a procedure in the right place wrong. But we do. Not very often – around once every 16,000 operations, and thankfully rarely causing severe harm – around once every 500,000 operations 2. Wrong site peripheral regional blocks are a somewhat unknown quantity, but clearly of interest to anaesthetists and patients. In this issue of Anaesthesia, Hopping et al. 3 estimate that they occur around once for every 56 years of clinical practice. Wrong site blocks are certainly uncommon, and by their nature they are highly unlikely, but not impossible, to cause severe or long-lasting harm. Wrong site blocks are deceptively simple. In almost all cases, one person (the patient) knows which limb needs an injection, and two people (the anaesthetist and his/her assistant) have ample opportunity to check. There are surgical marks on the affected limb, consent forms and most of the time, an awake patient. So, it cannot possibly go wrong. Yet it does. There has been recent resurgent interest in the theoretical understanding of the work that we do. One way to look at human work – in anaesthesia or anywhere else – is via four 'varieties of human work': work-as-imagined; work-as-prescribed; work-as-done; and work-as-disclosed (Fig. 1) 4. Work-as-imagined is both the work that we imagine others do and the work that we imagine we or others might do, currently or in the future. Work is imagined by policy makers in national and local government, regulators and inspectors, researchers, senior management and middle management, specialist non-clinical staff and clinicians of all kinds and of course patients, the media and the judiciary. All have a mental model of clinical work, which influences their thinking, planning, discourse and responding. In most cases, work-as-imagined involves simplification. The messy reality of the work context, which should be the starting point for designing new work (see ISO 942-210 5), is often ignored and not imagined. The degree of disparity and the consequences of this disparity are rarely considered in detail, unless perhaps an incident occurs. These consequences include inefficiency, misunderstandings, conflict, distrust and patient harm. Work-as-imagined is also our own mental models of what we do, or did or might do. We might imagine the processes involved in performing a regional block based on our past experience (itself a combination of our work-as-done and work-as-disclosed by others). This might perhaps be augmented by a limited observation of others, either in person or by the informal commentary of trainees and anaesthetic assistants (the dreaded 'Dr X doesn't do it like that'!). But we are also likely to include work-as-prescribed in our imagination. The policies and procedures of the local and national institution – a product of imagination – will inform our imagining. Indeed, the work of Hopping et al. 3 and Pandit et al. 6 on 'Mock-before-you-block' is imagined work. They have a mental model of how Stop- and Mock-before-you-block work, and how it could work. Our imaginations extend to the hypothetical – both in the future and the past. The coffee room discussion – 'How would you do x or y', and the retrospection of a past incident – 'If I were there I would have done it differently…' Work-as-prescribed is the formalisation or specification of work, as laws, regulations, rules, procedures, checklists, standards, job descriptions, and management systems. We can also say that it includes the unwritten rules by which work might be judged. Although these specifications are frequently criticised as being created by faceless bureaucrats who do not understand the way things actually work, often they are written by people with current experience. However well-meaning the work-as-prescribed is, it is always going to be hampered by the inadequacies of work-as-imagined, -done and especially -disclosed. It does not matter who writes the rules – they are never going to be able to capture the context of every piece of work, and are likely to be influenced especially by the way that they do, imagine that they do, or would like to do the work. Slavish obedience to the rules is a well-recognised tactic in the obstructionist playbook. In practice, work-as-done will tend to deviate from work-as-prescribed, for a range of reasons associated with human nature (e.g. our limitations and capabilities) and the contexts in which we work. Work-as-done is characterised by the real-time trade-offs and compromises that must be made to resolve conflicts between different goals (e.g. thoroughness vs. efficiency 7), and which seem reasonable at the time. But when things go wrong, gaps come into focus between work-as-imagined – disclosed on one hand, and work-as-prescribed – imagined on the other. When things go right, these gaps are rarely questioned. Although it can be easy to decry work-as-prescribed, let us not forget that it does have a purpose and legitimacy. It is one method of promoting consistency in practice across an organisation, or of implementing safe, effective or cost-efficient practice. Many rules and regulations are also borne out of previous harms. Although work-as-done does not reflect work-as-prescribed, no-one has any qualms with prescribing at least minimum standards of hygiene. Work-as-done is what actually happens. It is messy and completely context dependent. That context is described by the interplay between all the components of a complex, non-linear system. It is complex because of the nature of the variable interactions between the numerous actors (at its simplest, patient, anaesthetist and anaesthetic assistant), equipment, working procedures, organisational processes, working environments, and wider system influences. The messiness is increased by distractions 8, competing information and pressure. The relationship between these factors is non-linear and non-deterministic; there is no simple relation ship between all these factors and what actually happens. Distractions that 'cause' an error in one case may have no impact, or even benefit in another. Work-as-disclosed is what we say or write about work, and how we talk or write about it. We might expect that this matches work-as-done, and this would certainly help in designing safer systems. However, this is often not the case. Even in emotionally neutral situations – take, for example, the way we draw drugs up – it is difficult to describe what we do. Now add in the pressures of formal or informal norms of behaviours, or something having gone wrong, and the discrepancy between work-as-done and work-as-disclosed becomes larger. But work-as-disclosed is what is used to teach and to codify our processes. It is a combination of what we are able to describe and what we are prepared to describe, in verbal or written form. Work-as-done and -disclosed need attention – not in a judgemental way but as a window into the realities of the compromises and risks we have to make every day. Why do we do what we do? Is it actually safe and efficient (even though it is discordant with imagination and prescription), or do we need to address the underlying problems that make work-as-done unsafe or inefficient? So how does this apply to wrong site blocks, and to safe and effective practice in healthcare more widely? Stop-before-you-block is a local and now national initiative to reduce the incidence of wrong-site blocks. In concept, it is simple – a catchy internally rhyming command; clear instructions of what to do; and it can incorporate physical barriers and actions such a prompt cards, stickers on syringes and covers on ultrasound machines 9-11. Hopping's survey results and wider clinical experience suggests that the process fails at least some of the time. It is important to note that we have no idea how often it works though; there are no data we are aware of for near-misses. Evidence that is does not always work is not evidence that it does not work at all. performing the WHO surgical safety check list as usual, immediately before needle insertion for the nerve block, the correct side is confirmed again by: (1) visualising the surgical arrow indicating the site of surgery, (2) asking the patient to confirm the side of surgery (if conscious) and (3) double checking the consent form for operative side. In an attempt to mitigate the temporal delay between check and action, Stop- and Mock-before-you-block both advocate the stop moment 'immediately' before needle insertion. What are the designers of these systems imagining? What does immediately actually mean? Hopping et al. and Pandit et al. are right in their assumptions that a Mock-block cannot reasonably occur temporally distant from the block itself. The requirement for equipment makes this a forcing function and might reasonably be supposed to reduce the risks from distractions and patient movement; more so than Stop-before-you-block which occurs at a variety of moments. Their imagining of the moment may be different to ours. One of the authors (IM) works in the same theatres as the originators of Stop-before-you-block. In his mind, immediately is at the point when he starts preparing the block area. This is a point when he is not mentally committed to the block. He can move the ultrasound machine and recheck the notes with less of a mental barrier, leaving him free to concentrate on the block itself. In the minds of the original designers, leaving the check to the last moment removes all opportunities for distraction and movement. We do not know who is right – but our imagined work is different. Work-as-imagined is an important part of the what-if risk assessment for implementation of a new work-as-prescribed. Perhaps it is the benefit of hindsight that makes the situation described in Fig. 4 of Hopping's paper seem inevitable – putting a STOP sticker on the wrong leg. The description of Mock-before-you-block suggests using an empty syringe. It does not take a great imagination to foresee an unintended error here. Work-as-imagined highlights a missing part of Hopping's survey. These stop moments rely on an independent second check ('double checking' for Stop-block, 'assistant confirms' for the Mock-block). The work-as-imagined includes a fully engaged assistant who has the confidence, authority and engagement to stop the process. Unfortunately, we have no information about the role of the assistant in these self-reports, nor a wider systematic investigation into what the anaesthetic assistants actually do during regional block. If we did, perhaps we might focus more on their crucial function rather than – or as part of – re-engineering the process. Work-as-imagined and work-as-prescribed frequently fail to capture the realities of human behaviour 12. All these systems rely on remembering to actually carry out the checks and to do them properly. Hopping's results suggest that Stop-before-you-block is inconsistently performed even among those who have performed a wrong-site block. Training, culture and cognitive-aids may help, but it is naïve to believe that a stop-moments based system will ever prevent incidents from occurring. Work-as-imagined also influences our concept of why a particular practice should work. The assumption that Stop-before-you-block should (or should not) work is based on the psychology of human error. If that is the case, Mock-before-you-block might be an improvement. But perhaps it works well in some places and not in others as a meta-phenomenon to local safety culture, local champions and nay-sayers, or educational campaigns 13. Another question concerns the unintended consequences of mocking the block. How might mocking the block change the context and what secondary problems might result? Are there any competing practices that we have not imagined? And what is needed to embed and sustain the practice? An alternative approach to preventing wrong site blocks 14 involves locked needle cabinets with the key held by a third party. Does this imagined process survive contact with the real-world of compromises and trade-offs? We are missing our opportunities to learn from work-as-done that works as intended 15. Stop- and Mock-before-you-block are forcing functions acting as additional barriers to error, another layer of Reason's Swiss Cheese 16. Hollnagel 17, 18 and others promote a safety framework that not only looks at what went wrong (Safety-I) but also attempts to learn from what goes right, and – more generally – 'what goes' (Safety-II). Why do wrong site blocks (and wrong site surgery for that matter) not happen more often? Given the complexity of the system, one might expect that they would occur more frequently. How can we learn, in a systematic way, from the work-as-done that prevents, traps or mitigates errors? This is an important question, because changing practices without first understanding practice might change aspects of practice in unintended ways. If Hopping et al. are even close to right then the individual error rate of one wrong site block every half century of practice is worthy of note. Hopping's survey gives insight into work-as-disclosed. If the respondents in Hopping's survey were giving some version of the truth, regional blockade is accompanied by all manner of things that are not supposed to happen, and perhaps outside of work-as-imagined by non-clinicians: distractions, miscommunication, incorrect paperwork, etc. Stop-before-you-block and Mock-before-you-block are intended to mitigate these. Indeed, the complete description of the Stop-before-you-block process 10 highlights the very problems described by Hopping et al. 3: The anonymity of Hopping's survey may have encouraged a more candid disclosure of how work is done, and this is valuable. It is impossible to know how much the passage of time, and the competing influences of guilt, rationalisation and a desire to share the blame, have impacted on the responses. Regardless, these insights are useful as we endeavour to design safer processes based on the work that is actually done. What are the lessons for anaesthesia and healthcare more widely? None of these four concepts of work – done, disclosed, imagined and prescribed – provides us with a complete picture of safe and efficient healthcare. Understanding the differences and commonalities between all four is important and yet overlooked. Work-as-imagined provides opportunities and threats. We need people to imagine different ways of doing things – otherwise we will stay in an eternal tit-for-tat between work-as-done and work-as-prescribed. But we need to be careful that we do not imagine the unrealistic. There is a temptation to imagine for every incident a new initiative added to the current system will have an independent, additional benefit. Paying attention to work-as-done might disabuse us of this notion – the pressure of work, repetition and disengagement all impacting on safety upstream and downstream. To their credit, Pandit et al. 6 are re-engineering an existing step rather than introducing new barriers. We must also imagine the unintended consequences of these initiatives, and not to restrict imagination to the possible benefits of our efforts at redesigning the work. Work-as-prescribed is perhaps the biggest challenge. Somehow a balance must be found between improving work by design and acknowledging that healthcare practitioners must often make decisions in the moment in non-ideal conditions. Human factors/ergonomics works with and in this area of tension. Within healthcare some decisions are subject to huge scrutiny – new drugs and procedures for instance. We like to imagine that we have professional expertise throughout the pathway. Yet, few healthcare organisations have trained ergonomists or systems designers in their teams. Time will tell whether wrong site blocks become less frequent. Paying more attention to the alignment of work-as-done, -disclosed, -imagined and -prescribed may have benefits beyond these rare events. No external funding or competing interests declared.