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PSTRC

Learning to tolerate clinical uncertainty in the face of covid-19

By Emily Parker.

In a recent discussion with a senior doctor, I was told, ‘a doctor who isn’t taking risks is not doing their job.’ As a PhD student, rationalising my research into uncertainty management in the emergency department (ED) is a skill I am still learning, yet this doctor had done it for me in one sentence. When initially presented with this quote, it is understandable that people may be wary of doctors taking risks. However, risk and uncertainty are often irreducible in the ED. Patients present to EDs with severe illness, often unable to give a medical history and doctors have limited time to reach a decision1. Therefore, being able to manage risk and tolerate uncertainty is a vital skill for doctors.

When deciding to admit or discharge a patient, ED doctors make a probability assessment by considering the benefits and risks of both options. A lot of the time, what is central to this decision is whether the patient is safe, or unsafe, for discharge2. What is considered a safe discharge can vary between doctors. For example, some doctors might admit a patient to avoid their symptoms getting worse whilst some would discharge the same patient and ask them to return, if and when symptoms get worse.

Research suggests doctors with less experience are more inclined to test and admit patients than senior doctors3. A lower threshold for ‘safe discharge’ suggests a lower tolerance for the uncertainty associated with sending a patient home. We have all experienced a lot of uncertainty this year and can relate to the anxiety it brings. But these anxious feelings and thoughts of doubt don’t seem to follow admission decisions. Hospitals are perceived as a place of safety, allowing access to a specialist opinion and deferring the decision to discharge away from ED. Where decisions are uncertain, junior doctors often admit to avoid the negative feelings associated with an uncertain discharge.

That is, until 2020 when covid-19 added a new dimension to decision making in the ED. I was lucky enough to interview junior doctors and registrars working in the ED throughout the first and second wave of the pandemic. The interviews focused on factors which influence uncertain admission and discharge decisions which inevitably included covid-19. Covid-19 had huge impact on the experience of doctors in training.

Junior doctors spent eight months on one particular specialty rotation, as oppose to four, increasing exposure and confidence in that particular field but reducing it elsewhere. Structured teaching time, away from the ward, was limited. A lack of visitors meant the assistance of family members and carers in establishing a medical history was not possible and cancellations of elective surgery meant patients who would have once been admitted, were repeatedly discharged by ED doctors. In an already high-stakes environment, covid-19 created even more uncertainty, left to the doctors to tolerate.

What my interview study revealed was that despite hospitalisation always carrying substantial risk of infection, the coronavirus pandemic meant that conversations about the risks of being in hospital started taking place more frequently and admission to hospital was avoided wherever possible. This is an approach to decisions which Professor Steve Goodacre called for in 20063, suggesting discharge from the ED should be the default position and only where evidence points to the benefits of admission, should admission to hospital take place. The junior doctors I interviewed stressed the importance of this throughout the pandemic, particularly for elderly, vulnerable patients who are frequently admitted for social reasons alone. Despite only two months as an ED doctor, the decision making approach of junior staff aligned with that of Professor Steve Goodacre.

It has been an unprecedented year for the health service but if there is anything we can take away from this, it is that where admission to hospital is not clinically necessary, it shouldn’t need to occur. Exposing patients, particularly elderly patients, to the risks of being in hospital should be avoided long after the pandemic. Hospital acquired pneumonias, loss of independence and confusion are all very real risks of being in hospital. These often occur because the patient has no support network at home or there are no safe options to get the patient home at night time, resulting in a discharge process too uncertain for the doctor to tolerate.

Pushing for discharge where clinically appropriate should remain in place but this can only happen if the systems in place within the community and social care allow a patient to be discharged home in a moral and safe way. The structures and knowledge on which an ED doctor can call on, allowing them to tolerate a discharge decision must be strengthened.

My wider PhD project is focused on enhancing uncertainty tolerance amongst ED doctors and if you would like to follow the project, follow @emilyeparker22.

1. Platts-Mills TF, Nagurney JM, Melnick ER. Tolerance of uncertainty and the practice of emergency medicine. Annals of emergency medicine. 2020 Jun;75(6):715.
2. Goodacre S. Safe discharge: an irrational, unhelpful and unachievable concept. Emergency medicine journal. 2006 Oct 1;23(10):753-5.
3. Lawton R, Robinson O, Harrison R, Mason S, Conner M, Wilson B. Are more experienced clinicians better able to tolerate uncertainty and manage risks? A vignette study of doctors in three NHS emergency departments in England. BMJ quality & safety. 2019 May 1;28(5):382-8.

Introducing the AC-FRAIL tool: a novel tool to proactively identify older people with frailty for medication reviews

By David Mehdizadeh and George Peat.

Medicines are often thought of in terms of their ability to help manage and treat health conditions. Indeed, medicines are the most commonly used health intervention. However, if we are to continue to use medicines safely and appropriately, it is important that we also acknowledge that medicines can also lead to avoidable harm.

Anticholinergics are a class of medicines used to treat a wide range of conditions, from diseases of the lung to Parkinson’s disease. Despite their wide use they can be high risk and potentially inappropriate, particularly for older people living with frailty. Frailty can be understood in terms of the decline in body systems that typically occurs in later life, reducing resilience to stressors such as an infection, or indeed a medicine [1]. Everyone can potentially experience some side effects from medicines, however older people with frailty are more sensitive to medicines, and are less likely to tolerate adverse effects [2]. In particular, it is thought they are more susceptible to the adverse effects associated with the accumulation of anticholinergics, known as anticholinergic burden. These include physical impairments, falls and cognitive decline [3-5]. Consequently, it is important that patients living with frailty who are prescribed medicines with anticholinergic properties have their medicines routinely reviewed to ensure that they continue to be safe and appropriate [2].

Structured Medication Reviews or ‘SMRs’ are part of the national service specification delivered by Primary Care Networks (PCNs) in England. A priority patient cohort to attend an SMR are older patients living with frailty who may also have been prescribed high-risk medicines, such as those with anticholinergic properties. To ensure these patients are appropriately targeted, guidance on SMRs encourage the use of tools and technology. However, a paucity existed in appropriate tools to identify patients living with frailty who were also taking anticholinergic medicines.

To address this gap, the safe use of medicines theme in collaboration with the digital innovations theme, both of the NIHR Yorkshire and Humber Patient Safety Translational Research Centre, have developed the AC-FRAIL tool. This unique tool proactively identifies patients across a GP surgery’s patient population with high anticholinergic burden, and who live with frailty. This offers a useful and efficient tool for primary care clinicians to prioritise the most vulnerable patients for SMRs. The tool is designed to be easily installed within IT systems used by GP surgeries, with the output being a user-friendly platform which stratifies the practice population (aged 65 and over) by their estimated frailty severity, and number of anticholinergic medicines they are being prescribed. The outcome is a list of patients who are considered at greatest risk of adverse effects from their medicines, and should be prioritised for a SMR.  This is a proactive approach to the identification of patients, rather than reactive care.

Evidence of associations between anticholinergic burden and adverse outcomes in older people underpins the AC-FRAIL tool [1-3], in addition to literature highlighting how the frail are particularly vulnerable to stressors such as high-risk medicines [4-5]. Based on this evidence, we hypothesise that older people with advancing frailty are at greater risks from anticholinergic burden, compared to fitter older people, and hence why the AC-FRAIL takes a population stratification approach to identifying the most frail. However, evidence is limited in this field, and further research is required to investigate the extent of risks of anticholinergic burden across the frailty spectrum. Researchers within the safe use of medicines and digital innovations themes within the centre are conducting a variety of mixed-methods studies to further these investigations. These studies aim to understand the associations between anticholinergic medicines and adverse outcomes in frailty, and which anticholinergic medicines in particular may be of greatest concern to these populations. These include literature reviews, and analyses of patient datasets. Additionally, we have conducted interviews with 25 health care professionals to gather their perspectives of anticholinergic burden, frailty, and the use of tools to support safer prescribing decisions. These studies will help inform further development of the AC-FRAIL tool, as well as other tools to support safer prescribing.

We aim to continue to test and evaluate the AC-FRAIL tool as part of our ‘Deciding to Deprescribe’ study.  To find out more about our AC-FRAIL tool please read our recently published article at https://wchh.onlinelibrary.wiley.com/doi/full/10.1002/psb.1877

This research was funded by the National Institute for Health Research (NIHR) Yorkshire and Humber Patient Safety Translational Research Centre (NIHR Yorkshire and Humber PSTRC). The views expressed in this blog are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care.

 

References

  1. Clegg A, Young J, Iliffe S, Rikkert MO, Rockwood K. Frailty in elderly people. The lancet. 2013 Mar 2;381(9868):752-62.
  2. Hilmer SN, Gnjidic D. Prescribing for frail older people. Australian prescriber. 2017 Oct;40(5):174.
  3. Welsh TJ, van der Wardt V, Ojo G, Gordon AL, Gladman JR. Anticholinergic drug burden tools/scales and adverse outcomes in different clinical settings: a systematic review of reviews. Drugs & aging. 2018 Jun;35(6):523-38.
  4. Salahudeen MS, Duffull SB, Nishtala PS. Anticholinergic burden quantified by anticholinergic risk scales and adverse outcomes in older people: a systematic review. BMC geriatrics. 2015 Dec;15(1):1-4.
  5. Richardson K, Fox C, Maidment I, Steel N, Loke YK, Arthur A, Myint PK, Grossi CM, Mattishent K, Bennett K, Campbell NL. Anticholinergic drugs and risk of dementia: case-control study. bmj. 2018 Apr 25;361.

Is digital innovation in healthcare safe?: Experiences from an Academic Health Science Network workshop

By Ciarán McInerney

In late 2019, the Academic Health Science Network hosted an event exploring the effective use of the National Early Warning Score version 2 in Yorkshire and Humber. Such tools for monitoring patient deterioration are very relevant in the midst of the COVID-19 pandemic where healthcare practitioners are still learning how best to treat the disease. The Yorkshire and Humber PSTRC Digital Innovation theme was invited to run a workshop during which we posed the question “Digital Innovation in the NHS: Is it safe?”.

The NEWS2, the National Early Warning Score version 2, is a metric to indicate the health status of a patient based on six physiological measurements routinely collected in clinical practice (1). The integration of the NEWS2 into electronic health records is a good example of the type of innovation that the Digital Innovation theme evaluates for safety.

At the Academic Health Science Network event, we met with clinical, administrative, operations and managerial staff to discuss the safety implications of digital innovations and technology in healthcare. Through two collaborative activities, the attendees discussed attributes of digital and technological innovations in healthcare using case studies and their own experiences. Together we reflected on the stakeholders, rewards, risks, issues and solutions.

What did attendees think?

We summarised attendees’ views using the SEIPS 2.0 model, Systems Engineering Initiative for Patient Safety version 2 (2). At its highest level, the model has four parts that provide a lens through which we can view the safety of a healthcare system: Work system, Work processes, Outcomes, and Adaptations. The image below visualises the relative proportion of comments made by attendees that were associated with each part of the model.

When reflecting on their experiences of digital innovations in healthcare, attendees most often spoke about the Work System, which dealt with people, tasks, tools, rules the environment, and the relationships between them. Attendees recognised that digital innovations can improve patient safety often by streamlining care for more efficient use.

The Winter Pressures project from the Digital Innovation theme is an example of our work addressing a Work System. We are modelling the efficient flow of patients in the context of increased load during periods of heightened pressure (see our recent blog). We’re finding that modelling patient flow can be a useful application of digital technology that supports the decision-making capacity of healthcare staff.

In contrast to the Work System, attendees had little experience of the use of digital innovations for Adaptation, which describes how outcomes and processes are fed back to the system and what effects the feedback has. Through group discussion, attendees identified that risks and issues arising from digital innovations were associated with unanticipated and intermittent events. Networking, situational awareness, back-up plans and IT support were suggested by the group as solutions to these risks. The Digital Innovation theme’s Micronarratives project is investigating digital innovations that are specifically designed to promote these types of adaptive solutions. We aim to evaluate the effectiveness of these technologies at addressing the concerns put forward by the attendees.

Are digital innovations safe for patients?

Over the afternoon of workshops, attendees contributed a wall’s worth of perspectives on the stakeholders, rewards, risks, issues and solutions associated with digital innovation in healthcare. In this blog, we could only skim the surface of what was discussed so we have produced a visual report of the workshop that presents the views of the attendees in greater detail.

Each of the two workshop deliveries ended with a question for the attendees that introduced Erik Hollnagel’s [1] distinction between Safety-1 and Safety-2: should we focus on finding and preventing harm, or on finding and encouraging safe practice? For some attendees, considering safety in these terms was a change of perspective that made for a more nuanced question of whether healthcare is safe. The overwhelming answer to the question posed was “It depends”; stated factors included the activity being actioned, the expected outcome, and the available resources.

In the Digital Innovation theme, we recognise the complexity in considering the safety implications of digital technology, not least because it is interwoven into the systems, processes and reporting structures of healthcare. Through continued interaction with healthcare staff like those at the Academic Health Science Network event, we hope to understand the components, relations, levers and consequences of our combined efforts to deliver the best and safest care for patients.

How can I get involved?

The conversation doesn’t end in workshops like these. We want to know what you think.

Should we focus on finding and preventing harm, or on finding and encouraging safe practice? Let us know in the comments below.

 

References

  1. Royal College of Physicians. National Early Warning Score (NEWS) 2 [Internet]. London, UK; 2017. Available from: https://www.rcplondon.ac.uk/projects/outputs/national-early-warning-score-news-2
  2. Holden RJ, Carayon P, Gurses AP, Hoonakker PLT, Hundt AS, Ozok AA, et al. SEIPS 2.0: A human factors framework for studying and improving the work of healthcare professionals and patients. Ergonomics. 2014;56(11):1–30.

Developing a Care Opinion research community

By Professor Rebecca Lawton – Director of the NIHR Yorkshire and Humber PSTRC

The experiences of patients are increasingly being sought by health and social care organisations and, perhaps less frequently, used to make improvements.

These experiences come in different forms – as ratings on questionnaire items, informal feedback sought by staff or stories volunteered by patients and their families. Care Opinion provides an opportunity for the latter. This not-for-profit organisation provides a platform for unsolicited stories, reflecting both positive and negative experiences of care that are written and directed to the organisations providing that care.

This interest in the views and experiences of patients and families, and opportunities for their involvement in their care, has also been the subject of a growing number of research studies over the last decade, with broad categories of work including shared decision making, participatory forms of design such as experience based co-design, patient reported process and outcome measures.

In a new endeavour, the NIHR Yorkshire and Humber Patient Safety Translational Research Centre is collaborating with Care Opinion to bring these two agendas together, to create new opportunities for patients and carers to be involved in research.

In 2019 we asked over 500 people who had written a story on Care Opinion whether, in principle, they would consider volunteering to be part of a “research community”.

Of the 163 people who responded to this survey, the majority were very positive about being involved in research. Nearly all respondents felt that healthcare research was important (99%). They also agreed or strongly agreed (96%) that taking part in healthcare research improves healthcare and that Care Opinion authors may have experiences that would help research (96% agree or strongly agree).

Care Opinion authors also had some opinions on how they should be involved. They expressed a wish to be able to opt in or out of being asked to help (96%) and that they should be able to see the type of organisation they are being asked to work with, before deciding (97%). Knowing about the expected time commitment (90%) and knowing how their information is safeguarded 76%) was also important to respondents.

Using this information Care Opinion, with support from Yorkshire and Humber PSTRC, has enhanced its online platform so that story authors can be invited to join the research community and state their preferences for the kinds of involvement they would want.

Our plan for the next few months is to test this out with a small number of studies within the PSTRC which are currently recruiting patients as participants. We will continue to develop the system and once we are confident that patients and researchers are happy with the way things are working, we will begin to share this opportunity with other research groups who might also find it valuable.

Of course, there will be many discussions and perhaps some glitches along the way and this approach to participating in research won’t suit everyone. There will also be questions, as yet unanswered, about the representativeness of the research community on certain characteristics such as education, socio-economic status, age, gender and ethnicity. We will need to learn and share as we go along.

We are very excited about this new and open approach to widening research participation – and learning how we can offer people who have already shared online feedback additional ways to help improve health and social care services through research.


Patient Safety and COVID-19 – the importance of NIHR PSTRCs

Since 2012, the NIHR has supported research into patient safety through funding Patient Safety Translational Research Centres (PSTRCs). There are now three centres: Greater Manchester PSTRC, Imperial PSTRC and Yorkshire and Humber PSTRC. These centres operate as partnerships between a host NHS organisation and affiliated universities.

COVID-19 has brought to the fore the significance of patient safety like never before. Behavioural science has underpinned many of the most challenging safety concerns that have emerged during this time. This includes the effort to encourage the general public to follow government guidelines on physical distancing, the importance of staff wellbeing along with infection control in hospital. Understanding why people do what they do and promoting changes in behaviour are prominent features across the PSTRCs’ work.

The PSTRCs are dedicated to improving patient safety across specific areas of the NHS and social care. The centres are designed to be agile and responsive to emerging research priorities, focusing on applying novel approaches to unsolved questions. The PSTRCs proactively involve patients, gathering their experiences before creating interventions to improve specific patient safety concerns. New safety initiatives developed by PSTRCs are then tested or piloted in the appropriate healthcare setting such as a hospital, GP practice, care home or pharmacy.

The centres’ role in responding to the COVID-19 pandemic focuses on adapting existing work and building upon it to address some of the challenges facing the NHS. In addition, new research has been launched to understand and support the response to COVID-19.

An example from the Greater Manchester PSTRC is the launch of a study that looks at the mental health of survivors of COVID-19 as well as the general population within Greater Manchester including those with lived experience of homelessness. Another example is the roll out nationally of a digital triage system for use by GPs which had been previously designed by researchers within the Safety Informatics team based at the Greater Manchester centre.

Yorkshire and Humber PSTRC is exploring how healthcare organisations, such as hospitals and community pharmacies, have adapted operations to respond safely to the COVID-19 threat. It is also exploring the emotional support needs of healthcare staff and researching the impact of COVID-19 on people’s decisions to seek emergency healthcare.

Imperial PSTRC is assisting the WHO with guidance on medication safety during the pandemic and has launched a study looking at the impact of COVID-19 on digital technology in primary care. In addition, the centre is supporting the REal-time Assessment of Community Transmission (REACT) study, a national, Imperial-led programme investigating Covid-19 prevalence and the use of home testing.

The centres also recognise that this is a critical time for increasing the amount of research undertaken to support the NHS. Examples of this are developing online learning opportunities for those working in healthcare, online support communities and resources, and creating virtual research communities to allow work to continue even when face to face research isn’t possible.

The centres each focus work across specific themes* which span behavioural science, mental health, patients and carers, medication safety, transitions of care between healthcare settings, and digital interventions including designing dashboards and Artificial Intelligence. These themes are well placed to address the impact of COVID-19 on the wellbeing of the workforce, the resilience of specific areas of healthcare, the role patients and carers are playing in patient safety at this time, and access to healthcare by specific groups of patients such as those with lived experience of homelessness.

 

Read more about the work of Yorkshire and Humber PSTRC in this blog from the Centre Director, Professor Rebecca Lawton and Centre Manager Dr Beth Fylan –

https://yhpstrc.org/the-role-of-translational-patient-safety-research-during-the-covid-19-crisis/

 

Find out how the Imperial PSTRC involves people in its research, and how the Centre is adapting its involvement and engagement activities during COVID-19 in this blog: https://wwwf.imperial.ac.uk/blog/ighi/2020/05/20/its-people-who-shape-our-research-heres-how/

To learn more about the work of the Greater Manchester PSTRC during the COVID-19 pandemic read Centre Director Professor Stephen Campbell’s thoughts in his latest blog:

https://gmpstrc.wordpress.com/2020/06/03/the-role-of-translational-patient-safety-research-during-and-after-the-covid-19-crisis/

 

For more information on the PSTRCs please visit:

Great Manchester PSTRC http://www.patientsafety.manchester.ac.uk/

@PSTRC_GM

Yorkshire & Humber PSTRC https://yhpstrc.org/

@YH_PSTRC

Imperial – https://www.imperial.ac.uk/patient-safety-translational-research-centre/

@Imperial_PSTRC

 

Research themes:

 

GM PSTRC – Safety Informatics, Medication Safety, Marginalised groups (including two sub themes, Mental Health and Patients and Carers), Safer Care systems and Transitions of Care (including the Behavioural Science sub theme), and Safety in Marginalised Groups.

 

Yorkshire & Humber PSTRC – Patient Involvement in Patient Safety, Workforce Engagement and Wellbeing, Safe Use of Medicines, and Digital Innovation.

 

Imperial PSTRC – Safer Systems across the Continuum of Care, Partnering with Patients for Safer Care, Avoiding Deterioration in Complex Needs Patients, Enhancing the Safety of Medication and Technology, Improving Diagnostic Accuracy and Decision Making and Improving Diagnostic Accuracy and Decision Making.

The role of translational patient safety research during the COVID-19 crisis

By Dr Beth Fylan and Professor Rebecca Lawton

Over the past weeks we have witnessed the raised profile of health research and the fundamental role it is has in addressing the international crisis caused by COVID-19.  Health research organisations around the world have rallied to focus on identifying treatments and vaccines to aid prevention, recovery, save lives and enable societies to return to near-normal functioning. The hugely important role of behavioural science in understanding how best to persuade and support the general population to play their part has also been evident throughout. In the UK, the Government has placed its financial clout behind vaccine development and clinical trial centres are galvanised in establishing an evidence base to help clinical decision making. The RECOVERY trial established by the University of Oxford, for example, is currently testing a range of potential treatments for COVID-19 in 170 sites, including our own Bradford Teaching Hospitals NHS Foundation Trust.

Beyond this crucial, clinically focused work, applied research groups such as ours have been considering how their disciplinary expertise can contribute to benefit the healthcare system at this time. NIHR Patient Safety Translational Research Centres occupy a unique space in national healthcare research. Our role is to explore concepts, theories and methods that may have a role in increasing the safety of care but have not yet been developed or fully exploited. In short, we ‘aim to turn patient safety discoveries into practice’.1 We translate through developing new knowledge and understanding, or skills and tools which can be used or tested further.The commitment to funding such exploratory research is one of the reasons why the UK is at the forefront of health research internationally, recognising that innovation is key to enhancing the benefits gained from decades of work improving the safety of care.

We have come a long way in the UK since the publication of the report An Organisation with a Memory in 2000 3 in understanding the extent and nature of unintended harm to patients. Whilst the NHS has made great strides to eradicate many major of causes of harm to patients, such as wrong-site surgery and retained foreign object post-surgery (often called the ‘biggies’ of patient safety), harm is still prevalent (estimated to affect one in 20 patients).4 We have recognised the need in tandem to explore different ways of improving care.

Early translational research offers a route into these improvements and PSTRCs are a crucible for ideas yet untried and untested. Like others during this time of crisis, we find we have a role to play in the ongoing effort and the opportunity to adapt our work to address some of the challenges the NHS – and the public as a whole – faces. This means that, while some of our studies have been paused to reduce staff and patient burden, we can adapt quickly to the COVID-19 challenge by refocussing our early translational research where it can potentially bring benefits.

For example, our ongoing portfolio of work using resilient healthcare theory has given us the building blocks of a study to monitor and understand organisational response to the crisis. Similarly, our work to understand the impact of healthcare staff wellbeing and emotions in teams on care quality has enabled us to launch resources to support them given the unprecedented conditions that staff are working under. We are also adapting current studies in order to understand how patients and the public are supporting the health system by staying safe or why, in some instances, they may be staying at home, rather than seeking care if their health is deteriorating.

Having opened up new areas of enquiry based on our learning from previous work, we hope the findings from these studies will contribute to the growing knowledge of how we work together to respond to a patient safety crisis on a grand scale as well as how safety can be maintained when the norms and rules for delivering the service no longer work.

All us who have worked in health research for many years are deeply impressed, not only by the speed of the response of the academic and clinical research community to understanding this disease, but also to national bodies – such as the National Institute for Health Research (NIHR) and the Health Research Authority – which have swiftly adapted processes to agree funding for research studies, give due oversight to their protocols and approve them. We hope that collectively we can generate an organisational memory for working in a crisis that will help us think differently about safety in the future.

And, finally, we remain grateful for the extraordinary work of our frontline NHS, social care and key worker colleagues in tackling the COVID-19 crisis.

 

 

  1. National Institute for Health Research. £17 million invested in NIHR Patient Safety Translational Research Centres. 13 February 2017. https://www.nihr.ac.uk/news/17-million-invested-in-nihr-patient-safety-translational-research-centres/12278
  2. Aronson J. When I use a word . . . Defining translational research. BMJ Opinion 2017. https://blogs.bmj.com/bmj/2017/04/21/jeffrey-aronson-when-i-use-a-word-defining-translational-research/
  3. Department of Health. An organisation with a memory: report of an expert group on learning from adverse events in the NHS. London: The Stationery Office, 2000.
  4. Panagioti M, Khan K, Keers RN et al. Prevalence, severity, and nature of preventable patient harm across medical care settings: systematic review and meta-analysis. BMJ 2019; 366 :l4185