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  • Why investigate? Part 1. A series of blogs from Dr Martin Langham

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    After completing nearly 600 investigations and research projects in human factors, it might be worth sharing some observations of why we do incident (forensic) investigations.

    This will be a series of short blogs that will cover the investigation process, answer questions about humans and shine a light on the method of forensic investigations. 

    This will be undertaken alternating with the topic of human factors – the most misunderstood bit of science the healthcare sector deals with. In these posts I’ll cover what human is, the limits of human performance – covering the senses, fatigue – and why pilots and CRM is very dangerous to healthcare. Above all I want to get the idea that human factors is a science and it’s about understanding how human limits restrict how we deal with the built environment and complex systems.


    So, why do we investigate? In this part I’ll cover the philosophy of why we do it; later posts aim to provide an understanding of who might be the right person to do it. Having covered the why, I’ll do some posts about the when (always within 24 hours); the who (as in staff rather than the still-touring rock group); the what; and a few practical ‘top tips’ on the how.  

    Why do we investigate?

    Well investigation gives jobs to us investigators and, well, that concludes my piece.  Well let's at least think about the other reasons.

    Organisations investigate because their regulator or management team want it done. Sometimes investigations are done so the organisation feels good about itself. A report whose measure of impact and success is based on the weight of the printed pages, with a good report being 3–4 cms thick and the ultimate report keeping the door open in the summer, is not uncommon. It may be worth another post about communication of findings to achieve an action.  A poster on the wall is not a good idea, or courses on non-technical skills (NTS) or team talks. 

    Organisations often investigate in order to sack someone. Sack someone and the problem has gone. Well, while there is a feeling of action, this means very little learning is done, and from a human factors perspective it’s unlikely the human has done it deliberately. The organisation should really build a system that is tolerant of human error. In aviation, we (my company) were at the forefront of the no blame reporting systems.

    Protecting the organisations criminal and civil liability is often the reason for undertaking the investigation. Doing an investigation with only this in mind hampers the investigation team.  Yes, liability is an issue, but in healthcare there is an overriding duty of honesty and candour. If you investigate knowing the Coroner will ask you awkward questions, this will affect what you investigate. The legal side and compensation are a matter for the lawyers. In my view, your duty is to report what you find.

    The only reason to investigate is to stop it happening again. In the words of the philosophers – Metallica – nothing else matters (hopefully the reader is cognisant of rock music). The investigation is only there to prevent another incident occurring, by providing evidence, obtained through careful data collection, that means it simply will not occur again. 

    What’s an accident then?

    I’m now very conscious that we have got ahead of ourselves. We are talking about an investigation of an incident or accident or crash or oversight, but what do we mean by an incident or accidental death etc.?

    An accident is a typically defined as:

    ’"an unforeseen rare random event with multiple causes where in one moment in time something went wrong." 

    Let’s take each of those words and consider why we investigate.

    Unforeseen – if it was expected – then it’s not accidental and most likely the subject of a criminal investigation.

    Rare – well how many car crashes have you seen? How many planes have crashed while you watched them? How many trains have you travelled on that hit the buffers? Crashes, incidents etc. are thankfully rare.  Given what humans are designed to do – hangout and chill on the African Savannah lands – then its amazing how few incidents occur, especially with poor technology and the really badly built environment found in hospitals. I still recall watching an anaesthetist crawling under the patient’s bed as the room was too small to take a bed as well as the team.

    Random – you should not be able to predict precisely when they will happen. You may say there is an increased risk of an error in the operating theatre if the surgeons have loud rock music (Metallica) playing and the lamina flow is noisy, meaning no one hears the “I’m doing the left side here aren’t I?" But you can’t point at a patient and say they will die at 14:16pm, when we realise we have put the nerve block on the wrong side.

    Multiple causes – Human factors being a science means sad science types count the number of variables. In road transport back in 1972 (before mobile phones and Bluetooth that will not connect over 60mph – damn it – calm blue ocean) – where was I – oh yes over 1300 variables were identified.  Importantly, an incident does not have a single cause but typically 2–4 or so variables come together in a moment in time. Top tip – if anyone says an incident has one cause then smile and walk away.

    Moment in time – A split second later the train driver would have seen the red signal because the train spotter in the way would have leaned over a bit further. A millisecond earlier the scrub nurse would have noticed the tray was not on the trolley before her colleague distracted her with a question about the x-ray. Time is the essence. When investigating an incident, you have lots of time, the incident occurred in a millisecond. 

    Investigation therefore looks at a rare random event with the potential to have been caused by a complex failure in systems, equipment, human and environmental factors. Later in the series I’ll explain these factors in more detail.

    How do I know that I have investigated an incident to allow prevention to occur?

    Revisit the scenario and see if it could occur again. In one investigation that we did we found that a patient reporting in the emergency department and requiring a chat with a neurologist took 70 steps or stages in the booking process. This included a message to a fax machine whose location was a mystery.  Yes, deep breath, an error model means a near perfect failure rate and no fail-to-safe method (our investigation and remedy designed a system of just one stage – no possible error and even designed a leaflet about the patient not driving home afterwards). The simple test is to go into the Emergency Department in the role of a ‘patient’ who needs to speak to a neurologist and ask the team to walk you through their processes. True in this retest there were now two stages – but the system failed to safe, and the ED team remembered I like tea.

    If you do an investigation and a year later the incident could still occur, and nothing has changed, then you have wasted your time. Importantly – say this is so to whoever will listen.  As an investigator you sometimes need to spell things phone-net-ic-ally, so people understand that you will not go away and that sacking someone was not the answer. Ok, it maybe you that’s then sacked for asking a question phone-net-ic-ally...

    We have covered why we investigate and what an incident is. There is a long way to go before we reach the nirvana of incident free hospitals – but we have made a start. Well not really, it’s time to conclude with a confession. There is another reason why I investigate crashes/incidents, have done all that training, wear scrubs, body armour, get cold wet and damp (not at the same time hopefully). The other and for me main reason to investigate a fatality is to tell the family why their loved one died. It’s a privilege to explain why we think it occurred and give some reassurance that it will not occur again. I do investigations where police officers have died. I never expect the family to agree with me, but only to listen to what I have found. Sometimes after an investigation the family may come with us as we do experiments and be part of the world of science. It’s true they may cry and get emotional – but they are only doing in public what we do ourselves in private.

    Read the other blogs in this series

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    About the Author

    Martin is topic leader for the hub.

    He founded the Human Factors group at the University of Sussex (1999), which became User Perspective Ltd in 2003. Martin, User Perspective MD and Chief Scientist, aided by his team, has undertaken almost 600 research and forensic investigation projects. He is interested in human error and human factors.

    Martin is a research auditor for the UK government, EU academic networks and many governments worldwide. Within healthcare he has investigated matters as diverse as neonatal safety in transport, unexplained injuries in the hospital mortuary, sepsis diagnosis and retained instruments. Martin co-authored the very first Healthcare Safety Investigation Branch (HSIB) report that investigated orthopaedic surgery in the UK and Europe. His interest in the law and justice extends to his voluntary role as a justice of the peace (JP) in the Magistrate and Crown courts.

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    Briilliant and challenging, thanks Martin.

    How many investigations would be able to meet this criteria: 'How do I know that I have investigated an incident to allow prevention to occur? Revisit the scenario and see if it could occur again.?'

    I wonder how much of this insight will be reflected in the new SI framework that is due to be published by NHSI  'soon.'

    Looking forward to the next blog!

    @Claire Cox I saw that you've tweeted Martin's blog for wider covergae. Thx

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