MOI - Mechanism of Injury

Mechanism of injury is a term often bandied around on medical courses, so most people who have ever done a course will be familiar with it. But how much do you really know about it and what does it really mean? 

Quite simply MOI is used to estimate the force (or forces) that cause injury when they are applied to the body, in relation to traumatic injuries. 

This might sound like a bad thing, but MOI has very practical uses (especially if your casualty is unconscious) in working out what potential injuries have occurred. MOI can give us really valuable information as to what areas we should focus on once we’re happy that our Airway, Breathing and Circulation are in good working order!. 

As we approach our casualty, we are already assessing the mechanism of injury. In checking for danger, you will be surveying the scene, which will provide vital clues as to what has happened, and therefore what injuries your casualty might have.

The biggest killers in trauma are catastrophic haemorrhage, followed by obstructed airways. So we would aim to stabilise these as the priority. Of course we can’t save everyone, but simple things done at the scene can make a huge difference.

Mechanism of injury does involve a bit of science. Kinematics to be precise. But stick with us, and let's engage our inner science geek because this bit could be really useful!

Kinetic energy is formed by two factors - velocity and mass. Or speed and weight to the rest of us. Speed is generally the bigger risk factor, but a slow moving heavy object can do untold damage too. As an example, a high speed power boat collision could obviously cause serious injuries, but a ship touching the dockside would be slow and catastrophic if someone fell into the gap. 

Simply put, the transfer of massive energy will cause massive injuries.

Working out the mechanism of injury can direct your attention to less obvious injuries, or even previously unidentified casualties. 

Take a look at this UK commercial to promote the wearing of seatbelts. It talks about the different forces involved in an impact (not just cars!). In this case the vehicle stops with a violent decelerating force. Next the casualty stops, but the internal organs are still moving until they hit something solid. The result is catastrophic. But it’s a good illustration of how energy transfer works. (NOTE: it’s a bit gory if you’re of a squeamish nature!)


Let’s look at a couple of possible scenarios and think about what could have happened…
(We will assume there is no catastrophic haemorrhage in each case.)

Superyacht deckhand found unconscious at the bottom of a stairway.
  • They’ve fainted and fallen from standing where they are.
  • They’ve slipped on the stairs and fallen, knocking themselves out.
  • They’ve fainted and fallen down the stairs from the top.
  • They’re having a snooze.
If they’ve fallen from standing and were unconscious when they fell, their injuries should be relatively minor. But you need to consider the cause. Why have they fainted? Also, is there anything around that they could have hit their head on, or that could cause other injuries.

If they’ve sipped and fallen, initially they might have been able to help control the descent and protect their head and neck. But at the point of unconsciousness, this stops. Descent becomes rapid and uncontrolled, there is a risk of impact with the stairs, bulkheads, deck and anything else protruding. We would certainly consider possible head and cspine trauma, with an in depth top to toe survey (part of your secondary survey) to investigate for other injuries. 

If they’ve fainted and fallen down the stairs, they are unlikely to have been able to protect themselves in any way. Similarly to the above, we would be considering head and cspine injuries as a priority, then using a top to toe survey to look for chest, back, abdominal, pelvic and other musculo-skeletal (MSK) injuries. We would also be investigating the cause of the faint.

If they’ve decided on an unusual location for a snooze the worst that would happen is they’d probably be in for a bit of mickey taking! 

Man overboard from a middle deck. 
  • Slipped and fell into the water.
  • Fainted and fell overboard.
  • Injured during a task and fell into the water.
  • Jumped in on purpose.

In this case we have additional complications of a fall from height, submersion in water and possible hypothermia, plus getting the casualty out of the water into a safe area in order to conduct our assessment. 

If the casualty is conscious and slipped, they will try to protect themselves, but any unexpected fall means they aren’t in control. In this case we would suspect a cspine injury and investigate the possibility of multiple other injuries. Conscious casualties will try to look after their own airway, but the risk of inhaling or swallowing water is high.

If they are unconscious before they hit the water we have to consider head and cspine injuries, plus the possibility of multiple other injuries. The impact of an unconscious body into water from height is an extremely violent mechanism. We also have the risk of drowning as an unconscious casualty is unable to protect their airway. 

If an injury preceeds the fall, does our assessment change? The answer is no. We would consider head and cspine injuries, then carry out our top to toe survey to uncover other injuries, plus investigate the injury that caused the fall. 

If the person has jumped in on purpose, the chances are that they have planned the event and controlled the fall. The risk of injury is lower if they enter the water in a controlled manner. But there’s always the risk of a cspine/head injury that could cause paralysis if a dive causes them to hit the bottom head first, or a submerged obstruction. Or, if they go in feet first, the shock can travel up the legs and spine, resulting in a cspine injury. You should also ask the question why have they jumped in? It could simply be off duty fun with colleagues, but could also be psychologically motivated and an attempt to end their life.

So, in summary, understanding the mechanism of injury can be a really valuable tool in our tool box of casualty assessment. Thinking about what’s actually happened and the potential impact on a human body can provide big clues about the potential injuries and therefore help you to treat your casualty more efficiently and effectively.

If you’d like to try out one of the Red Square Medical onboard drills involving mechanism of injury, please get in touch.












by Rachel Smith 26 March 2025
In basic first aid classes, there is great emphasis on not moving a patient under any circumstances. But is this always right? Our Paramedic friends tell us about times they have arrived on scene to find an elderly faller virtually held down onto the icy ground they slipped on because they think it’s best. Or a care home resident who is unharmed, wriggling around but just unable to get themselves off the floor. Of course, if the person is ill or injured, care must be taken to prevent the condition from worsening, but certainly in our maritime environment there may be times when we MUST move a patient for both their and our safety and wellbeing. We may even need to move them into a safe space (such as lowering from height) before we can assess them and work out the potential injuries and associated risks. But how do you know when to move them? Or how to move them safely? Here are some situations where moving the patient might be essential: Immediate danger – if the patient is in immediate danger, and if it’s safe for you to help, they should be moved away in some manner. This could be due to fire, an unstable structure, in the water, an otherwise unsafe location. Cardiac Arrest – the patient must be on or moved to a hard, flat surface in order for compressions to be effective. Ideally with a bit of space for a team to work around them. To prevent further harm – if the patient is in a position where they could worsen, or something life threatening could develop, you may need to move, or at least reposition them. This could be due to vomiting, choking on blood, unable to maintain their own airway and could be as simple as sitting them up or rolling them over. Self-extricate – if the patient is able to self-extricate, they should do so. There has been a lot of recent research into this area and old techniques challenged and changed. For instance, in a road traffic collision, if the patient can get out of the car themselves, they should. You can find out more here: https://phemcast.co.uk/2022/09/15/extrication/ Worsening conditions – if the weather and environment change, then you may need to move your patient. For illness or injury, keeping someone warm is important, if not vital. Even in a tropical climate, a trauma patient can cool more rapidly than you think and those rain squalls may pass quickly but do a lot of soggy damage in a short time.
by Rachel Smith 26 February 2025
At the time of writing, the Caribbean superyacht season is in full swing and the Mediterranean season is looming just around the corner in a few months time. It can be a stressful time for any crew, from the most senior to the most junior - and we could all do with a little help to manage stress and our response to it. We’ve written a number of blogs about mental health and things you can do to help manage your own stress and mental health, and when to seek help. We’ve listed them at the end of this blog. But did you know that we can also offer a one day, onboard training session, for the whole crew? Stress Happens! is run in conjunction with the super experienced team at Impact Crew, so you benefit from a business, leadership and team perspective, together with the medical and wellness input. Stress Happens! was developed in response to feedback from superyacht crews and has been running for 4 years. It can be delivered in one day and is suitable for crew at any level. It’s also delivered onboard, making it easy to facilitate the whole crew to attend. The aim is to focus on mental wellbeing and stress, providing tools and techniques to help you to manage your own stress, helping others to manage their stress and knowing where to turn for help if it’s needed.
by Rachel Smith 12 February 2025
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by Rachel Smith 29 January 2025
Get ready for something super exciting! After a full year of intense planning and meticulous preparation, we're thrilled to announce the launch of our all-encompassing medical support service — FleetMed Support! Customised Maritime Medical Solutions Whether you have a fleet of ships or a single vessel, managing medical operations can be daunting without dedicated support. This makes FleetMed Support a perfect solution for the cruise, expedition and superyacht sectors. Our approach is simple: We take the burden of medical management off your shoulders, allowing you to focus on the bigger picture. With 24/7 support, we create a customized service level agreement for your fleet, ensuring that every detail is taken care of. So what’s new and why haven’t we done this before? Well, we're not a company that rushes into things. Instead, we take the time to thoroughly research and understand what's needed, ensuring we can deliver to the very high standards we set for ourselves and maintain those standards at all costs. Let's be honest, it's the continuous pursuit of excellence, the commitment to always improve, and the understanding that there's always more to learn that drives us forward each day. This means we are now ready to launch what we believe is a truly great portfolio of customisable services. So, how could this look for your company? Working with us is straightforward and hassle-free. We start by listening carefully to your specific requirements so that we can thoroughly understand your needs, and discuss your current gaps. Once we have a clear picture, we craft a tailored plan to deliver the precise services you require. Our process is marked by clear and concise communication at every step. We believe in total transparency, ensuring that you are kept in the loop throughout the entire process. We pride ourselves on our efficiency and dedication. Once the plan is in place, our experienced team gets to work, executing the agreed-upon services with precision and care. Our goal is to deliver exceptional results without any drama, making your experience as smooth and stress-free as possible.
by Rachel Smith 15 January 2025
From Flu jabs to far flung destinations… Vaccinations are a hotly debated topic across the globe, particularly after COVID-19 and the rapid response to the need for a vaccination to help reduce the burden on the health services in different countries. While the majority of healthcare workers and the general population support the ‘prevention is better than cure’ line of thinking, and therefore vaccinations, there are others who are determinedly against vaccinations for any disease, whatever the risk of mortality and death may be. In the UK, the BCG (Bacillus Calmette-Guerin) vaccination used to be given to all children in their teenage years to protect against tuberculosis. The vaccine has been so successful that TB is virtually eradicated now, and the majority of cases are due to migration. Now it’s only given to those deemed at high risk - babies and children at high risk, those travelling to high risk regions and adults coming into the UK from high risk countries. Depending on your country of origin, you should receive a range of vaccinations as a child or young adult. This will most likely include diphtheria, tetanus, polio and whooping cough, hepatitis and HIB (Influenza type B). Then MMR (measles, mumps and rubella), the pneumococcal vaccine (meningitis, pneumonia and sepsis) and HPV (Human Papilloma Virus) with a variety of boosters along the way. At the other end of the scale, the over 65s can receive vaccines for shingles, pneumococcal vaccine and respiratory syncytial virus along with flu and covid vaccines.
by Rachel Smith 30 December 2024
Reflection is an essential part of medicine and our regular followers will know that every year, we like to take a look back and assess where we started and how far we’ve come over the last 12 months. So, please join us on our whirlwind recap of 2024 as we get ready for a fabulous 2025… In 2024 we increased the number of STCW training clients to 4 organisations in 6 locations. We delivered STCW training at all levels to over 250 students. We delivered bespoke training to over 75 students onboard Superyachts and cruise ships. We delivered first aid at work or oxygen training to over 40 students, on land and on ships.
by Rachel Smith 18 December 2024
Welcome to our December blog, which is all about the recovery position and how to manage an unconscious casualty who is breathing normally. Unconsciousness is a medical emergency as the person is very vulnerable and may not be able to manage their own airway effectively. We also need to think about the cause of unconsciousness. Is it a simple fainting episode due to illness? Is it a massive hemorrhage causing hypovolemic shock? Or is it due to some kind of external factor or injury? This blog looks at how to manage an unconscious casualty. So, if we have a casualty who is unconscious, but who is breathing normally for themselves, and we’re not suspecting a serious injury, the recovery position is the best position to use while monitoring them. The recovery position keeps their airway open and makes sure that vomit or liquid won’t cause them to choke.
by Rachel Smith 11 December 2024
All the guest blogs! When we started adding blogs to our website back in early 2021, we did a little feature on each of our instructors of the time. They’re quite a fascinating bunch and the series proved quite popular amongst our followers. In addition to our amazing instructors, we work with some utterly incredible human beings all over the world, and the idea of sharing their stories grew and developed into what eventually became a monthly guest blog. It’s been interesting to find out more about how medical care at sea or in remote locations features in their work, and to discover a few fun facts along the way. This month, we thought that it might be a fun idea to give you a chance to go back into the archives and review all the guest blogs over the last few years! Maybe even let us know which your favourite one is?
by Rachel Smith 27 November 2024
We’ve taken a look at the 2023 Casualty Summary Report from the Maritime Authority of the Cayman Islands (MACI) to see what kind of incidents and trends their data shows us, even with relatively small data sets, and how this may be able to transfer to our own risk assessments and actual practice. You can find the report here: Cayman Maritime Report 2023 The first thing we noted was the authors note that the data is split out into incidents. This means that one incident may include a number of events. So a collision and any resulting injury is one incident, but is reported as two events, or more, if more than one person is injured. It made us wonder whether this method of reporting by an authority represents how incidents are reported onboard and whether it should be a consideration? Of course, for any set of statistics presented at the moment, we also have to consider the COVID-19 pandemic and the impact this has on trends including that period. While essential shipping continued, the cruise and superyacht sectors reduced activity and staffing, often to a skeleton crew while anchored somewhere. So this will be reflected in the historic data sets that we analyse from 2019 to 2021 and may not accurately reflect increases and decreases during and since then. In some situations, we may need to look further back for accurate data. We also need to consider whether increases in incidents and events is also down to increased reporting - suggesting an improvement in the awareness of reporting requirements and greater engagement from the industry and individual sectors - this can only be a good development. Since 2020, the type of injury has been recorded in 8 different categories, with hand and foot injuries topping the leaderboard, closely followed by head, body, and back injuries. So if you were looking to run drills, or practise medical skills, these would be the key areas to cover. Only one death was an occupational accident, and is being investigated here: MAIB Investigations (search for case #9229607). It relates to a fall down a ventilation shaft on a bulk carrier in a Greek shipyard. The full report was still pending at the time of writing. Merchant ships are heavily regulated by a number of authorities, and the requirements for personal protective equipment and safe systems of work are enforced and applied to reduce accidents and incidents onboard. This has led to a lower reporting of incidents than in the commercial yacht sector. Could there be room for improvement here in this area? We certainly think so. Many of the hand and foot injuries reported can be career ending or life changing, but are preventable. Follow up has shown that there is a link here with injuries being sustained when inappropriate or no PPE was used. The supply and use of appropriate PPE is mandatory on vessels subject to the MLC and it’s worth remembering that some PPE can be produced in styles and designs compatible with the aesthetics of a yacht if required! On a much wider scale, a lack of transparency and standardisation globally can affect the collection of data and the issue of under reporting. While the MACI figures may be accurate, we need other accurate figures to compare them to, in order to build a bigger picture across the world as we have in aviation. From December 2024, the Maritime Labour Convention (MLC) will be enforcing an amendment so that seafarer deaths will be recorded and reported annually. The MACI and Cayman Islands Shipping Registry produces a number of safety flyers that are publicly available HERE that may be useful. In summary, analysing data can sometimes result in more questions than answers. But even this can lead to interesting and important developments that result in improved safety and reduced incidents and accidents onboard. Key points to take from this report are: Use the correct PPE for the task. Employ approved systems of work and risk assessments for the task. Reporting is key for safety in the future of our industry. Enjoy a night ashore, but don’t over do the cocktails! As always, if you’d like any input on medical training onboard or ashore, or drills that you can run yourselves, please just get in touch. References: https://www.lloydslist.com/LL1145359/Increase-in-incidents-of-deaths-at-sea
by Rachel Smith 6 November 2024
Welcome to our latest guest blog where we’ve been chatting to James Griffiths, General Manager of Ocean Operations for Scenic Group and finding out more about what happens behind the scenes in order to keep a fleet of luxury expedition ships running. Here’s what James told us… As General Manager of Ocean Operations, I’m responsible for the operations of our fleet which includes four ships in service with around 850 colleagues. I currently live in Mumbles, near Swansea in the UK, but due to the nature of my work I spend a significant amount of time living in Croatia. Prior to this role, I spent many years working at sea and worked up through the ranks to Captain and over the last 15 years, my main focus has been on polar expedition travel. I hold a master mariner certificate of competency in addition to a degree in engineering and a post graduate diploma in law. Part of my job is to work with our medical service provider (Red Square Medical) to ensure that our ships are offering medical services that are appropriate for their deployment, and this can often be to some of the most extreme and remote locations around the world. It’s extremely varied, though during the COVID-19 pandemic, I came ashore when our operations paused for a significant period of time. I was fortunate enough to be given the opportunity to lead the restart of our Ocean Operations, which included setting up everything from a company to manage the ships, to selecting our crewing, medical, helicopter and submarine partners and providers, amongst many other things. Our areas of operation, and the nature of our cruises (expedition), plus having aircraft and submersibles onboard some, do mean additional elements involved in the management of these ships. You could say that this current position is more of a happy coincidence than one that I actually planned for! In some ways this is a great positive - I do think it’s possible to plan a little too much and then be disappointed if things don’t go quite the way you had imagined. But there’s no danger of that here!
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