Physiology in the Winch

Dr Alan Garner has a blog post in the context of a report just published. A catastrophe during a winching operation highlights the physiological challenges we sometimes add in the work we do. 

The death of a patient during a winching incident in Victoria in 2013 was distressing for everyone concerned.  I was asked by the Victorian Coroner’s Office to provide an expert opinion on the death based on some previous research I had conducted with one of our registrars, Dave Murphy, looking at the effects on respiratory function of various methods of helicopter rescue.  I’m pretty sure at the time we were the only group in Australia who had published in this area so I guess we were the obvious choice.

As part of trying to avoid a similar incident the coroner’s office agreed to us publishing the case in an appropriate scientific journal so that operators worldwide would benefit from the lessons learned rather than just the industry in Australia.  That report has just been published in Aerospace Medicine and Human Performance and can be found here.

The details of the case are now on the public record in both the coronial inquest and the ATSB investigation.  Our case report focuses more on the physiology of hoisting than either of these forums needed.

For those not aware of the case the brief version is that a man of approximately 60 years of age and BMI of 45 with borderline cardiac failure injured his ankle whilst on a hunting trip in Victoria about a kilometre from the nearest road.  Carrying him was considered risky for the rescuers (the terrain was steep) and a hoist extrication by helicopter was organised.  An accompanied single sling technique was utilised.

Unfortunately as they approached the aircraft skid the patient became combative and then unconscious.  He slipped from the strop despite the best efforts of the paramedic and crewman and fell to his death.  I can only imagine the distress of the crew when this occurred.

The actions of the crew on the day were consistent with their company/Ambulance Victoria procedures and were within the specifications of the equipment utilised. They were just doing their best to provide their best care as they’d been trained. Neither was any of the equipment found to be faulty.  The obvious question then is why did the fall happen?

What happens when you put someone in that hoist?

You need to go looking in the climbing literature to find the physiological effects of suspension with chest compression which is what happens when you are in a single strop.  As you would expect, there is a constrictive effect upon respiration but there is also a considerable decrease in cardiac output resulting from the decreased venous return with raised intrathoracic pressure.  The decrease in cardiac output has been demonstrated to be as much as a third in fit young climbers.  The decrease in respiratory function parameters is similar (in both the Murphy paper and the one referenced in the link in the previous sentence).

HMS Montrose conducts Rapid Roping and Winch Training
When you think through what’s involved, the physiology makes sense.

Given that the chest compression associated with hoist rescue is of short duration it is generally adequately tolerated long enough to complete the rescue in fit young people.  Having said that one of the best studies of the physiological effects of suspension in a chest harness was precipitated by the death of a 25 year old soldier who was left suspended in a single strop for just 6 minutes.  Cardiovascular collapse can occur surprisingly rapidly.  The man in the Victorian incident with his significant comorbidities was however not able to tolerate even a short period of thoracic compression and rapidly became unconscious.

The effects of single strop rescue in people who have been immersed even where they are otherwise fit and young is perhaps better known and the second sling under the knees (or hypostrop as it is often called) is in widespread use in this situation.  For winches of non-immersed persons it seems that the physiological consequences of various rescue techniques are not well known in the industry however.

Subsequent actions by Ambulance Victoria, the helicopter operator, the Victorian Coroner, CASA and the Australian Transportation Safety Bureau (ATSB) all rightly concentrated on determining how a repeat of the incident could be avoided by better educating both clinical and operational crews about the physiological implications of hoisting techniques.

What are the options?

We have previously published on the use of the Coast Guard Rescue Basket due to its benign effect on physiology compared with other techniques (Murphy).  It remains a surprise to us that this device is not in more widespread use.  Ambulance Victoria has now introduced a sit type harness which is definitely to be preferred in hoists over land.  The Rescue Basket can be used in winches out of water as well and we think is the more flexible option.

You can see that this sort of option would be easier on the physiology.

Should the single strop technique be banned entirely?  We don’t believe so. Every rescue is a balance of risks and sometimes the risk to either the patient, aircraft or both means that an immediate single sling extrication may be the safest option overall.  We certainly have not banned its use within CareFlight.  Knowing about the physiological downsides we have discouraged its use for many years and encouraged use of the rescue basket.  We have not removed it from the armamentarium however.  If a crew elect to use it they have to provide a report in writing to the chief pilot about why they chose that technique.  Knowing that there is that little bit of extra documentation required is enough to make teams make sure they’ve covered their options and risks carefully before they go ahead, but the option remains on the table.

Hoisting is risky for lots of reasons. We train for a range of safety considerations. And equally we have to make sure we’re aware of the physiological changes we might inflict on our all important patients.

Conflict of Interest Statement:

Neither I, nor either of my employers have any interest, financial or otherwise, in the manufacturer or distribution of the Coast Guard Rescue Basket.


The first image here is from the Royal Navy Media Archive while the second was posted by Jim Howard, both to the Creative Commons area of flickr. Both are unchanged.

And now those references.

First is the paper derived from this case:

Biles J, Garner AA. Loss of Consciousness During Single Sling Helicopter Hoist Rescue Resulting in a Fatal Fall. Aerospace Medicine and Human Performance. 2016;87:821-4.

Next is the paper written with Dave Murphy:

Murphy D, Garner A, Bishop R. Respiratory function in Hoist Rescue: Comparing Slings, Stretcher and Rescue Basket. Aviat Space Environ Med 2011; 82(2):123-27

And the first of the climbing things:

Roeggla M, Brunner M, Michalek A, Gamper G, Marschall I, Hirschl MM, et al. Cardiorespiratory response to free suspension simulating the situation between fall and rescue in a rock climbing accident. Wild Environ Med 1996;7(2):109-14

And the next one:

Madsen P, Svendsen L B, Jørgensen L G, Matzen S, Jansen E, Secher N H. Tolerance to head-up tilt and suspension with elevated legs. Aviat Space Environ Med 1998; 69(8):781-4

And you can find the ATSB report here.

Brighter Lights for Darker Nights (or How and Why to Set up Trauma Workshops for Your Local Volunteers)

Greg Brown, the person with the job of coordinating education at CareFlight on things anyone with a bit of background can do to help make the wide, brown land feel a little less remote. 

It is a dark and stormy night. It had been a long day at work and you are now driving home from a nearby town where you have been holding fort at what is loosely termed a “hospital”. Your mind drifts to all that is warm, dry and welcoming – family, a comfortable lounge, re-runs of your favourite show (obviously it’s Helicopter Heroes…) – only 40km to go…

These were your last conscious thoughts before you hit a kangaroo, lost control of your Tesla (okay, maybe a Camry) and crash into a tree.

A passer-by calls emergency services. They are on their way – but it’s a dark and stormy night and you don’t live in NSW (that’s Newcastle, Sydney or Wollongong) and the response will be made up of volunteer emergency services.

Meanwhile, a page goes out back in your hometown. Members from various volunteer agencies drop their food and head to their respective depots, don their respective protective uniforms (usually coloured yellow, orange or white), jump in their respective response vehicles and head to the scene where you are now cold, wet and sore.

You are still in your car – you cannot get out because the dashboard has collapsed into your lap. The passer-by tells you that the first response vehicle has arrived. You twist your head to see who it is – Police, Fire or Ambulance? It’s none of those – you don’t live in NSW (again, that’s Newcastle, Sydney or Wollongong) and the response is made up of volunteer emergency services: State (or Territory) Emergency Service, the volunteer bush fire brigade and some others that you didn’t even know existed.

“Where’s the ambulance?” you ask – but the nearest ambulance is at least another half an hour away – maybe more! They tried calling the local doctor but it turns out that was you.

Damn those “dark and stormy nights” you sigh……

Reds Mando Gomez
The other kangaroo probably looks even less impressed.

The Problem

If this scenario sounds far fetched then I encourage you to head out of the big smoke and go bush for a while. Situations such as this are not only real – they are an almost daily occurrence in Australia and many other parts of the world. Conservative estimates reveal that volunteer emergency services personnel outnumber their paid (professional) compatriots by a ratio of 20:1 in Australia with similar comparisons reported abroad.

But all is far from lost. The reality is that the vast majority of emergency services volunteers in Australia are highly capable, appropriately resourced and widely respected for the unpaid yet vital roles that they perform in serving their communities in times of need.

But (yes, there is always a but) those roles rarely include the provision of medical first response unless they are trained community first responders or volunteer ambulance officers. As such, it is also a reality that in non-metropolitan Australia the victim of trauma (vehicle, industrial or other) is likely to be treated initially by a volunteer with nothing but a generic first aid kit and some non-specific training – good if you need a splint or sling, not so good if you are seriously injured. What’s more, many of these volunteers lack the confidence to engage in the provision of medical first response.

The Challenge

Whilst it would be nice if an expertly trained and equipped pre-hospital care team was available in every postcode every hour of the day, we all recognise that this is simply not possible. But (yes, another but) we can do something to help the volunteers that are out there in regional and remote areas. It’s called training.

In the mid 2000’s a small group of “greybeards” at CareFlight were discussing the ways of the world over a few decaf-soy-mochaccinos (probably more likely double macchiatos…) and collectively voiced that if only those volunteers in regional and rural Australia felt appropriately trained and empowered to do a few extra small things for their casualties then they could make even more of a difference to the survivability of the people that they treat. Thus, the concept of the Trauma Care Workshop (formerly termed the Volunteer Trauma Course) was born. With this concept came a list of expectations. These included:

  • The training was to augment the participants’ current training content and systems, not replace them;
  • It needed to bridge the gap between high quality first aid and the care provided by professional medical responders;
  • The educators providing the training needed to be expert clinicians that were clinically current – credibility was going to be important;
  • The training needed to occur in the locations where the responders live – not in Sydney; and
  • Since the participants were likely to comprise mainly volunteers, the training had to be for free (or at least at no charge to the individuals).

Nothing like a good challenge to get the neurons firing…

The Role of AeroMed in Regional Trauma Training

There is little doubt that the sound of an aeromedical flight (helicopter or fixed wing) provides reassurance to both the injured patient and their carers, especially in regional and remote areas. The very sound of an inbound flight conjures up images of advanced medical care, expert clinical decision makers and the opportunity to whisk the patient away to a shiny hospital filled with white lab coats and machines that go “ping”.

The reality is that most trauma patients do not get better at the place their injury happens; they get better in hospitals. So the presence of an aeromedical retrieval team on scene does not in and of itself guarantee survival for the patient – but it can help. So too can that group of volunteer emergency services personnel – if they are trained and empowered to do so.

Herein lies the opportunity. Aeromedical providers owe it to the volunteers that they support to build local capacity and resilience within the regional and remote areas that they service. After all, at some point we all must recognise that we all exist for the same purpose – that is to save lives, speed recovery and serve the community. It is not about the colour of your uniform, nor is it about the company that pays you – it’s about people.

The same is true for clinicians working in regional and remote areas but not associated with an aeromedical provider. Clinic staff are often the second line of defence in the battle against trauma related morbidity and mortality. Supporting the local emergency response team in many ways makes your job easier, and who doesn’t want that?

So what can we offer? To me, we can offer three things: time, knowledge and support.

1. Time

Never underestimate the power of offering your time. I know you are busy – heck, we are all busy. But finding the time to head bush and conduct clinical teaching for those who are rarely exposed to it is one of the most powerful gifts that you can offer.

Emergency services personnel, particularly those of the volunteer varieties, want to know what you are thinking when you are presented with a casualty – any casualty. For you it may be a simple, run of the mill, seen it a thousand times before type of patient; but for the local volunteer emergency services personnel it will likely be new, difficult, unexpected, or perhaps all three! What are YOU thinking when you fly overhead? What goes through YOUR mind when you step onto the pre-hospital scene? How does YOUR clinical assessment process differ from that of a first aider? They can never learn from you if you don’t ever find the time to visit their locations and teach them. Your time is important – to both you and them.

2. Knowledge

Most readers of this article will have at some point in their careers been subjected to a training session delivered by an individual who knows their content but nothing more. This is all-too-often the case in first aid. The reality is that the process for teaching accredited first aid in Australia is highly regulated within the AQTF (that’s the Australian Quality Training Framework – if you’re having trouble sleeping you could look right about here). To pretend you can change or ignore this is perilous.

So aeromedical providers need to embrace the fact that the emergency services personnel that they work with already hold first aid skills and therefore seek to deliver complimentary training. In other words, fill the gaps but eliminate duplication.

What are the elements of casualty care that are easy to perform by a non-clinician yet not covered by the majority of first aid courses? Consider topics such as arterial tourniquets, the difference between crush injury and release syndrome, and the elements of aeromedical evacuation that they need to know (e.g. like not using flares when you’re flying on night vision goggles).

3. Support

The need to build resilience amongst emergency services personnel in Australia is well publicised (if you don’t believe me check out this or this or this).

Building this resilience is a long and involved process, but simple things can and do make a difference in the lives of emergency services personnel. It can be as simple as: acknowledging effort; involving them in decisions; asking them their opinions; and explaining what you are doing / thinking. But you can build resilience during training by offering your time to answer questions or “fill in the blanks”.

For example, in 2015 I taught a bunch of volunteer and professional emergency response personnel at a resort in an extremely remote part of Australia (note: details kept purposely vague). Whilst there we heard of a horrendous job that the local team attended which involved the death of a tourist. In 2016 our team taught a different bunch of response personnel in a different part of Australia and had the opportunity to informally debrief an individual who was effected particularly badly by the aforementioned incident – essentially, this individual volunteered to accompany and protect the deceased tourist overnight in the bottom of a canyon until a repatriation team could fly from the nearest urban centre.

This is an extreme example, but every time I teach I am afforded the privilege of hearing these personal stories. I like to think that every time an individual vents their job related emotions to me that “black dog” is pushed ever so slightly out of the picture.

CareFlight’s Trauma Care Workshop

As previously mentioned, the Trauma Care Workshop (TCW) concept was born out of numerous conversations had by the “greybeards” of CareFlight. It took a few years to secure the funding, purchase the equipment and, of course, write the content, but between January 2011 and June 2016 a total of 174 TCW’s were delivered to a total of 2711 emergency services and first response personnel across Australia – at no cost to the individual attendees.

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Trauma Care Workshop Locations 2011-2016

The TCW is an eight hour interactive workshop that is delivered either as a single day session or over two consecutive nights. Utilising the principles of adult learning (look up andragogy or Knowles’ principles of adult learning – or just go here) the content is delivered by professional pre-hospital care providers, many of whom also hold post-graduate or vocational qualifications in clinical education, training or assessment.

Any contemporary medical training that is worth the paper it is written on is interdisciplinary in nature. Therefore, the TCW works best when members from different services (e.g. state emergency services, bush fire brigades, rescue agencies, police, park rangers etc) all attend. After all, when was the last time you attended a pre-hospital scene and saw only one colour uniform?

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Park Rangers and Volunteer Ambulance Officers training together on Kangaroo Island, South Australia

The reality is that pre-hospital scenes are like an open bag of Skittles – every colour under the rainbow all mixed in together. But this goes for the Educators too. Where possible, the three Educators on any given TCW will come from diverse clinical backgrounds – critical care doctors, specialist flight / emergency nurses and professional paramedics.

Importantly, all content is evidence based and research centred. The content itself is delivered through a combination of pre-readings, didactic lessons, interactive skill sessions and immersive scenarios which cover the essentials of pre-hospital trauma care:

  • Patient assessment techniques;
  • Haemorrhage control;
  • Basic airway management;
  • Mass casualty triage;
  • Extrication;
  • Burns management;
  • Teamwork and communication strategies (including the need for a shared mental model); and,
  • The essentials of aeromedical evacuation.

But what the TCW does NOT do is change anybody’s scope of practice; the TCW is designed to augment previous training, not replace it. We are not there to take over the world or supersede anyone’s service – it’s about the patient, not the uniform.

If individuals who complete a TCW wish to see their scope of practice altered in light of their newfound knowledge and skills then the responsibility for achieving these changes rests with them (although we are always happy to provide the evidence to back up their case).

Kalgoorlie copy
Police and local mine rescue staff often form the frontline in emergency response in outback areas (photo from a course in Kalgoorlie, Western Australia).

But what about you?

Whilst at CareFlight we love delivering high quality evidence based training in locations that are off the beaten track the reality is that we cannot be everywhere. But if you are living and working as a clinician in regional areas then you can help.

Head down to the depot of your local volunteer emergency services agency and introduce yourself. Whilst there, ask them how you can help. They will most likely be looking for more volunteers but the purpose of this article is not to recruit those (although that would be a welcome side effect); instead ask them what medical-based training they’ve been looking for and seek to fill the gaps.

You may find this to be a challenge, especially if pre-hospital care is not your forte. However, the benefits for the community – you, the volunteers and the constituents alike – will be huge. You will need to conduct research, refresh some long forgotten knowledge and perhaps step outside of your comfort zone – all great professional development benefits.

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Park rangers, resort staff, volunteer emergency services and local cattle station workers all training together at a Trauma Care Workshop in the Northern Territory

The volunteers will benefit from the networking and the opportunity to expand their base of knowledge via education delivered by a local healthcare professional.  This will lead to increased confidence within the volunteer group and therefore positively affect their willingness to commence appropriate clinical treatment (even when their primary role is not a medical one). The community will benefit by having local emergency responders who are better trained, more empowered and have increased resilience.

In the words of Mr Dylan Campher (from Queensland Health’s Clinical Skills Development Service), “Economy of scale is produced by having a single agreed model and adapting that to the local needs”. In other words, training and working together makes sense. There are some caveats though:

  1. Don’t expect to change the world overnight – believe me when I say that the wheels of change turn slowly in highly regulated environments.
  2. Don’t attempt to teach something that you have no credibility in – differentiate between what you know (based on experience, training and research) versus what you think.
  3. And perhaps most importantly, don’t ever discredit their previous training. Is it perfect? Probably not. But has it helped serve the community prior to your arrival? Absolutely!

Remember: fill the gaps, eliminate duplication.

That dark and stormy night …

All is not lost. It turns out that the volunteers in their various coloured suits have trained for this very incident – in fact, judging by their shared mental model, it appears that they have trained together!

They rapidly assess the scene and make it safe then apply a “zero survey” to you. This “zero survey” has allowed them to sort any oxygenation issues and expedite your extrication from the car using appropriate spinal precautions. They then applied all the relevant clinical interventions within their scopes of practice including binding your pelvis and protecting you from the elements; all you need now is for the volunteer ambulance crew to arrive on scene so that you can be taken back to work (no re-runs of Helicopter Heroes for you tonight).

You gaze up at the volunteer in the yellow / orange / white uniform and ask “Who are you people, and where did you learn to do all of that?” Her response? “We are just the local volunteers – and your predecessor taught us.”


The Post Script:

If you want to know more about the CareFlight Trauma Care Workshop then go here.

If you would like to know about the other clinical education delivered by CareFlight then check out this spot.

If you would like to keep up with where we are and what we are doing then consider following us on Twitter where we travel under @MyCareFlight_Ed

The image of the kangaroos was posted by Mando Gomez under Creative Commons and is unchanged from the original post. All those appearing in the other photos have given previous permission.