NAP5 – Meh !?

Do you remember where you were in 2011 when the results from NAP4 came out? I do. I was doing some upskilling in anaesthesia in New South Wales and the results of NAP4 lead me (and I am sure, many others) to change my practice. It was about the same time that FOAMed was taking off, so there was a renewed enthusiasm to challenge current practices, question dogma and seek to be ‘better’. Even now, several years later, I find myself referring back to NAP4 to confirm data and inform research in my favourite topic – difficult airway management.

NAP4 changed my practice - for the better
NAP4 changed my practice – for the better

So I was kind of looking forward to NAP5 – the fifth national audit project of the Royal College of Anaesthesia and the Association of Anaesthetists of Great Britain & Ireland. This audit examined the issue of accidental awareness during anaesthesia. This is perhaps one of the most feared complications for an anaesthetist….and indeed for a patient. The possibility of being awake yet unable to move (due to concomitant administration of neuromuscular blockade) is terrifying.

NIAA_00342_L

Click HERE to access the NAP5 report

But the results of the audit have left me feeling a bit ‘Meh?’. There are 64 recommendations in the Executive Summary, but  a quick read of them just confirms what I thought we already knew – awareness can happen and good anaesthetic practice (which is essentially what the 64 recommendations summarise) can help mitigate this.

Perhaps that is a bit churlish. Audit is a tedious but necessary part of medicine. To quote Karim Brohi from #smaccGOLD when talking on the introduction of REBOA to a trauma service “you HAVE to sweep the floor….only then can you innovate

So what was the reported incidence of awareness in NAP5?

Thankfully awareness appears pretty rare in anaesthesia overall, with NAP5 suggesting a 1:19,000 anaesthetics overall, with not surprisingly the incidence increased by 7.5x when neuromuscular blockade is used compared to when not – hardly surprising – having the patient swing at the anaesthetist during the procedure is a fair clue that they are awake, whereas paralysed patients can’t punch! Actually, that’s not strictly true – the isolated forearm technique is one way of screening for awareness – but the number of anaesthetists who use this is vanishingly small. Of course aware patients can mount other responses, such as increased heart rate, blood pressure etc – but then again, reliance on these is inaccurate and somewhat cruel.

If you take GA as a “treatment” for unwanted consciousness and take awareness as “harm”
then the NNT is 1.00001 & the NNH is 17,0000!
[Dr John Berridge, Doctors.net.uk]

 

Incidence of Awareness in NAP5

~ 1:19,000 anaesthetics overall

(1:18,000 with neuromuscular blockade vs 1:136,000 without paralysis)

High risk areas included cardiothoracic (1:8,600) and obstetric anaesthesia (1:670).

YEP – THAT IS RIGHT – 1/670 in OBS ANAESTHESIA

(before any smart arse comments, they DID exclude those having their baby under neuraxial blockade alone – clearly these patients are conscious and aware).

I wonder if the possibility of drug error contributes? The NAP5 authors mention presence of “antibiotic syringe” as being a particular risk – all the more reason to push antibiotics as soon as decision is made to go to section, then induce with usual anaesthetic agents. Interestingly I’ve herd anecdotes that the Poms don;t use propofol much for obs anaes (it remains off-licence for obstetric use in the UK!) – the older specialists insisting on use of thio.

I can’t recall ever seeing thio used in obs anaes in Oz; another indiction of how much dogma needs to be lysed, particularly when there is potential for harm. Hard to confuse propofol with an antibiotic, much easier to confuse thio!

Other risks included :

OBESITY (I suspect underdosing of induction/maintenance agents)

USE OF THIOPENTONE (probably because of 500mg/vial insufficient dosing in the lardy and possible use as bolus vs titrated dosing at induction Another thought is that propofol has some amnestic effect, so may confound patient recall of awareness when receiving thiopentone vs the Jackson Juice).

USE OF NEUROMUSCULAR BLOCKADE – amazingly it seems that many anaesthetists aren;t using nerve stimulator TOF intra-operatively. Interesting. Maybe I am obsessive about this?

Listen up emergency and critical care docs : Induction, Emergence and TIVA are particular risks

Other high risk stages of anaesthesia include the dynamic phases – namely induction and emergence. NAP5 suggests that 2/3rd of reported awareness episodes occurred during these phases. Again, not surprising as this is when a failure to establish post-intubation anaesthesia, accidental disconnections or residual paralysis on extubation are most likely.

How is those relevant to critical care and emergency clinicians? well, we all obsess about airway management, best choice of induction & paralytic agent (answer = “rocketamine”)…but we may become complacent once the ETT is passed and forget to establish quickly a post-intubation sedation plan. Even if we DO, infusions can be disconnected, pulled out – or, worse still, sedation may be inadequate for the time when your roc is still effective. Prehospital and ED doctors need to be as vigilant for awareness as anaesthetists in theatre – perhaps MORE SO as our patients are at risk.

“The post-intubation phase is a time of particular risk – the patient has been induced with ketamine, paralysed with rocuronium & tube placed without hypoxia or hypotension.
Failure to ensure adequate ongoing sedation may lead to accidental awareness in the post-intubation paralysed patient. Be vigilant!”

Of particular interest to me was the fact that accidental awareness was more than twice as likely during total intravenous anaesthesia as when using volatiles; again, not surprising as the latter allows end-tidal volatile monitoring. An extra risk was TIVA using non-TCI techniques eg: intermittent manual bolus of agent, fixed-dose regimens etc. rather than the established TCI techniques available on sophisticated pumps.

“When transferring patients, whether it be from ED to CT, from OT to ICU or from Dingo Creek to tertiary centre as an aeromedical retrieval, this is when patients are at most risk” 

This is a problem and something that all involved in management of critical patients should consider – namely that TRANSFER OF PATIENTS IS A RISK FOR AWARENESS.

What to do with the data?

The NAP5 data does give us up-to-date numbers for the incidence of awareness and I will use these in explaining risks to my patients, as I already do. Indeed it suprised me that one of the NAP5 recommendations was that :

“Anaesthetists should provide a clear indication that a pre-operative visit has taken place, identifying themselves and documenting that a discussion has taken place”

Doesnt eveyone already do this? Apparently not – whilst here in South Australia there is a separate anaesthetic consent form, there were none when I was in NSW (this may have changed). Colleagues in the UK seem content to allow the surgeon to consent for the procedure – whilst I can undestand that the gynae reg can consent for the surgery, I really dont see how he/she can adquately explain the anaes risks. But I digress…

But – what about those fancy BRAIN WAVE MONITORS?

Some of the important questions remain unanswered….we’ve had new anaes monitors rolled out into country, apparently on the pretext that depth of anaesthesia monitoring is mandatory. So someone ordered a bunch of machines with BIS monitoring. BIS or bispectral index is one form of proprietary EEG (pEEG) monitor, marketed as giving an indication of ‘depth of anaesthesia’. My preference is to use measurement of end-tidal anaesthetic gas to decide if there is sufficient volatile on board.

Testing the BIS monitor before  a morning case on KI
Testing the BIS monitor before a morning case on KI

At present, use of proprietary EEG monitors is NOT considered a standard in anaesthesia in Australia. Moreover there is some evidence that reliance on a particular pEEG number to decrease concentration of volatile is more likely to cause accidental awareness (fully awake BIS = 100, brain dead = 0. Sort of. It’s a bit more complicated, but you get the gist).

Like many others, I remain unconvinced of the role of BIS during general anaesthesia with a volatile agent.

POP QUIZ – HOW DO YOU ‘ZERO’ THE BIS MONITOR?
ANSWER – USE THE ORTHOPAEDIC REGISTRAR

Again, perhaps the most risky aspect of anaesthesia is when using intravenous anaesthetic agents in the face of neuromuscular blockade. This is particularly pertinent to my current role in retrieval, where it is not uncommon for critically unwell patients to be induced with ketamine, paralysed with rocuronium then placed onto a maintenance infusion (propfol, fent/ketamine, morph/midaz etc) – if there is an omission of post intubation sedation, an accidental disconnect or even an under-dosing, then awareness under paralysis is a real possibility. Where possible paralyse then allow to wear off and use appropriate ventilator settings to allow spontaneous ventilation in transit.

Which begs the question – should the role of pEEG monitoring be targeted to those patients who are paralysed and undergoing TIVA – typically retrieval & some ICU patients? I am not aware of a transport monitor that allows measurement of pEEG. Should we be using it for some of our intubated and ventilated patients? Interested in others thoughts on this….

And finally – a checklist proposed as the cure to reduce accidental awareness!

The authors also propose use of checklists during ‘high risk of awareness’ occasions (such as transfer of patients). Moreover, the NAP5 authors recommended :

“the use of an ‘anaesthetic checklist’ (easily integrated with the World Health Organisation Safer Surgery checklist) to be used after transfer of patient, to prevent incidents of awareness arising from human error, monitoring problems, circuit disconnections and other ‘gaps’ in delivery of anaesthetic agent”

Now it is no secret that I am a fan of checklists – I argued passionately (and a little rudely) for their use by airway experts at smaccGOLD – but I would also advice caution in their use

Whilst the WHO surgical checklist is lauded as reducing complications, this is utterly dependent on successful implementation. Sadly for many units the WHO checklist has been opposed from on high, without opportunity for team buy in or local modification. In these circumstances, a checklist can become worse than useless – it can be a danger. We’ve all got anecdotes of the checklist being completed after induction of anaesthesia, of the whole process being reduced to a pointless tick-box hurdle to be rushed through, rather than a cognitive rallying point.

We MUST be cautious of checklist fatigue.

As I said at smacc, pehaps their use is best reserved for routine only when there is full team buy in and the checklist is implemented by the frontline users – not imposed from on high. The benefits of a checklist in anaesthesia crisis are predominantly through a challenge-response of ‘have you considered X‘ rather than a cookbook ‘the next step will be to do Y‘ approach.

So is NAP5 a gamechanger?

I don;t think so. Reading the recommendations in the Executive Summary reads more like a description of how a good anaesthetic should be given. I hope I am not alone in reading the 1-64 recommendations and going “yep – do that – and that…

I don’t think it really addressed the issue of pEEG monitoring. Intuitively they may seem ‘sensible’ but I maintain that there use is probably best confined to the paralysed patient on TIVA.

Are there lessons here for emergency doctors, intensivists and retrievalists (not just anaesthesia)? Absolutely. It may be that awareness of ‘awareness’ amongst emergency clinicians is less heightened than the archetypal OCD-anaesthetist….and yet our post-rocketamine patients are at particular risk.

I will leave the last word to that esteemed Professor of Hogwards, Prof Mad Eye Moody :

ETERNAL
ETERNAL VIGILANCE

…since posting, the Daily Mash have taken up the results of NAP5 – and twisted them

Click on the DAILY MASH link to read more
Click on the DAILY MASH link to read more

 

 

ATACC Manual – Quality FOAMed

For those of you have been reading KIDocs over the past year or so will know that I am a harsh critic of the ATLS course (EMST in Australia). Not because I think it’s pants – it’s not. It does what it says on the tin, namely it teaches a basic approach to trauma management for the single responder in a community hospital. The A-B-C-D-E approach is easily taught and easy to recall under times of stress. I have no doubt that the ATLS course has done a world of good in bringing structure to trauma care worldwide.

I’ve been teaching on ATLS-EMST since 2006 and a course Director here in Australia for the past few years. In recent times I’ve seen how quickly FOAMed can narrow the ‘knowledge translation’ gap from concept to practice – and become increasingly frustrated that the ATLS-EMST manual doesn’t really address nuances of modern trauma care.

It should be borne in mind that the ATLS-EMST course is considered mandatory for credentialling in many hospitals. Like many other courses (APLS, ELS, ALSO, ALS) I think this is fine when setting a minimum standard. However it frustrates me that experienced clinicians are expected to repeat these ‘alphabet’ courses every few years.

Don’t get me wrong – I am not saying that experienced clinicians don’t need regular updates and ‘benchmarking’ – but it would be good if the content of the course built upon the basics, not just repeated the entry-level content. I have heard that post-Fellowship emergency physicians in the UK have been required to complete an ATLS course as part of revalidation – when the skills that they apply in their day-to-day job far outstrip those taught on ATLS.

And of course, successful trauma management isn;t just about knowledge and procedural skill. It requires an understanding of how a trauma team functions. We’ve all seen dysfunctional trauma teams, despite the individual excellence of the clinicians, dysfunction arises because of a complex interplay including human factors.

Last year the Australians kicked off the Emergency Trauma Management course (ETMcourse), which is aimed not to replace ATLS-EMST, but to offer content that includes cutting edge FOAMed good ness as well as apply principles of teamwork (clearly human factors are important in how a trauma team functions – or fails). You can read a review of the ETMcourse here.

Other courses such as the anaesthetists EMAC and the retrievalists STAR courses also explore some of these aspects, as well as more challenging scenarios – details on available courses here.

 

Screen Shot 2014-09-11 at 5.05.24 pm

Introducing the Anaesthesia, Trauma & Critical Care Course (ATACC)

But there is another course – the ATACC course. I’d heard about this via doctors.net.uk and been in touch with the course organisers with a view to trying to get a course ‘down under’….which might be difficult! ATACC has an excellent reputation in the trauma world, for teaching real life scenarios in multi-disciplinary team. I am busting to attend one of these courses if I can get back to the UK

The ATACC Faculty include not just clinicians, but also luminaries of extrication such as Ian Dunbar (of the Holmatro extrication techniques app and book fame). Similarly the course is open to all – doctors, nurses, paramedics, physicians assistants, operating department practitioners – anyone who is involved in trauma. A far cry from the College of Surgeon’s ‘Advanced Trauma Life Support Course – for doctors’.

Screen Shot 2014-09-11 at 5.13.36 pm

 

ATACC Faculty includes Ian Dunbar (@Dunbarian) author of the excellent extrication manual sponsored by Holmatro – also available as a truly interactive app/iBook – worth every penny for anyone interested in prehospital care

 

ATACC Manual Available as FOAMed – PDF or iBook versions

 

So mega-kudos to the ATACC mob for launching their course manual as FOAMed – I’ve just got my hands on a copy and I can attest that it is thoroughly excellent.

Screen Shot 2014-09-11 at 5.01.13 pm

The PDF copy is available here

http://www.atacc.co.uk/e-learning/

or in iBook format via iTunes here

https://itunes.apple.com/us/book/anaesthesia-trauma-critical/id917866158?ls=1&mt=13

I cannot begin to tell you how good this manual is – it covers modern trauma management, is interactive and authoritative. It covers the usual trauma stuff, but is packed with some extra nuggets – I am a big fan of the MARCH approach and was pleased to see this included, along with some other adjuncts to haemorrhage control including haemostatic agents, clamps and the like. Up to date controversies (#dogmalysis) on topics such as cervical spine immobilisation are also covered – and my understanding is that content will be regularly updated.

Screen Shot 2014-09-11 at 5.17.56 pm
The ITclamp for haemostasis
The MARCH approach to roadside trauma
The MARCH approach to roadside trauma

One of the strengths of the manual is that it covers trauma from the roadside, through retrieval, the ED and to ICU. It’s trauma run by traumatologists (did I just say that? Bah!) – not by surgeons. As such I recommend it to anyone involved in trauma care – prehospital clinicians & retrievalists, rural docs, EM types, anaesthetists, doctors, nurses, paramedics…

Awesome
Everything is Awesome When You Are Part of A (Trauma) Team

That the authors have made it freely available as FOAMed is truly humbling! I remember that it was only a couple of years ago that ATLS made their course manual available for non-attendees…and they still charge a packet for the hardcopy. There is an ATLS app – but the less said about that, the better.

The ATACC manual is true FOAMed – quality medical education, up-to-date and freely available because the ATACC mob believe in what they do.

Kudos to you. Seriously.

Loving the section on cervical collars - mentions the Brisbane protocol, decision-making rules, clearance in ICU etc
Loving the section on cervical collars – mentions the Brisbane protocol, decision-making rules, clearance in ICU etc

I’ll let you know if I ever get to an ATACC course in the UK and review it online. From what I’ve heard and seen of the manual, the three day intensive course must be orders of magnitude of awesomeness!

Meanwhile, I will leave you with this thought on the 9th edition of ATLS-EMST (attribution unknown, apologies)

...seriously - does EVERY trauma patient need a rectal exam? ATLS dogma still says YES (except on courses I direct)
…seriously – does EVERY trauma patient need a rectal exam? ATLS dogma still says YES (except on courses I direct)

IMSANZ 2014 – ‘FOAMed Taking Life Long Learning by Storm’

I have been asked to speak at the Internal Medicine Society of Australia & NZ annual scientific conference, which will be  held in Adelaide this September.

The idea is to introduce physicians to the concept of #FOAMed. I reckon this could be a tough gig….there are only a few physicians active on SoMe in Aus/NZ and I am not sure how well the anarchic, free-form and rapidly moving concept of #FOAMed will be embraced by them.

Whilst emergency and critical care physicians have been the main early adopters of FOAMed, I reckon that physicians lie somewhere towards the right of the ‘innovation adoption lifecycle model’.

Screen Shot 2014-09-03 at 8.45.49 pm

So my cunning plan is to try and entice as many of the audience in, by playing a short video during the one hour lunch break before the scheduled afternoon session.

I am in a concurrent, going up against local cardiologist Julian Vaule talking on NOACs (“novel oral anti-coagulants”) – or, as I prefer to call them “evil Big Pharma meds that aren’t all they are supposed to be and unlike rat poison cannot be reversed“.

Now I dont know about you guys, but I have sat through a load of lectures on NOACs…but I don’t reckon I ever sat through a lecture on tools for lifelong learning, on metacognition, on use of Social Media to filter educational content for self-development.

The video borrows from the meme of ‘taking life ling learning’ by storm(trooper) – a concept I first saw in a FOAMed lecture from Chris Nickson of LITFL fame, then taken up by others such as Andy Neill from emergencymedicineireland.

The video allows the inclusion of stormtroopers twerking and shufflin’  - what’s not to like? It struck me that these talks plus the video could be used by others when preparing an audience for FOAMed…

I’ll bung up a slideshow of the IMSANZ on the day it is to be delivered – 19th Sept – as an example of a ‘flipped classroom’. Wish me luck! Gonna be a tough audience….

References

Chris Nickson’s talk is here “Why FOAMed? Facts, Fallacies & Foibles

Andy Neill’s pecha kucha talk is here “Effective Use of Social Media to Keep Up-to-Date

…and if you like Stormtroopers doing silly things

Stormtrooper images for slides – from JDHancock

Stormtrooper twerk – via ScottDW youtube channel

Stormtrooper shuffle – via MattLundeStudios on youtube

 

Resus Room Feng Shui

It’s been a pleasure to present at the biannual EMSA2014 (Emergency Medicine South Australia 2014) in Adelaide, South Australia.

Like smaccGOLD, the audience was an nice mix of clinicians – grizzled old rural doctors, hardcore emergency physicians, vastly experienced emergency nurses and paramedics…as well as a nice smattering of students.

As always, I suffer from a degree of ‘imposter syndrome’ – what can a rural doctor possibly have to say of interest to this sort of audience?

Spot the Imposter
Spot the Imposter

Unlike smaccGOLD, many of the audience were naive to the concept of #FOAMed (free open access medical education) – so I opted to tell a personal story of how my practice as a rural clinician has changed in the past 2 years, shaped by the mentors in the photo above

“as a rural clinician, FOAMed means there is no longer an excuse for my lack of knowledge to be the weak link in patient care”

In order to close the loop, I’ve made a commitment to put my slides and relative links up on the blog for new FOAMed acolytes to explore.

Resus Room Feng Shui video

FOAMed weblinks

smacc.net.au

RAGE podcast (resuscitationists awesome guide to everything)

BroomeDocs

PreHospitalMedicine

Intensive Care Network

Lifeinthefastlane

smacc podcast on iTunes

AmboFOAM

EMCrit

Levitan & Weingart on apnoeic diffusion oxygenation

Emergency Trauma Management course

So – don’t be scared – dive in, explore the FOAMed (free open access medical education)

Gar Pask – Anaesthetic Hero

I’ve been doing a bit of thinking about life-jackets after spending a few hours bobbing around in a heated pool during last week’s HUET (helicopter underwater escape training) course.

Whilst practicing in a pool is one thing, I did wonder how well one would cope if ditching in the cold waters of the Southern Ocean wearing a switlik & flight suit or immersion suit. Probably quite well – modern safety equipment has come a long, long way from it’s origins (the first description dates back to 870 B.C., with a stone carving showing Assur-Nassur-Pals’ army crossing a river wearing inflated animal skins as flotation devices).

“the bravest man in the RAF never to fly an aeroplane”

The development of modern lifejackets includes a vital contribution by British anaesthetist, Edgar ‘Gar’ Pask. His story is fascinating, not least for the fact that, like true eccentrics, he performed experiments using himself as a test subject.

pask03

Pask in flotation device

Pask is famous for having been asleep whilst completing most of the research for his thesis

In essence, Pask made three vital contributions, spurned on in part by necessary developments during WWII.

(i) the problem of ‘downed & drowned’ aircrew

Most of us are familiar with the “Mae West” – a US lifejacket considered the cutting edge in the war years. Whilst it did a great job of keeping downed aircrew afloat, sadly many airmen were found in a face down position. They survived bailing out of their aircraft, but drowned despite being kept afloat.

Edgar Pask was a British anaesthetist, seconded to the Physiological Laboratory in the RAR Research Station at Farnborough, UK under the encouragement of another anaesthetic great, Professor Macintosh. Pask’s doctoral thesis is infamous for being performed with the author mostly asleep – the reason being that Pask used himself as a test subject. He was anaesthetised and placed, unconscious, in a swimming pool whilst on a breathing circuit. By simulating an unconscious airman, Pask and colleagues were able to test a variety of different lifejackets, refining techniques such that modern lifejackets ensure the victim floats face up, rather than risk ending up face down in the Mae West lifejacket.

The video footage of this research is fascinating – a short clip is shown below. The experimental subject is Pask, intubated and breathing ether on a double-lumen, corrugated anaesthetic circuit, the tubing of which was weighted to neutral buoyancy. Essentially a Mapelson D circuit. He was then unceremoniously dunked in the pool, whereby he promptly sank.

(ii) the efficiency of different artificial respiration techniques

If downed aircrew were recovered, many expired when pulled form the water. The real problem here was actually cold water immersion syndrome – the redistribution of blood volume in a weightless water environment meant that cardiac output dropped markedly when aircrew were pulled (usually vertical) from the water. Attempts at artifical respiration were employed – in the 1940s, the Schafer method was most popular.

The second part of the above video shows an anaesthetised Pask undergoing various methods of artificial respiration whilst paralysed (at the 9:08 mark). They demonstrate Silvester’s method, Schafer’s method & Eve’s rocking method. Not currently approved by the Resus Council!

Silvester's Method
Silvester’s Method
Schafer's Method
Schafer’s Method
Eve's Rocking Method
Eve’s Rocking Method

These experiments are remarkable (and a little unsettling) – Pask was paralysed and then underwent two hours of artificial respiration, during which time measurements were made of ventilation rate, tidal volume and O2 consumption. This was in the days before apnoeic diffusion oxygenation!

(iii) high altitude decompression ‘time of useful consciousness’

The RAF leased B17 ‘flying fortress’ bombers from the USA. These lightweight aluminuim-skinned aircraft apparently flew at the height of Everest, unpressurised – posing hazards of cold & hypoxia to the crew. Pask explored the effects of bailing out at such high altitudes – again, using himself and colleagues as test subjects. They were exposed to various hypoxic mixtures in a decompression chamber – the records are disturbing, essentially describing young men being asphyxiated and then allowed to recover.

Here is a description of Gar Pask being asphyxiated, whilst hanging vertical in a parachute harness in a hypoxic mix in a decompression chamber. Extreme hyperbaric medicine!

The period of anxiety was more prolonged than in the ‘descent’ from 55,000 ft, with the subject sitting, and not until the sixth minute was it certain that the ‘descent’ could be completed.

The subject [Pask] made two attempts to raise himself in the harness by pulling on the parachute risers during 1 1/8 to 1 ½ mins. These attempts he could not remember afterwards. At 1 ½ minutes., the subject became limp and relaxed, the head falling forward, but although it must have been merely a matter of chance, it was not thought that laryngeal or pharyngeal obstruction actually developed, although vigorous inspiratory efforts were made.

Sweating was very profuse and liquid sweat fell from the forehead and formed a noticeable pool on the floor. Muscular twitching of the left arm was seen between 5th and 9th minutes. The pulse was not rapid – indeed a good deal slower than in previous ‘descents’ with this subject, but between 2nd and 6th minutes it was recorded as very feeble.

[the experimental record of one of Pask's 'descents']

The upshot of all this was that Pask demonstrated that 30,000 feet was the highest survivable altitude to bail out without supplemental oxygen. I somehow doubt that such experiments would get past a modern day Ethics committee!

Post War Years

Pask’s bravery was recognised with award of the OBE (Military Division) in 1944. His meticulous approach to experimentation ensured the success of his 1947 thesis, although public publication of his wartime research was delayed until 1957, no doubt for both secrecy reasons and also in view of the justifiable outrage concerning similar experimentation on non-willing volunteers by the Nazi’s at Dachau.

It is a tragedy of man’s inhumanity to man that the Luftwaffe used human prisoners in these experiments. An account of the abhorrent work of Nazi Dr Sigmund Rascher is here. A disturbing thought is whether the data from these brutal crimes could be used subsequently – an issue explored in the NEJM. Ironically Rascher was executed on the orders of Himmler, in part for falsifying his data.

Recognising the folly of ongoing human self-experimentation, Pask was instrumental in developing Sierra Sam, the forerunner of modern crash test dummies. This proved a safer method for testing modern lifejackets than anaesthetising Gar Pask!

Sierra Sam
Sierra Sam

Pask died in 1966, age 54 – no doubt the toll of a lifelong smoking habit and the high likelihood of aspiration during the ‘flotation tank trials’ contributed to his early demise.

References

You can read more about the amazing exploits of Gar Pask below :

History of lifejackets

Professor Pask

Edgar Pask – a hero of resuscitation

Pask – the bravest man never to have flown an aeroplane

 

 

 

HUET & Lessons for Medicine

I was a little apprehensive about undergoing HUET training, mostly due to some gentle winding up by the likes of Minh le Cong in Queensland & some of the GSA-HEMS mob. Comments about eliciting cremasteric reflexes, sinus douching and so on seemed to be setting the scene – made worse as undertaking HUET in the middle of Adelaide winter.

Augsburg
“Back in the day” – a young Dr Tim posing whilst C1 slalom training – Augsburg, Germany

Actually, I don’t know why I was concerned about being dunked. ‘Back in the day’ I was a keen (and expert) whitewater canoeist. I rose through the ranks in both kayak and canadian classes, competing regularly at premier level in slalom events in the UK and representing my country overseas. Being flipped over in the dark whilst training in the ice cold waters of the Thames weirs or on the grade IV rapids of Scottish rivers was no problem.

Competing at that level of performance, the difference between boat-body-blade was indiscernible, with movements practiced and fluid such that one could quickly (<1 second) roll up from an inverted position with barely an interruption to forward paddling movement.

Augsburg2
Boat-Body-Blade – it’s a bit like Arm-Laryngoscope-Epiglottis

But that was a long time ago. Being stuck inside a metal airframe and dunked upside down is completely different. And unlike a low volume carbon-kevlar canoe, there’s no element of control when a helicopter ditches…

Training took place at the heated (27 degrees, thank you) pool at the Adelaide Dive Centre, under the expert guidance of the team from RHO aviation.

Why bother with HUET?

Brian Burns of Sydney HEMS tweeted this slide today from the concordant HUET exercise in Sydney, demonstrating why it is vital that anyone being transported by a helicopter platform knows what to do in the event of ditching in water.

Butq1A8CYAAoZdI
Slide tweeted from GSA-HEMS training by Brian Burns @HawkmoonHEMS

Whilst it is possible to perform a controlled ditch on water, this will be subject to water conditions, aircraft performance and so on. Some helicopters have floats – but helicopters are inherently top heavy and are highly likely to invert. Or be attacked by sharks as in this clip below from Jaws 2 :

That said, helicopter transfer is reasonably safe. The most pertinent reference that I could find dates back almost 10 years and is from Dave Cooksley and (then registrar) Jim Holland when in Townsville, both nice FACEM chaps. However problems can occur and it makes to be prepared. Helicopter Underwater Escape Training (HUET) is designed to improve the chances of surviving a ditching episode.

As can be seen from the footage below, an uncontrolled ditch in water poses risks of disorientation, impact with unsecured equipment and debris from the impact. Add to this the confusing elements of inversion, cold water and poor/zero visibility, and it is easy to see why occupants can become disorientated and fail to survive. Add to this the myriad of different harness & door release mechanisms (over 35 of the latter, with no industry-standard!). HUET training is designed to increase chances of survival in an unlikely emergency.

US-Navy CH-46 Sea Knight crashes while landing on USNS Pecos

https://www.youtube.com/watch?v=CdlqCeQfGmo

Controlled ditching onto water, then disaster as rotor blades enter water

https://www.youtube.com/watch?v=2NiPbQVQrC4

So what did we learn?

The facilitators from RHO aviation were really good, working through educational material in a solid, stepwise manner with a clear goal (lessons there for meducationalists). They emphasised the importance of a pre-flight safety brief :

  • seat belts
  • loose items (secured)
  • lifejackets
  • identifiying primary & secondary exits, with reference points

It;s no secret that I am a fan of checklists in a crisis – when there is time. But the regular performance of a safety brief reinforces safety, mitigates against complacency and is something that I try to instil into the resus bay of my local hospital when awaiting a patient – checkling O2, suction, confirming presence of airway and crash carts, setting up vent and anticipating likely clinical needs…as well as backup plans. Cliff Reid has talked about the value of having a resus room safety officer….perhaps it’s not such a bad idea, especially in EDs where the resus is performed by a flash team (members who may never have worked together, or are used to another ED’s equipment/procedures). Minh le Cong (who never sleeps) has proposed a pre-ED RSI safety brief, albeit tongue-in-cheek.

Once the aircraft inverts, the importance of WAITING for cessation of violent movement was emphasised (to reduce risk of disorientation, injury), then calm performance of a well-rehearsed sequence :

  • orientate (use one hand to anchor as a fixed reference eg: underside of seat, with inboard hand)
  • locate (primary exit, use body movement eg knee or shoulder to locate door, then use outboard hand to locate exit release)
  • release (once exit open, keep outboard hand fixed on frame and then release inboard hand to undo safety harness)
  • vacate (use a low profile, pull inboard hand to join outboard hand at exit & pull head through – body will follow)
  • inflate (clear the surface of debris and inflate lifejacket if safe & appropriate to do so)

It was certainly easiest to perform this drill with eyes shut, avoiding the potential added disorientation of visual cues whilst inverted. Obviously an emergency ditching is a high stress environment – there will be a catecholamine surge and removing factors likely to add to panic is sensible

What’s the parallel in resus? There are probably a few. I was immediately reminded of similarity with CICO crisis training. I’ve had the misfortune of doing a few of these in real life, and have learned (by hard experience) to perform surgical airways as a tactile procedure (scalpel-finger-[bougie]-tube). But body mechanics are important in other things we do – threading a catheter onto a seldinger wire (use palmar aspect of both wrists to form a stable bridge, giving fine motor control) or effective laryngoscopy (understanding different mechanics of Mac 3 vs 4, elbow and wrist position to maximise force – a plug here for Rich Levitan’s airway course which certainly helped my airway technique).

Here’s a demo of the HUET in action – experimental test crash dummy Dr Francis Lockie uses his secondary exit, as the primary exit is blocked.

In summary

Despite the ‘wind up’ about HUET, I thought it was a well run course, delivered exactly what it was supposed to and has given a structure to dealing with a ditching crisis.

Could such lessons be applied to medicine? Absolutely – building muscle memory, relying on simple drills and regular sim are key.

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Dr Michael Edmonds (creator of the rather excellent adelaideemergencyphysicians website) keeps grinning despite the forthcoming dunking
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Dr Rhea Sicat assumes the position : brace-brace-brace!
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Forming a group huddle with new-found chums. Apparently the trick is to PEE INTO THE MIDDLE to create warmth…
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Thank God medSTAR kids rep Dr Naomi Spotswood is light as a feather, hauled aboard the life raft
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Survivors! Drs Paul Spedding, Naomi Spotswood & Kat Shelley after HUET completion. That yellow patch around Paul is sea dye….we think….