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As the longest bone in the body, when it breaks a fractured shaft of femur is a very painful and potentially life threatening injury. One of the main initial treatments for this injury is application of some sort of traction splint, designed to apply distracting force between the lower leg and the relatively “fixed” base of the pelvis, which pulls the displaced and shortened femur back into a more anatomical position.

The Fare-Tec CT-6 splint. Image source

There are two main reasons for use of traction splinting for fractured shaft of femur.

1) Analgesia

Movement is the main cause of fracture related pain, hence why splinting is part of the routine care of almost all fractures. However the anatomy of the femur makes application of the flexible aluminium/foam-padded splints, inflatable splints or plaster backslabs impractical and ineffective. Whilst none of the available traction splints support the thigh fully, application of traction will allow less movement than would occur with an unsupported leg. It also prevents the inevitable thigh muscle spasm from further displacing or moving the fracture (sometimes jamming the injured bone ends together) which can be very painful.

2) Haemorrhage control 

There are many misconceptions and incorrect descriptions in online articles/blog posts about how and why traction splinting reduces blood loss from a fractured shaft of femur, however it is commonly accepted that fractured femurs can bleed a lot.  How much? It seems no-one really knows and we’ve all been quoting a guesstimate.

I was unable to find any useful references that provide an accurate evidence base for the oft-quoted figure of 1500ml (or “4units… producing class III shock” – from the ATLS manual 8th edition which has no obvious reference for this figure) for the potential amount of blood that can be lost from a fractured femur.  Searching on PubMed there is a paucity of studies that provide any accurate calculations or estimates for this number.

A small, retrospective chart review that relied on changes in hematrocrit and several estimates/assumptions (for example: estimated total blood volume based on weight, assumed ml of blood loss per percent drop in hematocrit, requirement for transfusion based on symptomatology) showed an average estimated blood loss of 1,276 ml, with a wide range of 740ml-2,620 ml. Reference.  Interestingly the authors did not find an association between open, comminuted or segmental fractures (fracture types that have traditionally been assumed to result in higher blood loss) and estimated blood loss.

A paediatric study showed no significant haematocrit or haemodynamic change in children with isolated femur fractures, prompting the comment that even in cases of diagnosed femur fracture in children, dropping haematocrit or haemodynamic instability should prompt a search for bleeding elsewhere. Reference.

Perhaps the most useful demonstration of blood loss from a femoral fracture comes from Gunther’s ER:

NB: NSFW if you go past the 42:16 mark!

Suffice to say that yes, the medullary cavity of the femur is a highly vascular space that can bleed when fractured.

One can lose a moderate to large amount of blood which may potentially contribute to haemodynamic instability in adults, but probably not in children.

How does traction splinting reduce blood loss?

It’s a simple matter of geometry.  The thigh is generally in the shape of an inverted conical frustum (a cone with the pointy end cut off).

When the femur fractures and the thigh begins to fill with blood, it becomes more spherical in shape.

As it fills even more, it becomes cylindrical.

For geometric shapes of equivalent upper radius dimensions, a sphere has 2/3 the volume of cylinder and a cone (or frustum) has 1/3 the volume of a cylinder. This increase in volume is still apparent even if some relative shortening of the broken bone is taken into account (although obviously the exact 1/3:2/3:1 proportions may be slightly different).

So traction splinting endeavours to draw the thigh back into its more anatomical, frustum (or inverted cone) shape, which minimises the potential space for blood loss.

X-ray source: Radiopaedia

Obviously this is a theoretical assumption and given we don’t have an accurate way to measure blood loss from fractured femurs, we’ll never be able to tell how much traction splinting reduces blood loss.  But it’s a nice theory and given the other main benefit of stabilisation and analgesia and the lack of apparent serious harm (i.e. traction splints have not been shown to worsen blood loss), it is probably OK to continue using them for the purpose of haemorrhage control whilst remaining nascent of the limitations of the science behind the technique.

We haven’t touched on the best method or device for applying traction, complications of traction splinting, other methods of analgesia for femoral shaft fractures or other related issues but hopefully we can cover these in future posts.

Are there other benefits of traction splinting?

Do you have a reference that more accurately describes blood loss from femoral shaft fractures?

Feel free to leave a comment below.

Dr John Hinds whom many of you will know from his legendary appearances at SMACC, died yesterday from injuries sustained whilst providing medical cover at a motorsports event in Ireland.

All of us at ETM are deeply saddened by the loss of such an amazing trauma practitioner and educator.

The ETM flag is flying at half mast today.

Image courtesy of BBC News

John was campaigning for a HEMS service for Northern Ireland.

Please sign the petition started in his memory to help push this initiative forward.

Here’s some of the trauma education gold John left us with:

John’s superb talk on resuscitative thoracotomy from the recent SMACC Chicago conference

EMCrit Podcast 135 – Trauma Thoughts with John Hinds

The summary on this post is also worth a read, available here.

Cases from the races – John’s great presentation at SMACC Gold in 2014

NB: The audio was directly lifted from the RAGE Podcast site. Head over there to pay homage.

Click play on the player below, and then click through the slides.

The all-time classic cricoid debate with Brent May:

Rollcage Medic Podcast Episode 7

Off the back of the very successful trauma radiology course last year, Andrew Dixon and Frank Gaillard from Radiopaedia and Andy Buck from the ETM Course are presenting a new, one day, Emergency Radiology course on Saturday May 16th at the Alfred Hospital in Melbourne.

This promises to be a great course that will cover common and life threatening conditions seen on plain x-ray and CT in the ED (and maybe a few MRI’s as well!)

If you are interested, click on the picture below. Tickets are already selling fast so get in quick to avoid disappointment!

I thought it prudent to start the new ETM Journal Club with a local article (from my alma mater as it were), and from none other than the famed (ex) Red Rag, EMA.

We all know that bleeding is bad in trauma. Bleeding until you’re shocked is bad. If you’re bleeding and you’re shocked to the point where you need a blood transfusion, you are more likely to have more serious injuries, get sicker, and die as a result. The more blood you need to get you out of shock, the worse off you are. Wouldn’t it be great if we had a single, easy to calculate number that told us whether you were likely to need a massive transfusion? We could act on this from the pre-hospital notification, notify blood bank, get the MTP down and warm up the blood warmer. We may even detect your need for blood earlier in the ED resus phase. So welcome back Shock Index. Is this the magic number it’s being held up as? Read on to find out.

Reference:

Review article: Shock Index for prediction of critical bleeding post-trauma: A systematic review. Olaussen A, Blackburn T, Mitra B, Fitzgerald M. Emerg Med Australas. 2014 Jun;26(3):223-8

What’s this article about?

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This article is about use of an easily calculated clinical sign, the Shock Index (SI), or heart rate divided by systolic blood pressure in predicting critical bleeding. Critical bleeding was defined as that which required at least 4 units of packed red blood cells or whole blood in 24 hours.

SI = HR / SBP

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Who did the study and can we trust them?

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This article has been written by well-known Australian researchers from Monash University, The Alfred Hospital (largest volume trauma centre in Australia) and Ambulance Victoria. Pretty reasonable credentials!

No conflicts of interest were identified.

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How was this study conducted?

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This is a systematic review article, which looked at 5 papers related to the use of the Shock Index in predicting critical bleeding.  Interpreting advice from a review article can be difficult without pulling all of the individual references and analysing them.

In general, the higher the level of evidence (RCT > Cohort > Case Control > Case series) and homogeneity of the referenced articles, the higher the quality of the review, and the increased chance that meta-analysis of the studies will have meaning.

This is a review of mostly retrospective, heterogenous studies, therefore drawing conclusions from the data should be done with caution, and due to this, meta-analysis was not possible. This is acknowledged by the authors.

Heterogeneity issues in this paper include:

• Definitions of massive transfusion, shock index, and critical bleeding varied between studies
• The proportion of blunt vs penetrating trauma is not clear

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What did it find?

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In the reviewed studies, there was a positive correlation between degree of Shock Index, and critical bleeding/need for massive transfusion, however this varied from 3.4% to 39.6%.

A large number of limitations are identified in this paper, including:

Shock Index will be inaccurate in:

• Geriatric patients (reduced physiologic compensatory mechanisms)
• Pre-existing hypertension (baseline blood pressure will be higher, will have to drop more to raise SI)
• Athletes (lower resting heart rate, higher stroke volume/cardiac output)
• Pregnant (larger blood volume, faster resting heart rate)
• Illicit substance use (eg sympathomimetics – faster resting heart rate)
• Cardiopaths (beta-blockers/Ca2+ blockers, pacemakers, transplant)
• Spinal cord injury (neurogenic shock from sympathetic disruption)
• Hypotermia (causing bradycardia)

Eg:

Fit, healthy 24yo man, fall off horse onto right side, yelling in pain, RUQ tender ++, FAST positive, pink & well perfused (from all the yelling). HR = 100  BP = 120 SI = 0.83

75yo pedestrian vs car, amputated lower leg, you’re standing in a pool of blood that’s running off trolley. HR 110 SBP = 130 SI = 0.84 (On beta blocker, usual BP 180/110)

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Should this article change my practice?

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In short – No.

Whilst there are some interesting observations in this paper, the heterogeneity of the studies, the small number of papers reviewed (only 5 articles met inclusion criteria), their mostly retrospective nature, and the large number of variables and limitations that affect shock index means this “vital sign” should not be used to determine whether your patient has critical bleeding or will need massive transfusion, or at least it should be used with caution.

Until the defintions are tightened, and the end points clarified, (and potentially studied prospectively), I’d be cautious about using a single number to determine need for massive transfusion.

I think it falls into the “general interest” category, in that you knew your patient was bleeding (either externally or internally) from your excellent assessment, so you were already going to give blood instead of saline, and part of your decision included looking at their blood pressure and pulse, and their trends pre-hospital and while the patient was in the ED, and you weighed up other issues like haemostatic resuscitation principles (target SBP 90-100mmHg, regardless of pulse), time delay to surgery, co-morbidities, age, and blood results (e.g. haemoglobin which is usually available very rapidly from a blood gas).

i.e. “Look, my patient’s bleeding, I can’t stop it as quick as I’d like, they are clinically shocked so I better give them blood, and oh, by the way their SI is greater than 1.

It may come in handy as the authors suggest when comparing SI’s temporally, (eg from pre-hospital to ED, and during the ED resus. If the SI is going up over 1 or 1.1, especially if it rises despite fluid/blood administration, they have anywhere from a 3-40% chance of needing large volume transfusion, but hopefully you will have already realised that from other parameters, signs and detected injuries).

I’m also no good calculating percentages in my head. I’d have to get my calculator out on my phone, and that’s one more thing to remember to do in a busy resus!

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For our rural and remote colleagues, the Emergency Trauma Management Course is accredited for PDP/MOPS with the Australian College of Rural and Remote Medicine, as follows:

Activity Title:
Emergency Trauma Management Course – ETM – 2017-2019

Code:
E1401ETMC

Points + MOPS:
30 PRPD points
30 Emergency Medicine MOPS points
1 Anaesthetics Emergency Response

Procedural Grant
ETM Course is also recognised as a Tier 1 Emergency Medicine course and eligible for 3 days of Procedural Grant funding for eligible doctors, under the Anaesthetics or Emergency components. Refer to the Procedural Grants Program for further information. 

We look forward to welcoming more ACRRM practitioners to our course, so check out our course dates and register today!

Does your ED, ICU, trauma department or theatre change-room have a copy of the ETM Course brochure prominently displayed somewhere? If not, why not?

Here’s a copy of the ETM Course brochure, please feel free to download it, email it to your registrar and consultant groups, print it out (it’s 2-sided) and plaster it up around your department!

If you want a colour copy sent to you, drop me a line via our contact page and I’ll pop a few in the post.

Now in its 22nd year, the South West Area Network (SWAN) Trauma Conference at Liverpool Hospital promises to be yet another great conference. I attended my first SWAN conference last year, and was thoroughly impressed by the sheer calibre and world-class trauma experience of the speakers. With a range of local and international Surgical, ED, ICU, Anaesthetic and Radiology experts, and some great case-based panel discussions, you’d struggle to find a better cutting edge trauma education experience.

Low on hype, with minimal razzle-dazzle, but packed with more interdisciplinary trauma pearls than you’ll find anywhere else (in this hemisphere at least), I can’t recommend it highly enough. The only downside is that Liverpool Hospital is a pain in the backside to get to, and the surrounding suburbs are not renowned for their safety, but that just adds to the gritty trauma feel of the event. You know you’re going somewhere where they see real trauma, every day!

Check out the brochure here, and download the registration form here.  Earlybird registration finishes on the 30th of April.

If you’re going, be sure to let me know (best to tweet me) as I’d love to meet up and talk trauma!

Andy

DISCLOSURE:
I have no interest, financial or otherwise in this event, I just think it’s great!

This week we’ve launched the ETM Course Manual in iBook format.  It’s a groundbreaking new way to access information at a medical short course. Some of the features include:

• Digital images and galleries
• Videos
• Clickable links to PubMed references and FOAMed resources
• Highlights and Notes
• Turn your notes into study cards
• Copy and paste content into your personal study notes in word processing apps
• Share content via SMS, email, Twitter and Facebook

These photos show our manual in comparison to some other short course manuals.  No more heavy books to lug around or leave on your bookshelf.  Our manual fits on a USB stick, your iPad or iPad mini, meaning you can access it anywhere, anytime.

PLEASE NOTE:

The manual is currently only available to registered ETM Course participants. It is not for sale.

Here’s a video that shows the amazing features of the iBook manual in action: