Category Archives: All Updates

All Updates, Guidelines, ICU, Kids, PHARM, Resus

Is 4 Joules per kg enough in kids?

March 5, 2014 Cliff Leave a comment

Researchers from the Iberian-American Paediatric Cardiac Arrest Study Network challenge the evidence base behind defibrillation shock dose recommendations in children.
In a study of in-hospital pediatric cardiac arrest due to VT or VF, clinical outcome was not related to the cause or location of arrest, type of defibrillator and waveform, energy dose per shock, number of shocks, or cumulative energy dose, although there was a trend to better survival with higher doses per shock. 50% of children required more than the recommended 4J per kg and in over a quarter three or more shocks were needed to achieve defibrillation.

Shockable rhythms and defibrillation during in-hospital pediatric cardiac arrest
Resuscitation. 2014 Mar;85(3):387-91
[EXPAND Abstract]

OBJECTIVE: To analyze the results of cardiopulmonary resuscitation (CPR) that included defibrillation during in-hospital cardiac arrest (IH-CA) in children.

METHODS: A prospective multicenter, international, observational study on pediatric IH-CA in 12 European and Latin American countries, during 24 months. Data from 502 children between 1 month and 18 years were collected using the Utstein template. Patients with a shockable rhythm that was treated by electric shock(s) were included. The primary endpoint was survival at hospital discharge. Univariate logistic regression analysis was performed to find outcome factors.

RESULTS: Forty events in 37 children (mean age 48 months, IQR: 7-15 months) were analyzed. An underlying disease was present in 81.1% of cases and 24.3% had a previous CA. The main cause of arrest was a cardiac disease (56.8%). In 17 episodes (42.5%) ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT) was the first documented rhythm, and in 23 (57.5%) it developed during CPR efforts. In 11 patients (27.5%) three or more shocks were needed to achieve defibrillation. Return of spontaneous circulation (ROSC) was obtained in 25 cases (62.5%), that was sustained in 20 (50.0%); however only 12 children (32.4%) survived to hospital discharge. Children with VF/pVT as first documented rhythm had better sustained ROSC (64.7% vs. 39.1%, p=0.046) and survival to hospital discharge rates (58.8% vs. 21.7%, p=0.02) than those with subsequent VF/pVT. Survival rate was inversely related to duration of CPR. Clinical outcome was not related to the cause or location of arrest, type of defibrillator and waveform, energy dose per shock, number of shocks, or cumulative energy dose, although there was a trend to better survival with higher doses per shock (25.0% with <2Jkg(-1), 43.4% with 2-4Jkg(-1) and 50.0% with >4Jkg(-1)) and worse with higher number of shocks and cumulative energy dose.

CONCLUSION: The termination of pediatric VF/pVT in the IH-CA setting is achieved in a low percentage of instances with one electrical shock at 4Jkg(-1). When VF/pVT is the first documented rhythm, the results of defibrillation are better than in the case of subsequent VF/pVT. No clear relationship between defibrillation protocol and ROSC or survival has been observed. The optimal pediatric defibrillation dose remains to be determined; therefore current resuscitation guidelines cannot be considered evidence-based, and additional research is needed.

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All Updates

Modernising ED sedation practice with evidence

February 27, 2014 Cliff Leave a comment

I think some EDs still have an overcautious ‘ASA 1 or 2 only’ criterion for procedural sedation, which makes no sense whatsoever when one considers the spectrum of cases in which emergent procedural sedation may be required.
Fortunately, the assumption that a higher ASA grade would be associated with increased complications has now been debunked by Edinburgh’s Emergency Medicine Research Group.
For more procedural sedation-related dogmalysis (such as pre-procedural fasting) check out EMCrit’s Practical Evidence Podcast that discusses the recently updated ACEP Policy.
Dawson, N., Dewar, A., Gray, A., Leal, A., on behalf of the Emergency Medicine Research Group, Edinburgh. (2014).
Association between ASA grade and complication rate in patients receiving procedural sedation for relocation of dislocated hip prostheses in a UK emergency department.
Emergency Medicine Journal 31(3), 207–209

OBJECTIVE: To determine the association between the American Society of Anesthiologists (ASA) grade and the complication rate of patients receiving procedural sedation for relocation of hip prosthesis in an adult emergency department (ED) in the UK.

DESIGN: Retrospective study of registry data from a large UK teaching hospital ED. Consecutive adult patients (aged 16 years and over) in whom ASA grade could be calculated, with an isolated dislocation of a hip prosthesis between 8 September 2006 and 16 April 2010 were included for analyses (n=303). The primary outcome measure was association between ASA and complication rate (any of desaturation <90%; apnoea; vomiting; aspiration; hypotension <90 mm Hg; cardiac arrest). Secondary outcome measures were relationship between ASA grade and procedural success, choice of sedative agent and sedation depth, and complications and choice of sedative agent, arrival time and sedation depth.

RESULTS: There was no significant difference between ASA grade and the risk of complication (p=0.800). Moreover, there was no significant difference between ASA grade and procedural success (p=0.284), ASA and choice of sedative agent (p=0.243), or ASA and sedation depth (p=0.48). There was no association between complications and sedative agent (p=0.18), or complications and arrival time (p=0.12). There was a significant difference between sedative depth and complications (p<0.001).

CONCLUSIONS: There is no clear association between a patient’s physical status (ASA grade) and the risk of complications, chance of procedural success or choice of sedative agent in relocation of hip prostheses. There is a higher rate of complications with higher levels of sedation (p<0.001).

Acute Med, All Updates, ICU, PHARM, Resus

The 'Magic Eye®' method of rhythm assessment

February 9, 2014 Cliff Leave a comment

Are you someone who tries to determine whether an ECG trace is ‘irregularly irregular’ by drawing little dots on a piece of paper level with the R waves to see if they are evenly spaced? I’d done that for years until I read this fantastic suggestion, which I’ve been following for over a year now.
In the 1990s there was a popular series of posters and books called ‘Magic Eye‘. These contained a ‘random dot autostereogram‘ which appeared as a mish-mash of coloured dots, but when you stared at it for a while the illusion of a 3D image would emerge. They looked a bit like this (although this one won’t work at such reduced resolution):

Dr Broughton and colleagues from Cambridge, UK, discovered that this technique, which involves forcing a divergent gaze to get repeating patterns to appear to overlap, can be applied to an ECG trace.
Stereoviewing an ECG trace causes successive QRS complexes to visually overlap and produce a new image. As Broughton and colleagues point out:
“When achieved, this will lead to one of three outcomes. Entirely regular rhythms will ‘click’ into place as a new image at fixed depth. Rhythms with only mild irregularity may be stereoviewable, and if so, will appear to show successive QRS complexes at subtly varying depths. Rhythms with marked irregularity will not be stereoviewable, instead (in our experience) merely giving the viewer sore eyes after several failed viewing attempts.”
The authors assert that this can be applied to continuous ECG monitors, although unless you are really good at stereoviewing while moving your head/eyes horizontally, you should really freeze the trace on the screen first.
The ‘Magic Eye®’ method of rhythm assessment
Anaesthesia. 2012 Oct;67(10):1170-1

Acute Med, All Updates, PHARM, Resus

Not finding a difference doesn't prove equivalence

January 28, 2014 Cliff Leave a comment

The recent LINC trial was a randomised controlled trial comparing a mechanical chest compression device (LUCAS) with manual CPR(1). “No significant difference” was found for any of the main outcome measures considered.
So do you think the LINC trial demonstrated that mechanical CPR using the LUCAS device is equivalent, or at least not inferior, to manual CPR?
This was an interesting and important trial for those of us who manage prehospital cardiac arrest patients. In some social media discussions, it appears to have been interpreted by some as evidence that they are equivalent resuscitative techniques or that LUCAS is not inferior to manual CPR.

However, unless you see a p-value less than 0.05 in the table above, (issues of multiple hypotheses testing aside) no evidence of anything was demonstrated; not of difference and certainly not of equivalence. When faced with 2-sided p values >5%, investigators often conclude that there is “no difference” between the treatments, leading to an assumption among readers that the treatments are equivalent. A better conclusion is that there is “no evidence” of a difference between treatments (see opinion piece by Sackett, 2004(2)). In order to determine if treatments are equivalent, equivalence must be tested directly.
How can we test for equivalence?
First, we must define equivalence. It is crucial that this definition is provided a priori i.e. defined before the data are examined. As the focus of the LINC study was on superiority the investigators did not offer an a priori definition of equivalence. However, the CIRC study(3), conducted some time earlier and similar in design, did. (This study examined an alternative mechanical CPR device, the Zoll AutoPulse).
When establishing equivalence between treatments, instead of the more customary null hypothesis of no difference between treatments, the hypothesis that the true difference is equal to a specified ‘delta’ (δ) is tested (4).
To analyse the LINC results to look for equivalence, we can derive our delta values from the CIRC study, which as we’ve said did offer an a priori definition of equivalence. For the purpose of illustration, we will use the risk-difference stopping boundaries calculated for the CIRC study, rather than the odds ratio based equivalence margins, on the grounds of greater simplicity and clinical appropriateness. Therefore, we set our equivalence margins at -δ=-1.4% and δ=1.6%, meaning, where LUCAS fared no worse than manual CPR by 1.4% and no better by 1.6%, we will consider the two techniques equally efficacious. Thus, we will declare equivalence between LUCAS and manual CPR if the 2-sided 95% CI for the treatment difference lies entirely within -1.4% and 1.6%, and noninferiority if the one-sided 97.5% CI for the treatment difference (equivalent to the lower limit of the two-sided 95% CI) lies above -1.4%. (5).
These concepts and how they differ from a traditional comparison are more readily appreciated graphically (Fig. 1).
Figure 1. Two one-sided test procedure and the equivalence margin in equivalence/noninferiority testing between LUCAS and manual CPR
1a Traditional comparative study, such as the LINC trial, shows results with confidence intervals that show no evidence of a difference as they encompass 0.

1b. Using equivalence margins (-δ and δ) derived from a similar study (CIRC), we show that the LINC trial does not demonstrate that LUCAS and manual CPR are equally efficacious, since the 95% CI do not lie completely within the equivalence margins.

1c. The one sided CI lies above -δ for some outcomes, allowing us to declare non-inferiority on those measures.

Conclusion
The presentation of the LINC trial’s results shows no evidence of a difference in outcomes between mechanical and manual CPR, which is not the same as showing they are equivalent or that mechanical CPR is non-inferior. However if we re-examine their data using equivalence margins (-δ, δ) derived from a similar study (CIRC), there is some evidence that the LUCAS device is not inferior to manual CPR (but not necessarily equivalent) with respect to longer term good neurological outcome.

References
1. Rubertsson S, Lindgren E, Smekal D, er al. Mechanical Chest Compressions and Simultaneous Defibrillation vs Conventional Cardiopulmonary Resuscitation in Out-of-Hospital Cardiac Arrest
JAMA. 2014 Jan 1;311(1):53-61
2. Sackett D. Superiority trials, non-inferiority trials, and prisoners of the 2-sided null hypothesis
Evid Based Med 2004;9:38-39 [Open Access]
3. Lerner EB, Persse D, Souders CM, et al. Design of the Circulation Improving Resuscitation Care (CIRC) Trial: a new state of the art design for out-of-hospital cardiac arrest research
Resuscitation. 2011 Mar;82(3):294-9
4. Dunnett CW, Gent M. Significance testing to establish equivalence between treatments, with special reference to data in the form of 2X2 tables. Biometrics. 1977 Dec;33(4):593-602
5. Piaggio G, Elbourne DR, Pocock SJ, et al. Reporting of noninferiority and equivalence randomized trials: extension of the CONSORT 2010 statement. JAMA. 2012;308(24):2594-604. [Open Access]

Acute Med, All Updates, ICU, Resus, Ultrasound

Does RV enlargement on echo predict PE?

January 20, 2014 Cliff Leave a comment

A nice paper from Annals of Emergency Medicine showing the test characteristcs of some of the common signs we look for on basic 2D echo that suggest the presence of (sub)massive pulmonary embolism:
Right Ventricular Dilatation on Bedside Echocardiography Performed by Emergency Physicians Aids in the Diagnosis of Pulmonary Embolism
Ann Emerg Med. 2014 Jan;63(1):16-24
[EXPAND Abstract]

STUDY OBJECTIVE: The objective of this study was to determine the diagnostic performance of right ventricular dilatation identified by emergency physicians on bedside echocardiography in patients with a suspected or confirmed pulmonary embolism. The secondary objective included an exploratory analysis of the predictive value of a subgroup of findings associated with advanced right ventricular dysfunction (right ventricular hypokinesis, paradoxical septal motion, McConnell’s sign).

METHODS: This was a prospective observational study using a convenience sample of patients with suspected (moderate to high pretest probability) or confirmed pulmonary embolism. Participants had bedside echocardiography evaluating for right ventricular dilatation (defined as right ventricular to left ventricular ratio greater than 1:1) and right ventricular dysfunction (right ventricular hypokinesis, paradoxical septal motion, or McConnell’s sign). The patient’s medical records were reviewed for the final reading on all imaging, disposition, hospital length of stay, 30-day inhospital mortality, and discharge diagnosis.

RESULTS: Thirty of 146 patients had a pulmonary embolism. Right ventricular dilatation on echocardiography had a sensitivity of 50% (95% confidence interval [CI] 32% to 68%), a specificity of 98% (95% CI 95% to 100%), a positive predictive value of 88% (95% CI 66% to 100%), and a negative predictive value of 88% (95% CI 83% to 94%). Positive and negative likelihood ratios were determined to be 29 (95% CI 6.1% to 64%) and 0.51 (95% CI 0.4% to 0.7%), respectively. Ten of 11 patients with right ventricular hypokinesis had a pulmonary embolism. All 6 patients with McConnell’s sign and all 8 patients with paradoxical septal motion had a diagnosis of pulmonary embolism. There was a 96% observed agreement between coinvestigators and principal investigator interpretation of images obtained and recorded.

CONCLUSION: Right ventricular dilatation and right ventricular dysfunction identified on emergency physician performed echocardiography were found to be highly specific for pulmonary embolism but had poor sensitivity. Bedside echocardiography is a useful tool that can be incorporated into the algorithm of patients with a moderate to high pretest probability of pulmonary embolism.

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All Updates

How You Train is How You Fight

January 1, 2014 Cliff Leave a comment

Simulation makes us more effective. I think it’s good to consider how one would deal with emergency situations in every day life, and practice the response. There are ALWAYS learning points.
My four year old son Kal brought along his rubber red bellied black snake on a New Year’s Day bush walk with my family. Too good an opportunity to miss, so we practiced managing a snakebite scenario. What we did and what we learned are summarised in this three minute video:

This was a worthwhile exercise. Learning points were:
1. Carry a knife to help cut up the teeshirt (if you don’t carry bandages)
2. Call for help early – it takes several minutes to apply the pressure immobilisation bandage, so ideally these things are done in parallel rather than series.
3. Know how to get your coordinates from your smart phone. Several free apps are available.
On an Apple iPhone, they are displayed on the ‘Compass’ app but ONLY if you have enabled location services (Settings->Privacy->Location Services->Compass)

Learn more about pressure immobilisation technique and its indications from the Australian Resuscitation Council

Acute Med, All Updates, ICU, Resus

Sepsis research – let's get some answers

December 17, 2013 Cliff Leave a comment

There’s so much debate on which components of Early Goal Directed Therapy in sepsis really make a difference. The good news is that three randomised controlled trials in the UK, Australasia, and North America, aim to answer the question, and the study design from the outset has been a collaboration that will allow the results to be pooled.
ProMISe is taking place in the UK, ProCESS in the US, and ARISE in Australasia.

The Australasian study (ARISE) and is nearing completion. If you can recruit patients then please do. Listen to a podcast on this fantastic study with lead investigator Dr Anthony Delaney.

All Updates, ICU, PHARM, Resus, Trauma

London Trauma Conference Day 4

December 15, 2013 Cliff Leave a comment

London Trauma Conference Day 4 by Dr Louisa Chan
It’s the last day of the conference and new this year is the Neurotrauma Masterclass running in parallel with the main track which focuses on in-hospital care.
We heard a little from Mark Wilson yesterday. He believes we are missing a pre-hospital trick in traumatic brain injury. Early intervention is the key (he has data showing aggressive intervention for extradural haemorrhage in patients with fixed dilated pupils has good outcomes in 75%).
Today he taught us neurosurgery over lunch. If you have a spare moment over then go to his website and you too can learn how to be a brain surgeon!
Dr Gareth Davies talks about Impact Brain Apnoea. Many will not heard of this phenomenon. Clinicians rarely see patients early enough in their injury timeline to witness
Essentially this term describes the cessation of breathing after head injury. It has been described in older texts (first mentioned in 1894!) The period of apnoea increases with the severity of the injury and if non fatal will then recover to normal over a period of time. Prolonged apnoea results in hypotension.
This is a brain stem mediated effect with no structural injury.
The effect is exacerbated by alcohol and ameliorated by ventilatory support during the apnoeic phase.
Associated with this response is a catecholamine surge which exacerbates the cardiovascular collapse and he introduces the concept of Central Shock.
So how does this translate into the real world?
Well, could we be miscategorising patients that die before they reach hospital as succumbing to hypovolaemic when in fact they had central shock?
These patients essentially present with respiratory arrest, but do well with supported ventilation. Identification of these patients by emergency dispatchers with airway support could mean the difference between life and death.
Read more about this at: http://www.sciencedirect.com/science/article/pii/S0025619611642547
Prof Monty Mythen spoke on fluid management in the trauma patient after blood (not albumin, HES or colloids) and Prof Mervyn Singer explained the genetic contribution to the development of MODS after trauma.
Prof Brohi gave us the lowdown on trauma laparotomies – not all are the same! With important human factors advice:
1. Task focus kills
2. Situational awareness saves lives
3. The best communication is non verbal
4. Train yourself to listen
Prof Susan Brundage is a US trauma surgeon who has been recruited into the Bart’s and the London School of Medicine and the Royal College of Surgeons of England International Masters in Trauma Sciences for her trauma expertise.
She tells us that MOOCs and FOAM are changing education. Whilst education communities are being formed, she warns of the potential pitfalls of this form of education with a proportion of participants not fully engaged.
The Masters program is growing and if you’re interested you can read more here.
This has been a full on conference, with great learning points.
Hopefully see you next year!

Acute Med, All Updates, ICU, PHARM, Resus, Trauma

London Trauma Conference Day 3

December 13, 2013 Cliff Leave a comment

Dr Louisa Chan reports on Day 3 of the London Trauma Conference
There was a jam-packed line up for the Pre-hospital and Air Ambulance Day which was Co-hosted by the Norwegian Air Ambulance Foundation.

My highlights were:

HEMS

Dr Rasmus Hesselfeldt works in Denmark where they have a pretty good EMS system with ambulances, RRV’s and PHC doctors. Road conditions are good with the longest travel distance of 114 miles. So would the introduction of a HEMS service improve outcomes? He did an observational study looking at year of data post-trial and compared this with 5 months pre-trial. Trauma patients with ISS > 15 and medical emergencies greater than 30 min by road to the Trauma Centre (TC). Primary endpoint was time to TC, secondary outcomes were number of secondary transfers and 30 day mortality.
Results: Increase in on scene time 20 min vs 28 min, time to hospital increased but time to TC was less – 218 min vs 90 min, reduced mortality, increased direct transfer to TC and fewer secondary transfers.
Full article here: A helicopter emergency medical service may allow faster access to highly specialised care. Dan Med J. 2013 Jul;60(7):A4647

Airway
Prof Dan Davis ran through pre-hospital intubation. It seems that this man has spent his life trying to perfect airway management. Peter Rosen was his mentor and imprinted on him that RSI is the cornerstone of airway management.
So surely pre-hospital intubation saves lives. The evidence however begs to differ, or does it? As with all evidence we need to consider the validity of the results and luckily Prof Davis has spent a lot of time thinking through the reasons why there no evidence.
During his research he opened a huge can of worms:
1. Hyperventilation was common – any EtCO2 <30mmHg lead to a doubling in mortality.
2. First pass intubation is great, but not if you let your patient become hypoxic or hypotension or worse still both!
3. Hospital practice had similar issues.
So really the RSI processes he was looking at weren’t great.
The good news is that things have improved and he can now boast higher first pass rates and lower complication rates for his EMS system. His puts this success down to training.

The AIRPORT study was discussed at last years LTC. This year we have the results. 21 HEMS services in 6 countries were involved in the data collection including GSA HEMS. The headline findings are that intubation success rates are high (98%) with a complication rate of 10-12%. The more difficult airways were seen in the non-trauma group. 28.2% patients died (mainly cardiac arrest).

Matt Thomas reported on REVIVE – a pre-hospital feasibility study looking at airway management in OHCA (I-Gel vs LMA Supreme vs standard care). It was never powered to show a difference in these groups, the main aim was to see if research in this very challenging area was possible. And the answer is YES. The paramedics involved recruited more patients than expected and stuck to the protocol (prob better that docs would have!). A randomised controlled trial to look at the I-Gel vs ETT is planned.

(P)REBOA
Finally, Pre-hospital Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) seems eminently possible – Dr Nils Petter Oveland showed us the training manikin they developed for training. Through training on this manikin they achieved an average skin to balloon time of 3.3mins. Animal data supports this procedure as a bridge to definitive care in non compressible haemorrhage.
London HEMS will be starting (P)REBOA in the New Year.
So now it’s stand up science, I’m off for my glass of wine…………….
Check out what they’re saying about the London Trauma Conference on Twitter

Acute Med, All Updates, ICU, PHARM, Resus, Trauma

London Trauma Conference Day 2

December 12, 2013 Cliff Leave a comment

London Trauma Conference 2013 – Day 2 by Dr Louisa Chan
So I find myself torn today: do I join the the main track with a Major incident theme or the Cardiac Masterclass? I never liked the thought of missing out on anything so I went to a bit of both.

Cardiac Masterclass
A lot of people probably think that managing cardiac arrest isn’t challenging and a bit dull because the patient is dead. But the Cardiac Masterclass would inspire you to think of a bright future for cardiac arrest management.
Mark Whitbread reminded us of how important dispatch is in the chain of survival. How much focus do we put on improving bystander CPR rates? Dispatcher assisted CPR has been shown to improve outcomes and needs to be skilfully done.
Ajay Jain pushes for all OHCA patients to be taken to a Cardiac Arrest centre for PCI. Why? Because the results he has from his centre for PCI in OHCA patients results in 77% (101/132) patients surviving to hosp discharge, 65% neurologically intact.
He also tells us that the ECG post arrest is a very poor predictor of PCI findings (although STEMI predicts a positive result) so they all should have PCI.

More data from TOPCAT shows us that non survivors of OHCA are easy to cool.

And maybe we should be cooling DURING cardiac arrest to minimise the reperfusion injury.

For persistent VF Prof Redwood says revascularisation is the key; when that doesn’t work then reducing LV volume may help so aspiration or an Impella may work. Failing that – ECMO.

Major Incidents
Major Incidents by their nature do not happen every day, so experience in these incidents is limited. The challenge then is how can we learn from incidents?
A standardised reporting system for a major incident database would be a good idea – www.majorincidentreporting.org – is where you will find the standard report form and open access database.
And then all I can suggest is that you need to come to the LTC and listen to the accounts of those who have been there. We heard about the Tokyo Sarin attack, Mumbai, and a very compelling story of multiple drownings from Steen Barnung.
Lessons from Tokyo – Sarin attack:

It will happen again
It will be chaos
Crowds cannot be controlled
Comms will fail
Clinical diagnosis – need a senior clinician
Treatment must be immediately available – 3min to absorb sarin
Decontamination – get naked, 90% decon with clothes removal.
Stream casualties
Empower the man on the ground.

Gadgets
The great thing about the London Trauma Conference is that it’s not just about the content of the tracks, there’s the networking and the opportunity to see new pieces of equipment.
The Norwegians won on the equipment front with their Mobile Stroke Unit. It’s due to go on line in 2014.
So TTFN and more from me on Day 3 of #LTC2013

resusme