Tag Archives: Emergency Room

An even quicker way to rule out heart attacks

The majority of New Zealand emergency departments look for heart muscle damage by taking a sample of blood and looking for a particular molecule called a high-sensitivity troponin T (hsTnT).  We have now confirmed that rather than two measurements over several hours just one measurement on arrival in the ED could be used to rule out heart attacks in about 30% of patients.

What did we do?

We think this is a big deal. We’ve timed this post to meet the Annas of Internal Medicine timing for when our work appears on their website – here.  What we did was to search the literature to find where research groups may have measured hsTnT in the right group of people – namely people appearing in an emergency room whom the attending physician thinks they may be having a heart attack. We also required that the diagnosis of a heart attack, or not, was made not by just one physician, but by at least two independently.  In this way we made sure we were accessing the best quality data.

Next I approached the authors of the studies as asked them to share some data with us – namely the number of people who had detectable and undetectable hsTnT (every blood test has a minimum level below which it is said to be “undetectable” in hsTnT’s case that is just 5 billionths of a gram per litre, or 5ng/L).  We also asked them to check in these patients if the electrical activity of the heart (measured by an electrocardiogram or “ECG”) looked like there may or may not be damage to the heart (a helpful test, but not used on its own to diagnose this kind of heart attack).  Finally, we asked the authors to identify which patients truly did and did not have a heart attack.

What did we find?

In the end research groups in Europe, UK, Australia, NZ, and the US participated with a total of 11 studies and more than 9000 patients.  I did some fancy statistics to show that overall about 30% of patients had undetectable hsTnT with the first blood test and negative ECGs.  Of all those who were identifiable as potentially “excludable” or “low-risk” only about 1 in 200 had a heart attack diagnosed (we’d like it to be zero, but this just isn’t possible, especially given the diagnosis is not exact).

VisualAbstract AnnalsIM 170411

Pickering, J. W.*, Than, M. P.*, Cullen, L. A., Aldous, S., Avest, ter, E., Body, R., et al. (2017). Rapid Rule-out of Myocardial Infarction With a High-Sensitivity CardiacTroponin T Measurement Below the Limit of Detection: A Collaborative Meta-analysis. Annals of Internal Medicine, 166(10). http://doi.org/10.7326/M16-2562 *joint first authors.

What did we conclude?

There is huge potential for ruling out a heart attack with just one blood test.  In New Zealand this could mean many thousands of people a year can be reassured even more swiftly that they are not having a heart attack. By excluding the possibility of a heart attack early, physicians can put more effort into looking for other causes of chest-pain or simply send the patient happily home.   While not every hospital performed had the same great performance, overall the results were good.  By the commonly accepted standards, it is safe.  However, we caution that local audits at each hospital that decides to implement this “single blood measurement” strategy are made to double check its safety and efficacy.


Acknowledgment: This was a massive undertaking that required the collaboration of dozens of people from all around the world – their patience and willingness to participate is much appreciated. My clinical colleague and co-first author, Dr Martin Than provided a lot of the energy as well as intelligence for this project. As always, I am deeply appreciative of my sponsors: the Emergency Care Foundation, Canterbury Medical Research Foundation, Canterbury District Health Board, and University of Otago Christchurch. There will be readers who have contributed financially to the first two (charities) – I thank you – your generosity made this possible, and there will be readers who have volunteered for clinical studies – you are my heroes.

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Cheesecake files: A world second for heart attacks

Going to the Emergency Department with chest pain no longer means an almost certain night in hospital.  Friday saw the publication online of our randomised controlled trial comparing two different strategies to rapidly rule-out heart attacks in people who present with chest pain to hospitals.  Here’s a précis:

What’s the problem?

  • Chest pain is common – 10% or so of presentations to ED are for chest pain.
  • Heart attacks are not so common – only ~10-15% in NZ (and less overseas*) actually have a heart attack.
  • It is devilishly difficult for most chest pain to rapidly rule out the possibility of a heart attack.
  • Consequently, most people get admitted to hospital (in 2007 93% of those presenting with chest pain).

But – led by Dr Martin Than in Christchurch and an international group including Dr Louise Cullen in Brisbane – a series of observational studies and one randomised control trial have resulted in a gradual increase in the proportion discharged.  The trial was the first of its kind, it compared standard practice at assessing chest pain to a purpose built accelerated diagnostic pathway (ADP), which we called ADAPT.   In that study 11% of patients in the standard practice (control) arm and 19.3% in the ADAPT ADP arm (experimental arm) were discharged home from ED within 6 hours.  A great improvement which led to that ADP being adopted in Christchurch hospital.

So why another study?

Two reasons: First, 19% still means that there are many patients being admitted who potentially don’t need to be in hospital.  Second, the ADP was based around a risk assessment tool designed to rule-in heart attacks rather than rule-out.  In the meantime, the team had constructed a purpose build risk assessment tool that in observational studies looked like it could rule out 40-50% of patients.

What is the study just published?

The world’s second randomised controlled trial of assessment of chest pain compared the ADAPT ADP in use (now the control arm) with a new ADP based on the new Emergency Department Assessment of Chest pain Score (EDACS)[the experimental arm].  The only difference between the two arms of the study was the risk assessment tool used. The tool gave a risk score. Patients with a low score, no unusual electrical activity in the heart, and no elevated heart muscle injury proteins in either of two blood samples measured 2 hours apart, were considered low risk.

An important aspect of the study was that it was pragmatic.  This means that the doctors didn’t have to follow the ADP and could decide to send a patient home, or not send them home, based on any factors they thought clinically relevant.  This makes it very tough to run a trial, but it makes the trial more “real life.”

What were the results?

558 patients were recruited.  They all volunteered and are marvellous people.  I love volunteers.

The primary outcome was the proportion of patients safely discharged home within 6 hours.  We assessed safety by looking at all medical events that happened to a patients over 30 days to check to see if any patients discharged home had a major cardiac event that could potentially have been picked up in the ED.

34% of the control arm and 32% of the experimental arm were discharged within 6 hours.  In other words, there was no difference in early discharge rates between the two arms.  The surprising feature of this is that between 2012/3 (when the first trial was run) and 2014/15 the proportion of patients the first ADP ruled out increased from 19% to 34%.  This was unexpected, but pleasing. There were no safety concerns with any patients.

The secondary outcome was simply the proportion each arm of the study classified as low risk (ie not considering whether this led to early discharge or not).  The control (ADAPT ADP) classified 31% and the experimental (EDACS ADP) 42%.  This was a real and meaningful difference which suggests that there is “room for improvement” in early discharge rates as the clinicians become more familiar with the EDACS ADP.

Since 2007 in Christchurch hospital over three times more patients who present with chest pain can be reassured from within the ED that they are not having a heart attack and discharged home (see the infographic).EDACS infographic v2

What was your role?

My role: I managed aspects of the data collection for the later 2/3rds of the patients recruited, did the statistical analysis and co-wrote the manuscript.  In reality, there were a lot of people involved, not least of whom were the wonderful research nurses and database manager who did a lot of the “grunt work”.

What now?

Over the last year all EDs in New Zealand have implemented or in the process of implementing an accelerated diagnostic pathway.  The majority have chosen to use the EDACS pathway.  I am part of a team nationwide helping implement these pathways and monitor their efficacy and safety.

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This study was funded by the Health Research Committee of New Zealand. The work was carried out with the collaboration or the University of Otago Christchurch, Christchurch Heart Institute, and the Canterbury District Health Board Emergency Department, Cardiology Department, General Medicine, and Canterbury Health Laboratories. My salary is provided through a Senior Research Fellowship in Acute Care funded Canterbury Medical Research Foundation, Canterbury District Health Board and the Emergency Care Foundation.

*Not because we have more heart attacks, just an efficient and well funded primary care sector that keeps the very low risk patients out of the ED.

**Featured Image: Creative Commons Share-Alike 3.0 http://tcsmoking.wikispaces.com/heart%20attack

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The effect of cannabis legalisation on Emergency Care 

Medical cannabis application guidelines are to be reviewed, announced Associate Health Minister Peter Dunne this week. Co-incidently a paper was published* in the Annals of Emergency Medicine on the effect on Emergency Care of legalising medical marijuana use in Colorado. Alas, this article is behind a paywall.  It does not have a lot of detail. However, it is relevant to the New Zealand debate.  Not so much as to any possible change in guidelines on applications made to the minister, but rather to the effect a broader legalisation of marijuana for medical purposes may  have an on our emergency departments. i.e. just one of the many factors which need to be taken into account in the debate.

In 2009 the prosecution of marijuana users and suppliers was halted in the state of Colarado where the use of medical marijuana had been previously legalised and licensed.  Within 2 years the number of registered medical marijuana licences increased 24 times from 5000 to nearly 120,000.  This was not the only effect:

  • The percentage of 18 to 25 year olds reporting marijuana use increased from 35% to 43%
  • The percentage of those aged 26+ perceiving marijuana posed “great risk” dropped from 45% to 31%.

While these numbers may reflect in part the readiness to be “honest” after the law change, the following statistic probably is truly related to increased use:

  • The hospitalisations after marijuana use nearly doubled from 15 per 100,000 hospitalisations to 28 per 100,000 hospitalisations.

As the authors concluded:

“It is clear that marijuana availability and use in Colorado significantly increased after the commercialization of medical marijuana. Providers in states with impending legalization measures should become familiar with the symptoms and management of acute marijuana intoxication, as well as understand the effects on chronic diseases frequently observed in the ED.”

I was fascinated that in a population of 5.4 million there were nearly 120,000 licensed medical marijuana users in Colorado.  That is 1 in 45 people! That strikes me as amazingly high proportion. However, I guess that it all depends on just what medicinal purposes may mean.  The process to get a license (at least now), seems relatively easy involving a few simple forms.  The Physician recommends the number of plants to be grown and ticks a box stating one of eight conditions: Cancer, Glaucoma, HIV or AIDS positive, Cachexia, Severe Nausea, Severe Pain, Persistent muscle spasms, Seizures.  The patient sends in a form too, with $15.

According to the latest statistics on the Colorado medical marijuana registry there are currently 107,000 active patients registered with an average age of 43. 21-40 year olds comprised 43% pf the patients.  93% report severe pain.  Hmmm… it seem Colorado has an epidemic of “severe” pain amongst their young adults.

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ps. Before you jump in with comments, recognise that there is a lot of misconception around medical cannabis in New Zealand. Minister Peter Dunne cleared some of them up in a press release in January. (eg did you know that there is already a cannabis product approved for therapeutic use?).

Note: Recreational marijuana became legal in Colorado in 2014.

Disclaimer:  I an not an expert in the field, merely I came across this article because it was published in a journal I access for my other research concerning emergency departments.  If you believe the methods to measure these things, Ann Emerg Med is the top ranked Emergency medicine journal

*Kim, H., & Monte, A. A. (2016). Colorado Cannabis Legalization and Its Effect on Emergency Care. Annals of Emergency Medicine, http://doi.org/10.1016/j.annemergmed.2016.01.004

Photo: Public Domain, from Wikipedia.

Major government health directive monitored for efficacy and safety

Last year I was fortunate to become part of a team at Christchurch hospital led by emergency care physician, Dr Martin Than. About 7 years ago in response to some local issues with how patients presenting with chest pain were being evaluated for potential heart attacks, Dr Than began a research program that investigated what clinical, demographic, and biological (blood) factors could best be used to safely and efficiently rule-out a heart attack.

Someone turning up at the doors of the Emergency Department with chest pain desperately wants to hear those reassuring words “You are not having a heart attack.” Unfortunately, for the ED staff this a very difficult conclusion to come to rapidly. As a result, around the world, as many as 90% of patients being assessed for possible heart attack end up being admitted to hospital overnight or longer, although only 20% of them end up being diagnosed with a heart attack. Obviously this is not good for the patient or the hospital – especially given tight budgets and lack of bed space. Dr Than’s work addressed the problem with a large multi-national observational study which assessed if a decision making pathway (called an accelerated diagnostic pathway or ADP for short) could increase the proportion of patients who could potentially not be admitted to hospital instead referred for some outpatient testing(1). This was further refined in another observational study which reduced the number of blood biomarkers that needed testing(2). Finally, and uniquely a randomised controlled trial of the new ADP verse standard practice was run at Christchurch Hospital. This was very successful, nearly doubling the proportion of patients who could be discharged to outpatient care within 6 hours of arriving in the ED(3). More has been done since on refining the ADP … but that is for another post.

The Ministry of Health liked what they saw as did ED physicians and Cardiologists throughout the country. This has resulted in the MOH asking all EDs within New Zealand to implement an accelerated diagnostic protocol. In doing so they will join all of Queensland, and a sprinkling of hospitals throughout the world that have recently adopted an ADP. This kind of positive outcome to local research is what every scientist dreams of, and Dr Than and his team have a right to be proud. But wait, as they say, there is more. Thanks to a Health Innovation Partnership grant from the Health Research Committee we are able to put in place a mechanism to monitor the effect and safety of an ADP at eight hospitals around New Zealand. This is where I come in, as I am collecting, collating and analysing the data for this project.   It is very exciting to be involved not only in helping implement a change of practice, but to be able to assess if that change is effective across a range of New Zealand hospitals from major inner-city hospitals to small rural hospitals, each of which has to adapt an ADP to meet their own particular circumstances. As I write Middlemore, North Shore, Wellington, Hutt Valley, Nelson and Christchurch hospitals all have new ADPs in place. Most if not all EDs will have them by the end of the year.

Some of where accelerated diagnostic pathways have been implemented.

Some of where accelerated diagnostic pathways have been implemented.

The model of observational research -> randomised controlled trial -> local implementation with further research -> mandatory national implementation -> research the effect of that change on local and national levels -> refine processes etc, is I believe a very good one and one that should be standard practice for major health initiatives. The MOH, HRC, and various district health boards that have bought into this process should be commended. There are other similar initiatives happening around the country and a look forward to when as a health consumer I can have confidence in any procedure I may face as been similarly thoroughly assessed.

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Thanks to my Acute Care Fellowship sponsors: Sponsors

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and to the grant funding body:

HRC

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References

  1. Than, M. P., Cullen, L., Reid, C. M., Lim, S. H., Aldous, S., Ardagh, M. W., et al. (2011). A 2-h diagnostic protocol to assess patients with chest pain symptoms in the Asia-Pacific region (ASPECT): a prospective observational validation study. Lancet, 377(9771), 1077–1084. doi:10.1016/S0140-6736(11)60310-3
  2. Than, M. P., Cullen, L., Aldous, S., Parsonage, W. A., Reid, C. M., Greenslade, J., et al. (2012). 2-Hour accelerated diagnostic protocol to assess patients with chest pain symptoms using contemporary troponins as the only biomarker: the ADAPT trial. Journal of the American College of Cardiology, 59(23), 2091–2098. doi:10.1016/j.jacc.2012.02.035
  3. Than, M. P., Aldous, S., Lord, S. J., Goodacre, S., Frampton, C. M. A., Troughton, R., et al. (2014). A 2-hour diagnostic protocol for possible cardiac chest pain in the emergency department: a randomized clinical trial. JAMA Internal Medicine, 174(1), 51–58. doi:10.1001/jamainternmed.2013.11362

Oh hell

Oh Hell, that hurts!  I sat down in a hurry. My first thought was “I’m having a heart attack.”  My second was “Don’t be silly you’re only 49 and probably just gobbled lunch too quickly, again.”  Jess came up to me and said “Gosh, you look pale.”  I mumbled something about a bit of pain.  It bit again, Jess noticed my grimace and said the inevitable “We should call a doctor.”  I tried to argue but to be honest, felt lousy and a little bit scared.  Before, I knew it I was bundled up off to the Emergency department.

Rule #1: Never ignore chest pain!

Rule #1: Never ignore chest pain!

As soon as I got in ED there were nurses and doctors questioning me, taking some blood, and sticking little metal electrodes all over my chest.  I later found out they were measuring in my blood something called troponin which goes up with a heart attack (well… they used the words like myocardial infarction and acute coronary syndrome … but all I cared about was whether I was having a heart attack or not).  The electrodes I learnt were measuring the electrical activity of my heart – they called it an ECG.  They told me that if either the troponin levels were high or the ECG squiggles were not where they were meant to be then I would be admitted to the cardiology ward.  They were going to repeat all the measurements a couple of hours later.  I was a little annoyed by all the questions to start with, but I soon learnt that sometimes the troponin levels are low and the ECG negative but people can still have a serious heart problem.  They use the questions to come up with a risk score which helps them make a clinical judgment.  The questions were about the usual stuff – smoking, family history of heart disease etc as well as some specifically about where the pain was, what kind of pain (mine was definitely sharp), and whether it moved to the arms or shoulders.

Pretty soon after I arrived someone came up to me who called herself a research nurse and asked if I would consider joining a study. She was lovely. She explained the study was all about trying to rapidly rule out a heart attack.  Apparently only a quarter of those presenting with chest pain actually have a heart problem needing attending too.  However, it’s difficult to tell quickly if someone is in that quarter or not and so a huge percentage of patients get admitted to hospital, usually staying overnight, and certainly costing the tax payer heaps.  Well, I’d just paid a massive tax bill so I signed up pretty darn quick.  Also, I can’t stand hospitals and so I’ll support anything that keeps me out of them!  Of course, this research wasn’t going to help me now, but who knows in the future.  Actually, for the price of another round of questions and a little more blood (fortunately they didn’t need to stick any more needles in me) it seemed a small price to “do my bit” for science… ‘All I have to offer you is blood, sweat…’

After a couple of hours and a repeat of all the tests, I was told they had all come out negative and my risk score was low.  The docs saw nothing else that rang alarm bells.  They signed me up for a treadmill test the next day “just in case” (served me right, I’d been avoiding the gym) and sent me on my way.  I felt a bit of a berk, but they were so good to me and kept reiterating that it is much much better to be safe than sorry.  Besides, I got to participate in some science which was rather cool.

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Author’s note:  Research in Christchurch Hospital Emergency Department lead by Dr Martin Than has enabled nearly a doubling of the numbers of people in whom a heart attack can be ruled out early.  I have been fortunate to join the team this year as we run a randomised controlled trial of two scoring regimes to see if one will increase the rates of safe early discharge.

More women injured in quakes

A Christchurch researcher is trying to understand why so many more women than men were injured in the Canterbury earthquakes.

Professor Mike Ardagh is Chair of the RHISE (Researching the Health Implications of Seismic Events) group.

Professor Ardagh leads a team investigating the health system response to the quakes. His team found the health system responded remarkably well to a massive event, including the activation of well-practiced plans and innovation to overcome issues such as loss of power. Looking at ACC statistics, they discovered that significantly more women than men were injured, across all degrees of injury.

“We have a few hypotheses about why this is but have not proven anything yet. We are working on this question in collaboration with Professor David Johnston of Massey University.’’

quakepicProfessor Johnston is studying how people behave during earthquakes and is probing whether certain behaviours, such as running or staying still, put some at greater risk.

Some of the other topics being explored by the RHISE group are:

  • Variations in stress according to peoples’ homes or workplaces, and their exposure to quake damage.
  • The impact on older peoples’ health.
  • The impact on front line workers’ occupational health.
  • The on-going psychological impact.

The gender and injury project will take at least a year.

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This guest post was written by Kim Thomas,  Senior Communications Advisor, University of Otago, Christchurch, www.uoc.otago.ac.nz.  Several more posts related to the work of the University of Otago Christchurch will follow.

Did you know?

• The University of Otago, Christchurch, has about 600 postgraduate students, mostly health professionals such as nurses.

• This year 45 science and medical students will get a taste of research with our Summer Studentship programme.

• Thousands of doctors have done their final clinical years training in Christchurch.

• We are home to many excellent research groups such as the Christchurch Heart Institute, the Christchurch Health and Development Study and the Centre for Free Radical Research.