Good times part 1: DIDO-30 for STEMI

DIDO 30 2.001

STEMI is one of the true medical emergencies.  We all know that the sooner our patient gets revascularisation, the better they do.  We’ve known this for years.  In a very nice meta-analysis, Eric Boersma showed how the survival benefit from thrombolysis decayed exponentially with time from symptom onset.  That relationship’s so marked that if we were to give thrombolysis to a a patient with STEMI 30 minutes after their symptoms started, we’d save 30 lives for every 1,000 patients treated.  If we managed to get there just a minute earlier, we’d save an extra 2 lives per 1,000 patients treated.  And if we managed to get the thrombolysis in just 5 minutes earlier, we’d save an extra 11 lives per 1,000 treated.  As you can see from the pic below, there’s a similar story with primary PCI.

The relationship between time to PCI and survival in STEMI
The relationship between time to PCI and survival in STEMI

A few years ago when we were still routinely prescribing thrombolysis for patients with STEMI, Emergency Departments really owned this problem.  We had targets and quality indicators and everyone was focused on getting the quickest door to needle time.  Now, in the age of primary PCI, you can’t help but feel that we’ve lost ownership of the problem.  It’s become the cardiologists’ domain.  And maybe – just maybe – we’ve taken our eye off the ball when it comes to getting fast revascularization.  In Greater Manchester, our local data suggest there might be some truth in that.

CTB (Call to balloon time) for STEMI in Greater Manchester.  Direct transfers are those taken straight to the Cath Lab by the ambulance service.  Indirect transfers are those who pass through the ED.
CTB (Call to balloon time) for STEMI in Greater Manchester. Direct transfers are those taken straight to the Cath Lab by the ambulance service. Indirect transfers are those who pass through the ED.

Now, clearly there are reasons why it takes longer to get revascularization if you pass through the ED.  The cases tend to be more complex, the diagnoses more subtle, the patients are sicker.  You’ve also got the problem that patients simply walk in, unannounced, amid the masses of other patients with more minor ailments.  BUT – if there’s one area we should focus on if we want to improve the care we provide for patients with STEMI, clearly it should be for the ‘indirect’ transfers.

Some people might say that everyone should just go directly to the Cath Lab.  But that’s just impossible.  Patients still walk in to the ED with STEMI.  And paramedics won’t spot every diagnosis.  The subtle ones – the challenging ones – will still be our domain.  And our local data suggest that it’s still a big problem for EDs.  Almost half of all patients with STEMI still pass through the ED.

[DDET The DIDO-30 Project]

In Greater Manchester, we think we can do better – so we started the DIDO-30 project.  In this project we aim to get the Door In, Door Out (DIDO) times down to below 30 minutes for all patients with STEMI in the ED.  How can we do this?  Well, part of it is about putting STEMI back on the agenda, getting people to think about it, providing education.  And part of it is about thinking through our pathways, identifying where we might make the marginal gains that will make a huge difference to our patients.


[DDET What ‘marginal gains’ can we make?]

There are loads of possibilities.  In this mini series, we’ll talk about some of them in detail.  To get the ball rolling, let’s talk about something dead simple but dead important – recording ECGs.  If you don’t record an ECG quickly, you can’t achieve a good time.  Clearly, it’d be ideal if all patients have a 12-lead ECG recorded before they even get to the ED.  But that won’t happen when patients continue to self-present with STEMI.  International guidelines tell us that an ECG should be recorded within 10 minutes of arrival in the ED.

That gives us quite a challenge, especially given that we’re mainly talking about patients who walk in to the ED.  How can we differentiate those with STEMI from the masses of other patients?  There are several ways we might achieve that.  In this blog post, we’ll look at just one of them…


[DDET ECG at triage]

Primary triage in Christchurch, New Zealand (post-earthquake, 2011)
Primary triage in Christchurch, New Zealand (post-earthquake, 2011)

In Christchurch, New Zealand, they have a great system.  When patients walk in to the ED, the first person they see is a triage nurse who completes a primary triage.  If the patient’s stable, they then register before a secondary triage takes place.  The primary triage makes sure that the sickest patients can be whisked off and treated without any delays.  For patients with possible STEMI, that means that a trained nurse will almost certainly identify them and have an ECG recorded right away.

For other departments, there are reasons why primary nurse triage either isn’t feasible or isn’t desirable.  At Central Manchester, we can have so many patients  arriving that queues build up for triage very easily.  We’d rather at least know who those patients are by booking them in quickly.  Our target is to achieve triage within 15 minutes of arrival.  If we achieve that, you’ll have noticed that 15 is greater than 10 – so we still won’t be able to get an ECG within 10 minutes of arrival for patients with possible STEMI.  We dealt with that by arranging for those patients to have an “immediate ECG”.

The immediate ECG

This means that patients who have a primary complaint of non-traumatic chest pain will be given a red card by reception staff, which says “Immediate ECG”.  This acts as a kind of baton, which is given to the patient.  The patient is then asked to immediately hand the card to a member of the clinical staff.  That person must then either record an immediate ECG or hand it on (usually to a Clinical Support Worker).  Using this strategy, we managed to go from achieving a door to ECG time of less than 10 minutes in around 30% of our patients to around 70% of our patients.

The ‘immediate ECG’ strategy isn’t without its problems.  Staff can get disillusioned by having to rush to record ECGs in patients who clearly look fine.  Medically untrained reception staff can’t be expected to know how to identify patients with heart attack, which means you need a simple rule.  We restricted our criteria to non-traumatic chest pain in patients aged over 30 years, using evidence gained in the derivation of the Graff decision rule.


[DDET What else could help?]

So far our DIDO-30 project has led to a lot of ideas about how we might improve our Door in, Door Out times.  They include:

  • Stop clocks, which will be started when patients have a diagnostic ECG for STEMI.  The time itself isn’t the most meaningful stat.  It’s the fact that the staff have a visual reminder that the clock is ticking!
  • Senior ECG sign off.  We encountered a number of cases of ECG misinterpretation, often by junior medical staff.  We therefore implemented senior sign off, whereby every ECG recorded on arrival is taken to a registrar or consultant for immediate interpretation and action where necessary.  This has to go hand in hand with ECG training for the juniors though – and we’re planning to develop an e-learning package so that the juniors can have their competency formally assessed, which would enable them to sign ECGs
  • Direct activation of the Cath Lab without involving a cardiologist.  We do this for unequivocal cases with no clear contra-indication to immediate PCI
  • STEMI leads at each ED.  This gives a named person responsibility for improving times – and a link for the regional team
  • Regular feedback on local data.  This is a work in progress for us.  If we can get hold of regular data, disseminating it regularly so that everyone knows how they’re performing can only help


[DDET Treating STEMI is just like Formula One]

I really love the analogy that treating STEMI is just like a Formula One pitstop.  Have you seen a Formula One pitstop?  If not, check out this video…

This was a world record from Ferrari at the Japanese grand prix in 2013.  It took just 1.95 seconds.  In that time, they’ve directed the car in, stopped it, jacked it up, changed all four tyres, jacked it down, cleared the driver to go and then he’s driven off.  Now, compare that to how they did it in 1950…

To get to 1.95 seconds, the team has to think through every step to cut out wasted time.  They have one person guiding the car in and controlling the jack.  They have a team of four ‘wheel nut’ guys loosening the wheels, a team of four ‘wheels off’ guys taking off the old wheels and another team of four ‘wheels on’ guys to put on the new ones.  They work together so closely and they practice, practice, practice.

When was the last time you practised managing a STEMI in your ED?  In situ sim, anyone?!

Top ten tips for In Situ Sim at St.Emlyns.


[DDET The DIDO Challenge]

So, let’s finish with a challenge.  What are your ideas to improve DIDO times?  How does your ED work like a Ferrari pitstop?  How quickly can you record an ECG?

And how quickly can you get from DI to DO?

All the best!


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Cite this article as: Rick Body, "Good times part 1: DIDO-30 for STEMI," in St.Emlyn's, April 3, 2015,

12 thoughts on “Good times part 1: DIDO-30 for STEMI”

  1. Great post Rick have you heard of anywhere using self check in style and getting DIDO 30? I know Hull does anyone?

    1. I’m not sure. I don’t think anyone in Greater Manchester is using self check in – certainly not the sites I’ve visited. It would make it more challenging unless you have an automated system to alert staff that the patient needs an immediate ECG.

  2. Great article. Pleased to note that we already have most of the marginal gains leading to DIDO-30 in our unit. The main thing that we do not have is PPCI on site so we are dependent on the ambulance service getting the patient out in time as well to a HAC 60 miles in any direction – 150 mins is tough to make and I’m frequently reflective on whether our patients are getting the best (evidence based) deal and whether we should be lysing more of these patients – how long do you give your ambulance to arrive before resorting to the needle: 30 + 10? 30 + 20?

    1. I’m glad David raised this important question that afflicts any remote non-PCI centre. These commentaries (as usual come) from a high volume referral centre.

      In our institution, all the aforementioned initiatives already occur – ECG within 10 min for all patients triaged with ‘chest pain’, senior ECG review and ED-activated ‘Code STEMI’. Anything anything after this are marginal gains We have a highly engaged cardiology unit which also means all the line-ball and equivocal cases (not conventionally eligible for lysis) are likely to get a cath. Nonetheless, we still need to be reminded that the NNT is much smaller for these low-risk groups anyway.


      There is inadequate guidance (and evidence) for remote facilities about the right reperfusion strategy where we already know the baseline outcome are already poorer. If you had a patient with an acute anterior MI who arrives within 30 minutes of a rural hospital, would you choose to thrombolyse (and virtually abort the infarct) or wait for the retrieval service who might take 2 hours to get you to a cath centre. No researcher is properly asking the question because now the conventional answer now is cath, cath, cath whatever the circumstances.

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  4. Hi David and Derek,

    Thanks a lot for taking the time to reply. You make really good points. In Greater Manchester the DIDO-30 project covers all of our local hospitals, of which there are 12 (more now that we’re also covering Lancashire) and I’ve connected with 9 of them for this project so far. The issues around secondary transfer are really important. Although I work in a tertiary centre, we also have to deal with secondary transfers on occasion because the out of hours Heart Attack Centre service is shared between two tertiary centres in the area.

    We split the DIDO-30 time into two: 22 minutes for the ED to call for an ambulance to transfer the patient and 8 minutes for the ambulance response. This is important because, if we do fail to hit the 30-minute DIDO time, we need to know which area to focus on: ambulance response times or ED care.

    Derek, you asked the 6 million dollar question: at what point do you give thrombolysis over PPCI if there’s a delay? Actually, NICE took a really good look at this in the STEMI guidance. You can find an awesome summary of the evidence for clinical and cost-effectiveness here:

    The relevant section begins on page 42. NICE’s bottom line is that, if there is a 120 minute delay to PPCI, then thrombolysis becomes preferable. This is mainly based on two meta-regression studies by Boersma and Pinto (2006), and it seems to agree with the conclusions of a later study by Pinto (2011).

    Interestingly, though, the study by Pinto in 2006 ( suggested that this might not be a one size fits all time. For patients aged <65 years with anterior STEMI, the time at which thrombolysis became superior to PPCI appeared to be as little as 40 minutes!

    That's more than a 4-fold difference compared to non-anterior STEMI in an >65 year old, which I think re-iterates the urgency of that situation for any revascularisation.

    All the best,


    1. Thanks for the reply Rick. IIRC (without looking at the link, cause it’s late) DANAMI-2 was clear about the 120 min crossover between benefit for PPCI v fibrinolysis. The reason I quoted 150 mins as a cutoff is because that is the target time we work to in my region. A cynic would say that this is because that how long it takes to get to a HAC from Aldeburgh and EVERYONE must have access to PPCI equitably, whatever the evidence might say but I’m too young to be cynical yet…

      DocXology is correct about the push for cath. I would expect to be intensely questioned by a HAC cardiologist if I lysed a STEMI and then sent them to the HAC for potential rescue PPCI these days, despite the evidence above. Our region and my gaff in particular had excellent results from pre- and in-hospital thrombolysis and some of the best STEMI outcomes in the country prior to the fixation with the balloon. We protested heavily when lytics were being removed due to the distances and time involved getting patients to a HAC (which in our view was not based in evidence) to the point that the cardiac tsar had to perform a review. I still have concerns about this.

      Certainly I am greatly concerned about anyone who is shocked after a STEMI – ambulance service are reluctant to take to a HAC lest the patient deteriorate or die on the way, intensivists won’t facilitate transfer with ambulance service unless tubed but HAC won’t accept with tube in place etc etc. I know I’m slightly off topic at this point but as our EPs de-skill because we see “routine” STEMIs so rarely, I worry about the care of the STEMI patient who wanders in the front door, who is complicated or who is REALLY sick as I am concerned they are at risk of a worse outcome than 5 years ago. We have recently built an elective PCI facility and one can only hope we can persuade the commissioners of the need for a primary facility in East Suffolk and North-East Essex (pop ~400,000) in the medium term.

      In the meantime I think I’ll be stocking more rTPA next time pharmacy ask.



    2. More relevant is not door-to-revascularisation, but symptom-to-revascularisation. The decision making process is going to be different between a patient who walks through the door 30 minutes into their infarct compared to at six hours.

      1. Hi Derek,

        I agree – definitely. We’re measuring DIDO time because that’s what we can affect in the ED – but symptom – revasc time is a much more meaningful predictor of outcome overall.

        Patients presenting at >12h are excluded from analysis in our DIDO project.

        Thanks for all your insightful comments – they’re always greatly appreciated and make the blog much better!


  5. Another important intervention here to reduce delays is a state wide 24 hr hotline that provides immediate advice to rural GPs for patients with suspected ACS. There is a standardised ACS assessment tool, POC testing and the GP can fax the ECG to a cardiologist. This can also be linked in with our state retrieval service.

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