CT scans – coming soon to an ambulance near you?

Back in the dark ages, when I first entered the ambulance service, stroke was something that was not treated with any particular degree of urgency.  Dispatch was typically without lights and sirens, as was transport, and the feeling was that the damage was done and little more could be gained for these patients.  Fast forward a few years, and we are racing lights and sirens to strokes prior to urgent transport to designated stroke centres for treatment – we are treating brain attacks, not CVA or stroke!  All because we have that wonderful drug, tissue plasminogen activator (tPA) to bust the clots and save the day.  Now comes the next evolution in stroke care – CT and thrombolysis in the back of the ambulance!

Well… maybe not.  This is an interesting pilot study from Germany (a system which often runs with emergency physicians on the cars) to see how quickly tPA could be administered to stroke victims.  The premise is that the sooner the tPA is given, the better.  On the face of it, that doesn’t sound like an unreasonable assumption: most conditions show improvement the sooner intervention is instituted after all, and tPA seems to be the treatment of choice for occlusive strokes.

Having equipped an ambulance with a CT scanner, and staffed it with a neurologist, radiographer and a paramedic (someone has to drive!) they sent the unit to cases that were flagged as stroke through calltaking.  It was subsequently found that the door to needle time could be reduced from nearly 100 minutes to about 60.

Sounds great.  However it is probably worth having a look at the fundamental concept of this study: that tPA is beneficial in stroke.  I suspect that many paramedics will not be aware of the controversy that rages over the use of tPA for stroke.  We are instructed to transport expediently to a designated stroke centre, with early notification to allow for the neuro team to be ready.  9 times out of 10 the patient will get an urgent CT and more often than not (assuming the stroke is not haemorrhagic of course) tPA will be administered.  I have certainly never seen any soul searching on behalf of the neuro doctors as to whether it is the right thing to do, and so was unaware for quite some time of the controversy that had been brewing.

However, this year the latest and greatest tPA in stroke trial, the IST-3 trial was published, and glancing at the abstract (as most of us do) it would seem to be a raging success: “For the types of patient recruited in IST-3, despite the early hazards, thrombolysis within 6 h improved functional outcome. Benefit did not seem to be diminished in elderly patients.”  That sound pretty clear cut doesn’t it?  Only it turns out it’s not as simple as that.

It seems that indeed there is no statistically significant benefit in giving tPA found in this trial: treatment with tPA failed to reduce mortality or morbidity, which was the primary outcome measure in this study (36.5% alive and independent versus 35% in the control arm at six months).  What’s more, it seems there is no correlation between the time tPA is given and the supposed benefit to patients.  So how was this conclusion that tPA is of benefit reached?  It beats me!  However, fortunately for us all, we have the brilliant mind of David Newman to enlighten us.  It seems that the authors dredged back through their data using a strange stastical method that would not commonly be used and found some categories of patients in whom there was a trend towards a better outcome.  An outcome that doesn’t mean that they are alive and independent (the only real outcomes that matter) doesn’t seem to be ‘better’ to me, especially in light of the catastrophic harms that can come from using this drug.

So where does this leave us, the paramedics who are taking these patients to stroke centres?  Well, if you are a braver paramedic than I, you could perhaps front your friendly local neurologist and demand some answers.  However, like it or not, tPA for stroke is the standard of care and it falls to us to play our part in providing that care in the best way possible.  This means doing what we can to reduce door to needle time for stroke.  The other thing to consider is: we do know that early and aggressive rehabilitation IS of benefit to stroke victims.  The sooner they are able to deal with things like swallowing, the less likely they are to die from aspirating their meds.  Physical therapy helps get people up and moving and increases their independence and quality of life.  These benefits are not in any doubt.

To get the benefit of rehabilitation patients need to be taken to hospitals with specialist services – stroke centres.  So while there is doubt about the efficacy of some hospital based intervention, I don’t think that there is any doubt that good quality care from paramedics with expedient transport to a suitable hospital can still be of benefit.  Make sure you cover the basics well:

  • Consider stroke mimics and get baselines of vitals signs, including (most importantly) a blood sugar level.
  • Consider the need for intensive care backup.  Of course, there is nothing further that an IC paramedic can do, unless there is airway compromise that you cannot manage on your own.  I suspect that having to intubate a stroke patient is probably not a good prognostic sign…
  • Start an IV on the way.  Maybe two.  Opinions vary, but I am aware that some neurologists prefer a larger cannula for their contrast studies in CT.  Of course you don’t need to try and be a hero, just get in what you can where you can (I’ll rant about IV placement another time).
  • Alert the hospital that you are coming in with a stroke patient.  Be succinct and clear in your radio report – you are not giving them a full handover, they don’t need to know when the patient last saw their GP or what they had for breakfast (there’s another topic for a rant).  They just need to know what cubicle to get ready and which team to page.
  • Grab the patient details to give to the clerks as this will speed registration of the patient.
  • Above all, look after your patient.  Keep them warm, keep them comfortable and spend some time talking to them and their family on the way to hospital.  This is a terrifying situation for the patient and their family to be in.  Most people have a fair idea of what to look forward to post stroke, and it is not often a rosy scene.

So ends my first real blog post.  Let me know what you think.  Too much or too little?  Too complex or too simple?  Feedback is good, so let me know what you think, and what you would like to see in the future.

For those who are interested, my primary sources for the info on IST-3 are Amit Maini’s wonderful post on his blog EDTCC and David Newman’s superb, brain-frying deep dive podcast and editorial from SmartEM.  My thanks to both of these guys for their work.

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