Sometimes you just feel like a bit of a fool. Like today when I wrote the post below and then asked Dr May to have a look at it. Can you guess her response? You might if you love #FOAMed because she pointed out that Brent Thoma has already blogged on this paper back in October and to be honest you should go over there right now and read his post. It’s fantastic and has more content and rationale than mine. I did think about binning this post, but it’s such a lovely subject and with due credit to Brent I am posting it for completeness (in my head anyway).
So, if you want a revision piece, a link to an amazing video of cardiac resuscitation and the St.Emlyn’s perspective then read on…..
…….Oh how I love a bit of drama in the resus room. A life or death situation saved by the simple, rapid and expert techniques of the emergency physician. Something like the precordial thump for example. You know the drill.
A monitored patient arrests in resus with VF on the monitor, you recognise the life threatening situation and apply a few thousand newtons of force through the ulna border of your hand to the patient’s sternum.
A flicker on the monitor followed by sinus rhythm and an awakening patient means that you are truly awesome and worthy of the title ‘resuscitationist’.
It’s not even in all the guidelines anymore , yet it still holds an appeal for some (Ed- it must be the drama). Really though? Does this actually work? Do is make a difference that often and indeed could it do more harm than good?
These are all good questions addressed in an interesting article from Australia (featuring the rather awesome Stephen Bernard from the Alfred). As always, have a look at the abstract but also make sure that you read the full paper if you can get access (not #FOAMed 🙁 ).
[DDET How did they manage to do this study?]
Our Australian colleagues have a great resource to study cardiac arrest outcomes in the form of the Victorian Ambulance Cardiac Arrest Registry which has produced some really interesting research in recent years. Such databases allow researchers to look back for factors which may be associated with survival or death. This type of research is helpful when looking at large populations but it’s not the same as an interventional trial such as an RCT. It is essentially observational data that tells us what has happened but not necessarily why or whether factors are causally linked or just associated.
Having said that, for hypothesis generation and for the observation of rare events databases are fantastic. [/DDET]
[DDET What’s a precordial thump again??]
This is a great bit of video. I love the fact that the team work quietly, efficiently and fabulously to get a great outcome……., I’m just no longer sure about what happens at 2:33 !
[DDET Who was studied?]
This is a study of adult cardiac arrest patients in Melbourne, Australia over 9 years. In that time the ambulance service attended just under 30,000 cardiac arrests with 1379 patient records showing a cardiac arrest witnessed by paramedics. Of these 434 had monitored cardiac arrest with VF or VT.
434 is a fair number of patients, although that’s under 50 a year, and of the 434 only 103 cases (or on average less than 9 a year) had a precordial thump recorded. So although this is a long term, well recorded study the number of patients in whom the intervention was 1, possible and 2, delivered is quite small. [/DDET]
[DDET What did they find?]
The main outcome is the success of a precordial thump, but let’s stop and think about what we mean by success. Does it mean a return of spontaneous circulation, a reduction in complications or a neurologically intact survival benefit. Clearly the last is most important to our patients, but we may have to settle for a proxy outcome.
Interestingly those patients who received a precordial thump were more likely to have multiple arrests (28% vs 36.9% p=0.09) and less likely to achieve ROSC after first shock (57/8% vs 47.8% p=0.09).
Not only that but several patients had a deterioriation of their rhythm (i.e. to a non-shockable rhythm) following a thump. Although some patients did get a ROSC, overall the patients were twice as likely to deteriorate as improve.
Sadly, because of the small numbers none of this is statistically significant, but it’s enough to make me think and wonder why we are not seeing any benefit. [/DDET]
[DDET Are the results reliable?]
This is always worth asking in database studies as the quality of data ‘out’ depends on the quality of the data ‘in’ (Ed – Garbage in = Garbage out). The authors recognise this and accept that not all thumps could have been recorded and that changes to rhythm post thump may not have been accurately recorded.
We must also consider the long time line for this study leading up to the de-emphasis of precordial thumps in VF in 2011.
Whilst these factors may have affected the results my view is that an successful PT would be more likely to be recorded than an unsuccessful one so if anything the results should skew in favour of PT. [/DDET]
[DDET What’s the bottom line here?]
With guidelines changed in 2011 to de-emphasise the PT it is highly unlikely that we are going to see any better evidence in this area and although the paper has limitiations it is truly time to abandon the precordial thump (and we don’t mean the awesome Chris Nickson aka @Precordialthump). [/DDET]
[DDET So what next?]
Aha, I blogged this paper because I was on the look out for another VACAR paper and it’s just been published in the last hour…….expect a blog post very soon 😉 [/DDET]