Clinical Case 055: Tolchock to the gulliver… part 2 – the evidence

OK on with the case – our man has been intubated and is stable enough for a venture to radiology….

]CT shows…

If I a looking at this CT in my hospital, far from help, or a neurosurgeon it is a bad day.  I think we need to act now and decompress the cranium ASAP, certainly we cannot transfer this chap – just too far.  When I started writing this post I was on-call, and went into theatre to do an appendix, and noticed in the store room at the back of the OR we actually have a box labelled “Burr Hole Kit”  with a drill, some drapes and a drain in it.  Cool, good to know, but seeing the box does make me a more comfortable with the idea.  Turns out there are a lot of emergency neurosurgeries done in remote Australia – with pretty good outcomes.  Treacy published this review of cases out of Darwin in ANZ Journ Surgery 2005.

  • 305 emergency neurosurgical procedures done by general surgeons (not Neuro)
  • Extradurals and chronic subdurals did pretty well
  • Time delay from injury to operation was a significant factor in determining a poor outcome in 48%
So if you are the doc on the spot in the above case – what are you going to do?
I think the right answer is to talk to a Neurosurgeon on the phone ASAP and get some clear advice, instructions and a plan in place early.
The guys at Scancrit posted this on Emergency burr holes featuring an article out of Scand J Trauma Resusc Emerg Med. 2012.  It features a remarkable concise and practical step-step guide to burr holes in the ED for the novice trephinator.  Worth a read – especially if you are in the situation described above!
Ok, lets assume you are going to do burr holes, or alternatively not do them and you want to manage the raised ICP in the ED whilst awaitng transfer.  What is the evidence fo rthe various techniques?  Here we go – summary time:
We use them for brain tumours, meningitis – but do they work for acute traumatic brain injury? A Cochrane review of the data in 2009 looked a few trials, including one big one and found that there was actually an increase in mortality (borderline CI) with steroids – so I think the answer is DONT give them for this indication.
Another Cochrane review in 2009 looked a t a few smallish trails and came up with pretty wide range of data which widely cross the magic 1 for relative risk – so not good data which showed no good benefit for this intervention.  So I think the goal should be normocapnea – most guidelines suggest aiming for low end of normal – which we usually do to stop the patient fighting the ventilator.  But no clear evidence to go lower than 35 mmHg.  You might argue it is OK for a short period whilst you get other therapies in place that do work!
Mannitol is one that I know has been used in Australia in the past. Does it work? The theory is that you can “shrink the brain” using osmotic pressure – however there is also a risk of diuresis and decreasing BP / perfusion.  The Cochrane folks looked at 4 trials which were underwelming in their conclusion – no clear benefit, better than phenobarb, but did not do as well as hypertonic saline.  So I would only give this if the Neurosurgeon insisted.
This is the new thing in the resus literature coming out of the Mid-East war zones. The study by Vialet et al, 2003 that looked at mannitol vs. HTS in the above Cochrane review showed that super-salt did better in terms of ICP control.  Hypertonic saline has also been compared to CSL / Ringer’s with a benefit shown.  So in conclusion hypertonic saline seems the best option in terms of “hyperosmolar therapy”.  Not widely available in remote EDs though!. 
The Ca-Channel blocker nimodipine has been shown to be effective for SAH patients, so how about other intracranial injury….? The RCTs out there unfortunately do not show the same benefit when we look at head injury / trauma patients – so no, not an option in our patient.
The idea is that preventing seizures in acute brain injury, prevent the secondary injury that a fit might cause – sounds like a good idea. does it work? Summary from Cochrane: phenytoin & carbamazepine reduced the number of seizures (NNT ~10), but no clear benefit in terms of mortality – for me this seems good enough – the last thing I want in the scenario above is a convulsion, makes things that bit more complex and a loading dose of phenytoin is relatively cheap and easy in most small EDs.  So I would do this in discussion with the receiving team.
We have seen an explosion in cooling for medical VT / VF arrest. And the concept of neuroprotective cooling make sense from the POV of neonatal resus and other scenarios. So does it work with traumatic brain injury? There have been a series of trails which have mixed results – all close to being negative / null. the best trails failed to show a benefit. For me this means no go – in the context of trauma cooling carries too many other risks esp. coagulopathy – just too hard, not enough benefit for the risk / work involved.
This one was a big surprise to me on my review of the literature. Progesterone is postulated to decrease the oxidative stress on the brain in severe trauma – and there are 3 small RCTs that have all shown significant benefits not much downside.  It is still early days – and not something we need to start in the ED, but it seems like this might be going mainstream in Neuro ICU in he future?
OK, that is the wrap up on severe head injury – the acute management is largely an evidence free zone – check out the Twitter conversation for opinions from the world of experts.  There is a bit of evidence around specific interventions and some things that I think we should know when making decisions and planning treatment in our small EDs.  On the whole though the moral of the story was summed up nicely by Dr Nickson – “avoid hypoxia, avoid hypotension”
Good luck with your next head trauma, hope this has helped! Casey

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