Recently, two sets of guidelines for neuroprognostication following cardiac arrest were released – almost simultaneously.
In a perfect world, two evidence-based guidelines based on the same evidence would be the same. But of course, this isn't actually the case. The guidelines differ significantly.
The Neurocritical Care Society guidelines recommended this general approach:(36949360)
Meanwhile, the Canadian Cardiovascular Society Position Statement recommends this general approach:(37028905)
This illustrates some ugly truths about evidence-based guidelines in general:
- Guidelines are evidence-based, but they also incorporate judgements made by the guideline authors.
- Guidelines are merely guidelines – they don't represent the absolute truth, nor must they be followed rigidly.
Nonetheless, having an organized approach to neuroprognostication post cardiac arrest is enormously helpful. And any such approach should be based on guidelines.
Prior to these two new guidelines, the best guideline for neuroprognostication post cardiac arrest was the 2021 ESICM guideline summarized below.(33765189)
The Canadian guidelines and the ESICM guidelines are actually quite similar. Compared to the ESICM guidelines, the Canadian guidelines include a couple of significant improvements:
- Greater description and incorporation of quantitative CT scan analysis with the grey/white ratio (more on this here).
- Less emphasis on neuron specific enolase (NSE).
Overall the Canadian and ESICM guidelines provide a more detailed algorithm for determining which patients have a poor prognosis, which is useful for clinicians. As such, the Canadian/ESICM guidelines could serve as the backbone for any approach to neuroprognostication.
The neurocritical care society guidelines include both positive and negative prognostic features for outcome. Explicitly incorporating both features is a useful addition to guidelines (rather than merely focusing on poor prognostic indicators).
Below is my current approach to neuroprognostication. This approach is based primarily on the ESICM guidelines, with some updates taken from the Canadian guidelines. Subsequently, positive prognostic features from the Neurocritical Care Society guidelines were added.
Of course, clinical judgement is always needed, with any set of guidelines. In particular, be very wary of confounding factors (e.g., hypothermia to 33C and benzodiazepine or opioid infusions).
Different practitioners and different centers will utilize different approaches. And that's fine. Perhaps the most important aspect is merely having an organized, systematic approach. Of course, any strategy should be utilized thoughtfully, with a thorough understanding of each diagnostic test.
That's it for now. For more discussion on neuroprognostication, see the IBCC chapter here.
Opening image credits: Photo by 愚木混株 cdd20 on Unsplash
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