Use of Prehospital RSI predicts survivors after out of hospital cardiac arrest
Here is the article
What was the objective of the authors ? : To examine the relationship between advanced airway management and survival in a prehospital care system with RSI capability. Their hypothesis was that those patients who required RSI for prehospital intubation would be more likely to survive than those intubated without RSI drugs because of an underlying better prognosis.
How did they do this ? : Retrospective cohort analysis of a single large metropolitan EMS system in Seattle, between 2007-2011 using cardiac arrest registry and a separate advanced airway registry.
What did they find ?: Those who did not get intubated had the best survival rates (71% left hospital). Those who got intubated with prehospital RSI did next best (48% left hospital). Those who got intubated without RSI did worse ( 11% left hospital)
What on earth does this all mean? :
Why do you need RSI to intubate a clinically dead person you ask? Good question..well this paper found that sometimes..in fact not infrequently you DO need RSI drugs to intubate someone in cardiac arrest! Why? Well think about it…it all depends on how long a person is in cardiac arrest for. Its not like the heart suddenly stops flow and everything stops working right? The paper notes that in almost half of arrest victims, there is still agonal gasping soon after collapse as a result of ongoing brainstem activity. And if you start CPR immediately and restore some flow to the brainstem, then its not inconceivable that airway reflexes can be maintained even in full cardiac arrest. And here is where this paper makes sense…immediate CPR, restored brain perfusion..these are all things that likely contribute to better outcomes in cardiac arrest. So paradoxically the need to use RSI drugs to intubate is an associated factor that predicts those who are going to do better.
Now why does anyone care about this at all….well there have been prior prehospital studies ( notably this one by Hasegawa et al) to suggest that intubation was making things worse for cardiac arrest patients..not better as we all thought for years!
This paper refutes that assertion, saying that its not the intubation itself that is causing the worse outcomes, its the fact that if you can intubated a dead person without RSI drugs, they are of course going to do badly regardless!
Limitations of study : No supraglottic airway use employed during study period. Self reported airway registry data. Not easily extrapolated to other prehospital/EMS systems who do not have RSI capability.