New in EM 011: How often does consciousness occur during CPR?

4 Jun

Originally Published on RCEM Learning Podcast October 2017

As part of the RCEM Learning Podcast I record reviews of recent literature with Dave McCreary. We’ve been doing this for about a year now and you can hear them all on the RCEM Learning Podcast each month. I’d like to have them here and searchable on this site too so I’ll be posting the ones I find most relevant here. You can hear the newest ones by subscribing to the free RCEM Learning Podcast. 

Audio:

Title: Consciousness induced during cardiopulmonary resuscitation: An observational study

Author: Olaussen, Jan 2017, Resuscitation

Background:

– There was the fascinating study a few years ago – the AWARE study that looked into the out of body experience where survivors picture themselves rising above their body and watching their resuscitation. They actually studied this and put pictures on shelves that would be out of sight when supine but easily seen if you were able to float above your bed during resus and then asked the survivors if they saw them. Most people didn’t remember anything and the two patients who had the floating experience both had it in areas where they didn’t have the shelf with the picture but for one of them they were able to identify quite a few verifiable details about his resuscitation despite being in VF.

Anyhow… People may be more awake than we think even when they’re dead…

I think most of us have been involved with a cardiac arrest case where the patient kept moving their arms causing all kinds of disruptions while we check the pulse and the monitor to confirm that yes they’re still in VF and now that we’ve stopped CPR they’ve stopped moving. We turn on the LUCAS again and they start moving their arms. In the couple of cases I’ve been involved with they’ve both been the younger acute STEMI patients who have gone on to do quite well.

Methods:

– retrospective review of the victorian cardiac arrest registry (this is Steve Bernard’s baby so it’s fairly high quality data set)

– the main weakness here of course is that they have no systematic means of documenting consciousness and could only identify it if someone happened to write it down

– they actually had a primary outcome of survival to hospital discharge – in other words is movement during CPR a good prognostic factor and something that suggests we should keep going or go for ECPR

Results

– out of 17000 cardiac arrest patients they found 112 (0.7%) relevant patients with possible CPR consciousness

– these people fulfilled all the other good prognostic features (down time, age, rhythm, witness, bystander…)

– 20% of them were described as being combative (can’t blame them)

– 44% survival to discharge here.

– they did look at meds given and found that if patients with CPR induced consciousness got sedation (typically midazolam) then they did substantially worse than those who didn’t. They note in their discussion that this might be due to depressed vasomotor tone and that several regions have developed SOPs that involve a slug of Ketamine if consciousness occurs during CPR.

– only a small number had mechanical CPR (though it’s my very limited experience that you see this more with mechanical CPR)

Bottom Line

– consciousness (or at least purposeful movements) during CPR is a thing albeit quite rare

– if it does happen it’s probably a good prognostic sign

– it can make CPR difficult and sedation is probably needed and benzos might be a bad way to do it

– Kudos to our buddies Justin and Casey on their lit review podcast for highlighting this paper

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