Abstract 387: Awareness and Cognitive Activity During Cardiac Arrest

Abstract

Background: While 50% of cardiac arrest (CA) survivors report negative psychological outcomes including post-traumatic stress disorder (PTSD), depression, and anxiety, 10% report a positive transformational outcome associated with recall of cognitive activity and 2-3% report external awareness during CPR. Though, often referred to using the poorly defined term of near-death experiences (NDE), this aspect of CA survivorship remains ill understood. Methods: In an ongoing prospective study (AWARE-II) we piloted methods to administer audiovisual stimuli to test implicit and explicit memories using a tablet computer with images and sounds delivered during on-going CPR. Results: Among 465 in-hospital CA lasting >5 min, 44 (9%) survived and 21 were interviewed. Of these, 4 (19%) reported explicit memories, including (internal) cognitive processes such as feeling peace, joy, and a perception of seeing relatives, while other memories were suggestive of (external) awareness e.g. hearing people talking, drugs given. One of 19 correctly recalled the audio stimuli given during CPR, but none identified the visual test. In this limited sample, there were no signs of implicit learning. We then compared these to 22 self-reported memories from a registry of CA survivors, Additional themes emerged as follows: 1) a sense of joy and peace (95%), perception of a light (86%), a tunnel (59%), a review and judgment of major life events including a person’s own actions and intentions (54%), and an overall feeling of positive transformation after the event (95%). Conclusion: External awareness and internal cognitive activity may occur during CA. However, it is unclear whether explicit recall sufficiently describes the entirety of cognitive processes during CA, or whether implicit memories may also form. In some survivors, memories lead to greater life-meaning and a positive transformation, which contrasts with negative psychological outcomes such as PTSD. In this context, in place of NDE a more appropriate term might be transformative experience of death (TED). Further studies, are needed to delineate the role of implicit and explicit learning and how cognitive activity during CPR may relate to brain resuscitation quality and overall psychological outcomes.