Abstract 236: A Multi Center Study of Awareness During Resuscitation

Awareness during anesthesia is characterized by auditory perceptions, pain, and dream like states and associated with PTSD. Few studies have examined awareness during cardiac arrest. Although, these two phenomena share similarities, there are also differences. In particular during CA, patients may report visual perceptions (‘seeing’ and recalling events). Furthermore, some experiences are associated with the scientifically imprecise entity of ‘near death experiences’ (NDE). Methods: A prospective cohort study at 25 hospitals in the US, UK and Austria to determine the incidence of awareness (i.e. visual or auditory) during CA as well as the characteristics of patients’ recollections was conducted. We further examined the feasibility of testing the accuracy of visual and auditory recollections using standardized tests by pre-installing shelves containing images as well as instructing research staff to provide set auditory cues during CPR where possible. Survivors underwent a structured interview which included questions on visual and auditory impressions as well as the Greyson questionnaire to quantify experiences typically classified as NDE (score >=7) Results: 2060 cardiac arrest events were recorded with a reported survival of 32% (n=657). 23% (n=152) were interviewed. Information on visual or auditory impressions during CA was available on 89% of interviewed subjects. Of these, 37 % responded that they had experienced visual and/or auditory impressions during their time of unconsciousness and CA. Among those with auditory and/or visual impressions, 70% had a Greyson score >0 and 30% had a Greyson score >=7, consistent with a conventionally defined “NDE”. Two had visual recollections of being able to ‘see’ events, and one accurately described details corresponding with a verifiable period of at least 3-5 minutes of CA. Placement of images corresponded with only 33% of all CA locations. The two patients did not have CA in areas with images. Conclusions: Auditory and/or visual experiences during unconsciousness may be a relatively common phenomenon. Even though these experiences may not reflect the conventionally defined NDE and may be different, they may indicate that consciousness may not cease as expected with cessation of heartbeat during CA