One out of three bystanders of out-of-hospital cardiac arrests shows signs of pathological psychological processing weeks after the incident - results from structured telephone interviews.

Background: Witnessing an out-of-hospital cardiac arrest (OHCA) is a traumatic experience. This study analyses bystanders` psychological processing of OHCA. We examined the potential impact of bystanders performing resuscitation and the influence of the relationship between bystander and patient (stranger vs. family/friend of the patient) on the psychological processing.

Methods: A telephone interview survey with bystanders, who witnessed an OHCA of an adult patient was performed weeks after the event between December 2014 and April 2016. The semi-standardized questionnaire contained a question regarding the paramount emotion at the time of the interview. In a post-hoc analysis statements given in response were rated by independent researchers into the categories "signs of pathological psychological processing", "physiological psychological processing" and "no signs of psychological distress due to the OHCA".

Results: In this analysis 89 telephone interviews were included. In 27 cases (30.3%) signs of pathological psychological processing could be detected. Bystanders performing resuscitation had a higher rate of "no signs of psychological distress after witnessing OHCA" compared to those not resuscitating (54.7% vs. 26.7%, p < 0.05; relative risk 2.01; 95%CI 1.08, 3.89). No statistical significant differences in the psychological processing could be shown for gender, age, relationship to the patient, current employment in the health sector, location of cardiac arrest or number of additional bystanders.

Conclusions: One out of three bystanders of OHCA suffers signs of pathological psychological processing. This was independent of bystander´s age, gender and relationship to the patient. Performing resuscitation seems to help coping with witnessing OHCA.