Critical Illness Related Cardiac Arrest (CIRCA): an Investigation of the Incidence and Outcome of Cardiac Arrest Within Intensive Care Units in the United Kingdom

Cardiac arrest is often categorised by location, out-of-hospital or in-hospital (IHCA), as there are important differences in population characteristics and aetiology. The National Cardiac Arrest Audit (NCAA) was established to audit resuscitation teams in response to IHCA, and collects information about patient characteristics, resuscitation processes, and patient outcomes. However, it does not audit IHCAs that are not attended by the resuscitation team.

Critically ill patients managed in ICUs are experiencing failure of one or more organs and therefore more intensive and invasive therapies are needed to support these failing organs. As a result, ICUs have higher nursing and medical staffing ratios, and monitoring is usually continuous. Moreover, the skill mix of the multidisciplinary team is geared to advanced life support. Thus, the risk of cardiac arrest occurring, the involvement (or not) of the resuscitation team, and the probability of return of spontaneous circulation are all likely to be different to other IHCAs.

Accurate data on cardiac arrests in ICU are lacking and the investigators do not know how many IHCA occur in ICU in the UK, nor is the impact of an IHCA in ICU on outcome known. In addition, it is not known if these IHCAs in ICUs represent an unavoidable consequence of critical illness or, more importantly, whether they can be predicted and/or prevented.

CIRCA is a prospective, multi-centre observational cohort study nested in the Case Mix Programme (CMP) and NCAA national clinical audits. The investigators aim to determine the incidence and outcomes of IHCA in UK ICUs and explore associated risk factors with ICU and hospital survival and quality of survival following hospital discharge.