Prevalence of intracranial hemorrhage amongst patients presenting with out-of-hospital cardiac arrest: A systematic review and meta-analysis

Introduction: An unknown proportion of out-of-hospital cardiac arrest (OHCA) is caused by intracranial hemorrhage (ICH). There is uncertainty over the role of early head computed tomography (CT) in non-traumatic OHCA due to uncertain diagnostic yield and ways to identify high-risk patients. This study aimed to identify the prevalence of ICH in non-traumatic OHCA and possible predictors.

Methods: PubMed, EMBASE, and the Cochrane library were searched from inception to January 2022. Data extraction and quality assessment were independently reviewed by two authors. Meta-analyses estimated the prevalence of ICH amongst OHCA patients and pre-specified subgroups and geographical settings. Subgroup analysis were used to explore potential clinical predictors.

Results: 23 studies involving 54,349 patients were included. The pooled ICH prevalence was 4.28% (95%CI: 3.31-5.24). Asia had a significantly larger risk ratio (RR = 3.93, P value < 0.0001) than Europe. The ICH subgroup was significantly more likely to be female (OR: 2.16; 95%CI: 1.10-4.26), and less likely to experience shockable rhythms compared with non-shockable rhythms (OR: 0.22; 95% CI: 0.04-1.22), achieve ROSC prior to arrival (OR: 0.27; 95%CI: 0.10-0.77), and survive to discharge compared to those without ICH (OR: 0.26; 95%CI: 0.11-0.59).

Conclusions: One in twenty OHCA have ICH at the time of presentation. An early head CT scan should be strongly considered after return of spontaneous circulation (ROSC), especially in patients who are female, with non-shockable rhythm and did not attain ROSC prior to arrival. These finding should influence clinical protocols to favor routine scans especially in Asia where prevalence is higher.