Incidence, predisposing factors, management and survival following cardiac arrest due to subarachnoid haemorrhage: a review of the literature.

INTRODUCTION: The prevalence of cardiac arrest among patients with subarachnoid haemorrhage [SAH], and the prevalence of SAH as the cause following out-of-hospital cardiac arrest [OHCA] or in-hospital cardiac arrest [IHCA] is unknown. In addition it is unclear whether cardiopulmonary resuscitation [CPR] and post-resuscitation care management differs, and to what extent this will lead to meaningful survival following cardiac arrest [CA] due to SAH.

AIM: We reviewed the literature in order to describe; 1.The prevalence and predisposing factors of CA among patients with SAH 2.The prevalence of SAH as the cause of OHCA or IHCA and factors characterising CPR 3.The survival and management of SAH patients with CA.

MATERIAL AND METHODS: The following sources, PubMed, CinAHL and The Cochrane DataBase were searched using the following Medical Subheadings [MeSH]; 1. OHCA, IHCA, heart arrest and 2. subarachnoid haemorrhage. Articles containing relevant data based on the abstract were reviewed in order to find results relevant to the proposed research questions. Manuscripts in other languages than English, animal studies, reviews and case reports were excluded.

RESULTS: A total of 119 publications were screened for relevance and 13 papers were included. The prevalence of cardiac or respiratory arrest among all patients with SAH is between 3-11%, these patients commonly have a severe SAH with coma, large bleeds and evidence of raised intracerebral pressure on computed tomography scans compared to those who did not experience a CA. The prevalence of patients with SAH as the cause of the arrest among OHCA cases vary between 4 to 8% among those who die before hospital admission, and between 4 to 18% among those who are admitted. The prevalence of SAH as the cause following IHCA is low, around 0.5% according to one recent study. In patients with OHCA survival to hospital discharge is poor with 0 to 2% surviving. The initial rhythm is commonly asystole or pulseless electrical tachycardia. In IHCA the survival rate is variable with 0-27% surviving. All survivors experience brief cardiac arrests with short latencies to ROSC.

CONCLUSION: Cardiac arrest is a fairly common complication following severe SAH and these patients are encountered both in the pre-hospital and in-hospital setting. Survival is possible if the arrest occurs in the hospital and the latency to ROSC is short. In OHCA the outcome seems to be uniformly poor despite initially successful resuscitation.