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Key information

Title: Out-of-Hospital Cardiac Arrest Outcomes (OHCAO)

Chief Investigator: Professor Gavin Perkins

Sponsor: Warwick Medical School, National Ambulance Service Medical Directors

Funder: British Heart Foundation, Resuscitation Council (UK)

Registration Number: ISRCTN10428536


Cardiac arrest is the term used to describe sudden cessation of heart function. After cardiac arrest occurs, blood stops being circulated to the vital organs and consciousness is lost within seconds. Unless resuscitation is started promptly death will occur within a few minutes. Each year about 30,000 people receive resuscitation for an Out-of-Hospital Cardiac Arrest (OHCA) in the United Kingdom (UK). Only one in every twenty people that have a cardiac arrest survive to go home from hospital.

Information collected by the Department of Health has shown large differences in the number of people that survive an OHCA depending on where they live. In simple terms people in some parts of the country are twice or three times more likely to survive than in other areas.

This project is working with UK Ambulance Services to try and find out the reasons behind such big differences in survival. It has develop a standard way of collecting information about OHCA and for finding out if a resuscitation attempt was successful.

The study uses existing information collected by ambulance services during the course of their routine duties. Information about individuals that receive resuscitation for OHCA will be securely transferred to researchers at the University of Warwick.

The information will be used to obtain a better understanding of why survival rates vary so widely. It will work out which are the most effective treatments and help ambulance services improve the quality of care for victims of OHCA.

The project has received approvals from both the National Research Ethics and Confidentiality Advisory Group to collect sensitive data via the secure web server. Only data that has been mapped/transformed and agreed by the Trusts will be imported.

Sample size:

OHCAO is a prospective study, collecting information on all out-of-hospital cardiac arrests in the UK.

Data is provided by the Ambulance Services.

Primary outcome:

Survival to discharge.


Current funding to 2023.


Search the OHCAO website:


Tel: 02476 572725


Warwick Clinical Trials Unit
Warwick Medical School
University of Warwick
Gibbet Hill Road

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