POSED - Prehospital Optimal Shock Energy for Defibrillation

Each year, the UK ambulance services attempt to restart the hearts of 30,000 people who have suffered cardiac arrest (when the heart stops beating). Performance of good chest compressions (CPR) and, where appropriate, delivery of an electric shock to the heart (defibrillation) are the only proven methods of reviving these patients. Defibrillators (electric shock machines) can deliver a range of shock strengths (low, medium or high). Because we don’t currently know the best shock strength to deliver, there is variation between UK ambulance services.

POSED is a feasibility study, necessary to help ensure time and money would be well spent on a full-scale trial. This involves:

• Programming defibrillators to deliver different shock strategies. All of these shock strengths are currently used in UK ambulance services.
• Finding the ‘recruitment rate’ by comparing the number of patients included with the number who could have been included (from 999 call records).
• Tracking patients’ condition in hospital for the following 30 days.

90 participants, recruited over 2 years

The primary objective of the study was to establish whether it is feasible to conduct a large-scale definitive trial by establishing the number of eligible patients and the number recruited.

The trial is now complete. Please see Publications for links to the published trial results.