An ambulance service in special measures is to review whether any patients have been harmed by problems locating defibrillators during emergency calls.

South East Coast Ambulance Service Foundation Trust, which was rated inadequate last month, believes more than 5,000 calls may have been affected since 2013.

Last week HSJ reported the many issues it is experiencing with its computer aided despatch system. One of these was that call operators cannot always accurately locate the nearest defibrillator when dealing with an emergency call involving a possible cardiac arrest. This could mean that members of the public cannot be directed to a nearby defibrillator, which could be used to shock the patient’s heart back to a normal rhythm.

Trust board papers reveal a group is being set up to review whether any patients were harmed by this and to make any suggestions of changes in practice.

It will look at all “red one” calls – the most urgent – over this period and a sample of red two calls, where there were difficulties locating a public access defibrillator. The papers suggest there were only a handful of red one calls possibly affected but 5,588 red two calls.

The group is expected to complete the review by Christmas.

The trust has been criticised in the past for retrospectively checking whether emergency calls were made close to a defibrillator and, if so, counting them as having been “responded’” to. Guidance introduced by NHS England this year makes it clear this can only be counted as a response if the defibrillator is brought to the patient’s side and someone is able to use it.