The report focuses on the equipment and support systems that are used by and assist ambulance crews in diagnosing a STEMI. The findings highlight key issues concerning not only the ECG equipment’s ability to recognise a STEMI, but also the ambulance crews’ recognition and the level of clinical support available to them during interpretation. We heard from ambulance crews that it was easy to interpret an obvious or “barn door” STEMI from a 12 lead ECG. However, it was more challenging to identify one where patients had less obvious signs and symptoms.
Patient story
The report highlights three patient stories illustrating the difficulties of ECG interpretation for ambulance crews. One case involved a 33 year old male who called an ambulance after experiencing chest pain and vomiting. His heartbeat was recorded as faster than usual via an ECG, but a STEMI was not recognised by the ambulance crew and their clinical impression was that it was non-cardiac chest pain due to possible anxiety, his age and other stressors. He was taken to the local emergency department and once he was there a consultant identified that the patient was experiencing a STEMI. The patient went into cardiac arrest and sadly died before he could be transferred to a specialist centre. The Trust incident report noted that if the STEMI had been recognised, the crew could have discussed the patient’s case with the specialist centre team and been taken to the right place for emergency treatment.
Recognising a STEMI
Our investigation identified that the monitor/defibrillator auto interpretation algorithms were not designed to replace clinical decision making by a suitably experienced clinician but may be used[DO1] [DF2] by ambulance crews to assist or help confirm the diagnosis of a STEMI. However, the report emphasises that the accuracy of algorithms dropped significantly for ‘borderline’ cases which is when ambulance crews need the most assistance. A review of nine ambulance trust investigations into a missed STEMI showed there was only one incident where the auto-interpretation had stated ‘STEMI’. In the other incidents, the auto-interpretation had stated there was an abnormality of some description.
When examining the support crews have access to, we identified risks in relation to further clinical advice and support and communication. Ambulance services have set up clinical support hubs, which were initially to provide advice to newly qualified paramedics. They have evolved to provide advice and second opinions to all ambulance crews. The investigation identified that staff on those clinical advice lines may not have any additional specialist education, training or experience in ECG interpretation. They also couldn’t access all information relating to the patient’s medical history to then provide holistic support to the crews.
Furthermore, the investigation identified that the specialist centres treating STEMIs (known as primary percutaneous coronary intervention (PPCI) had limited capacity to provide ECG advice to ambulance crews as they are not commissioned to provide this service. HSSIB’s report highlights that some PPCI centres had implemented two-way communication, to allow for the provision of specialist cardiology advice about suspected STEMI to ambulance crews. This is beneficial for ensuring the patient gets to the right point of care quickly and pressure on surgical teams is also reduced.
Safety recommendations
The report makes two recommendations. One is focused on procurement and ambulance trusts assessing devices to make sure the equipment is suited to their needs. The second recommendation is aimed at amending the service specifications for PPCI centres to enable communication with ambulance crews and shared decision making about patients with a suspected STEMI.
Investigator's view
“As the patient cases in our report demonstrate, delays in treating a STEMI can cause extensive heart damage and lead to severe harm or death. It is essential that ambulance crews are supported in recognising these emergencies—whether through ECG devices that reflect real-world use or through timely access to expert advice when symptoms are less clear. Our findings and recommendations focus on strengthening these areas to ensure that patients experiencing such a distressing event receive the right treatment, in the right place, at the right time.”
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