Out-of-Hospital Cardiac Arrest Registry algorithm improves outcomes, efficiencies and is cost-effective

Two-year outcomes from the Out-of-Hospital Cardiac Arrest Registry have demonstrated that the implementation of an algorithm – developed after analysing data from the registry – improves patient outcomes, workforce efficiencies and is cost-effective. We spoke to Registry Lead and Consultant Cardiologist, Dr Thomas Keeble (Essex Cardiothoracic Centre), about the aims of the registry, the implementation of the algorithm and how it has transformed patient care in the region.

“The data for cardiac arrest patients in the UK in general terms lacks fidelity and makes quality improvement in this lethal condition a challenge. The currently collected data is the Warwick Out of Hospital Cardiac Arrest Registry, which is essentially a collection of ambulance service data, merged with mortality data from the ONS data set. While useful for public health purposes it lacks any diagnostic, expected mortality risks, and does not include any information about the hospital treatment or ultimate diagnosis.”

This means there is a significant data missing, ranging from what treatment did they get and where were they treated and by who, why were they taken to hospital A and not hospital B etc. To fill this data vacuum, the research team at Essex Cardiothoracic Centre, working in conjunction with Dendrite Clinical Systems and utilising the company’s intuitive and robust ‘Intellect-Web Registry’ software, developed the British Cardiovascular Interventional Society (BCIS) Out-of-Hospital Cardiac Arrest Pilot Registry. The Registry, records information from the time of cardiac arrest, right through hospital stay and extended follow-up of patients. The Registry started collecting data in October 2022 and now has over 1,000 patient records.

“The initial six-month data allowed us to look at treatment and referral patterns. Using this data, we developed a new pre-hospital conveyance algorithm designed to offer guidance to ambulance staff on which centres to take a patient to if they recover a pulse after an out of hospital cardiac arrest. This pathway diverts patients with a potential higher chance of having a cardiac cause for their arrest and needing acute cardiac care to a cardiac arrest centre where they can receive more specialist cardiovascular care 24 hours a day, 365 days of the year.”

For example, if a patients required a defibrillator for their cardiac arrest, then those patients would definitely be sent to the cardiac centre without discussion. Prior to starting the conveyance algorithm only 44% of these patients were sent to a cardiac centre – that means over 56% of people with a shockable rhythm (a cardiac cause) were incorrectly sent to emergency departments without specialist cardiovascular facilities.

“Our algorithm stipulates that if you have a heart attack on your ECG or you have a shockable rhythm causing your arrest, you come straight to our cardiac centre. If you have a non-shockable rhythm, you go straight to a local emergency department and you can switch between the two, but we want that to be minimal,” he added. “We want you to come to the right place the first time. Before we brought in the algorithm in April 2023, we had an overall survival rate across our population of 18%. After launching the algorithm and looking at our data after 18 months, we increased our survival rate of all comers to 33%.”

Dr Keeble said the response to the algorithm from ambulance staff in particular has been extremely positive, as they now know exactly where to take patients. Previously, they could spend vital minutes speaking to a hospital or a cardiac centre, sending ECGs etc. The algorithm is simple – if there’s a shockable rhythm and you’ve defibrillated them, or they have a heart attack on their ECG – they go to the cardiac centre. As a result, inter-hospital transfers (arriving at an emergency department and then transferring the patients to the cardiac centre) have decreased in two years from 9% (between April 2022 and September 2022) to 2%.

“This fourfold decrease in the number of secondary transfers has not only saved lives, but it has saved money. If you take the patients to the wrong place, you have needlessly wasted precious time and resources – an anaesthetist, nurses, a paramedic crew etc – so for these reasons the algorithm is hugely beneficial. As we are only interested in patients with cardiac issues, we were worried that we might be denying other patients the benefit of coming to a cardiac centre too. However, the Kaplan-Myer curves for the non-shockable rhythms did not change across the whole time period. This shows we are picking the right patients at the right time with cardiac problems to come to our cardiac centre to get the appropriate treatments. The most important thing is that the overall good quality survival has doubled.”

Dr Keeble and his team recently performed a cost effectiveness analysis, which revealed the algorithm saves significant amounts per patient just by getting the right patient to the right place at the right time. The primary saving is due to the reduced costs from a shorter ICU stay. Despite the clear success of the algorithm, there are a number of regions including Wales who are considering adoption of the BCIS OHCA conveyance algorithm.

Some regions are reluctant to adopt the algorithm. The Essex Cardiothoracic Centre was already a busy cardiac arrest centre, the algorithm has resulted in an extra 50 patients a year being admitted to our ICU, but high volume centres are more expert resulting in better patient outcomes.

The majority of patients who die following a cardiac arrest do so from a brain injury due to no blood supply to the brain during the arrest.  Alongside the algorithm Dr Keeble has developed a highly robust OHCA neuro-prognostication team which means that neurological death and futility can be assessed daily with neuro-physiology tests (EEG and SSEP) and expert clinical evaluation in line with European guidance. This too has resulted in a shortened length of stay.

Dr Keeble firmly believes that the success of the Registry is because of the quality of the data and the quality of the people entering the data. He explained a significant amount of work went into developing the Registry, establishing a clear dataset, and ensuring he had colleagues who believed in the project and understood the need for high quality data entry.

“I’ve got dedicated people paid to make it work and as soon as I don’t have that, then I know the data will be prone to error. Another important aspect is the robustness and flexibility of the Registry, because it’s web-based this means that we can have people simultaneously in Southend, Basildon, Chelmsford, Harlow, all putting data in with different codes and different passwords, it has just worked so well.”

Despite the successes of the Registry, in future he may consider making it slightly lighter so it’s more sustainable. As a high-quality research tool, the Registry has served its purpose in the respect that the team has proven that the centralisation of care for these patients improves their outcomes.

“Overall, I think this is an important piece of work – it does show that in the modern NHS you can create better outcomes in complex conditions, and you can save money in complex conditions”, he concluded. “Yes, we have to remember its observational, not randomised data, but we have collected data from all-comers from our region over three years, so it’s hard to ignore.”

According to Dr Keeble, one of the key advantages of using Dendrite’s system was its unique electronic patient-reported outcome measures (ePROMs) facility, that gave his team the ability to assess a patient’s health status (QoL) at a particular points in their follow-up. This is crucial in assessing whether the interventions were improving outcomes in the longer term.

About Dendrite

Dendrite Clinical Systems is a UK-headquartered international company with over a 30-year track record as a specialist provider of secure clinical registries, analysis software and consultancy services for the international healthcare sector, specifically for clinical research, multi-centre real-world studies, observational registries, international, national and hospital clinical databases.

Dendrite has been recognised as a leading provider of clinical registries across various specialties with a unique track record of implementing over 200 major clinical registry systems globally including systems for major research projects for medical device companies, CROs and pharmaceutical companies.