Previous research work:
Project Title:
A study of the effectiveness and cost effectiveness of Public Access Defibrillation in urban and rural populations in Northern Ireland.
Funding:
- Research and Development
Office of the DHSSPSNI (Department of Health,
Social Services and Public Safety Northern Ireland)
- Engineering &
Physical Sciences Research Council (EPSRC) RCUK Academic Fellowship (2005-2010)
Background:
- Sudden cardiac arrest victims can be saved by administering an electric
current across the heart (defibrillation) with a machine called a
defibrillator.
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With minimal training, automated versions of these devices (called Automated External Defibrillators (AEDs)) can be used by members of public.
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Equipping volunteers from local communities with AEDs may result in life-saving defibrillation treatment being administered sooner, thus increasing a victim's chances of survival.
Purpose:
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The Northern Ireland Public Access Defibrillation (NIPAD) project aimed to assess the benefits of equipping volunteers throughout communities with AEDs. This has been done in three stages:
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by first observing how sudden cardiac arrests occur in different groups of people across two different geographical areas;
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organising and observing the effects of a volunteer-based Public Access Defibrillation trial; and
- using the results from the trial to determine if it would be worthwhile for the NHS in Northern Ireland to organise and fund a full-time project.
Main Findings:
- Stage I Findings:
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Sudden cardiac arrests patients were found to be predominately male (65%).
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The majority of arrests occurred in homes (83%).
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In many cases (53%) the victim had no previous medical history of cardiac disease.
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Not all arrests were witnessed (only 31%).
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The initiation of cardiopulmonary resuscitation (CPR) by bystanders only occurred in 30% of cases.
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Only a small percentage of patients (16%) had an irregular heart rhythm that could respond to defibrillation (known as Ventricular Fibrillation (VF)) upon commencement of treatment.
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Ambulance response times were typically faster in the urban region compared to the rural region.
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Stage II Findings:
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A volunteer-based scheme was set up with over 800 volunteers recruited (police officers and members of the public).
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In this scheme pagers were used to alert volunteers of possible arrests in their locality.
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The level of participation was found to vary between regions and between volunteers themselves.
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The scheme was most successful when a smaller number of enthusiastic volunteers were recruited who were willing to hold an AED for a month or more at a time.
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Volunteers were only paged to a subset of all cardiac arrests (57%/40% in urban/rural region). In the urban region 18/226 (8%) of cardiac arrests were reached by a volunteer before an ambulance compared to 23/122 (19%) in the rural region. None of the 41 victims were resuscitated or survived.
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Response times were compared between the two-periods: the ambulance only response in 2004 was compared to the combined ambulance/Public Access Defibrillation response in 2005/06. Improvements in response were found to be significant. Not all of the improvements can be attributed to the Public Access Defibrillation scheme due to improvements in the ambulance response itself between the two time-periods.
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Stage III Findings:
A Monte-Carlo simulation-based model was built to determine if it would be worthwhile for the NHS in Northern Ireland to organise and fund a full-time project.
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The response-times of volunteers and the emergency ambulances were modelled in order to assess the impact of the scheme.
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The model can quantify the likely number of additional lives that would be saved if Public Access Defibrillation were implemented in different geographical regions.
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It can also assess the scheme’s effectiveness by quantifying the total additional life years gained as a result of Public Access Defibrillation (adjusted for each patient’s quality of life) – given in units of Quality Adjusted Life Years (QALYs) gained.
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Improvements in effectiveness due to the Public Access Defibrillation scheme have been combined with its associated costs to produce the Incremental Cost-Effectiveness Ratio (ICER). The ICER is useful in order to compare the benefits of Public Access Defibrillation to many other different emerging health treatments. Note that due to the element of chance, output estimates are quantified in terms of their mid-values together with a measure of their spread given by the Inter-Quartile Range (IQR).
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Models were run to assess the impact of Public Access Defibrillation schemes over a five year period in two different geographical regions: in the West and South of Northern Ireland.
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In each case the model suggested it was extremely probable that there would be additional survivors as a result of the scheme (97.1% in West; 99.9% in the South).
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The ICER is £48,200/QALY (IQR 33,900 to 85,900) in the West and £40,000/QALY (IQR 30,800 to 56,100) in the South.
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Given these ICERs exceed a threshold set of £30,000/QALY it suggests the scheme would not be the most efficient use of NHS resources.
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However it could start to address the existing imbalance in emergency-response provision found between rural and urban regions.
- Indeed, these results highlight that some potential sub-regions of Northern Ireland may benefit from the scheme more than others.
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