What is the best shock energy for out-of-hospital cardiac arrest?
| ISRCTN | ISRCTN16327029 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN16327029 |
| IRAS number | 277693 |
| Secondary identifying numbers | CPMS 47559, IRAS 277693 |
- Submission date
- 26/01/2021
- Registration date
- 23/06/2021
- Last edited
- 15/03/2024
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Circulatory System
Plain English summary of protocol
Background and study aims
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). Currently, less than 10% of people survive. 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. If we can find the best shock energy levels, we can restart hearts more quickly and save more lives.
POSED is a feasibility study that will help researchers to make good decisions about a full-scale trial to make sure that time and money would be well spent.
Who can participate?
Patients who have been treated for cardiac arrest
What does the study involve?
Patients are put into different groups to receive different shock strategies. All of these shock strengths are currently used in UK ambulance services. All surviving patients will be invited to take part in the follow up which happens 30 days after the cardiac arrest. This will involve a research paramedic scoring how well they have recovered either by talking with the patient or by reading their medical notes.
What are the possible benefits and risks of participating?
Since all of the shock strategies are currently used by NHS Ambulance services it is not thought that being in the study presents any additional risk. It is not known whether any of the strategies may be better than the others. Although meeting with the Research Paramedic will take time, participants and their families may find it useful to be able to ask questions about the resuscitation process. Some may find this difficult or upsetting to talk about, but Research Paramedics are experienced in providing support and guidance to people in this situation. The relatives of non-survivors, who receive a letter telling them that their relative was in the study, may find this causes additional emotional burden at an already difficult time. We have taken advice from many experts, patients and members of the public about the best way to word the letter and the best time to send it.
Where is the study run from?
Warwick Clinical Trials Unit (UK)
When is the study starting and how long is it expected to run for?
May 2019 to February 2023
Who is funding the study?
National Institute for Health Research (NIHR) (UK)
Who is the main contact?
Ms Jes Rai, POSED@warwick.ac.uk
Prof. Gavin Perkins, cturesources@warwick.ac.uk
Mrs Helen Pocock, helen.pocock@warwick.ac.uk
Contact information
Scientific
Warwick Clinical Trials Unit
University of Warwick
Gibbet Hill Campus
Coventry
CV4 7AL
United Kingdom
 ORCID ID |
0000-0001-7648-5313 |
|---|---|
| Phone | +44 (0)2476 715173 |
| Helen.pocock@warwick.ac.uk |
Public
Warwick Clinical Trials Unit
University of Warwick
Gibbet Hill Campus
Coventry
CV4 7AL
United Kingdom
| Phone | +44 (0)2476 573369 |
|---|---|
| POSED@warwick.ac.uk |
Scientific
Warwick Clinical Trials Unit
University of Warwick
Gibbet Hill Campus
Coventry
CV4 7AL
United Kingdom
| ORCID ID |
0000-0003-3027-7548 |
|---|---|
| Phone | +44 (0)2476 150925 |
| cturesources@warwick.ac.uk |
Study information
| Study design | Interventional randomized controlled feasibility study |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised controlled trial |
| Study setting(s) | Other |
| Study type | Treatment |
| Participant information sheet | ISRCTN16327029_v1.8_24Mar2021.pdf |
| Scientific title | A feasibility study of Prehospital Optimal Shock Energy for Defibrillation (POSED) |
| Study acronym | POSED |
| Study objectives | Is it feasible to conduct a randomised, pragmatic clinical effectiveness trial to identify the optimal energy for defibrillation? |
| Ethics approval(s) | Approved 19/01/2021, London Harrow REC (Level 3, Block B, Whitefriars, Lewins Mead, Bristol, BS1 2NT, UK; +44 (0)207 104 8098; harrow.rec@hra.nhs.uk), REC ref: 20/LO/1242 |
| Health condition(s) or problem(s) studied | Cardiac arrest |
| Intervention | Current intervention as of 08/01/2024 to 11/07/2022: This study will involve putting defibrillators into one of three groups to deliver one of the three different shock strategies in current UK use. All other treatments and care will be given in the usual way. The three groups will treat the same number of patients (30 each). To try to make sure the groups are the same to start with, each defibrillator will be put into a group by chance (randomly). Whether patients receive the shock strategy requested, what other care the patient received and whether the patients survive to hospital discharge and to 30 days will be collected for the three groups. It is possible to collect this data without the patient having to do anything, as long as the patient does not object to us collecting this data from their medical notes. By looking at ambulance service 999 call records the number of patients that could have been included will be compared to the actual number included to find the ‘recruitment rate’. All patients who survive the cardiac arrest will be contacted by the Research Paramedic in hospital once they are on the ward and the initial emergency has passed. The Research Paramedic will explain the trial and that the patient has been included. The Research Paramedic will give the patient an information sheet to read. When the patient has had time to read the sheet the Research Paramedic will answer any questions and check with the patient if they are happy for us to continue to collect data and take part in the follow up. If someone does not have the mental capacity to consent, the Research Paramedic will inform their next of kin, known as the personal consultee, and ask if they think that the patient would be happy to take part. All surviving patients will be invited to take part in the follow up which happens at hospital discharge and at 30 days after the cardiac arrest. This will involve a research paramedic scoring how well they have recovered either by talking with the patient or by reading their medical notes. Members of the public have helped us to decide how we should let patients and their relatives know that they have been included in the study. Sadly, most of the patients in the study will not survive. We were not sure how to let the relatives of these patients know that they were included in the study. Members of the public told us that we should write a letter. They have helped to design these letters so that they are easy for patients and relatives to understand. _____ Previous intervention as of 11/07/2022: This study will involve putting defibrillators into one of three groups to deliver one of the three different shock strategies in current UK use. All other treatments and care will be given in the usual way. The three groups will treat the same number of patients (30 each). To try to make sure the groups are the same to start with, each defibrillator will be put into a group by chance (randomly). Whether patients receive the shock strategy requested, what other care the patient received and whether the patients survive to hospital discharge and to 30 days will be collected for the three groups. It is possible to collect this data without the patient having to do anything, as long as the patient does not object to us collecting this data from their medical notes. By looking at ambulance service 999 call records the number of patients that could have been included will be compared to the actual number included to find the ‘recruitment rate’. All patients who survive the cardiac arrest will be contacted by the Research Paramedic in hospital once they are on the ward and the initial emergency has passed. The Research Paramedic will explain the trial and that the patient has been included. The Research Paramedic will give the patient an information sheet to read. When the patient has had time to read the sheet the Research Paramedic will answer any questions and check with the patient if they are happy for us to continue to collect data and take part in the follow up. If someone does not have the mental capacity to consent, the Research Paramedic will inform their next of kin, known as the personal consultee, and ask if they think that the patient would be happy to take part. All surviving patients will be invited to take part in the follow up which happens at hospital discharge and at 30 days after the cardiac arrest. This will involve a research paramedic scoring how well they have recovered either by talking with the patient or by reading their medical notes. I will also speak to the ambulance staff involved to find out what makes it easier or more difficult to record what happens to patients after treatment. Where I find difficulties, I will try to work out how I can reduce these difficulties so that a large study will work. Members of the public have helped us to decide how we should let patients and their relatives know that they have been included in the study. Sadly, most of the patients in the study will not survive. We were not sure how to let the relatives of these patients know that they were included in the study. Members of the public told us that we should write a letter. They have helped to design these letters so that they are easy for patients and relatives to understand. _____ Previous intervention: This study will involve putting defibrillators into one of three groups to deliver one of the three different shock strategies in current UK use. All other treatments and care will be given in the usual way. The three groups will treat the same number of patients (30 each). To try to make sure the groups are the same to start with, each defibrillator will be put into a group by chance (randomly). Whether patients receive the shock strategy requested, what other care the patient received and whether the patients survive to 30 days will be collected for the three groups. It is possible to collect this data without the patient having to do anything, as long as the patient does not object to us collecting this data from their medical notes. By looking at ambulance service 999 call records the number of patients that could have been included will be compared to the actual number included to find the ‘recruitment rate’. All patients who survive the cardiac arrest will be contacted by the Research Paramedic in hospital once they are on the ward and the initial emergency has passed. The Research Paramedic will explain the trial and that the patient has been included. The Research Paramedic will give the patient an information sheet to read. When the patient has had time to read the sheet the Research Paramedic will answer any questions and check with the patient if they are happy for us to continue to collect data and take part in the follow up. If someone does not have the mental capacity to consent, the Research Paramedic will inform their next of kin, known as the personal consultee, and ask if they think that the patient would be happy to take part. All surviving patients will be invited to take part in the follow up which happens 30 days after the cardiac arrest. This will involve a research paramedic scoring how well they have recovered either by talking with the patient or by reading their medical notes. I will also speak to the ambulance staff involved to find out what makes it easier or more difficult to record what happens to patients after treatment. Where I find difficulties, I will try to work out how I can reduce these difficulties so that a large study will work. Members of the public have helped us to decide how we should let patients and their relatives know that they have been included in the study. Sadly, most of the patients in the study will not survive. We were not sure how to let the relatives of these patients know that they were included in the study. Members of the public told us that we should write a letter. They have helped to design these letters so that they are easy for patients and relatives to understand. |
| Intervention type | Device |
| Pharmaceutical study type(s) | |
| Phase | Not Applicable |
| Drug / device / biological / vaccine name(s) | Defibrillator |
| Primary outcome measure | Current primary outcome measure as of 08/01/2024 to 21/07/2023: Recruitment rate calculated from the number of eligible participants and the number recruited by the end of the study _____ Previous primary outcome measure as of 21/07/2023: Recruitment rate calculated from the number of eligible participants and the number recruited in the study by 24 months _____ Previous primary outcome measure: Recruitment rate recorded as the number of eligible participants enrolled in the study by 24 months |
| Secondary outcome measures | Current secondary outcome measures as of 31/07/2023: 1. Treatment adherence rate recorded as the proportion of patients receiving the allocated treatment prior to hospital admission 2. Data completeness of clinical outcomes, defined as the proportion of enrolled patients who by the end of trial have data relating to: 2.1. Return Of Organised Rhythm capable of sustaining a pulse (ROOR) assessed using defibrillator data recorded 2 min post-shock 2.2. Resulting rhythm (VF/pVT/PEA/asystole) assessed using defibrillator data recorded 2 min post-shock 2.3. Re-arrest rate (re-fibrillation) assessed using defibrillator data recorded during the out-of-hospital phase of resuscitation 2.4. Survived event (return of spontaneous circulation (ROSC)) using ambulance records at hospital handover 2.5. Survival assessed using hospital records at hospital discharge and at 30 days post cardiac arrest 2.6 Neurological outcomes (mRS score) measured using the Rankin Focused Assessment at hospital discharge and 30 days post cardiac arrest 3. Data completeness of process outcomes: 3.1. Quality of CPR (chest compression rate, chest compression depth, chest compression fraction, pre-shock pause, post-shock pause) measured using defibrillator data from the out-of-hospital phase of care 3.2. Number of shocks measured using defibrillator data from the out-of-hospital phase of care 3.3. Advanced airway applied (% advanced airway applied and % supraglottic airway or endotracheal tube) measured using patient clinical records from the out-of-hospital phase of care 3.4. Intravenous medicines administered (% cases where medicines administered and % adrenaline, amiodarone) measured using patient clinical records from the out-of-hospital phase of care 3.5. Transported to hospital (% transported) measured using Ambulance Service data from the out-of-hospital phase of care _____ Previous secondary outcome measures as of 21/07/2023: 1. Treatment adherence rate recorded as the proportion of patients receiving the allocated treatment prior to hospital admission 2. Data completeness of clinical outcomes, defined as the proportion of enrolled patients who by the end of trial have data relating to: 2.1. Return Of Organised Rhythm capable of sustaining a pulse (ROOR) assessed using defibrillator data recorded 2 min post-shock 2.2. Resulting rhythm (VF/pVT/PEA/asystole) assessed using defibrillator data recorded 2 min post-shock 2.3. Re-arrest rate (re-fibrillation) assessed using defibrillator data recorded during the out-of-hospital phase of resuscitation 2.4. Survived event (return of spontaneous circulation (ROSC)) using ambulance records at hospital handover 2.5. Survival assessed using hospital records at hospital discharge and at 30 days post cardiac arrest 2.6 Neurological outcomes (mRS score) measured using the Rankin Focused Assessment at hospital discharge and 30 days post cardiac arrest _____ Previous secondary outcome measures: 1. Treatment adherence rate recorded as the proportion of patients receiving the allocated treatment prior to hospital admission 2. Data completeness of clinical outcomes, defined as the proportion of enrolled patients who by the end of trial have data relating to: 2.1. Neurological outcomes (mRS score) measured using the Rankin Focused Assessment at 30 days post cardiac arrest 2.2. Return Of Organised Rhythm capable of sustaining a pulse (ROOR) assessed using defibrillator data recorded 2 min post shock 2.3. Resulting rhythm (VF/pVT/PEA/asystole) assessed using defibrillator data recorded 2 min post shock 2.4. Re-arrest rate (re-fibrillation) assessed using defibrillator data recorded during the out-of-hospital phase of resuscitation 2.5. Survival assessed using hospital records at 30 days post cardiac arrest 3. Data completeness of process outcomes: 3.1. Quality of CPR (chest compression rate, chest compression depth, chest compression fraction, pre-shock pause, post-shock pause) measured using defibrillator data from the out-of-hospital phase of care 3.2. Number of shocks measured using defibrillator data from the out-of-hospital phase of care 3.3. Advanced airway applied (% advanced airway applied and % supraglottic airway or endotracheal tube) measured using patient clinical records from the out-of-hospital phase of care 3.4. Intravenous medicines administered (% cases where medicines administered and % adrenaline, amiodarone) measured using patient clinical records from the out-of-hospital phase of care 3.5. Transported to hospital (% transported) measured using Ambulance Service data from the out-of-hospital phase of care |
| Overall study start date | 04/05/2019 |
| Completion date | 28/02/2023 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Adult |
| Sex | Both |
| Target number of participants | Planned Sample Size: 90; UK Sample Size: 90 |
| Total final enrolment | 38 |
| Key inclusion criteria | Current inclusion criteria as of 21/07/2023: 1. Patients suffering OHCA attended by a crew from participating ambulance service 2. Resuscitation attempted and shock delivered as per Resuscitation Council (UK) and JRCALC guidelines _____ Previous inclusion criteria: 1. Patients suffering OHCA attended by a crew from participating ambulance service 2. Resuscitation attempted and shock indicated as per Resuscitation Council (UK) and JRCALC guidelines |
| Key exclusion criteria | Patients known or suspected to be under 18 years old |
| Date of first enrolment | 22/03/2022 |
| Date of final enrolment | 28/02/2023 |
Locations
Countries of recruitment
- England
- United Kingdom
Study participating centre
Bicester
OX26 6HR
United Kingdom
Sponsor information
University/education
Research and Impact Services
Coventry
CV4 7AL
England
United Kingdom
| Phone | +44 (0)2476522746 |
|---|---|
| wmssponsorship@warwick.ac.uk | |
| Website | http://www2.warwick.ac.uk/ |
"ROR" |
https://ror.org/01a77tt86 |
Funders
Funder type
Government
No information available
Results and Publications
| Intention to publish date | 31/12/2024 |
|---|---|
| Individual participant data (IPD) Intention to share | Yes |
| IPD sharing plan summary | Available on request |
| Publication and dissemination plan | Planned publication in a high-impact peer-reviewed journal. |
| IPD sharing plan | The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. De-identified data underlying results reported in the article will be made available for 5 years following article publication. Proposals for data access should be directed to Prof. Gavin Perkins at cturesources@warwick.ac.uk. Investigators require approval for the use of the data by an independent review committee identified for this purpose. Requestors will need to sign a data-sharing agreement. |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Participant information sheet | version v1.8 | 24/03/2021 | 23/06/2021 | No | Yes |
| Protocol file | version v2.0 | 15/04/2021 | 19/07/2021 | No | No |
| Protocol file | version 3.0 | 10/11/2021 | 11/07/2022 | No | No |
| Statistical Analysis Plan | version 0.2 | 27/06/2022 | 11/07/2022 | No | No |
| Protocol article | 06/10/2022 | 17/10/2022 | Yes | No | |
| Protocol file | version 5.0 | 12/12/2022 | 30/01/2023 | No | No |
| HRA research summary | 28/06/2023 | No | No | ||
| Results article | 09/02/2024 | 15/03/2024 | Yes | No |
Additional files
Editorial Notes
15/03/2024: Publication reference and total final enrolment added.
08/01/2024: The following changes have been made:
1. The interventions were updated.
2. The primary outcome measure was updated.
31/07/2023: The following changes have been made:
1. The overall study end date has been changed from 30/12/2023 to 28/02/2023 and the plain English summary updated accordingly.
2. The secondary outcome measures have been changed.
21/07/2023: The following changes have been made:
1. The participant inclusion criteria have been changed.
2. The primary outcome measure has been changed.
3. The secondary outcome measures have been changed.
05/04/2023: The recruitment end date was changed from 30/06/2023 to 28/02/2023.
30/01/2023: Uploaded protocol v5.0 (not peer-reviewed) as an additional file.
17/10/2022: Publication reference added.
11/07/2022: The following changes have been made:
1. The intervention has been changed.
2. An updated protocol has been uploaded.
3. A SAP has been uploaded.
25/03/2022: The following changes have been made:
1. The recruitment start date has been changed from 16/03/2022 to 22/03/2022.
2. The study contact has been updated and the plain English summary has been updated accordingly.
14/03/2022: The recruitment start date was changed from 01/03/2022 to 16/03/2022.
14/02/2022: The recruitment start date was changed from 15/02/2022 to 01/03/2022.
07/02/2022: The recruitment start date was changed from 01/02/2022 to 15/02/2022.
10/01/2022: The recruitment start date has been changed from 10/01/2022 to 01/02/2022.
17/11/2021: The recruitment start date was changed from 01/11/2021 to 10/01/2022. The contact details were updated.
15/09/2021: The recruitment start date was changed from 01/09/2021 to 01/11/2021.
05/08/2021: Internal review.
21/07/2021: Internal review.
19/07/2021: The following changes were made to the trial record:
1. The recruitment start date was changed from 01/07/2021 to 01/09/2021.
2. Uploaded protocol (not peer-reviewed) as an additional file.
23/06/2021: The participant information sheet has been uploaded.
26/01/2021: Trial’s existence confirmed by National Institute for Health Research (NIHR).
