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HeMS McLachlan: Quality of bystander cardiopulmonary resuscitation (CPR) in out of hospital cardiac arrest (OHCA): development and validation of a measure

Faculty: Health, Medicine and Social Sciences

Supervisors: Dr Sarah McLachlan; Prof Hilary Bungay; Dr Tom Keeble

Location: Chelmsford

The interview for this project is expected to take place on Wednesday 24 April.

Apply online by 3 March 2024

Out of hospital cardiac arrest (OHCA) is a major international public health challenge. Incidence in Europe is between 67 to 170 per 100,000 inhabitants (Gräsner et al., 2021), and in the United Kingdom there are over 30,000 OHCAs each year (British Heart Foundation, 2023).

Survival rates are low: a meta-analysis of global survival reported that 8.8 percent of adult patients survive to hospital discharge and only 7.7 percent survive to one year (Yan et al., 2020).

Rates are similar in Europe, with survival to hospital discharge averaging eight percent (Gräsner et al., 2021). Locally, survival rates for OHCA patients attended by the East of England Ambulance Service NHS Trust were reported at 5.8 percent for 2022.

The ‘chain of survival’ describes a sequence of actions that maximise likelihood of survival following OHCA (British Heart Foundation, 2023). Of critical importance in the chain of survival is cardiopulmonary resuscitation (CPR) (Giugni et al., 2018). Survival and favourable outcome in OHCA increase between two- and fourfold with early bystander CPR (Holmberg et al., 2000; Kragholm et al., 2017).

Early CPR following OHCA is often performed by public bystanders, defined as persons not responding as part of an organised emergency response system (Perkins et al., 2015). Reflecting its fundamental importance, there are national and international initiatives to train the public in CPR and the use of automated external defibrillators.

Although the importance of bystander CPR is widely recognised, little is known about the quality of CPR (Gyllenborg et al., 2017). This is important to address, as the effect of early bystander CPR on survival depends on the quality of CPR performed (Wik et al., 1994).

Existing measures for evaluation of the quality of basic life support (BLS) have been designed for retrospective assessments from video recordings and data from training manikins rather than real-life scenarios (van Dawen et al., 2018). Further, attempts to describe quality of bystander CPR in real-life OHCA have not been comprehensive in the indicators of quality included.

European Resuscitation Council 2021 Guidelines on BLS (Olasveengen et al., 2021) and a systematic review (Chen et al., 2019) have highlighted heterogeneity across studies in CPR quality measurement.

The international Utstein reporting template provides a structured framework to report on OHCA and compare emergency medical services (Perkins et al., 2015). This template includes bystander CPR as a reporting element but does not incorporate assessment of quality.

Further, clinical research exploring the effectiveness of other interventions for OHCA has employed a dichotomous measure of bystander CPR without accounting for quality of CPR provided (Scales et al., 2017; Perkins et al., 2019; Perkins et al., 2015). It is difficult to draw conclusions on the effectiveness of interventions for OHCA without controlling for effects of bystander CPR quality.

This project will address this by developing and validating a measure of quality of bystander CPR for use in real-life scenarios.

The first stage will be a literature review on quality of bystander CPR. Findings will inform the development of a modified Delphi study (McKenna, 1994) with an expert panel, to establish consensus on quality indicators for the measure and a scoring system.

Representatives of key stakeholder groups will be invited to participate in the Delphi process, for instance, the International Liaison Committee on Resuscitation. A simulation study using video recordings or virtual reality films will be used to assess inter- and intra-rater reliability of the measure with ambulance service personnel.

A prospective observational study will then be conducted to validate and refine the measure, using technology such as GoodSAM to provide emergency call handlers with access to video footage of bystander CPR and enable collection of data on CPR quality in real-life scenarios.

Predictive validity of the measure will be assessed by using this data to predict OHCA outcomes, including return of spontaneous circulation, survival to hospital and survival at 30 days.

The project will be supported by Essex & Herts Air Ambulance (EHAAT), which has recently established a Centre for Excellence with a focus on OHCA. The student will benefit from additional guidance from two clinical advisors within EHAAT.

The project will be ideally suited to a candidate from an allied health professional or social science background. Experience of quantitative data analysis is desirable.

If you would like to discuss this research project please contact Sarah McLachlan: [email protected]

Apply online by 3 March 2024

Funding notes

The successful applicant for this project will receive a Vice Chancellor’s PhD Scholarship which covers the tuition fees and provides a UKRI equivalent minimum annual stipend for three years. For 2023/4 this was £18,622 per year. The award is subject to the successful candidate meeting the scholarship terms and conditions. Please note that the University asserts the right to claim any intellectual property generated by research it funds.

Download the full terms and conditions.