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4-year PhD Studentship: Development of a multi-component intervention to prevent delirium after cardiac surgery.

   Faculty of Health Sciences

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  Dr Maria Pufulete, Dr Ben Gibbison  No more applications being accepted  Self-Funded PhD Students Only

About the Project

There are 32,000 episodes of cardiac surgery in the UK per year. Delirium is the most common complication after cardiac surgery, affecting 25-50% of patients (translating to between 8,000 and 16,000 episodes of delirium)[1]. It is a disturbance in attention /cognition developing over a short period of time as a direct consequence of another medical condition (e.g. surgery). It develops in the first days after surgery and is characterised by confusion /loss of awareness. Patients typically become agitated or quiet and withdrawn. Delirium is traumatic for patients and families and challenging for staff to manage. It is associated with prolonged hospitalisation, increased mortality and substantial psychological morbidity (including post-traumatic stress disorder[2] and long-term cognitive dysfunction)[3]. Delirium adds around 20% to the inpatient costs of the surgery. Prevention of delirium offers the opportunity to avoid both the clinical and cost implications of delirium after cardiac surgery. Multiple interventions have been trialled with the aim of preventing / reducing delirium after cardiac surgery, including pharmacological and non-pharmacological. However, the optimal strategy has not been defined. Although there are some care-packages which seek to prevent delirium after cardiac surgery, none of these have an evidence-based design, development, and testing.

Aims and Objectives

The aim of the proposed project is to design a complex intervention to prevent delirium after cardiac surgery. Specific objectives are to:

  1. Describe perioperative practice in cardiac surgery centres in the UK.
  2. Scope the literature to identify potential barriers/facilitators to implementation of different components of a complex delirium prevention intervention.
  3. Develop a logic model for a multicomponent delirium prevention intervention for cardiac surgery patients.
  4. Define the complex intervention using formal consensus methods of all stakeholders including patients.
  5. Implement the intervention in 1-2 local centres and conduct a process evaluation.


We recently received funding to conduct a systematic review and network meta-analysis of RCTs to identify pharmacological and non-pharmacological interventions that are effective at preventing delirium (complete March 2023). The proposed project is organised in work packages (WP).

WP1. SURVEY: all UK cardiac surgery centres to describe perioperative practice relevant to delirium prevention and specific interventions/protocols currently in use to prevent delirium.

WP2. SCOPING LITERATURE REVIEW: qualitative and quantitative studies to identify potential barriers and facilitators related to implementation of the specific components into the cardiac surgery pathways.

WP3. LOGIC MODEL: the systematic review will be used to develop a logic model including all interventions identified as efficacious (these will be the components of the complex intervention) to describe the causal relationship between them and how they interact to prevent delirium.

WP4. FORMAL CONSENSUS: consensus development conference and modified Delphi survey using information from WP1-3 to define the complex intervention by relevant stakeholders (patients, families, healthcare professionals, commissioners).

WP5. FEASIBILITY OF IMPLEMENTATION WITH PROCESS EVALUATION: the complex intervention defined in WP4 will be implemented in 1-2 local cardiac surgery centres. The process evaluation will include surveys and qualitative studies with patients who received the intervention and healthcare professionals who delivered it.


Cardiac surgery delirium post-operative complications qualitative research systematic review meta-analysis process evaluation intervention development.

How to apply for this project

This project will be based in Bristol Medical School - Translational Health Sciences in the Faculty of Health Sciences at the University of Bristol.

Please visit the Faculty of Health Sciences website for details of how to apply

Funding Notes

This project is open for University of Bristol PGR scholarship applications (closing date 25th February 2022)
The University of Bristol PGR scholarship pays tuition fees and a maintenance stipend (at the minimum UKRI rate) for the duration of a PhD (typically three years but can be up to four years).


1. Whitlock EL, Vannucci A, Avidan MS. Postoperative delirium. Minerva Anestesiol 2011; 77: 448-56.
2. Wolters AE, Peelen LM, Welling MC, et al. Long-Term Mental Health Problems After Delirium in the ICU. Crit Care Med 2016; 44: 1808-13.
3. Girard TD, Jackson JC, Pandharipande PP, et al. Delirium as a predictor of long-term cognitive impairment in survivors of critical illness. Crit Care Med 2010; 38: 1513-20.
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