Developing a core outcome set and feasibility trial to test a dysphagia intervention in cardiac surgical intensive care patients

  • Sallyanne Duncan

Student thesis: Doctoral ThesisDoctor of Philosophy


Oropharyngeal dysphagia or swallowing difficulties are common in critical care, affecting approximately 62% of critically ill patients who have been intubated and mechanically ventilated for prolonged periods. Cardiac surgery intensive care patients are one such group at risk of developing swallowing difficulties following prolonged intubation.

Complications of dysphagia include aspiration leading to chest infection and pneumonia, malnutrition, increased length of hospital stay and readmission to hospital. This PhD aims to design a relevant, evidence based intervention for cardiac surgery intensive care patients that is acceptable for delivery and ready for testing in a trial with internationally accepted outcome measures. The project is underpinned by the Medical Research Council’s framework for developing a complex intervention and includes three studies.

Study 1 assessed the evidence by conducting the first systematic review of dysphagia intervention trials in acute and critical care settings. Studies were included if conducted with adults in acute care settings or intensive / critical care settings and were randomised or quasi-randomised controlled trials. The primary outcome was time taken to return to oral intake. Study 2 developed an intervention by discussing systematic review findings and a potential intervention with expert advisors and engaging with clinicians and ex-patients to further refine the proposed intervention. A live national survey was conducted with UK speech and language therapy clinicians working in critical care settings to gather their feedback on the proposed intervention. A focus group was conducted with ex-ICU patients to gather their views and feedback on the proposed intervention also. Study 3 developed the first international core outcome set for critical care dysphagia trials using Delphi consensus methodology. Ex-patients, critical care clinicians and researchers rated outcomes (identified from a number of information sources) in a 2-round online survey.

Three consensus meetings were then conducted to discuss, agree and vote on definitions and measures for the core outcomes identified from the Delphi survey.

The systematic review identified 22 studies (19 stroke, 2 intensive care stroke and 1general intensive care) testing 9 interventions and representing 1700 patients. Swallowing treatment showed no evidence of a difference in the time to return to oral intake (n = 33, MD (days) − 4.5, 95% CI − 10.6 to 1.6, 1 study, P = 0.15) (very low certainty). An intervention for intubated cardiac patients involving sensory electrical stimulation and tongue resistance exercises was designed and deemed acceptable following expert advisory discussion (n=7) and engagement with patients (n=4) and clinicians (n=64). One hundred and sixty participants (researchers, clinicians and ex-patients) from 22 countries
(6 continents) completed a 2-round Delphi study. Six core outcomes were identified: aspiration; severity of aspiration; swallow function; efficiency of cough; pneumonia and mortality. Measures and time points were agreed for five of the six outcomes via consensus meetings.

These three studies culminated in the development of a robust randomised controlled trial protocol with an appropriate intervention and outcome measures that can be taken forward for feasibility testing.

Thesis is embargoed until 31 July 2024
Date of AwardJul 2023
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SponsorsNorthern Ireland Public Health Agency
SupervisorDanny McAuley (Supervisor) & Bronagh Blackwood (Supervisor)


  • Dysphagia intervention
  • critical care
  • systematic review and meta-analysis
  • Core Outcome Set (COS)

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