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Critical illness, critical care, intensive care, concept analysis
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Jerrard K, O'Neill B, Bradley JM and Connolly B. Examining concepts related to critical illness and the management of critically ill patients: a protocol for a scoping review [version 1; peer review: awaiting peer review]. NIHR Open Res 2026, 6:8 (https://doi.org/10.3310/nihropenres.14140.1)
NOTE: If applicable, it is important to ensure the information in square brackets after the title is included in all citations of this article.
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Examining concepts related to critical illness and the management of critically ill patients: a protocol for a scoping review
[version 1; peer review: awaiting peer review]
PUBLISHED 14 Jan 2026
OPEN PEER REVIEW
REVIEWER STATUS
Abstract
Plain Language Summary
Corresponding author:
Bronwen Connolly
Competing interests:
No competing interests were disclosed.
Grant information:
This project is funded by the National Institute for Health and Care Research (NIHR) under its Health Technology Assessment (HTA) Programme (Grant Reference Number NIHR130454). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care.
Additional funding is provided by the Belfast Health and Social Care Trust Charitable Trust Funds Research (Reference J-2425-505). The Sponsor for the MARCH trial is Belfast Health and Social Care Trust. Funding for the MARCH trial process evaluation is, in part, from the Northern Ireland Public Health Agency (PHA) Research and Development Division (Reference EAT/5781/24), via a Doctoral Fellowship Programme (KJ).
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Copyright:
© 2026 Jerrard K et al.
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
How to cite: Jerrard K, O'Neill B, Bradley JM and Connolly B. Examining concepts related to critical illness and the management of critically ill patients: a protocol for a scoping review [version 1; peer review: awaiting peer review]. NIHR Open Res 2026, 6:8 (https://doi.org/10.3310/nihropenres.14140.1)
First published: 14 Jan 2026, 6:8 (https://doi.org/10.3310/nihropenres.14140.1)
Latest published: 14 Jan 2026, 6:8 (https://doi.org/10.3310/nihropenres.14140.1)
Additional funding is provided by the Belfast Health and Social Care Trust Charitable Trust Funds Research (Reference J-2425-505). The Sponsor for the MARCH trial is Belfast Health and Social Care Trust. Funding for the MARCH trial process evaluation is, in part, from the Northern Ireland Public Health Agency (PHA) Research and Development Division (Reference EAT/5781/24), via a Doctoral Fellowship Programme (KJ).
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Background
Critically ill patients often present with life-threatening, complex, and multifaceted needs, requiring intensive treatment from multiple clinical specialities1. Effective multidisciplinary team collaboration, both across and within specialities, is fundamental to delivering optimised, evidence-based, and high quality patient care2. This is especially relevant in this population as the care pathway of critically ill patients can span a wide variety of settings including the emergency department, intensive care unit (ICU) and high dependency unit, general wards, rehabilitation settings, and ultimately the home/community environment following discharge. Care delivered both before and after ICU admission plays a crucial role in optimising outcomes for patients3,4. However, at each stage of the care pathway, patients may be managed by different teams, often with varying staffing levels and expertise, clinical priorities, professional cultures, and organisational pressures5. These differences can lead to inconsistencies in care delivery, such as variations in treatment decisions, which may impact patient outcomes.
As the primary setting for the management of critically ill patients, the ICU is a distinct geographical and clinical setting, characterised by higher staff to patient ratios, specialised training in the management of critical illness, the use of high-risk and complex interventions, advanced physiological monitoring, and varying levels of care depending on the degree of organ support4. For example, care may range from Level 1 (patients at risk of deterioration or requiring basic support) to Level 2 (those needing support for multiple organs or prolonged respiratory support), and Level 3 (patients requiring advanced respiratory or multi-organ support)6. In such a complex and dynamic environment, a wide range of concepts7 (principles or ideas) may be applied to guide clinical decision-making8. However, when patients transition into or out of the ICU setting these concepts may be inconsistently understood or operationalised differently, resulting in fragmented patient care. A shared understanding of concepts is essential to support effective collaboration across teams, promote consistent use of terminology, and optimise patient outcomes; therefore, they require clear and agreed definitions. A lack of clarity and poor communication may lead to ambiguity, inconsistency in clinical practice, and an increased risk of patient harm5.
One methodological approach used to clarify complex clinical concepts is concept analysis9. This method has been applied in healthcare to define concepts such as clinical decision-making8,10, end-of-life care11, and post-intensive care syndrome12. Different frameworks to concept analysis have been described, including those by Walker and Avant13, Rodgers14, Schwartz-Barcott and Kim, Chinn and Kramer9. These frameworks share some common elements, but also contrast with each other9. For example, both Walker and Avant13 and Rodgers14 emphasise the importance of identifying the attributes of the concept, while Walker and Avant13 and Chinn and Kramer9 highlight the need to clearly choose the concept under analysis. However, Walker and Avant13 employ a linear, stepwise process, whereas Rodger’s Evolutionary Method14 adopts a cyclical model that emphasises iterative analysis, reflecting the dynamic nature of concepts9.
Concept analysis typically involves several steps to clarify the meaning of a concept and explore its defining features9, including selection of a concept of interest, determining the purpose of the analysis, identifying all the various uses of the concept (often through a literature review), and characterising its defining attributes. Walker and Avants approach also involves identifying antecedents (events or circumstances that must occur before the concept can arise) and consequences (outcomes or effects resulting from the presence of the concept), as well as developing exemplar case studies to illustrate the concept, clarify its boundaries and consider its practical application in context9. For example, concept analysis of post-intensive care syndrome12 using Walker and Avant’s framework clarified the multidimensional nature of the syndrome. By systematically reviewing relevant qualitative and quantitative literature, the analysis provided a comprehensive and holistic insight into the syndrome’s defining attributes and subsequently a theoretical basis to inform clinical practice, research, and future application. Regardless of the adopted approach, concept analysis provides an opportunity to enhance conceptual clarity and promote consistency in clinical practice.
Although various concepts relating to the care of critically ill patients have been explored through concept analysis in the literature11,12,15–17, there has been no systematic synthesis to date examining how these concepts map to the entire care pathway. Mapping which concepts have been explored in the literature could support shared understanding among multidisciplinary team members and facilitate knowledge translation across the critical illness care pathway, benefiting clinicians both within and beyond the ICU environment. This, in turn could inform clinical practice and guide future research.
Therefore, the aim of this review is to identify, synthesise, and map concepts related to critical illness and the management of critically ill adult patients across the stages of the care pathway.
Rationale for a scoping review
A scoping review was chosen for this study as its methodology is well-suited to exploring and mapping broad, complex topics18. This scoping review will examine diverse concepts, definitions, and the frameworks used to analyse these concepts in relation to the management of critically ill adult patients along the care pathway. A preliminary search of Open Science Framework registries and Figshare was conducted on 11th July 2025 and no current or planned scoping reviews on this topic were identified.
Research question and objectives of the review
Research question
What concepts related to critical illness and the management of critically ill patients have been examined through concept analysis?
Objectives
1. To identify and describe the concepts that have been explored related to the management of critically ill adult patients.
2. To describe the concept analysis frameworks used to conduct these concept analyses.
3. To identify the populations, clinical contexts, and stages of the care pathway (e.g. pre-ICU, ICU, recovery) in which these concepts have been studied.
4. To visually map identified concepts to illustrate their distribution across the care pathway.
Protocol
Methodology and registration
The protocol was developed in accordance with updated JBI recommendations18 and the PRISMA Extension for Scoping Reviews (PRISMA-ScR) Checklist19. It was reviewed and revised by the study team (KJ, BO’N, JB, BC) before being finalised. The final protocol was registered prospectively on the Open Science Framework (OSF) registries (https://doi.org/10.17605/OSF.IO/Z63CW)20 on 31st July 2025. This scoping review forms part of a process evaluation of the NIHR Health Technology Assessment Programme-funded MARCH trial in which concept analysis will be employed as one methodological and analytical approach (MARCH; Mucoactive drugs for acute respiratory failure: A 2×2 factorial, randomised, controlled, open-label, Phase 3, pragmatic, clinical and cost effectiveness trial with internal pilot, https://www.fundingawards.nihr.ac.uk/award/NIHR130454).
Patient and Public Involvement
Patients and members of the public were first involved in this research during the planning phase, through consultation with the MARCH trial’s Patient and Family Advisory Group (PFAG) The aim, purpose, and proposed methods of this review were discussed with the PFAG, who expressed strong support and highlighted the novelty and relevance of the study.
PFAG members were keen to understand who defines the concepts used in clinical care, what sources of literature are used to support these definitions, and which stakeholders are involved in shaping them. Their lived experience informed the development of the research questions, particularly around improving communication and understanding through clearer, more standardised terminology used by healthcare professionals across different care settings (which reflected their real-world experience).
PFAG members also contributed to the design and conduct of the review, by raising important context-specific considerations. These included geographical variation in clinical practice, differences in service provision, and resource availability. They recommended that the review be transparent about the applicability and transferability of its findings across different healthcare jurisdictions and settings. This feedback will be reflected in data analysis, interpretation, and discussion.
One member provided feedback on the plain English summary, noting it was clear and emphasising that this is a vital piece of research for healthcare professionals, patients and their loved ones. PFAG members were also interested in understanding how the review could benefit patients and how its findings could be shared with both healthcare professionals and patients at different stages of the critical illness journey. The group agreed to share their perspectives on the review findings, and to co-develop strategies for effective dissemination.
Eligibility criteria
Studies will be selected according to the Population-Concept-Context framework18.
Population
We will include studies relating to adult patients, aged 16 years and over, with critical illness (as defined by the original study authors), regardless of diagnosis or underlying condition.
Concept
We will include studies that explicitly use any concept analysis method to explore, define, or clarify concepts relating to the management of critically ill adult patients.
Context
We will include studies conducted at any stage of the patient’s critical illness care pathway, including but not limited to:
Pre-ICU care (e.g. emergency department, ward)
ICU and high dependency unit (HDU)
Post-ICU care (e.g. ward, rehabilitation unit, follow-up clinic)
Types of studies
We will include any study types that align with the research question. To maximise inclusivity, no language restrictions will be applied. Non-English publications will be translated where local resources permit.
Information sources and search strategy
To identify potentially relevant literature, we will search the following electronic databases for full text published literature: MEDLINE ALL, EMBASE, CINAHL Complete, and Web of Science Core Collection from inception until date of search. To capture grey literature, we will search ProQuest Dissertations & Theses Global using a combination of key terms related to the population, concept, and context. To assess the relevance of grey literature, 10% of the most relevant search results will be screened by one reviewer (KJ). Following the initial screening, the study team will determine whether further review of the remaining grey literature is warranted. Only full-text sources will be included.
Where full texts are unavailable, the reviewer (KJ) will contact the primary or corresponding author to confirm publication status. Finally, the reference lists of included studies and the research team’s personal libraries will be reviewed to identify any additional relevant studies.
The search strategy was initially drafted by one of the reviewers (KJ) and subsequently refined in collaboration with an experienced health science librarian to identify suitable MeSH terms and keywords. Final search strategies for MEDLINE ALL and ProQuest Dissertations & Theses Global are provided as additional project files associated with the OSF registration20,21. The search strategy will be adapted as needed for each database to ensure comprehensive retrieval of relevant literature.
Screening, selection, and data extraction procedure
Search results will be collated and uploaded into reference software management programme EndNote 21 (Clarivate Analytics, PA, USA) by one reviewer (KJ) to allow for removal of duplicates and non-relevant results. Remaining search results will be imported into a systematic review programme, Covidence (Veritas Health Innovation, Melbourne, Australia), for screening. To ensure rigour, the screening process will be piloted by two reviewers (KJ and one other); a random sample of up to 25 titles and abstracts will be screened using the eligibility criteria, any discrepancies will be discussed. Following completion of the pilot, all titles and abstracts will be screened independently by two reviewers (KJ and one other). Potentially relevant sources will be retrieved in full along with any associated supplementary material and imported into Covidence. The full text of selected citations will be assessed in detail for inclusion independently by two reviewers (KJ and one other). Reasons for excluding sources of evidence at full text stage will be recorded and reported. The results of the search and the study inclusion process will be reported in a PRISMA flow diagram.
Data will be extracted into a pre-defined Microsoft Excel database, initially developed by one reviewer (KJ) and finalised in collaboration with the study team (KJ, BO’N, JB, BC). The data extracted will focus on:
1. Individual study characteristics (e.g. author, year, country of conduct, setting)
2. Population characteristics (e.g. whether the concept is related to a specific disease or condition)
3. Concept characteristics (e.g. concept name, description, clinical application, detail of method)
4. Context characteristics (e.g. the stage of the patient’s critical illness care pathway– pre-ICU, ICU, or recovery)
The data extraction template will be piloted by two reviewers (KJ and one other) to confirm all relevant data are captured in a consistent manner and ensure consistency in application. An iterative approach will also be used to refine the template as appropriate, should new insights regarding data extraction emerge during the review. Any modifications made will be detailed in the final report. Data from each eligible study will be extracted independently by two reviewers (KJ and one other) and then cross-checked for completeness. Data will be stored on a university (Queen’s University Belfast) server.
Any disagreements in screening and data extraction between reviewers will be resolved via discussion, with arbitration by a third reviewer, if necessary, where consensus cannot be achieved.
Risk of bias assessment
In keeping with established scoping review methodology, a formal assessment of risk of bias for the included studies will not be conducted. Risk of bias assessment would not influence data extraction, analysis, or synthesis.
Data analysis and synthesis
Extracted data will be analysed using descriptive statistics and narrative synthesis. Study characteristics will be summarised and presented in tabular form. We plan to visually map the identified concepts in diagrammatic form, aligned with the phases of the critical illness care pathway (e.g. pre-ICU, ICU, or recovery), to illustrate how these concepts are distributed across the pathway. Additionally, we will identify whether each concept identified is broadly applicable to all critically ill adult patients or specific to a particular subgroup of disease or condition.
Discussion
This scoping review will provide a comprehensive overview of concepts related to critical illness and the management of critically ill adult patients that have been examined using concept analysis methodology. Mapping these concepts across different stages of the critical illness care pathway and identifying their clinical and population specific applications, this review will offer valuable insights into current conceptual understandings in this area. It is anticipated that the findings will help inform clinical practice, guide future research, and highlight potential areas in existing literature which would benefit from further exploration. Importantly, the review may also benefit patients and their families by supporting clearer communication and improving their understanding of key concepts used throughout the critical illness journey, helping them feel more informed and engaged in their care.
The review will adhere to rigorous JBI methodology18 and will be reported in accordance with PRISMA-ScR guidelines19, ensuring a systematic and transparent approach. To enhance transparency and mitigate the risk of reporting bias, the protocol has been prospectively registered on OSF20. Search strategies were developed in collaboration with expert input to maximise the identification of potentially relevant literature. These strategies encompass a broad range of databases as well as unpublished and grey literature. To promote inclusivity, we will include studies written in any language. Screening and data extraction will be piloted and conducted independently by two reviewers to ensure consistency and reduce bias. Finally, the research team comprises individuals with experience in both clinical practice and research methodology, which will ensure robust data identification and interpretation. One potential limitation of the review is the absence of a formal quality appraisal of the included studies, though this falls outside the remit of a scoping review. Furthermore, given the heterogeneity of critically ill patients and the different management needed for subsequent treatment, this may result in diverse concepts identified in the literature. Our planned approach to synthesis should offer some mitigation to this by considering the generalisability versus specificity of these concepts.
Dissemination
Following completion of the synthesis, the results of this review will be submitted for publication in a peer-reviewed journal. We will also engage with the MARCH PFAG to discuss how best to share the results with patients and the public, ensuring the findings are accessible and meaningful across different stages of the critical illness journey.
List of abbreviations
PFAG; Patient and Family Advisory Group
PRISMA-ScR; Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols Extension for Scoping Reviews
ICU; Intensive Care Unit
OSF; Open Science Framework
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Jerrard K, O'Neill B, Bradley JM and Connolly B. Examining concepts related to critical illness and the management of critically ill patients: a protocol for a scoping review [version 1; peer review: awaiting peer review]. NIHR Open Res 2026, 6:8 (https://doi.org/10.3310/nihropenres.14140.1)
NOTE: If applicable, it is important to ensure the information in square brackets after the title is included in all citations of this article.
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