Background: Intensive care treatment can be life-saving but is invasive and distressing for patients receiving them, and not always successful. Deciding whether or not a patient will benefit from intensive care is a difficult clinical and ethical challenge. Objectives: To explore the decision-making process around referral and admission to the intensive care unit (ICU) and develop and test an intervention to improve it. Methods: A mixed methods study including: a) Two systematic reviews investigating factors associated with decisions to admit to ICU and the experiences of clinicians, patients and families. b) Observation of decisions and interviews with ICU doctors, referring doctors, patients and families in six NHS Trusts in the UK Midlands. c) A Choice Experiment survey distributed to UK ICU consultants and Critical Care Outreach Nurses. Participants eliciting their preferences for factors used in decision-making for ICU admission.. d) Development of a Decision Support Intervention (DSI) informed by the previous work streams, including an ethical framework for decision-making, supporting referral and decision support forms and patient and family information leaflets. Implementation feasibility was tested in three NHS Trusts.
e) Development and testing of a tool to evaluate the ethical quality of decision-making related to ICU admission, based on assessment of patient records. The tool was tested for inter-rater and inter-site reliability in 120 patient records.

Results: Influences on decision-making identified in the systematic review and ethnographic study included age, presence of chronic illness, functional status, presence of DNACPR order, referring specialty, referrer seniority, and ICU bed availability. ICU doctors used a gestalt assessment of the patient in making decisions. The CE showed age was the most important factor in consultant and CCOR nurses preferences for admission. The ethnographic study illuminated the complexity of the decision-making process, the importance of inter-professional relationships, and good communication between teams and with patients and families. Doctors found it difficult to articulate and balance benefits and burdens of ICU treatment for a patient. There was low uptake of the DSI although doctors who used it noted that it improved articulation of reasons for decisions and communication with patients. Limitations: Limitations existed in each of the component studies: for example we had difficulty in recruiting patient and family in our qualitative work. However, the project benefitted from a mixed method approach which mitigated for potential limitations of the component studies. Conclusions: Decision-making surrounding referral and admission to ICU is complex: This study has provided evidence and resources to help clinicians and organisations aiming to improve decision-making for, and ultimately the care of, critically ill patients. Future Work: Further research is needed into decision-making practices, particularly in how best to engage with patients and families during the decision process. The development and evaluation of training for clinicians involved in these decisions should be a priority for future work.