Data collection was conducted across three workstreams. In workstream (WS) 1, 17 ICU clinicians/researchers, and eight patient and public involvement (PPI) contributors with experience of working on ICU studies, took part in semi-structured telephone interviews about the problems and potential solutions in recruitment and consent to ICU studies. This informed the development of the survey for WS2. In WS2, 1453 participants from 14 ICUs in England took part in the survey, which explored experiences and views of ICU research recruitment and consent process. Forty-four surveys were either duplicates or had substantial missing data so 1409 surveys were included in the analysis. Of these, 333 surveys were from ICU patients, 488 from family members (of whom 63 were bereaved) and 588 were from healthcare practitioners. Thirty five percent (115/333) of patient surveys and 32% (157/488) of family member surveys were from individuals who reported having been approached about research in the ICU, while 44% (260/588) of healthcare practitioner surveys were from those who indicated they had a role in research. For WS3, a purposive sample of 60 participants, 54 of whom had completed the WS2 survey, took part in semi-structured interviews to explore their survey responses and their wider perspectives on ICU research in more depth. This included 13 patients, 30 family members (of whom 4 were bereaved before completing the survey, and 5 were bereaved since they or another family member completed the survey), and 17 healthcare practitioners. Of interviewed patients and family members, 25 had been approached about a study while in the ICU. Of healthcare practitioners, 12 had research roles at the time of their interview (3 doctors, 7 research nurses and 2 pharmacists). The six additional interviewees comprised: four family members of surveyed patients where the family member had visited the patient’s during their ICU stay; two ICU patients whose family members had completed a survey. Although these six interviewees had not completed the WS2 survey, the protocol permitted interviews with such individuals if they had close ties to WS2 participants.Clinical research in intensive care units (ICUs) is essential for improving treatments for critically ill patients. However, invitations to participate in clinical research in this situation pose numerous challenges. ICU studies frequently take place within a narrow time window and patients will often be unconscious and unable to consent. Consent must, therefore, be sought from representatives or proxies of a patient, usually the patient's relatives. Conversations about research participation in this setting will be difficult, as relatives are often overwhelmed and some will feel uneasy about making decisions on behalf of their loved ones. In some circumstances, legislation allows doctors act as representatives so patients can be enrolled in research. Despite these and other distinctive practices in recruitment and consent to ICU research, prior to the Perspectives study there was little good quality evidence and guidance on stakeholders’ perspectives to inform how recruitment and consent is carried out in ICU studies. Knowledge of stakeholder perspectives was needed to avoid basing recruitment and consent processes on presumptions about peoples’ experience of ICU research. The Perspectives study explored the views of stakeholders with recent first-hand experience of ICU treatment and research to inform approaches to recruitment and consent. Established social science methods and empirical ethics were employed to balance the interests of the various stakeholders and justify recommendations. The findings were used to inform good practice guidance on recruitment and consent to future ICU studies. Researchers and an expert Advisory Group of key stakeholders (including patients, relatives, ICU doctors, nurses and research regulators) contributed throughout the process of developing the guidance bringing different viewpoints to interpreting the evidence and informing the guidance.

Workstream (WS) 1 was a qualitative interview study that described the problems and potential solutions in recruitment and consent to ICU studies. Participants were a purposive sample of ICU clinician-researchers and PPI advocates involved in the design and implementation of studies. Data comprise anonymised transcripts of semi-structured telephone interviews. WS2 was a survey conducted in 14 English hospitals to quantify perspectives on i) ICU recruitment and consent and ii) problems and solutions identified in WS1. This also informed purposive sampling for WS3. Sampling at most sites was opportunistic and respondents were ICU frontline clinicians, patients and their relatives. WS3 was a qualitative interview study that described accounts of: i) views and experiences of ICU recruitment and consent and ii) reasons for responses to the WS2 survey. Participants largely comprised a purposely sampled sub-set of the WS2 survey respondents and included frontline ICU clinicians, patients and their relatives. Data comprise anonymised transcripts of semi-structured telephone and face-to-face interviews. An integrative analysis of workstreams 2 and 3 took place giving rise to WS4, an ethical analysis which lead to the development of good practice guidance to enhance recruitment and consent processes for research in ICUs.