Recruitment for clinical trials in acute care settings, including intensive care units (ICUs), emergency departments, and peri-operative environments, presents distinctive ethical and practical challenges. These include time-sensitive decision-making, impaired patient capacity, complex consent processes, and reliance on surrogate decision-makers (SDMs). Despite growing attention to research ethics, there is a limited synthesis of how these challenges impact patient consent and trial recruitment.

Following PRISMA-ScR guidance, a systematic search of PubMed/MEDLINE (2010–2025) was conducted, supplemented by a targeted ClinicalTrials.gov search to identify ongoing and completed trials. Data were extracted and classified into overarching domains to map the breadth of barriers and proposed solutions.

Fifteen studies were included, spanning randomised controlled trials, qualitative studies, surveys, and reviews. Key barriers were: (1) timing and capacity constraints in high-pressure environments; (2) comprehension challenges with technical consent documents, especially in minority populations; (3) regulatory variability limiting harmonisation of alternative models ( e.g. , deferred and staged consent); and (4) under-representation of vulnerable groups, leading to selection bias. Nine additional randomised clinical trials identified in ClinicalTrials.gov explored innovative consent tools such as digital aids and AI chatbots; two had published results. Promising strategies included multimodal consent, culturally tailored materials, early SDM engagement, and patient and public involvement (PPI).

Acute-care and anaesthetic trials require adaptive consent frameworks that balance ethical rigour with operational feasibility. Adoption of inclusive recruitment strategies and harmonised international standards may enhance both equity and efficiency in future critical-care research.