Abstract
Effective management of patient mental state deterioration in acute hospital settings is crucial due to its significant impact on both patients and staff. However, inconsistencies in management strategies highlight the need for standardised approaches. We adopted a realist evaluation approach to gain insights into staff perceptions and experiences, exploring how, for whom and under what circumstances the DIvERT (De-escalation, Intervention, Early, Response, Team) system, a rapid response system functions in practice. We conducted 23 semi-structured interviews with clinical staff from two pilot acute hospital settings. The qualitative data were analysed to identify key themes and contextual factors that influence the system's functioning, providing insights into the mechanisms through which DIvERT facilitates proactive intervention. Findings indicated that ward staff valued a structured approach and benefited from interdisciplinary collaboration with mental health experts, which improved their clinical knowledge and confidence. A supportive ward culture, characterised by teamwork and open communication, facilitated collaboration and response effectiveness. However, bedside nurses often deferred escalation decisions to senior staff, have to balance prioritising immediate medical needs over proactive risk management. Inconsistent training, unclear escalation pathways and knowledge gaps, particularly among new graduates, limited system efficiency. Resource shortages and scheduling conflicts further constrained timely responses. Addressing these barriers through structured training, clear escalation pathways and proactive risk management is essential to improving mental state deterioration management. A ward culture that promotes communication, teamwork and effective resource allocation can strengthen the implementation and effectiveness of rapid response systems in acute hospital settings.