Nurse staffing models that rely on employment of temporary nurses: A realist review.

Background: Nurse shortages are a global issue. Adequate nurse staffing is considered crucial for the quality and safety of care. To efficiently address demands for care, healthcare organisations often employ temporary nursing staff to maintain adequate staffing levels. However, evidence concerning the association between the use of temporary staffing and patient and nurse outcomes is mixed. Work environment, patient needs, nurses' characteristics, and their perspectives on best care practices influence the match between care demand and supply, ultimately leading to different outcomes. Objective: As part of a multi-phase realist review, we aimed to test an initial programme theory on nurse staffing models that frequently use temporary nurses unfamiliar with the unit to determine through which mechanisms these models produce patient, staff, and health system outcomes in particular contexts. Methods: We systematically searched for empirical evidence on nurse staffing models that frequently used temporary nurses. After extracting context-mechanism-outcome configurations from the empirical evidence, we categorised data as supporting, explaining, or refuting our initial theory and synthesized findings to generate a refined and rival programme theory. To augment and refine our programme theory, we conducted a realist focus group and an interview with purposively selected managers and directors from care organisations and agencies, as well as a temporary nurse. Results: We included 49 studies in our analysis that met thresholds of relevance, richness, and rigour. Findings partially supported the initial programme theory, which proposed that heavy reliance on temporary nurses unfamiliar with their assigned units could threaten care continuity, overburden permanent staff, and lead to adverse outcomes. However, this held particularly when staffing levels were low at baseline. A rival programme theory emerged, showing the advantages of using temporary nurses if there is a supportive work environment. Both theories underscore the importance of situated, often tacit knowledge, held by permanent nurses that influences staffing success. Conclusions: With temporary nurses a continuing staffing presence, we have highlighted the need for more research on nurse staffing models that integrate both permanent and temporary nurses. Because care organizations must ensure adequate nursing staff levels, they should consider focusing on strengthening collaboration by creating supportive work environments that are fuelled with situational knowledge. Key strategies may include fast onboarding and orientation for temporary nurses to familiarise them with patients and contexts. In intuitive work environments, temporary nurses may be able to utilise their experience and expertise, consequently enabling mutual learning.