Background and Aims: Procedural pain experienced by infants in the neonatal intensive care unit (NICU) remains undertreated, despite the availability of evidence-based pain management interventions (Courtois et al., 2016). Despite recognizing implementation barriers and facilitators, it is unclear which determinants and implementation strategies enhance pain interventions in the NICU. The study objectives were to identify barriers and facilitators to the effective implementation of pain interventions in the NICU; synthesize and evaluate evidence on the most effective implementation strategies and mechanisms for facilitating implementation; and report on the implementation, clinical, and infant pain outcomes. 

Methods: A systematic integrative review of the literature was conducted using MEDLINE, CINAHL, EMBASE, Web of Science, and Cochrane databases. Titles, abstracts, and full-text articles were screened independently according to eligibility criteria. Integrative review methods informed data extraction and synthesis. The Expert Recommendations for Implementing Change (ERIC; Powell et al., 2015) compilation and the Consolidated Framework for Implementation Research (CFIR 1.0; Damschroder et al. 2009) were used to identify implementation strategies; and synthesize and organize data on determinants and outcomes, respectively. The Standards for Reporting Implementation Strategies (Pinnock et al. 2017) and the Mixed Methods Appraisal Tool (Hong et al., 2018) were used to appraise the reporting and methodological quality of included studies, respectively.

Results:  Twenty-two studies identified 14 determinants, 21 implementation strategies, and 17 outcomes related to clinical practice, infant pain, and implementation. Most implementation facilitators (supportive leadership, positive communication and collaboration, sufficient access to resources) and barriers (inadequate staffing and time, low relative priority of the intervention) pertained to the inner-setting domain. The most widely used implementation strategy was conducting education and training sessions and distributing educational materials. The studies provided limited information on how implementation strategies were selected and whether and how they addressed the relevant determinants in the implementation setting. The mechanisms through which these strategies impacted barriers received minimal attention. The most frequently measured clinical outcomes were the proportion of documented procedural pain assessments and pain management practices after implementation. The feasibility of pain interventions was the most investigated implementation outcome. 

Conclusions: This integrative review highlighted the salience of inner-setting factors in effectively implementing pain interventions in the NICU. Enhancing implementation and improving infant pain outcomes in the NICU requires implementing strategies that address identified barriers and facilitators. Additionally, exploring the mechanisms through which these strategies promote effective implementation could lead to a more thorough understanding of which implementation strategies work in what contexts, how and why.