Barriers and facilitators influencing pain assessment practices among nurses caring for non communicative adult icu patients: a systematic review

Pain assessment is challenging when critically ill adults cannot self-report because of mechanical ventilation, sedation, neurological injury, delirium, or altered consciousness. Nurses must interpret behavioural and contextual indicators, but use of validated tools and organizational support remains inconsistent. This review systematically identified, appraised, and synthesised barriers and facilitators influencing nurses’ pain-assessment practices for non-communicative adults in intensive care units. PubMed, Embase, CINAHL, and Google Scholar were searched from inception to 30 April 2024 and updated to 30 April 2026; Google Scholar was screened as a supplementary source. Eligible primary qualitative, quantitative, mixed-methods, and quasi-experimental studies involved nurses in adult intensive care and examined determinants of pain assessment when patients could not self-report. Two reviewers independently screened studies, verified data extraction, and applied design-appropriate Mixed Methods Appraisal Tool criteria. Only findings specific to pain assessment were synthesised; management-only findings were excluded. Quantitative findings were transformed into textual statements and integrated with qualitative evidence through thematic synthesis. Heterogeneity precluded meta-analysis. Fifteen studies involving 2,521 nurses across 13 countries were included, predominantly cross-sectional self-report studies (11 of 15). Five themes emerged: uncertainty without self-report; limitations in knowledge, confidence, and clinical reasoning; inconsistent use of validated behavioural tools; workload, staffing, documentation, and protocol constraints; and relational, cultural, and interdisciplinary influences. Facilitators reported in the included studies were competency-based education, availability of the Critical-Care Pain Observation Tool or Behavioral Pain Scale, continuity of care, explicit protocols, and responsive physician prescribing; documentation prompts, audit and feedback, and leadership accountability were implementation strategies proposed rather than evaluated. Clinically reliable pain assessment appears to require more than nursing knowledge. Because the evidence is largely cross-sectional and self-reported, multifaceted strategies integrating competency development, validated tools, supportive workflows, interdisciplinary collaboration, audit, and leadership accountability are recommended but remain to be tested. Future studies should prioritise observed assessment practices and patient-level outcomes.