Acute Pain During Intensive Care: Prevalence, Predisposing Factors and Pain Trajectories. A Prospective Multicenter Observational Study

BACKGROUND: A considerable proportion of patients in the intensive care unit (ICU) experience pain. The objective of this prospective observational cohort study was to investigate the prevalence of pain, factors associated with pain and pain trajectories in ICU patients. METHODS: Critically ill adult patients admitted to four ICUs across two tertiary university hospitals between 2018 and 2020 were recruited. Patients were followed during ICU stay for up to 14 days. Pain was measured using the Numeric Rating Scale (NRS), the Critical Care Pain Observation Tool (CPOT) and the Verbal Rating Scale (VRS). The primary outcome was the prevalence of at least moderate pain at rest defined as NRS ≥ 4, VRS ≥ moderate pain or CPOT ≥ 3. Risk factors for pain were analyzed with mixed effects logistic regression models. To enable a visual analysis of pain prevalence, a trajectory model was constructed based on pain assessment data. RESULTS: In total, 711 patients participated in the study. Most patients (76.4%) had at least moderate pain at some point during their ICU stay. Female sex, surgical reason for admission and opioids administered during ICU stay were all associated with increased odds for pain, whereas continuous sedation and a higher SAPS II score decreased the odds. The prevalence of at least moderate pain did not decline during ICU stay. CONCLUSION: The prevalence of at least moderate pain is relatively high in critically ill patients despite frequent use of opioids in the ICU. Identifying patients at risk for pain may aid in individualising pain management. EDITORIAL COMMENT: In this prospective study in a mixed adult ICU cohort, pain prevalence, character and trajectory is described. The majority of cases reported pain at rest, and case factors are presented.