Comparison of Self-Reported and Behavioral Pain Assessment Tools in Critically Ill Patients.

Background: Self-reported and behavioral pain assessment scales are often used interchangeably in critically ill patients due to fluctuations in mental status. The correlation between scales is not well elucidated. The purpose of this study was to describe the correlation between self-reported and behavioral pain scores in critically ill patients.

Methods: Pain was assessed using behavioral and self-reported pain assessment tools. Behavioral pain tools included Critical Care Pain Observation Tool (CPOT) and Behavioral Pain Scale (BPS). Self-reported pain tools included Numeric Rating Scale (NRS) and Wong-Baker Faces Pain Scales. Delirium was assessed using the confusion assessment method for the intensive care unit. Patient preference regarding pain assessment method was queried. Correlation between scores was evaluated.

Results: A total of 115 patients were included: 67 patients were nondelirious and 48 patients were delirious. The overall correlation between self-reported (NRS) and behavioral (CPOT) pain scales was poor (0.30, = .018). In patients without delirium, a strong correlation was found between the 2 behavioral pain scales (0.94, < .0001) and 2 self-reported pain scales (0.77, < .0001). Self-reported pain scale (NRS) and behavioral pain scale (CPOT) were poorly correlated with each other (0.28, = .021). In patients with delirium, there was a strong correlation between behavioral pain scales (0.86, < .0001) and a moderate correlation between self-reported pain scales (0.69, < .0001). There was no apparent correlation between self-reported (NRS) and behavioral pain scales (CPOT) in patients with delirium (0.23, = .12). Most participants preferred self-reported pain assessment.

Conclusion: Self-reported pain scales and behavioral pain scales cannot be used interchangeably. Current validated behavioral pain scales may not accurately reflect self-reported pain in critically ill patients.