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, P = .018). In patients without delirium, a strong correlation was found between the 2 BPSs (0.94, P < .0001) and 2 self-reported pain scales (0.77, P < .0001). Self-reported pain scale (NRS) and BPS (CPOT) were poorly correlated with each other (0.28, P = .021). In patients with delirium, there was a strong correlation between BPSs (0.86, P < .0001) and a moderate correlation between self-reported pain scales (0.69, P < .0001). There was no apparent correlation between self-reported (NRS) and BPSs (CPOT) in patients with delirium (0.23, P = .12). Most participants preferred self-reported pain assessment.

CONCLUSION: Self-reported pain scale and BPS cannot be used interchangeably. Current validated BPSs may not accurately reflect self-reported pain in critically ill patients.