Pain Measurement in Mechanically Ventilated Patients After Cardiac Surgery: Comparison of the Behavioral Pain Scale (BPS) and the Critical-Care Pain Observation Tool (CPOT)

Objectives The Behavioral Pain Scale (BPS) and Critical-Care Pain Observation Tool (CPOT) are behavioral pain assessment tools for sedated and unconscious critically ill patients. The aim of this study was to compare the reliability, internal consistency and discriminant validation of the BPS and the CPOT simultaneously, in mechanically ventilated patients post-cardiac surgery. Design A prospective observational cohort study. Setting A 20-bed closed-format ICU with mixed medical, surgical and cardiac surgery patients in a teaching hospital in Amsterdam, the Netherlands Participants 72 intubated and mechanically consecutive ventilated patients post-cardiac surgery who were not able to self-report pain. Measurements and Main Results Two nurses assessed the BPS and CPOT simultaneously and independently at four moments – during: rest, a non-painful procedure (oral care), rest and a painful procedure (turning). Both scores showed a significant increase of two points between rest and turning. The median BPS score of nurse1 showed a significant increase of one point between rest and the non-painful procedure (oral care), whereas both median CPOT scores did not change. The interrater reliability of the BPS and CPOT showed a fair to good agreement of 0.74 overall. During restI&II values ranged from 0.24 to 0.46. Cronbach’s alpha values for the BPS were 0.62 (nurse1) and 0.59 (nurse2), compared to 0.65 and 0.58 for the CPOT. Conclusions: The BPS and CPOT are reliable and valid pain assessment tools in a daily clinical setting. However, the discriminant validation of both scores seems less satisfactory in sedated or agitated patients and this topic requires further investigation.