Facial expression as an indicator of pain in critically ill intubated adults during endotracheal suctioning.

Background: Facial expression is often used to evaluate pain in noncommunicative critically ill patients.

Objectives: To describe facial behavior during endotracheal suctioning, determine facial behaviors that characterize the pain response, and describe the effect of patient factors on facial behavior during pain response.

Methods: Fifty noncommunicative patients receiving mechanical ventilation were video recorded during 2 phases (rest and endotracheal suctioning). Pain ratings were gathered by using the Behavioral Pain Scale. Facial behaviors were coded by using the Facial Action Coding System for 30 seconds for each phase.

Results: Fourteen facial actions were associated more with endotracheal suctioning than with rest (z = 5.78; P < .001). The sum of intensity of the 14 actions correlated with total mean scores on the Behavioral Pain Scale (ρ = 0.71; P < .001) and with the facial expression component of the scale (ρ = 0.67; P < .001) during suctioning. In stepwise multivariate analysis, 5 pain-relevant facial behaviors (brow raiser, brow lower, nose wrinkling, head turned right, and head turned up) accounted for 71% of the variance (adjusted R² = 0.682; P < .001) in pain response. The sum of intensity of the 5 actions correlated with total mean scores on the behavioral scale (ρ = 0.72; P < .001) and with the facial expression component of that scale (ρ = 0.61; P < .001) during suctioning. Patient factors had no association with pain intensity scores.

Conclusions: Upper facial expressions are most frequently activated during pain response in noncommunicative critically ill patients and might be a valid alternative to self-report ratings.