Observer Scales of Facial Pain Expression Can Significantly Predict Acute Postoperative Pain in the Recovery Room

Immediately after surgery and general anesthesia patients may experience periods of dizziness, disorientation, and sedation, which can hinder valid pain reports. Observational pain assessment, especially focusing on the face, may add to the subjective pain report in the recovery room. With the present study, we wanted to test this assumption. Sixty-three patients who had undergone a wide range of surgical procedures under general anesthesia were observed twice: 10 and 40 minutes after arrival in the recovery room. At these 2 time points, a trained examiner observed the patients' facial expression and filled out the face items of the Brief Pain Scale Non-intubated (BPS-NI) and of the Pain and Impaired Cognition-15 (PAIC-15) scale. After that, a nurse asked the patients to rate their pain on a Numerical Rating Scale (NRS). For both time points, the observer scales significantly predicted NRS ratings, with the BPS-NI being slightly superior (moderate/strong effect sizes) compared with the PAIC-15 (small/moderate effect sizes). On a group level, observational pain assessment showed a decrease in pain across the 2 time points, whereas NRS ratings remained stable. Despite this disparity, individual changes in pain ratings between the 2 time points were also significantly predicted by changes in both observer scales (moderate effect sizes). In the recovery room, observational pain assessment can serve as a valid predictor of subjective pain. Thus, in cases where the validity of the pain report may be hampered, especially the face item of the BPI-NI, may give substitute information about acute postoperative pain.