Facial expressions of pain in daily clinical practice to assess postoperative pain in children: Reliability and validity of the facial action summary score

Abstract

Background: Behavioural pain scales are recommended to assess postoperative pain for children who are too young to use self-report tools. Their main limitation is underestimation of pain in the days following an intervention. Although relevant, facial expression is not used in daily clinical practice. This prospective study aimed to assess the validity and reliability of the Facial Action Summary Score (FASS), a fiveitem scale, to assess postoperative pain until hospital discharge in children <7 years. Methods: Assessments of pain and anxiety of 123 children using FASS and validated scales were used to study the psychometric validity of the FASS in clinical practice. Results: The content validity was previously investigated in a development study. The internal validity of the FASS was high with excellent reliability (intraclass coefficient = 0.94) and a high Cronbach α (0.89). Convergent validity with pain scales (FLACC [Face, Legs, Activity, Cry, Consoling] and FPS-R [Faces Pain Scale -Revised]) was high (r > 0.8). Sensitivity to change was verified by a significant decrease in the score after rescue analgesia. For a threshold of 2/5, the FASS shows excellent specificity (97%) and sensitivity (82%). The low number of false negatives is the main strength of this tool. Conclusions: This work highlights the interest in using facial expression in daily clinical practice to manage postoperative pain. The FASS is easy to use with excellent psychometric properties and is particularly sensitive to measure pain in the days following surgery. Significance: The aim of this study was to prove that facial expression of pain can be used in clinical practice to measure postoperative pain in children. The reduced number of false negatives is the main strength of this tool.

The Clinical Suitability of an Artificial Intelligence–Enabled Pain Assessment Tool for Use in Infants: Feasibility and Usability Evaluation Study

“…This is further supported by the high levels of accuracy and precision. It is worth mentioning that the cutoff threshold identified in this study is similar to that reported for the FASS using the FLACC as a comparator in postoperative pain [25]. The FASS and the NFCS-R are unidimensional tools, made up of 5 facial items.…”

“…This is comparable to the NFCS-R, which contains 5 items (reduced from the 10 items that made up the original version of the tool) [ 23 , 24 ]. The Facial Action Summary Score (FASS), another unidimensional observational pain assessment tool, also includes 5 facial items [ 25 ]. The Faces, Legs, Arms, Cries, and Consolability (FLACC), multidimensional tool used for the assessment of procedural pain, has 5 domains; however, it uses an ordinal scoring system, such that the user is required to look for a variety of possible behaviors within each domain to determine absence or presence and intensity [ 26 ].…”

“…PainChek Infant is a unidimensional, observational pain assessment tool that uses automated facial recognition and analysis to identify the presence of 6 pain-related facial AUs. It has a similar construct to the NFCS-R and the FASS, both of which rely on an assessment of facial expressions by the user to evaluate the presence and intensity of pain [ 23 - 25 ].…”

“…The FASS and the NFCS-R are unidimensional tools, made up of 5 facial items. Based on achieving a combination of the highest specificity and sensitivity, Bringuier et al [ 25 ] reported a threshold of ≥2/5. In the Médecins Sans Frontières clinical guidelines, it is indicated that a score of ≥2 in the NFCS suggests serious pain [ 37 ].…”

Bispectral Index Monitoring and Observer Rating Scale Correlate with Dreaming during Propofol Anesthesia for Gastrointestinal Endoscopies

“…Observing facial expressions is part of the frequently used pain rating scales. Pain may be influenced by the procedures themselves, and patients subjected to unpleasant and painful procedures may have low observer rating scores [15].…”