Reliability and Validity of the Face, Legs, Activity, Cry, Consolability Behavioral Tool in Assessing Acute Pain in Critically Ill Patients

Abstract

Background Few investigators have evaluated pain assessment tools in the critical care setting. Objective To evaluate the reliability and validity of the Face, Legs, Activity, Cry, Consolability (FLACC) Behavioral Scale in assessing pain in critically ill adults and children unable to self-report pain. Methods Three nurses simultaneously, but independently, observed and scored pain behaviors twice in 29 critically ill adults and 8 children: before administration of an analgesic or during a painful procedure, and 15 to 30 minutes after the administration or procedure. Two nurses used the FLACC scale, the third used either the Checklist of Nonverbal Pain Indicators (for adults) or the COMFORT scale (for children). Results For 73 observations, FLACC scores correlated highly with the other 2 scores (ρ = 0.963 and 0.849, respectively), supporting criterion validity. Significant decreases in FLACC scores after analgesia (or at rest) supported construct validity of the tool (mean, 5.27; SD, 2.3 vs mean, 0.52; SD, 1.1; P < .001). Exact agreement and κ statistics, as well as intraclass correlation coefficients (0.67–0.95), support excellent interrater reliability of the tool. Internal consistency was excellent; the Cronbach α was 0.882 when all items were included. Conclusions Although similar in content to other behavioral pain scales, the FLACC can be used across populations of patients and settings, and the scores are comparable to those of the commonly used 0-to-10 number rating scale.