Validity and reliability of the Behavioural Observational Pain Scale for postoperative pain measurement in children 1-7 years of age.

OBJECTIVE: Pain measurement is a necessity in pain treatment but can be difficult in young children. The aim of this study was to evaluate the validity and reliability of the Behavioural Observational Pain Scale (BOPS) as a postoperative pain measurement scale for children aged 1-7 yrs. The scale assesses three elements of pain behaviors: facial expression, verbalization, and body position. DESIGN: A prospective study. SETTING: A day surgery care unit for children and a neurosurgical postoperative care unit. PATIENTS: Seventy-six children aged 1-7 yrs (4.5 +/- 1.8) undergoing elective surgical procedures were observed. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The study was divided into interrater reliability, concurrent validity, and construct validity. The interrater reliabilities of the observers were very good with a high agreement between the different nurses' BOPS scores. Each item of the BOPS scale ranged from kappa(w) 0.86 to 0.95. In the concurrent validity, BOPS and Children's Hospital of Eastern Ontario Pain Scale scores had a positive correlation indicating that both tools described similar behaviors (r(s) = .871, p < .001). In construct validity, the effect of analgesic was tested before analgesic administration and at 15, 30, and 60 mins after analgesic administration. The differences in BOPS score between the time intervals were significant (p < .01) before administration of analgesia and at 15, 30, and 60 mins. There was also statistical significance in the BOPS score (p < .01) between 15 and 60 mins after administration of analgesia. CONCLUSIONS: With BOPS, the caretaker can evaluate and document pain with high reliability and validity and thereby improve postoperative pain treatment in preschool children. The simple scoring system makes BOPS easy to incorporate in a postoperative unit.