The Modified Behavioral Pain Scale (MBPS) may represent a reliable tool for assessing procedural pain but may not allow discrimination between pain- and non-pain-related distress in infants and young children, according to study findings published in the Journal of Pain.
In this prospective, observational study, investigators evaluated the feasibility and reliability of the MBPS for detecting pain in 100 pediatric patients (age 6-42 months) undergoing painful procedures in the emergency department.
The 10-point MBPS assesses 3 behavioral components (face, movement, and cry) as an indication of a patient’s experience of pain.
Children presenting to the emergency department were filmed during 1 of 4 procedures deemed either painful (insertion of a nasogastric tube or of an intravenous catheter) or distressing but not painful (medication inhalation by mask and spacer device and oxygen saturation measurements).
The average MBPS scores during nasogastric tube insertion were found to be higher than those assessed during saturation measurement (8.78±1.09 vs 1.99±0.86, respectively). Investigators observed high interrater and intrarater reliability (0.87 and 0.89, respectively) and strong correlations between the MBPS and the observed visual analog scores for pain and distress (r=0.74 and r=0.87, respectively).
MPBS scores were lower for non-painful vs painful procedures, indicating this tool’s ability to discriminate between the two (3.4±2.7 vs 7.5±2.3, respectively; P =.001). Responsiveness of the MBPS scale to painful stimuli, added to its capacity to differentiate painful vs non-painful stimuli, indicates construct validity, according to the authors.
A second review of the filmed footage was associated with a 28% change in final MBPS scores, indicating the potential usefulness of including additional reviews when assessing for pain.
Although this study demonstrated construct validity of MBPS, the investigators did not evaluate the scale’s content validity. In addition, score assessment may have been prone to error, resulting in misclassification of painful symptoms in some patients.
The investigators suggest that clinicians “are probably well advised to regard the [MPBS] scale as a measure of procedure-related distress (including pain) and not specifically pain alone.”
Crellin DJ, Babl FE, Santamaria N, Harrison D. The psychometric properties of the MBPS scale used to assess procedural pain [published online February 15, 2018]. J Pain. doi: 10.1016/j.jpain.2018.01.012