Development and Verification of a New Method for Evaluating Facial Expressions Based on the Premature Infant Pain Profile-Revised

Abstract

Introduction: The use of reliable, validated, and multidimensional tools for pain evaluation has been recommended to manage neonatal pain. However, these tools have limited use in Japan due to their complexity, which involves numerous evaluation and observation items, making thorough observation challenging.

Methods: We developed a new method based on the Premature Infant Pain Profile-Revised (PIPP-R), a multidimensional evaluation tool that includes physiological and behavioral indicators, to simplify the evaluation of facial expressions. Instead of assessing three facial expressions individually, we evaluate them in four categories. We also created a system that automatically records changes in vital signs and calculates scores. In this study, we determined if the facial expression score aligns with the conventional PIPP-R-based facial expression score. The scoring methods were categorized into three types: (1) a real-time new method, where facial expressions were evaluated concurrently with the puncture procedure using a new method; (2) an individual assessment method using recorded videos from the puncture sessions with facial expressions scored later using the PIPP-R; and (3) a new video-based method, in which facial expressions were evaluated using the new method while watching recorded videos.

Results: The study included 63 healthy neonates (born at ≥37 weeks' gestation) delivered at our hospital. The degree of agreement among the methods and the inter-rater agreement showed high levels of consistency.

Conclusion: The new facial expression assessment method based on the PIPP-R demonstrated equivalence to conventional scoring in full-term neonates. Further validation, particularly in preterm infants and diverse clinical settings, is needed.

Keywords: Facial expression scores; Neonatal pain; Neonatal pain scale; Premature Infant Pain Profile-Revised.