Psychometric analysis of a Taiwan-version pain assessment scale for preterm infants

Abstract

Aim: To determine the inter-rater reliability, internal consistency, construct and concurrent validity and feasibility of the pain assessment scale for preterm infants.

Background: Repeated exposure to painful procedures has an adverse impact on preterm infants' health outcomes. Although many scales are available for assessing these infants' pain, only a few reliably and validly assess pain and no gold standard has been established in clinical practice.

Design: Instrument development and psychometric analysis.

Methods: Preterm infants (n = 60) born 27·6-36·3 weeks gestational age were assessed for pain 3 minutes before (phase I), during (phase II), 3 minutes after (phase III) and the tenth minute after (phase IV) heel-stick procedures. Pain scores were independently coded from video recordings and observations by three trained nurses using our pain-assessment scale, premature infant pain profile and visual analogue scale.

Results: Scores on the pain assessment scale for preterm infants differed significantly across four phases of heel-stick procedures (F = 56·86, p < 0·0001). Internal consistency was 0·84 and inter-rater reliability was 0·88-0·93. Scores on our pain scale correlated well with scores on the premature infant pain profile (0·74-0·83) and visual analogue scale (0·72-0·81).

Conclusions: The pain assessment scale for preterm infants integrates all possible pain indicators, with each item modified for clinicians' simple and easy pain measurement to potentially yield different information. Our scale is valid, reliable and feasible for preterm infants with gestational age > 27 weeks. Further examination of the scale's psychometrics is recommended with diverse samples of infants and different painful procedures.

Relevance to clinical practice: The pain assessment scale for preterm infants clearly defines item scoring and weighting, consistently discriminates different levels of pain and helps nurses to recognise infants' pain. Nurses can easily remember the definition of each item, allowing them to use our scale to evaluate preterm infants' pain at any time and to provide pain-relief interventions when needed.