AIM: To validate and evaluate the psychometric properties of the ALPS-Neo, a new pain assessment scale created for the continuous evaluation of pain and stress in preterm and sick term infants.

METHODS: A unidimensional scale for continuous pain, Astrid Lindgren Children's Hospital Pain Scale (ALPS 1), was developed further to assess continuous pain and stress in infants treated in the neonatal intensive care unit (NICU). The pain scale includes observations of five behaviours. A manual was created, clarifying the scoring criteria. An internal and an external panel assessed face validity. Psychometric properties were evaluated in three different steps. Inter-rater reliability was estimated from video-based assessments (n = 625) using weighted kappa statistics (test I). Inter-rater reliability was further evaluated in test II (n = 125) and test III (n = 96) by real-time assessments using the intraclass correlation coefficient (ICC) and Cronbach's alpha.

RESULTS: The final inter-rater reliability (test III) was assessed as good with ICC 0.91 for the total score and 0.62-0.81 for the five items. Cronbach's alpha showed 0.95 for the total score.

CONCLUSION: ALPS-Neo is a new assessment tool for optimising the management of pain and stress in newborn infants in the NICU. It has proved easy to implement and user-friendly, permitting fast, reliable observations with high inter-rater reliability.