Is the ABC pain scale reliable for premature babies?

Aim: We recently developed the ABC scale to assess pain in term newborns. The aim of the present study was to assess the reliability of the scale in preterm babies. Material and methods: The scale consists of three cry parameters: (a) pitch of the first cry, (b) rhythmicity of the bout of crying and (c) cry constancy. Changes in these parameters were previously found to distinguish medium and high levels of pain as evaluated by spectral analysis of crying. We enrolled 72 babies to perform the steps usually requested to validate a scale, namely the study of the concurrent validity specificity and sensibility. Moreover, we assessed the interjudge reliability and the clinical utility and ease of the scale. Results: A good correlation (r = 0.68; r(2) = 0.45; p < 0.0001) was found between scores obtained with the ABC scale and the premature infant pain profile (PIPP) scale, demonstrating a good concurrent validity. The scale also showed good sensitivity and specificity (we found statistically significant differences between mean values of scores obtained in babies who underwent pain and babies who underwent non-painful stimulus.) Interobserver reliability was good: Cohen's kappa = 0.7. Conclusion: The good correlation between the two scales shows that the ABC scale is also reliable for premature babies.