The Role of Substance P, Neurokinin A, Neuropeptide Y, and Cortisol in Assessing Neonatal Pain.

Our aim was to investigate biomarkers of neonatal pain and their association with two pain scales. This prospective study included 54 full-term neonates. Levels of substance P (SubP), neurokinin A (NKA), neuropeptide Y (NPY), and cortisol were recorded and two pain scales (Premature Infant Pain Profile [PIPP] and Neonatal Infant Pain Scale [NIPS]) were used. A statistically significant decrease in the levels of NPY ( = 0.02) and NKA ( = 0.03) was detected. A significant increase in NIPS scale ( < 0.001) and PIPP scale ( < 0.001) postpainful intervention was also detected. There was a positive correlation between cortisol and SubP ( = 0.01), NKA and NPY ( < 0.001) and between NIPS and PIPP ( < 0.001). A negative correlation was found for NPY with SubP ( = 0.004), cortisol ( = 0.02), NIPS ( = 0.001) and PIPP ( = 0.002). Novel biomarkers and pain scales may help in designing an objective tool for the quantification of neonatal pain in the everyday practice.