Introduction Proper pain management in the neonatal intensive care unit (NICU) is essential. The clinical pain assessment depends on objective measurement of indirect behavioural and physiological pain indicators. Cortical pain processing has been observed in preterm infants from 24 weeks gestational age but no study has focused exclusively on cortical pain response in extremely premature infants (≤28 weeks gestational age).
Aims This study aimed to demonstrate cortical pain processing in extremely preterm infants. Furthermore, the study aimed to investigate the impact of analgesic drugs on cerebral haemodynamics and the relationship between behavioural and cortical pain responses.
Material and Methods A clinical study was performed in the NICU, including preterm infants ≤28 weeks gestational age or with a birth weight ≤1500 grams. Patients with severe on-going intraventricular haemorrhage or hydrocephalus were excluded. The infants were studied during routinely performed venepunctures and endotracheal tube suctions. Near-infrared spectroscopy was used for the study of cortical activity, parallel to observation of systemic haemodynamics and pain assessment with the Premature Infant Pain Profile and Échelle Douleur Inconfort Nouveau-Né.
Results During the procedures significant increases in the cerebral concentration of oxygenated haemoglobin were observed bilaterally during venepuncture and unilaterally during endotracheal tube suctions. Simultaneously, minor alterations in systemic haemodynamics occurred. The cerebral pain response was significantly reduced by analgesia.
Conclusions These results indicate the existence of cortical pain processing in very premature infants. Analgesia reduces this cortical response.