<title>Abstract</title> <bold>Background:</bold> Cerebral blood flow alterations can be discerned through the analysis of endothelial frequencies. The hypothesis posits that there exists a disparity in endothelial activity between asphyxiated newborns with and without neuronal lesions. <bold>Methods</bold>. A retrospective longitudinal study was carried out in which newborns receiving hypothermia treatment for moderate and severe asphyxia participated, segmented into two groups according to the presence or absence of neuronal damage. The study sought to investigate the temporal endothelial involvement in regulating cerebral blood flow control in both groups. Regional cerebral oxygen saturation (rScO2) was measured using near-infrared spectroscopy (NIRS), and the temporal series were subsequently transformed into the frequency domain. <bold>Results.</bold> A total of 88 patients were included in the study. Of these, 53% (47/88) were male, and 33% (29/88) had brain lesions detected by magnetic resonance imaging. 86% (76/88) had a gestational age, according to the Ballard scale, greater than 37 weeks, while 81% (71/88) had a birth weight greater than 2500 grams. The Cohen's d effect size was determined to assess the magnitude of the impact between the means of both groups. The results of Cohen's d indicated that there was a small effect size in endothelial energy between the groups based on the results of the cerebral magnetic resonance imaging, with a Cohen's d value for Day 2 = 0.2351 and for Day 3 = 0.2325. <bold>Conclusion: </bold>Relationship between neuronal damage and endothelial function, providing a perspective on the underlying control mechanism endothelial participating in the cerebral blood flow regulation.