The use of near-infrared spectroscopy in the acute phase of hypoxic-ischemic encephalopathy in newborns

Detection of new markers of renal hypoperfusion in full-term infants during therapeutic cooling in moderate or severe hypoxic-ischemic encephalopathy to prevent the progression of acute kidney injury (AKI). Aim. To evaluate the significance of using continuous peripheral NIRS monitoring in full-term infants with hypoxic-ischemic encephalopathy for early detection of renal hypoperfusion against the background of prophylactic use of methylxanthines. Materials and methods. A prospective randomized controlled trial was conducted from 2019 to 2022 on the basis of the Neonatal Intensive Care Department of the Zaporizhzhia Regional Clinical Children’s Hospital. We included 50 full-term infants who underwent a program of total therapeutic hypothermia for moderate or severe hypoxic-ischemic encephalopathy. The infants were divided into 2 groups, each receiving methylxanthine to prevent the progression of AKI. Continuous NIRS monitoring of renal and brain tissues was performed throughout the cooling phase and until the end of the warming period. The relationship between NIRS and the development of AKI, which was determined according to the modified neonatal scale KDIGO (2012) by increasing serum creatinine and decreasing urine output during the first 5 days, was studied. Results. NIRS monitoring revealed that changes in cerebral CrSO2 were observed somewhat earlier than renal RrSO2, as the kidneys were less susceptible to autoregulation and perfusion changes than the brain. The level of CrSO2 was identical in 2 groups and did not change after the administration of caffeine citrate or theophylline. The average peripheral renal saturation rates were slightly higher than CrSO2 and tended to increase during the observation period due to the development of renal reperfusion after hypoxia. While the level of renal oxygen extraction decreased. The results obtained indicated that the warming period was characterized by normalization of perfusion, increase in regional renal saturation and decrease in renal oxygen excretion. In general, acute kidney injury in stage I developed in 4 (8.00 %) newborns, and stage II – in 1 (2.00 %), which was equivalent in both study groups (P = 0.8009; U = 299.00). Instead, the other children had stage 0 – 45 (90.00 %). None of the neonates had stage III according to KDIGO (2012) and required renal replacement therapy. Conclusions. The combined use of methylxanthines and the maintenance of optimal postnatal hemodynamics through NIRS diagnostics are vital for the prevention and treatment of acute kidney injury in neonates with moderate or severe hypoxic-ischemic encephalopathy.