Near-infrared spectroscopy: bilateral brain monitoring in termed newborns with hypoxic-ischemic lesions

Assessment of cerebral oxygenation using near-infrared spectroscopy (near-infrared spectroscopy, near-infrared spectroscopy, NIRS) has significant strong correlation with the assessment of brain perfusion using MRI in full-term infants with severe hypoxic-ischemic encephalopathy. However, there are still no recommendations on the use of NIRS monitoring data for making important clinical decisions in newborns with asphyxia and hypoxic-ischemic encephalopathy in routine clinical practice. The role of interhemispheric variations in the values of regional tissue oxygen saturation (rSO2) in severe hypoxic-ischemic encephalopathy against the background of therapeutic hypothermia remains unexplored. The aim of the study was to evaluate the results of bilateral brain monitoring using NIRS in full-term newborns with severe hypoxic-ischemic lesions (with and without destructive changes in brain tissue). All examined children were full-term newborns with severe asphyxia at birth, who underwent therapeutic hypothermia. We analyzed the results of NIRS recordings of 33 newborns who did not have signs of destructive hypoxic-ischemic brain damage, and NIRS data of 15 newborns who were diagnosed with signs of destructive hypoxic-ischemic brain damage. The hemisphere difference in cerebral oximetry indices was presented in the form of statistical processing results - average, median, mode, 25th percentile, 75th percentile of pairwise comparisons, namely the difference of values (ΔrSO2) of the measurement “ΔrSO2=rSO2on the right-rSO2on the left” in each moment of recording (12000-22000 measurement moments during the monitoring session), as well as the percentage of recording time when the ΔrSO2 value was recorded below the 25th percentile and above the 75th percentile. Reliable correlations between the fact of the formation of destructive hypoxic-ischemic brain lesions in full-term newborns and the average ΔrSO2 values of the NIRS record (R=-0.410), median values (R=-0.400), modes (R=-0.357), and values 25-the percentile ΔrSO2 (R=-0.326) and the 75th percentile ΔrSO2 (R=-0.429) were registered. In 73.3% of children with destructive hypoxic-ischemic lesions, the average ΔrSO2 values were higher for the right hemisphere (the average ΔrSO2 value of the group was 0.11±2.39%). In 93.9% of children without destructive brain damage, the average rSO2 values were higher for the right hemisphere (the average ΔrSO2 value of the group was 6.92±0.80%). Significant differences in mean ΔrSO2 (p=0.005) were determined. Mean ΔrSO2 median for the group with destructive brain lesions was 0.33±2.38%, for the group without destructive lesions - 6.88±0.82% (p=0.004), the average ΔrSO2 mode for the group with destructive brain lesions was 1,46±1.73%, for the group without destructive lesions - 6.51±0.92% (p=0.014). The average of the 25th percentile of ΔrSO2 values for the group with destructive brain lesions was (-1.93)±2.72%, and for the group without destructive lesions it was 4.42±0.84% (p=0.026). The average of the 75th percentile of ΔrSO2 values for the group with destructive brain lesions was 2.87±2.11%, and for the group without destructive lesions it was 9.33±0.80% (p=0.003). The results of bilateral brain monitoring using NIRS in full-term newborns with severe hypoxic-ischemic lesions on the background of therapeutic hypothermia have significant dif­ferences between groups of children with and without destructive changes in brain tissue. In newborns with destructive brain lesions, a decrease in manifestations of dominance of rSO2 indicators of the right hemisphere was recorded, namely, significantly lower mean ΔrSO2, median, mode, average values of the 25th and 75th percentiles ΔrSO2.