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

Abstract

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=rSO_{2on the right}-rSO_{2on 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.