Near-Infrared Spectroscopy Monitoring of Cerebral Oxygenation and Influencing Factors in Neonates from High-Altitude Areas

Regional cerebral oxygen saturation in the healthy population of western Sichuan: a multicenter cross-sectional study

Regional cerebral oxygen saturation (rSO2) may vary in healthy individuals with different characteristics. Therefore, this study aimed to explore rSO2 in a healthy population of western Sichuan. This cross-sectional study enrolled healthy volunteers from the Health Management Center and Inpatient Department of Ya'an People's Hospital, Ya'an Vocational and Technical College, Ya'an Geriatric University, and Liziping Yi Township in Shimian County, Ya'an City, Sichuan Province. Brain rSO2 was measured by near-infrared spectroscopy (NIRS) between January 2020 and December 2022. A total of 661 volunteers were enrolled, with a mean age of 28.3 ± 23.1 years old and 276 males. There was significantly higher rSO2 of the left brain in females (63.46 ± 3.01 vs. 63.17 ± 2.90, P = 0.015), males (63.91 ± 3.54 vs. 63.42 ± 3.32, P = 0.002), Han (65.10 ± 3.67 vs. 64.38 ± 3.43, P < 0.001), and volunteers aged 14-59 years (P < 0.05) compared with the right brain. Volunteers with Han ethnicity had significantly higher rSO2 than those with Yi ethnicity (64.65 ± 3.29 vs. 62.68 ± 3.66, P < 0.001). Volunteers with past illness had significantly lower rSO2 than those without past illness (62.41 ± 3.06 vs. 62.68 ± 3.66, P = 0.021). Pearson correlation analysis showed a significantly negative correlation of rSO2 with age, ethics, past illness, and body mass index (BMI) but a significantly positive correlation with head circumference and height (all P < 0.05). The rSO2 values in the left brain are significantly higher than in the right brain. Sex, ethnicity, age, BMI, and past illness are closely related to rSO2 values in the healthy population.

[Amplitude-integrated electroencephalography monitoring results of hospitalized neonates in plateau areas]

OBJECTIVES

To investigate the amplitude-integrated electroencephalography (aEEG) monitoring results of hospitalized neonates in plateau areas.

METHODS

A retrospective analysis was conducted on 5 945 neonates who were admitted to the Department of Neonatology, Kunming Children's Hospital, and received aEEG monitoring from January 2020 to December 2022. According to the aEEG monitoring results, they were divided into a normal aEEG group and an abnormal aEEG group. The incidence rate of aEEG abnormalities was analyzed in neonates with various systemic diseases, as well as the manifestations of aEEG abnormalities and the consistency between aEEG abnormalities and clinical abnormalities.

RESULTS

Among the 5 945 neonates, the aEEG abnormality rate was 19.28% (1 146/5 945), with an abnormality rate of 29.58% (906/3 063) in critically ill neonates and 8.33% (240/2 882) in non-critically ill neonates (P<0.05). The children with inherited metabolic diseases showed the highest aEEG abnormality rate of 60.77% (79/130), followed by those with central nervous system disorders [42.22% (76/180)] and preterm infants [35.53% (108/304)]. Compared with the normal aEEG group, the abnormal aEEG group had significantly lower age and gestational age, as well as a significantly lower birth weight of preterm infants (P<0.05). Among the 1 146 neonates with aEEG abnormalities, the main types of aEEG abnormalities were sleep cycle disorders in 597 neonates (52.09%), background activity abnormalities in 294 neonates (25.65%), and epileptiform activity in 255 neonates (22.25%), and there were 902 neonates (78.71%) with abnormal clinical manifestations. The sensitivity and specificity of aEEG monitoring for brain function abnormalities were 33.51% and 92.50%, respectively.

CONCLUSIONS

In plateau areas, there is a relatively high rate of aEEG abnormalities among hospitalized neonates, particularly in critically ill neonates and those with smaller gestational ages and younger ages, suggesting a high risk of brain injury. Therefore, routine aEEG monitoring for the hospitalized neonates can help with the early detection of brain function abnormalities, the decision-making in treatment, and the formulation of brain protection strategies.

[Cerebral oxygen metabolism and brain electrical activity of healthy full-term neonates in high-altitude areas: a multicenter clinical research protocol]

Further evidence is needed to explore the impact of high-altitude environments on the neurologic function of neonates. Non-invasive techniques such as cerebral near-infrared spectroscopy and amplitude-integrated electroencephalography can provide data on cerebral oxygenation and brain electrical activity. This study will conduct multiple cerebral near-infrared spectroscopy and amplitude-integrated electroencephalography monitoring sessions at various time points within the first 3 days postpartum for healthy full-term neonates at different altitudes. The obtained data on cerebral oxygenation and brain electrical activity will be compared between different altitudes, and corresponding reference ranges will be established. The study involves 6 participating centers in the Chinese High Altitude Neonatal Medicine Alliance, with altitude gradients divided into 4 categories: 800 m, 1 900 m, 2 400 m, and 3 500 m, with an anticipated sample size of 170 neonates per altitude gradient. This multicenter prospective cohort study aims to provide evidence supporting the impact of high-altitude environments on early brain function and metabolism in neonates.

Predictive Utility of Near-Infrared Spectroscopy for the Outcomes of Hypoxic-Ischemic Encephalopathy: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to assess the utility of near-infrared spectroscopy (NIRS) in predicting the perinatal outcomes of neonates with hypoxic-ischemic encephalopathy (HIE). We conducted a literature search on Medline via PubMed, Web of Science, Scopus, and CENTRAL Library. We included studies that utilized early NIRS monitoring to study the accuracy of NIRS in predicting the perinatal outcomes of neonates with hypoxic-ischemic encephalopathy. Nine studies that met our eligibility criteria were included. These studies were published between 2012 and 2023. In this meta-analysis, no significant differences in regional cerebral oxygen saturation (cSpO2) were found between normal and abnormal groups at 12 hours (MD = 0.21, 95% CI: -6.39 to 6.82, P = 0.95) and 24 hours (MD = -1.96, 95% CI: -6.95 to 3.03, P = 0.44). However, at 48 hours, cSpO2 was significantly lower in the normal group (MD = -4.9, 95% CI: -5.91 to -3.89, P < 0.00001). At 72 hours, our analysis revealed a significant difference with lower cSpO2 in the normal group (MD = -3.0, 95% CI: -5.5 to -0.5, P = 0.02). Regarding cerebral fractional tissue oxygen extraction (FTOE), no significant differences were observed at 12 hours (MD = 0.03, 95% CI: -0.02 to 0.09, P = 0.24). After 24 hours, the normal group exhibited lower FTOE (MD = -0.03, 95% CI: -0.04 to -0.01, P < 0.001), while after 48 hours, the normal group had higher FTOE (MD = 0.07, 95% CI: 0.04 to 0.10, P < 0.0001). Early cerebral NIRS monitoring is beneficial in predicting the outcomes of HIE in term neonates. Our analysis showed that several NIRS parameters, such as regional cSpO2 and cerebral FTOE, are significantly associated with adverse outcomes in the first 72 hours of birth.

Stroke analysis and recognition in functional near-infrared spectroscopy signals using machine learning methods

Stroke is a high-incidence disease with high disability and mortality rates. It is a serious public health problem worldwide. Shortened onset-to-image time is very important for the diagnosis and treatment of stroke. Functional near-infrared spectroscopy (fNIRS) is a noninvasive monitoring tool with real-time, noninvasive, and convenient features. In this study, we propose an automatic classification framework based on cerebral oxygen saturation signals to identify patients with hemorrhagic stroke, patients with ischemic stroke, and normal subjects. The reflected fNIRS signals were used to detect the cerebral oxygen saturation and the relative value of oxygen and deoxyhemoglobin concentrations of the left and right frontal lobes. The wavelet time-frequency analysis-based features from these signals were extracted. Such features were used to analyze the differences in cerebral oxygen saturation signals among different types of stroke patients and healthy humans and were selected to train the machine learning models. Furthermore, an important analysis of the features was performed. The accuracy of the models trained was greater than 85%, and the accuracy of the models after data augmentation was greater than 90%, which is of great significance in distinguishing patients with hemorrhagic stroke or ischemic stroke. This framework has the potential to shorten the onset-to-diagnosis time of stroke.

Melatonin treatment during chronic hypoxic gestation improves neonatal cerebrovascular function

BACKGROUND

Fetal chronic hypoxia is associated with blood flow redistribution and oxidative damage in the brain, leading to increased perinatal morbimortality. Melatonin reduces oxidative stress, improves vascular function, and has neuroprotective effects.

OBJECTIVES

This study aimed to determine the effects of an oral melatonin treatment to pregnant ewes at high-altitude, on the cerebrovascular function of their neonates.

STUDY DESIGN

Ten high-altitude pregnant sheep received either vehicle or melatonin (10 mg/d) during the last third of gestation until delivery. Postnatal daily hemodynamic measurements were recorded from lambs until 12 days old. In addition, lambs were submitted to a graded oxygenation protocol to assess cerebrovascular responses. Subsequently, lambs were euthanized, and middle cerebral arteries (MCA) were collected for vascular function, protein levels, and morphostructural analyses.

RESULTS

Antenatal treatment doubled plasma levels of melatonin in pregnant ewes. Melatonin increased carotid flow and decreased carotid vascular resistance in the lambs by the end of the first week. Furthermore, melatonin increased MCA's maximal vasoconstrictor and vasodilator responses, associated with nitric oxide-dependent and independent mechanisms.

CONCLUSIONS

An oral treatment with melatonin during pregnancy promotes postnatal cerebral perfusion in chronically hypoxic neonates. Melatonin is a potential treatment for cerebrovascular dysfunction due to perinatal chronic hypoxia.