Defining the reference range of regional cerebral tissue oxygen saturation using a new portable near-infrared spectroscopy device for term infants

Comparison of the Effects of Anaesthesia Methods Used in Caesarean Delivery on Neonatal Cerebral and Renal Oxygenation: A Randomised Controlled Trial

Background: During a newborn's adaptation to extrauterine life, many changes take place that are influenced by various factors. The type of delivery and anaesthesia strategy utilised during labour can modify these adaptive modifications. In this regard, this study was designed to compare the effects of general and spinal anaesthesia on cerebral and renal oxygenation after elective caesarean deliveries. Methods: This randomised controlled study comprised sixty parturient women who were over 18 years old and had a gestational age between 37 and 41 weeks. All participants had an ASA (American Society of Anesthesiologists) classification of II. Neonatal cerebral (CrSO2) and renal (RrSO2) regional oxygen saturations were assessed using near-infrared spectroscopy. Additionally, the 1st-5th min Apgar scores, preductal and postductal peripheral oxygen saturation (SpO2), and perfusion index were recorded in both the general anaesthesia and spinal anaesthesia groups. Results: There was no statistically significant difference between the two groups in terms of CrSO2 or RrSO2 values. The values of CrSO2 and RrSO2 in both groups showed a significant rise from the 10th to the 15th min, respectively. Conclusions: General and spinal anaesthesia techniques used for cesarean delivery have similar effects on neonatal cerebral and renal oxygenation.

The Use of Cerebral Near-Infrared Spectroscopy in Neonatal Hypoxic-Ischemic Encephalopathy: A Systematic Review of the Literature

BACKGROUND

Cerebral near-infrared spectroscopy (cNIRS) is a noninvasive technology used to trend cerebral perfusion at the bedside. cNIRS has potential as a valuable tool in the evaluation of infants with suspected hypoxic-ischemic encephalopathy (HIE). Trending cerebral perfusion with cNIRS can provide information regarding cerebral metabolism as HIE is evolving, which may offer insight into the extent of brain injury.

PURPOSE

The purpose of this systematic review is to investigate the use of cNIRS as a neurocritical tool in the management of neonatal HIE by evaluating its ability to detect acute neurological compromise, including acute brain injury and seizure activity, as well as its potential to identify infants at high risk for long-term neurodevelopmental impairment.

METHODS

A literature search was conducted using PubMed, CINAHL, and Web of Science databases to review articles investigating cNIRS technology in the acute management of HIE.

RESULTS

Eight studies were identified and included in this systematic review. Correlations were observed between cNIRS trends and neurological outcomes as later detected by MRI. cNIRS has potential as a bedside neuromonitoring tool in the management of HIE to detect infants at high risk for brain injury.

IMPLICATIONS FOR PRACTICE

Existing research supports the value of trending cNIRS in HIE management. Documented normal cNIRS values for both term and preterm infants in the first few days of life is approximately 60% to 80%. A steadily increasing cNIRS reading above an infant's baseline and a value of more than 90% should prompt further evaluation and concern for significant neurological injury.

Cross-sectional association between red blood cell distribution width and regional cerebral tissue oxygen saturation in preterm infants in the first 14 days after birth

Background

Hypoxia can threaten the metabolic functions of different systems in immature neonates, particularly the central nervous system. The red blood cell distribution width (RDW) has recently been reported as a prognostic factor in neurologic diseases. Herein, we examined the correlation between RDW and regional cerebral tissue oxygen saturation (rcSO2).

Methods

This cross-sectional study included 110 preterm infants born at a gestational age (GA) of <32 weeks, or with a birth weight (BW) of <1,500 g at our institution between January and June 2,022. The rcSO2 was monitored using near-infrared spectroscopy, and RDW was extracted from the complete blood count during the first 14 days after birth. RDW and rcSO2 measurements were analyzed using a cross-sectional research method.

Results

We divided the study population into two groups, with a mean rcSO2 value over the first 14 days. Fifty-three preterm had rcSO2 ≥ 55% and 57% < 55%. The 14-days-mean in the study population showing an association of lower rcSO2 values with higher RDW values. Significantly higher RDW values were observed in the low rcSO2 group compared with those in the high rcSO2 group. Threshold effect analysis showed that rcSO2 decreased with RDW values ≥18% (β, -0.03; 95% CI, -0.04 and -0.02; p ≥ 0.0001). After adjusting for potential confounders, an RDW of ≥18% was determined as the predictive cutoff value for preterm infants with low rcSO2 (Model I: OR, 3.31; 95% CI, 1.36-8.06; p = 0.009; and Model II: OR, 3.31; 95% CI, 1.28-8.53; p = 0.013).

Conclusions

An RDW of ≥18% in the first 14 days is associated with rcSO2 of <55% in preterm infants.

Hemodynamics and Vascular Histology of Keloid Tissues and Anatomy of Nearby Blood Vessels

Keloids are red' invasive scars that are driven by chronic inflammation in the reticular dermis. The role of blood vessels in keloid behavior remains poorly understood. In the present study with 32 keloid patients, we examined the hemodynamics of keloid tissue, the anatomy of the blood vessels feeding and draining the keloids, and the vascular histology of keloids.

Methods

Ten patients with large anterior chest keloids underwent near-infrared spectroscopy, which measured regional saturation of oxygen and total hemoglobin index in the keloid and surrounding skin. Another 10 patients with large chest keloids and three healthy volunteers underwent multidetector-low computed tomography. The extirpated chest keloids of 12 patients were subjected to histology with optical, CD31 immunohistochemical, and electron microscopy.

Results

All keloids had a low regional saturation of oxygen and a high total hemoglobin index, which is indicative of blood congestion. Multidetector-low computed tomography revealed dilation of the arteries and veins that were respectively feeding and draining the keloid leading edge. Hematoxylin-eosin staining and CD31 immunohistochemisty revealed considerable neovascularization in the keloid leading edge but not in the center. Electron microscopy showed that the lumens of many vessels in the keloid center appeared to be occluded or narrowed.

Conclusions

Keloids seem to be congested because of increased neovascularization and arterial inflow at the leading edge and blocked outflow due to vascular destruction in the center. The surrounding veins seem to expand in response to this congested state. Methods that improve the blood circulation in keloids may be effective therapies.

Three Physiological Components That Influence Regional Cerebral Tissue Oxygen Saturation

Near-infrared spectroscopy (NIRS) measurement of regional cerebral tissue oxygen saturation (rcStO2) has become a topic of high interest in neonatology. Multiple studies have demonstrated that rcStO2 measurements are feasible in the delivery room during immediate transition and resuscitation as well as after admission to the neonatal intensive care unit. Reference ranges for different gestational ages, modes of delivery, and devices have already been published. RcStO2 reflects a mixed tissue saturation, composed of arterial (A), venous (V), and capillary signals, derived from small vessels within the measurement compartment. The A:V signal ratio fluctuates based on changes in oxygen delivery and oxygen consumption, which enables a reliable trend monitoring of the balance between these two parameters. While the increasing research evidence supports its use, the interpretation of the absolute values of and trends in rcStO2 is still challenging, which halts its routine use in the delivery room and at the bedside. To visualize the influencing factors and improve the understanding of rcStO2 values, we have created a flowchart, which focuses on the three major physiological components that affect rcStO2: oxygen content, circulation, and oxygen extraction. Each of these has its defining parameters, which are discussed in detail in each section.

Normal regional tissue oxygen saturation in neonates: a systematic qualitative review

BACKGROUND

The aim of this systematic qualitative review was to give an overview of reference ranges defined as normal values or centile charts of regional tissue oxygen saturation measured by near-infrared spectroscopy (NIRS) in term and preterm neonates.

METHODS

A systematic search of MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials was performed. Additional articles were identified by manual search of cited references. Only human studies in neonates were included.

RESULTS

Nineteen studies were identified. Eight described regional tissue oxygen saturation during fetal-to-neonatal transition, six during the first 3 days after birth, four during the first 7 days after birth, and one during the first 8 weeks after birth. Nine described regional tissue oxygen saturation in term, nine in preterm neonates, and one in both. Eight studies published centile charts for cerebral regional tissue oxygen saturation, and only five included large cohorts of infants. Eleven studies described normal values for cerebral, muscle, renal, and abdominal regional tissue oxygen saturation, the majority with small sample sizes. Four studies of good methodological quality were identified describing centile charts of cerebral regional tissue oxygen saturation.

CONCLUSIONS

In clinical settings, quality centile charts are available and should be the preferred method when using NIRS monitoring.

IMPACT

Near-infrared spectroscopy (NIRS) enables a bed-side non-invasive continuous monitoring of tissue oxygenation. When using NIRS monitoring in a clinical setting, centile charts with good quality are available and should be preferred to normal values. High-quality reference ranges of regional tissue oxygenation in term and preterm born neonates are an important step toward routine clinical application of NIRS.

A Review of Monitoring Methods for Cerebral Blood Oxygen Saturation

In recent years, cerebral blood oxygen saturation has become a key indicator during the perioperative period. Cerebral blood oxygen saturation monitoring is conducive to the early diagnosis and treatment of cerebral ischemia and hypoxia. The present study discusses the three most extensively used clinical methods for cerebral blood oxygen saturation monitoring from different aspects: working principles, relevant parameters, current situations of research, commonly used equipment, and relative advantages of different methods. Furthermore, through comprehensive comparisons of the methods, we find that near-infrared spectroscopy (NIRS) technology has significant potentials and broad applications prospects in terms of cerebral oxygen saturation monitoring. Despite the current NIRS technology, the only bedside non-invasive cerebral oxygen saturation monitoring technology, still has many defects, it is more in line with the future development trend in the field of medical and health, and will become the main method gradually.