Role of Optical Neuromonitoring in Neonatal Encephalopathy—Current State and Recent Advances

Abstract

Neonatal encephalopathy (NE) in term and near-term infants is a significant global health problem; the worldwide burden of disease remains high despite the introduction of therapeutic hypothermia. Assessment of injury severity and effective management in the neonatal intensive care unit (NICU) relies on multiple monitoring modalities from systemic to brain-specific. Current neuromonitoring tools provide information utilized for seizure management, injury stratification, and prognostication, whilst systemic monitoring ensures multi-organ dysfunction is recognized early and supported wherever needed. The neuromonitoring technologies currently used in NE however, have limitations in either their availability during the active treatment window or their reliability to prognosticate and stratify injury confidently in the early period following insult. There is therefore a real need for a neuromonitoring tool that provides cot side, early and continuous monitoring of brain health which can reliably stratify injury severity, monitor response to current and emerging treatments, and prognosticate outcome. The clinical use of near-infrared spectroscopy (NIRS) technology has increased in recent years. Research studies within this population have also increased, alongside the development of both instrumentation and signal processing techniques. Increasing use of commercially available cerebral oximeters in the NICU, and the introduction of advanced optical measurements using broadband NIRS (BNIRS), frequency domain NIRS (FDNIRS), and diffuse correlation spectroscopy (DCS) have widened the scope by allowing the direct monitoring of oxygen metabolism and cerebral blood flow, both key to understanding pathophysiological changes and predicting outcome in NE. This review discusses the role of optical neuromonitoring in NE and why this modality may provide the next significant piece of the puzzle toward understanding the real time state of the injured newborn brain.

Assessing cerebral blood flow, oxygenation and cytochrome c oxidase stability in preterm infants during the first 3 days after birth

“…Continuous monitoring was achieved using a hybrid system combining hsNIRS and DCS. While hsNIRS is less common that conventional NIRS system that emit light at a few wavelengths, it has the advantage of providing a direct assessment of oxygen metabolism by measuring oxCCO, and there is an increasing interest in this metabolic marker in neonatal studies 31 . The challenge with combining hsNIRS and DCS is avoiding cross contamination, in particular, blocking the DCS laser that can easily saturate the spectrometer used to measure ΔoxCCO 28 .…”

Early Plasma Magnesium in Near-Term and Term Infants with Neonatal Encephalopathy in the Context of Perinatal Asphyxia

“…Current issues in NE management support the emerging concept of neurocritical care. The principal aim of this approach is to potentiate the neurological outcome of these vulnerable infants through continuous bedside monitoring of brain function, close therapeutic adjustment and the limitation of environmental aggression throughout the stay in the intensive care unit [ 27 , 28 ]. Biological monitoring, including screening of multiorgan failure, brain dysfunction, inflammatory response and trophic factors, was included in this global management of NE [ 29 , 30 ].…”

Optical Monitoring in Neonatal Seizures

“…FTOE is, therefore, an indirect measure of mitochondrial oxidation but can be measured from a commercial NIRS system. The need to measure cerebral metabolism directly resulted in further developments in broadband (multiwavelength) NIRS (BNIRS) [ 58 ]. Compared to commercial NIRS systems that use only limited NIR wavelengths, BNIRS uses hundreds of NIR wavelengths to obtain complete NIR spectra of the brain tissue.…”