Perfusion and Metabolic Neuromonitoring during Ventricular Taps in Infants with Post-Hemorrhagic Ventricular Dilatation

Abstract

Post-hemorrhagic ventricular dilatation (PHVD) is characterized by a build-up of cerebral spinal fluid (CSF) in the ventricles, which increases intracranial pressure and compresses brain tissue. Clinical interventions (i.e., ventricular taps, VT) work to mitigate these complications through CSF drainage; however, the timing of these procedures remains imprecise. This study presents Neonatal NeuroMonitor (NNeMo), a portable optical device that combines broadband near-infrared spectroscopy (B-NIRS) and diffuse correlation spectroscopy (DCS) to provide simultaneous assessments of cerebral blood flow (CBF), tissue saturation (StO2), and the oxidation state of cytochrome c oxidase (oxCCO). In this study, NNeMo was used to monitor cerebral hemodynamics and metabolism in PHVD patients selected for a VT. Across multiple VTs in four patients, no significant changes were found in any of the three parameters: CBF increased by 14.6 ± 37.6% (p = 0.09), StO2 by 1.9 ± 4.9% (p = 0.2), and oxCCO by 0.4 ± 0.6 µM (p = 0.09). However, removing outliers resulted in significant, but small, increases in CBF (6.0 ± 7.7%) and oxCCO (0.1 ± 0.1 µM). The results of this study demonstrate NNeMo’s ability to provide safe, non-invasive measurements of cerebral perfusion and metabolism for neuromonitoring applications in the neonatal intensive care unit.

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

“…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 . NNeMo avoids crosstalk by incorporating a multiplexing system to collect data from the two subsystems sequentially 30 . The trade-off with this approach is lower temporal resolution compared to hybrid designs that provide simultaneous CBF and StO 2 monitoring using NIRS techniques involving only a few wavelengths 21 , 32 , 33 .…”

“…The NNeMo system combines hsNIRS and DCS by incorporates a multiplexing shuttering system to cycle between acquisitions from the two subsystems 29 , 30 . For this study, hsNIRS and DCS data were each acquired at a sampling frequency of 4 Hz in consecutive 3-s intervals, resulting in full data sets every 7 s (with a 0.5-s dead-time between subsystems).…”

“…With the goal of providing continuous bedside monitoring of CBF and oxCCO, a hybrid hsNIRS/DCS device was built (NNeMo: Neonatal NeuroMonitor) 30 . The aim of this study was to evaluate CBF and oxCCO stability within the first 72 h of life in preterm infants less than 32 weeks GA and weighing less than 1500 g. It was hypothesized that oxCCO would remain relatively independent of CBF fluctuations due to compensatory changes in oxygen extraction.…”

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

“…Rajaram et al have used a similar combined BNIRS and DCS platform in a pre-clinical piglet experiment to provide information regarding clinically significant hemodynamic events prior to the onset of brain injury, which holds great potential for use particularly in the preterm neonatal population (70). The same group have also used this dual platform to monitor cerebral hemodynamics and metabolism in a cohort of neonatal patients with posthaemorrhagic ventricular dilatation undergoing ventricular tap (111). In the NE population, this dual monitoring will pave the way for further work utilizing the combined measurements of metabolic and autoregulatory disturbances in order to develop a robust cot side biomarker of injury.…”

Improving Infant Hydrocephalus Outcomes in Uganda: A Longitudinal Prospective Study Protocol for Predicting Developmental Outcomes and Identifying Patients at Risk for Early Treatment Failure after ETV/CPC

“…We have developed novel frequency-domain near-infrared combined with diffuse correlation spectroscopy (FDNIRS-DCS) technology to measure SO 2 , cerebral blood flow (CBF), and cerebral metabolic rate of oxygen consumption (CMRO 2 ) non-invasively. We have demonstrated that these measurements are feasible at the bedside [22,23] and sensitive in measuring common infant brain pathologies, including intraventricular hemorrhage [24] and hypoxic-ischemic encephalopathy [25]. In pilot studies at Boston Children's Hospital (BCH) and CCHU, we show they are also sensitive to monitoring the progression and treatment of post-hemorrhagic hydrocephalus (PHH) and PIH.…”