Multichannel near infrared spectroscopy indicates regional variations in cerebral autoregulation in infants supported on extracorporeal membrane oxygenation

Abstract

Abstract. Assessing noninvasively cerebral autoregulation, the protective mechanism of the brain to maintain constant cerebral blood flow despite changes in blood pressure, is challenging. Infants on life support system (ECMO) for cardiorespiratory failure are at risk of cerebral autoregulation impairment and consequent neurological problems. We measured oxyhaemoglobin concentration (HbO 2 ) by multichannel (12 channels) near-infrared spectroscopy (NIRS) in six infants during sequential changes in ECMO flow. Wavelet cross-correlation (WCC) between mean arterial pressure (MAP) and HbO 2 was used to construct a time-frequency representation of the concordance between the two signals to assess the nonstationary aspect of cerebral autoregulation and investigate regional variations. Group data showed that WCC increases with decreasing ECMO flow indicating higher concordance between MAP and HbO 2 and demonstrating loss of cerebral autoregulation at low ECMO flows. Statistically significant differences in WCC were observed between channels placed on the right and left scalp with channels on the right exhibiting higher values of WCC suggesting that the right hemisphere was more susceptible to disruption of cerebral autoregulation. Multichannel NIRS in conjunction with wavelet analysis methods can be used to assess regional variations in dynamic cerebral autoregulation with important clinical application in the management of critically ill children on life support systems.

Optimal wavelength combinations for near-infrared spectroscopic monitoring of changes in brain tissue hemoglobin and cytochrome c oxidase concentrations

“…Numerous experimental and clinical studies have been carried out to delineate the biological basis of optical signals obtained from healthy and injured brain. These studies present sound evidence that NIRS-derived changes in chromophore concentrations can act as markers of cerebral physiology and pathology; the results offer significant insights into the feasibility of NIRS for observation of functional activation [5,6], detection of autoregulation or metabolic failure during routine surgery or after brain injury [7,8], and assessment of impending neurological damage due to hypoxia-ischemia (HI) in adults or neonates [9][10][11].…”

Spatial mapping of dynamic cerebral autoregulation by multichannel near-infrared spectroscopy in high-grade carotid artery disease

“…7 One recent study using 12-channel NIRS found regional variations of cerebral autoregulation in critically ill infants. 19 Multichannel NIRS has also been applied for perfusion measurement in adults with MCA stenosis and a delayed perfusion predominantly in the vascular border zone has been found in Ref. 20.…”

Designing and Implementing a Portable Near-Infrared Imaging System for Monitoring of Human's Brain Functional Activity1

“…The cerebral hemispheres, the diencephalons, the brain stem, and the cerebellum are four main regions of the brain [5]. An outer layer of grey matter covers the cerebral hemispheres, which is called the cerebral cortex and its thickness is approximately 5mm in adults.…”

“…But to calculate changes in concentrations of oxygenated and deoxygenated hemoglobin, the effect of scattering is negligible since it does not change over time [5,13].…”

“…At a cellular scale, there is a mismatch in refractive index causing light scattering in tissue, which is mostly because of refractive index variations between the cell membranes and organelles within each cell [5]. Red blood cells constitute only 2% of solid content and they have a low contribution to scattering [13].…”