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Detection of Brain Hypoxia Based on Noninvasive Optical Monitoring of Cerebral Blood Flow with Diffuse Correlation Spectroscopy.
- Source :
-
Neurocritical care [Neurocrit Care] 2019 Feb; Vol. 30 (1), pp. 72-80. - Publication Year :
- 2019
-
Abstract
- Background: Diffuse correlation spectroscopy (DCS) noninvasively permits continuous, quantitative, bedside measurements of cerebral blood flow (CBF). To test whether optical monitoring (OM) can detect decrements in CBF producing cerebral hypoxia, we applied the OM technique continuously to probe brain-injured patients who also had invasive brain tissue oxygen (PbO <subscript>2</subscript> ) monitors.<br />Methods: Comatose patients with a Glasgow Coma Score (GCS) < 8) were enrolled in an IRB-approved protocol after obtaining informed consent from the legally authorized representative. Patients underwent 6-8 h of daily monitoring. Brain PbO <subscript>2</subscript> was measured with a Clark electrode. Absolute CBF was monitored with DCS, calibrated by perfusion measurements based on intravenous indocyanine green bolus administration. Variation of optical CBF and mean arterial pressure (MAP) from baseline was measured during periods of brain hypoxia (defined as a drop in PbO <subscript>2</subscript> below 19 mmHg for more than 6 min from baseline (PbO <subscript>2</subscript> > 21 mmHg). In a secondary analysis, we compared optical CBF and MAP during randomly selected 12-min periods of "normal" (> 21 mmHg) and "low" (< 19 mmHg) PbO <subscript>2</subscript> . Receiver operator characteristic (ROC) and logistic regression analysis were employed to assess the utility of optical CBF, MAP, and the two-variable combination, for discrimination of brain hypoxia from normal brain oxygen tension.<br />Results: Seven patients were enrolled and monitored for a total of 17 days. Baseline-normalized MAP and CBF significantly decreased during brain hypoxia events (p < 0.05). Through use of randomly selected, temporally sparse windows of low and high PbO <subscript>2</subscript> , we observed that both MAP and optical CBF discriminated between periods of brain hypoxia and normal brain oxygen tension (ROC AUC 0.761, 0.762, respectively). Further, combining these variables using logistic regression analysis markedly improved the ability to distinguish low- and high-PbO <subscript>2</subscript> epochs (AUC 0.876).<br />Conclusions: The data suggest optical techniques may be able to provide continuous individualized CBF measurement to indicate occurrence of brain hypoxia and guide brain-directed therapy.
- Subjects :
- Adult
Brain Injuries diagnostic imaging
Brain Injuries physiopathology
Coma diagnostic imaging
Coma physiopathology
Female
Humans
Male
Middle Aged
Neuroimaging methods
Neuroimaging standards
Neurophysiological Monitoring standards
Optical Imaging methods
Optical Imaging standards
Spectroscopy, Near-Infrared methods
Spectroscopy, Near-Infrared standards
Arterial Pressure physiology
Cerebrovascular Circulation physiology
Hypoxia-Ischemia, Brain diagnostic imaging
Hypoxia-Ischemia, Brain physiopathology
Neurophysiological Monitoring methods
Subjects
Details
- Language :
- English
- ISSN :
- 1556-0961
- Volume :
- 30
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Neurocritical care
- Publication Type :
- Academic Journal
- Accession number :
- 30030667
- Full Text :
- https://doi.org/10.1007/s12028-018-0573-1