Can Cerebrovascular Reactivity Be Measured With Near-Infrared Spectroscopy?

Smielewski, Peter; Kirkpatrick, Peter J.; Minhas, Paven; Pickard, John D.; Czosnyka, Marek

doi:10.1161/01.str.26.12.2285

Cited by 132 publications

(135 citation statements)

References 38 publications

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“…However, reactivity and diameter changes have been demonstrated in the fetus and newborn (20,21), bringing into question the validity of the TCD technique. Our findings and those of others (22,23) suggest a correlation between measurements made by NIRS and TCD.…”

Section: Discussionsupporting

confidence: 88%

Identification of Pressure Passive Cerebral Perfusion and Its Mediators after Infant Cardiac Surgery

et al. 2005

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Cerebrovascular pressure autoregulation (CPA) regulates cerebral blood flow (CBF) in relation to changes in mean arterial blood pressure (MAP). Identification of a pressure-passive cerebral perfusion and the potentially modifiable physiologic factors underlying it has been difficult to achieve in sick infants. We previously validated the near-infrared spectroscopy-derived hemoglobin difference (HbD) signal (cerebral oxyhemoglobin Ϫ deoxyhemoglobin) as a reliable measure of changes in CBF in animal models. We now sought to determine whether continuous measurements of ⌬HbD would correlate to middle cerebral artery flow velocity (CBFV), allow identification and quantification of pressure-passive state, and help to delineate potentially modifiable factors. We enrolled 43 infants (2 d to 7 mo old) who were undergoing open cardiac surgery and cardiopulmonary bypass. At 6 and 20 h after surgery, we measured changes in HbD, CBFV (by transcranial Doppler), and MAP at different end-tidal CO 2 levels. We assigned a pressure-passive index (PPI) to each study on the basis of the relative duration of significant coherence between ⌬MAP and ⌬HbD. We found a significant relationship between ⌬HbD and ⌬CBFV at both time points. At 6 h after surgery, we showed high concordance (coherence Ͼ0.5; PPI Ն41%) between ⌬MAP and ⌬HbD, consistent with disturbed CPA in 13% of infants. End-tidal CO 2 values Ն40 mm Hg and higher MAP variability both were associated with increased odds (p Ͻ 0.001) of autoregulatory failure. This approach provides a means to identify and quantify disturbances of CPA. High Recent advances in infant cardiac surgery and critical care medicine have translated into high survival rates for infants with congenital heart disease. As mortality has decreased, the clinical focus has shifted to the prevention of perioperative neurologic injury (1). Previous studies have focused primarily on intraoperative cerebral hypoxia-ischemia as a key mechanism for neurologic dysfunction. However, recently it has become clear that multiple potential mechanisms, operating at different times, may be implicated in the pathogenesis of neurologic dysfunction after infant cardiac surgery (2). In the current research, we focused on the early postoperative period because of its high risk for hemodynamic instability and therefore potential for brain injury.

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Section: Discussionsupporting

confidence: 88%

Identification of Pressure Passive Cerebral Perfusion and Its Mediators after Infant Cardiac Surgery

et al. 2005

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“…Changes in cerebral blood flow velocity in this frequency range are believed to represent autoregulatory compensatons to slow hemodynamic oscillations. [34][35][36] Our results support our prior findings showing that NIRS can be exploited for autoregulation monitoring. 16,24,37,38 In a piglet laboratory model we found that cerebral oximetry index was significantly correlated with cerebral blood flow autoregulation monitoring based on laser Doppler methods.…”

Section: Discussionsupporting

confidence: 90%

Predicting the Limits of Cerebral Autoregulation During Cardiopulmonary Bypass

Joshi¹,

Ono²,

Brown³

et al. 2012

Survey of Anesthesiology

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Background-Mean arterial blood pressure (MAP) targets are empirically chosen during cardiopulmonary bypass (CPB). We have previously shown that near-infrared spectroscopy (NIRS) can be used clinically for monitoring cerebral blood flow autoregulation. The hypothesis of this study was that real-time autoregulation monitoring using NIRS-based methods is more accurate for delineating the MAP at the lower limit of autoregulation (LLA) during CPB than empiric determinations based on age, preoperative history, and preoperative blood pressure.

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“…In one study (40), increases in cutaneous blood flow have been reported. We here observe that both the NIRS signals from the cheek and cutaneous plethysmography (forehead) detected increase in blood volume in a large percentage of cases, all these signals being moderately correlated with tHbi.…”

Section: Hvmentioning

confidence: 95%

Inconsistent detection of changes in cerebral blood volume by near infrared spectroscopy in standard clinical tests

Canova

Roatta

Bosone³

et al. 2011

Journal of Applied Physiology

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The attractive possibility of near infrared spectroscopy (NIRS) to noninvasively assess cerebral blood volume and oxygenation is challenged by the possible interference from extracranial tissues. However, to what extent this may affect cerebral NIRS monitoring during standard clinical tests is ignored. To address this issue, 29 healthy subjects underwent a randomized sequence of three maneuvers that differently affect intra- and extracranial circulation: Valsalva maneuver (VM), hyperventilation (HV), and head-up tilt (HUT). Putative intracranial (“i”) and extracranial (“e”) NIRS signals were collected from the forehead and from the cheek, respectively, and acquired together with cutaneous plethysmography at the forehead (PPG), cerebral blood velocity from the middle cerebral artery, and arterial blood pressure. Extracranial contribution to cerebral NIRS monitoring was investigated by comparing Beer-Lambert (BL) and spatially resolved spectroscopy (SRS) blood volume indicators [the total hemoglobin concentration (tHb) and the total hemoglobin index, (THI)] and by correlating their changes with changes in extracranial circulation. While THIe and tHbe generally provided concordant indications, tHbi and THIi exhibited opposite-sign changes in a high percentage of cases (VM: 46%; HV: 31%; HUT: 40%). Moreover, tHbi was correlated with THIi only during HV ( P < 0.05), not during VM and HUT, while it correlated with PPG in all three maneuvers ( P < 0.01). These results evidence that extracranial circulation may markedly affect BL parameters in a high percentage of cases, even during standard clinical tests. Surface plethysmography at the forehead is suggested as complementary monitoring helpful in the interpretation of cerebral NIRS parameters.

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Can Cerebrovascular Reactivity Be Measured With Near-Infrared Spectroscopy?

Cited by 132 publications

References 38 publications

Identification of Pressure Passive Cerebral Perfusion and Its Mediators after Infant Cardiac Surgery

Identification of Pressure Passive Cerebral Perfusion and Its Mediators after Infant Cardiac Surgery

Predicting the Limits of Cerebral Autoregulation During Cardiopulmonary Bypass

Inconsistent detection of changes in cerebral blood volume by near infrared spectroscopy in standard clinical tests

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