Quantitation of cerebral blood volume in human infants by near-infrared spectroscopy

1990 ◽  
Vol 68 (3) ◽  
pp. 1086-1091 ◽  
Author(s):  
J. S. Wyatt ◽  
M. Cope ◽  
D. T. Delpy ◽  
C. E. Richardson ◽  
A. D. Edwards ◽  
...  
Keyword(s):  
Blood Volume ◽  
Near Infrared ◽  
Cerebral Blood Volume ◽  
Arterial Oxygen Saturation ◽  
Newborn Infants ◽  
Nir Spectroscopy ◽  
Hemoglobin Concentration ◽  
Large Vessel ◽  
Arterial Oxygen ◽  
Human Infants

Current methods for measuring cerebral blood volume (CBV) in newborn infants are unsatisfactory. A new method is described in which the effect of a small change (5-10%) in arterial oxygen saturation (SaO2) on cerebral oxyhemoglobin [HbO2] and deoxyhemoglobin [Hb] concentration is observed by near-infrared (NIR) spectroscopy. Previous experiments in which the NIR absorption characteristics of HbO2 and Hb and the pathlength of NIR light through the brain were defined allowed changes in [HbO2] and [Hb] to be quantified from the Beer-Lambert law. It is shown here that CBV can then be derived from the expression CBV = (delta[HbO2] - delta[Hb])/(2. delta SaO2.H.R.), where H is the large vessel total hemoglobin concentration and R to the cerebral-to-large vessel hematocrit ratio. Observations on 12 newborn infants with normal brains, born at 25-40 wk of gestation and aged 10-240 h, gave a mean value for CBV of 2.22 +/- 0.40 (SD) ml/100 g, whereas mean CBV was significantly higher 3.00 +/- 1.04 ml/100 g in 10 infants with brain injury born at 24 to 42 wk of gestation and aged 4-168 h (P less than 0.05).

Quantification of concentration changes in neonatal human cerebral oxidized cytochrome oxidase

1991 ◽  
Vol 71 (5) ◽  
pp. 1907-1913 ◽  
Author(s):  
A. D. Edwards ◽  
G. C. Brown ◽  
M. Cope ◽  
J. S. Wyatt ◽  
D. C. McCormick ◽  
...  
Keyword(s):  
Cytochrome Oxidase ◽  
Near Infrared ◽  
Cerebral Blood Volume ◽  
Arterial Oxygen Saturation ◽  
Hemoglobin Concentration ◽  
Carbon Dioxide Tension ◽  
Arterial Oxygen ◽  
Neonatal Brain ◽  
Concentration Changes

The oxygenation of cerebral cytochrome oxidase in vivo was investigated in eight newborn preterm infants. Near-infrared spectroscopy was used to quantify changes in the concentration of oxidized cytochrome oxidase ([CytO2]) observed during alterations in arterial oxygen saturation (SaO2) in the range of 85–99% and of carbon dioxide tension (PaCO2) in the range of 4.3–9.6 kPa. No relation was found between changes in SaO2 and [CytO2]. Alterations in PaCO2 were positively related both to changes in [CytO2] and total cerebral hemoglobin concentration [( Hb]t). The changes in [CytO2] ranged from 0.09 to 0.33 (median 0.21) mumol.l-1.kPa-1. The ratio [CytO2]/[Hb]t ranged from 0.06 to 0.12 (median 0.08). The relation of delta [CytO2] to the change in cerebral blood volume (delta CBV) was calculated: delta [CytO2]/delta CBV ranged from 0.09 to 0.18 (median 0.11) mumol/ml. These results define a fraction of cerebral cytochrome oxidase in the newborn infant that is oxidized after an increase in PaCO2 but demonstrate that a change in SaO2 in the range studied was not sufficient by itself to change [CytO2]. They differ from results of studies in adults; this may reflect significant differences between adult and neonatal brain.

Cerebral oxygen availability by NIR spectroscopy during transient hypoxia in humans

1990 ◽  
Vol 69 (3) ◽  
pp. 907-913 ◽  
Author(s):  
N. B. Hampson ◽  
E. M. Camporesi ◽  
B. W. Stolp ◽  
R. E. Moon ◽  
J. E. Shook ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Volume ◽  
Near Infrared ◽  
Cerebral Blood Volume ◽  
Minute Ventilation ◽  
Nir Spectroscopy ◽  
Redox Status ◽  
Total Blood ◽  
Arterial Ph

The effects of mild hypoxia on brain oxyhemoglobin, cytochrome a,a3 redox status, and cerebral blood volume were studied using near-infrared spectroscopy in eight healthy volunteers. Incremental hypoxia reaching 70% arterial O2 saturation was produced in normocapnia [end-tidal PCO2 (PETCO2) 36.9 +/- 2.6 to 34.9 +/- 3.4 Torr] or hypocapnia (PETCO2 32.8 +/- 0.6 to 23.7 +/- 0.6 Torr) by an 8-min rebreathing technique and regulation of inspired CO2. Normocapnic hypoxia was characterized by progressive reductions in arterial PO2 (PaO2, 89.1 +/- 3.5 to 34.1 +/- 0.1 Torr) with stable PETCO2, arterial PCO2 (PaCO2), and arterial pH and resulted in increases in heart rate (35%) systolic blood pressure (14%), and minute ventilation (5-fold). Hypocapnic hypoxia resulted in progressively decreasing PaO2 (100.2 +/- 3.6 to 28.9 +/- 0.1 Torr), with progressive reduction in PaCO2 (39.0 +/- 1.6 to 27.3 +/- 1.9 Torr), and an increase in arterial pH (7.41 +/- 0.02 to 7.53 +/- 0.03), heart rate (61%), and ventilation (3-fold). In the brain, hypoxia resulted in a steady decline of cerebral oxyhemoglobin content and a decrease in oxidized cytochrome a,a3. Significantly greater loss of oxidized cytochrome a,a3 occurred for a given decrease in oxyhemoglobin during hypocapnic hypoxia relative to normocapnic hypoxia. Total blood volume response during hypoxia also was significantly attenuated by hypocapnia, because the increase in volume was only half that of normocapnic subjects. We conclude that cytochrome a,a3 oxidation level in vivo decreases at mild levels of hypoxia. PaCO is an important determinant of brain oxygenation, because it modulates ventilatory, cardiovascular, and cerebral O2 delivery responses to hypoxia.

Blood Volume Changes in Patients With Cystic Fibrosis

PEDIATRICS ◽  
1977 ◽  
Vol 59 (4) ◽  
pp. 588-594
Author(s):  
Amnon Rosenthal ◽  
Lawrence N. Button ◽  
Kon Taik Khaw
Keyword(s):  
Cystic Fibrosis ◽  
Blood Volume ◽  
Arterial Oxygen Saturation ◽  
Hemoglobin Concentration ◽  
Pulmonary Involvement ◽  
Progressive Increase ◽  
Cor Pulmonale ◽  
Arterial Oxygen ◽  
Mean Corpuscular Hemoglobin ◽  
Total Blood

Simultaneous red blood cell (RBC) and plasma volume determinations were obtained in 16 patients with cystic fibrosis (CF) and moderately severe pulmonary involvement. Hypervolemia with an increase in both RBC and plasma volumes was observed. Changes in blood volume were marked when values were indexed by weight but less significant when indexed by height. Decreasing systemic arterial oxygen saturation was associated with a progressive increase in RBC mass, hematocrit value, and hemoglobin level and a decrease in mean corpuscular hemoglobin concentration. RBC and total blood volumes were highest in patients with cor pulmonale and congestive heart failure. However, the compensatory polycythemic response in patients with CF was inadequate when compared with the response to hypoxemia in patients with cyanotic congenital heart disease. The insufficient oxygen-carrying capacity may compromise tissue oxygen delivery and necessitate treatment.

Involuntary breathing movements improve cerebral oxygenation during apnea struggle phase in elite divers

2009 ◽  
Vol 107 (6) ◽  
pp. 1840-1846 ◽  
Author(s):  
Zeljko Dujic ◽  
Lovro Uglesic ◽  
Toni Breskovic ◽  
Zoran Valic ◽  
Karsten Heusser ◽  
...  
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Arterial Oxygen Saturation ◽  
Arterial Oxygen ◽  
Breath Holding ◽  
Breath Hold ◽  
Peripheral Vasoconstriction ◽  
Total Hemoglobin

We investigated whether the involuntary breathing movements (IBM) during the struggle phase of breath holding, together with peripheral vasoconstriction and progressive hypercapnia, have a positive effect in maintaining cerebral blood volume. The central hemodynamics, arterial oxygen saturation, brain regional oxyhemoglobin (bHbO2), deoxyhemoglobin, and total hemoglobin changes and IBM were monitored during maximal dry breath holds in eight elite divers. The frequency of IBM increased (by ∼100%), and their duration decreased (∼30%), toward the end of the struggle phase, whereas the amplitude was unchanged (compared with the beginning of the struggle phase). In all subjects, a consistent increase in brain regional deoxyhemoglobin and total hemoglobin was also found during struggle phase, whereas bHbO2 changed biphasically: it initially increased until the middle of the struggle phase, with the subsequent relative decline at the end of the breath hold. Mean arterial pressure was elevated during the struggle phase, although there was no further rise in the peripheral resistance, suggesting unchanged peripheral vasoconstriction and implying the beneficial influence of the IBM on the cardiac output recovery (primarily by restoration of the stroke volume). The IBM-induced short-lasting, sudden increases in mean arterial pressure were followed by similar oscillations in bHbO2. These results suggest that an increase in the cerebral blood volume observed during the struggle phase of dry apnea is most likely caused by the IBM at the time of the hypercapnia-induced cerebral vasodilatation and peripheral vasoconstriction.

scholarly journals Cerebral perfusion and oxygenation are impaired by folate deficiency in rat: Absolute measurements with noninvasive near-infrared spectroscopy

2011 ◽  
Vol 31 (6) ◽  
pp. 1482-1492 ◽  
Author(s):  
Bertan Hallacoglu ◽  
Angelo Sassaroli ◽  
Sergio Fantini ◽  
Aron M Troen
Keyword(s):  
Cognitive Impairment ◽  
Infrared Spectroscopy ◽  
Oxygen Saturation ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Arterial Oxygen Saturation ◽  
Hemoglobin Concentration ◽  
Microvascular Dysfunction ◽  
Common Finding ◽  
Arterial Oxygen

Brain microvascular pathology is a common finding in Alzheimer's disease and other dementias. However, the extent to which microvascular abnormalities cause or contribute to cognitive impairment is unclear. Noninvasive near-infrared spectroscopy (NIRS) can address this question, but its use for clarifying the role of microvascular dysfunction in dementia has been limited due to theoretical and practical considerations. We developed a new noninvasive NIRS method to obtain quantitative, dynamic measurements of absolute brain hemoglobin concentration and oxygen saturation and used it to show significant cerebrovascular impairments in a rat model of diet-induced vascular cognitive impairment. We fed young rats folate-deficient (FD) and control diets and measured absolute brain hemoglobin and hemodynamic parameters at rest and during transient mild hypoxia and hypercapnia. With respect to control animals, FD rats featured significantly lower brain hemoglobin concentration (72±4 μmol/L versus 95±6 μmol/L) and oxygen saturation (54%±3% versus 65%±2%). By contrast, resting arterial oxygen saturation was the same for both groups (96%±4%), indicating that decrements in brain hemoglobin oxygenation were independent of blood oxygen carrying capacity. Vasomotor reactivity in response to hypercapnia was also impaired in FD rats. Our results implicate microvascular abnormality and diminished oxygen delivery as a mechanism of cognitive impairment.

Experimental and theoretical comparison of NIR spectroscopy measurements of cerebral hemoglobin changes

1998 ◽  
Vol 85 (5) ◽  
pp. 1915-1921 ◽  
Author(s):  
Michael Firbank ◽  
Clare E. Elwell ◽  
Chris E. Cooper ◽  
David T. Delpy
Keyword(s):  
Coefficient Of Variation ◽  
Near Infrared ◽  
Cerebral Blood Volume ◽  
Nir Spectroscopy ◽  
Hemoglobin Concentration ◽  
Vessel Diameter ◽  
Theoretical Comparison ◽  
Before And After ◽  
The Difference ◽  
Absolute Measurements

Two near-infrared spectroscopy (NIRS) methods are available for measuring changes (Δ) in total cerebral hemoglobin concentration (CHC): 1) a continuous measurement of the changes in total hemoglobin concentration (Δ[Hb]tot) and 2) the difference between two absolute measurements of CHC, each derived from a small, controlled change in inspired O2 fraction. This paper investigates the internal consistency of these two methods by using an experimental and theoretical comparison. NIRS was used to measure [Hb]tot in five newborn piglets before and after a change in arterial[Formula: see text]. Δ[Hb]totdemonstrated a low coefficient of variation of 2.8 ± 2.8 (SD) % which allowed changes in CO2-cerebral blood volume reactivity to be clearly discriminated. However, a high coefficient of variation of 22.8 ± 3.5% on the ΔCHC measurements obscured any CO2 reactivity changes. A theoretical analysis demonstrates the effects of optical pathlength, background absorption, scatter, and blood vessel diameter on both methods. For more accurate monitoring of CHC, individual measurements of optical pathlength and more accurate pulse oximetry are required.

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

2011 ◽  
Vol 110 (6) ◽  
pp. 1646-1655 ◽  
Author(s):  
D. Canova ◽  
S. Roatta ◽  
D. Bosone ◽  
G. Micieli
Keyword(s):  
Infrared Spectroscopy ◽  
Blood Volume ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Cerebral Blood Volume ◽  
Valsalva Maneuver ◽  
Hemoglobin Concentration ◽  
Clinical Tests ◽  
Arterial Blood ◽  
Total Hemoglobin

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.

scholarly journals Cerebral Oxygenation and Hemodynamics During Induction of Extracorporeal Membrane Oxygenation as Investigated by Near Infrared Spectrophotometry

PEDIATRICS ◽  
1995 ◽  
Vol 95 (4) ◽  
pp. 555-561
Author(s):  
K. D. Liem ◽  
J. C. W. Hopman ◽  
B. Oeseburg ◽  
A. F. J. de Haan ◽  
C. Festen ◽  
...  
Keyword(s):  
Extracorporeal Membrane Oxygenation ◽  
Blood Volume ◽  
Near Infrared ◽  
Cerebral Blood Volume ◽  
Cerebral Oxygenation ◽  
Cerebral Arteries ◽  
Newborn Infants ◽  
Infrared Spectrophotometry ◽  
Membrane Oxygenation ◽  
Before And After

Objective. To investigate cerebral oxygenation and hemodynamics in relation to changes in some relevant physiologic variables during induction of extracorporeal membrane oxygenation (ECMO) in newborn infants. Methods. Twenty-four newborn infants requiring ECMO were studied from cannulation until 60 minutes after starting ECMO. Concentration changes of oxyhemoglobin (cO2Hb), deoxyhemoglobin (cHHb), total hemoglobin (ctHb), and (oxidized-reduced) cytochrome aa3 (cCyt.aa3) in cerebral tissue were measured continuously by near infrared spectrophotometry. Heart rate (HR), transcutaneous partial pressures of oxygen and carbon dioxide (tcPo2 and tcPco2), arterial O2 saturation (saO2), and mean arterial blood pressure (MABP) were measured simultaneously. Intravascular hemoglobin concentration (cHb) was measured before and after starting ECMO. In 18 of the 24 infants, mean blood flow velocity (MBFV) and pulsatility index (PI) in the internal carotid and middle cerebral arteries were also measured before and after starting ECMO using pulsed Doppler ultrasound. Results. After carotid ligation, cO2Hb decreased whereas cHHb increased. After jugular ligation, no changes in cerebral oxygenation were found. At 60 minutes after starting ECMO, the values of cO2Hb, saO2, tcPo2, and MABP were significantly higher than the precannulation values, whereas the value of cHHb was lower. There were no changes in cCyt.aa3, tcPco2, and HR, whereas cHb, decreased. The MBFV was significantly increased in the major cerebral arteries except the right middle cerebral artery, whereas PI was decreased in all measured arteries. Cerebral blood volume, calculated from changes in ctHb and cHb, was increased in 20 of 24 infants after starting ECMO. Using multivariate regression models, a positive correlation of ΔctHb (representative of changes in cerebral blood volume) with ΔMABP and a negative correlation with ΔtcPo2 were found. Conclusions. The alterations in cerebral oxygenation after carotid artery ligation might reflect increased O2 extraction. Despite increase of the cerebral O2 supply after starting ECMO, no changes in intracellular O2 availability were found, probably because of sufficient preservation of intracellular cerebral oxygenation in the pre-ECMO period despite prolonged hypoxemia. The increase in cerebral blood volume and cerebral MBFV may result from the following: (1) reactive hyperperfusion, (2) loss of autoregulation because of prolonged hypoxemia before ECMO and/or decreased arterial pulsatility, or (3) compensation for hemodilution related to the ECMO procedure.

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