Measurement of Optical Path Length for Cerebral Near-Infrared Spectroscopy in Newborn Infants

Wyatt, JS; Cope, M; Delpy, DT; Zee, Pieter van der; Arridge, Simon; Edwards, A. David; Reynolds, E. O. R.

doi:10.1159/000111843

Cited by 168 publications

(65 citation statements)

References 12 publications

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“…On the basis of previous studies in postmortem infants (22), an optical path length of 4.4 times the measured interoptode distance was assumed. Arterial O2 tension and Paco2 were estimated continuously using a transcutaneous monitor [Novametrix 850 (Novametrix Medical Systems, Wallingford, CT) or HewlettPackard 78834A (~ewlett-~ackard CO.; Palo Alto, CA)] calibrated against arterial blood gas measurement.…”

Section: Materlals and Methodsmentioning

confidence: 99%

Response of Cerebral Blood Volume to Changes in Arterial Carbon Dioxide Tension in Preterm and Term Infants

et al. 1991

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ABSTRACT. The response of cerebral blood volume (CBVR) to a small induced change in arterial carbon dioxide tension was studied by near-infrared spectroscopy in 17 newborn infants born from 26 wk of gestation to term. All 17 infants were undergoing mechanical ventilation but had apparently normal brains. The CBVR per kPa change in arterial carbon dioxide tension within the range 3.9 to 9.6 kPa was calculated from the change in total cerebral Hb concentration (

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Section: Materlals and Methodsmentioning

confidence: 99%

Response of Cerebral Blood Volume to Changes in Arterial Carbon Dioxide Tension in Preterm and Term Infants

et al. 1991

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“…In piglets each optode was positioned between the midline of the skull and the ear. Interoptode spacing was >2.5 cm, to ensure a constant path length multiplying factor (13), which has been stated to be 4.39 times the interoptode spacing (14). As the optical path length is wavelength-dependent, some modification of the algorithm has been made (15).…”

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Disturbance of Cerebral Oxygenation and Hemodynamics Related to the Opening of the Bypass Bridge during Veno-Arterial Extracorporeal Membrane Oxygenation

et al. 1995

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The objective of this study was to investigate changes of cerebral oxygenation and hemodynamics related to opening of the bypass bridge during veno-arterial extracorporeal membrane oxygenation (ECMO). Ten newborn infants and 12 piglets were studied during opening of the bridge for 10 and 1 s, respectively. Changes in cerebral concentration of oxyhemoglobin (c02Hb), deoxyhemoglobin (cHHb), (oxidized-reduced) cytochrome aa, (cCyt.aa,), and blood volume (CBV) were continuously measured by near infrared spectrophotometry. Heart rate, arterial 0, saturation (saO,), and mean arterial blood pressure (MABP) were measured simultaneously. In the piglets, central venous pressure (CVP), intracranial pressure (ICP), and left common carotid artery blood flow (CaBF) were also measured. Opening of the bridge for 10 s in the infants resulted in a significant decrease in MABP, sa02, and cO,Hb, whereas cHHb increased. CBV did not change significantly. In piglets biphasic changes were observed for MABP, CaBF, c02Hb, and CBV, showing an initial decrease followed by a smaller increase. cHHb and CVP showed reverse biphasic changes. ICP increased but sa02 was unchanged. In all cases heart rate and cCyt.aa, did not change significantly. Opening of the bridge for 1 s resulted in minor changes in only a few variables. In conclusion, opening of the bridge resulted in a decrease of CBV and cerebral 0, supply due to a decrease of cerebral blood flow, followed by a compensatory increase of cerebral 0, extraction and vasodilatation. The return of oxygenated blood after reclosing resulted in an increase of CBV with overcompensation of cerebral 0, supply. (Pediatr Res 38: 124-129, 1995) Abbreviations ECMO, extracorporeal membrane oxygenation NIRS, near infrared spectrophotometry cO,Hb, oxyhemoglobin concentration2 cHHb, deoxyhemoglobin concentration2 ctHb, total Hb concentration2 cCyt.aa,, (oxidized-reduced) cytochrome aa, concentration CBV, cerebral blood volume CBF, cerebral blood flow CaBF, mean carotid blood flow saO,, arterial 0, saturation MABP, mean arterial blood pressure CVP, central venous pressure ICP, intracranial pressure ECMO improves the survival rate of newborn infants with (3,4). Cerebrovascular injury is one of the important predictors severe respiratory failure, who do not respond to conventional of poor neurodevelopmental outcome (3). treatment (1, 2). In many short-term follow up studies the In the ECMO circuit a bypass bridge is placed between the handicap rate among survivors was reported to be about 20% arterial and the venous tubing to allow continuation of blood circulation in the ECMO system during an emergency when the Received June 30, 1994; accepted March 9, 1995. patient is taken off ECMO by clamping both cannulae (5, 6).

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“…in a reflection-like geometry. Due to lack of direct determination of optical path length, we used the interoptode distance in cm multiplied by a fixed path length factor of 4.4 (9). [HbO,] and [Hb] were calculated from the attenuation of the emitted light at three wavelengths, i-e. 774, 806, and 910 nm (3).…”

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Cerebrovascular Responses to Carbon Dioxide as Detected by Near-Infrared Spectrophotometry: Comparison of Three Different Measures

Brun

Greisen

1994

Pediatr Res

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Near-infrared spectrophotometry can be used to measure cerebral concentrations of oxyhemoglobin and deoxyhemoglobin. This has been applied to developing methods for quantifying cerebral blood volume glob i which is relevant for the investigation of the pathogenesis of brain injury in newborn infants as well as older infants. This study investigates the internal consistency between measurements of CBV using two methods: the oxygen method, which is able to determine absolute values of CBV, and the total Hb method, which can detect changes in CBV only. Cerebral blood flow (CBF) was also measured. Fifteen premature infants were examined. Due to practical problems, in only eight of these was a minimum of two CBF and two CBV values obtained both before and after a change in arterial Pco, of at least 0.5 kPa. A significant difference between the CBV-CO, reactivity found by the two methods was demonstrated: 0.89 mUlOO g/kPa (95% confidence interval = 0.63-1.26) for the oxygen method and 0.22 mUlOO g/kPa (95% confidence interval = 0.084.36) for the total Hb method. This finding is substantiated by the absolute values of CBV [mean value = 3.7 mUlOO g (SD = 1.1)], CBF [mean value = 11.3 mUlOO glmin (SD = 5.9)], and CBF reactivity 159 2 9% (SEM)]. All the values Measuring CBV is relevant in the investigation of the pathophysiology of hemorrhagic and hypoxic-ischemic brain injury. Methods used so far for absolute quantification such as radioactive erythrocyte labeling have not been feasible for clinical practice.NIRS is a method for measuring changes in [Hb] and [HbO,] using the Beer-Lambert relationship between the attenuation of the emitted light and the concentration of absorber. This has led to methods for quantifying CBF and CBV (1, 2). NIRS is a relatively fast, easily reproducible, noninvasive method that may appeal to clinicians for use in a number of settings. In particular it is tempting to use the directly available trace of the sum of correspond well with previous findings, although the CBV reactivity determined by the oxygen method has not been reported previously. The reason for the discrepancy between the two methods is unclear, but induced changes in the scattering properties of the brain would give rise to errors influencing the total Hb method rather than the oxygen method. (Pediatr Res 36: 20-24, 1994) Abbreviations CBV, cerebral blood volume CBV,, cerebral blood volume measured by the oxygen method CBV,, change in cerebral blood volume as detected by the total Hb method CBF, cerebral blood flow CBF,, cerebral blood flow measured by the oxygen method NIRS, near-infrared spectrophotometry Sat, arterial oxygen saturation [Hb], cerebral concentration of deoxyhemoglobin [HbO,], cerebral concentration of oxyhemoglobin FiO,, fraction of inspired oxygen 01, oxygenation index CI, confidence interval the oxyhemoglobin and deoxyhemoglobin signals, the total Hb, as an indicator for changes in CBV, and it has already been used in a number of reports (3-7).The aim of this study was to quantitate the CBV-CO, reactivity...

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Measurement of Optical Path Length for Cerebral Near-Infrared Spectroscopy in Newborn Infants

Cited by 168 publications

References 12 publications

Response of Cerebral Blood Volume to Changes in Arterial Carbon Dioxide Tension in Preterm and Term Infants

Response of Cerebral Blood Volume to Changes in Arterial Carbon Dioxide Tension in Preterm and Term Infants

Disturbance of Cerebral Oxygenation and Hemodynamics Related to the Opening of the Bypass Bridge during Veno-Arterial Extracorporeal Membrane Oxygenation

Cerebrovascular Responses to Carbon Dioxide as Detected by Near-Infrared Spectrophotometry: Comparison of Three Different Measures

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