Determinants of Cerebral Fractional Oxygen Extraction Using Near Infrared Spectroscopy in Preterm Neonates

Wardle, S P; Yoxall, C W; Weindling, A M

doi:10.1097/00004647-200002000-00008

Cited by 122 publications

(104 citation statements)

References 56 publications

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“…This previous study described lower cerebral OEF in a cohort of 11 infants, with two preterm infants having extremely low CMRO 2 and cerebral OEF. The values demonstrated in our study, however, are comparable with more recent studies of cerebral OEF in both preterm infants (Wardle et al, 1998) and in older children undergoing cardiopulmonary bypass (Wardle et al, 2000). The discrepancy between our data and that of Altman et al most probably reflects the differences between the two study populations.…”

Section: Discussionsupporting

confidence: 55%

Cerebral Fractional Oxygen Extraction is Inversely Correlated with Oxygen Delivery in the Sick, Newborn, Preterm Infant

Kissack

Garr

Wardle

et al. 2005

J Cereb Blood Flow Metab

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Cerebral blood flow (CBF) is known to be low in newborn infants, but this has not been shown to be damaging. The purpose of this study was to investigate the relationships between cerebral haemoglobin flow, blood flow, oxygen delivery, oxygen consumption, venous saturation, and fractional oxygen extraction (OEF) in newborn, preterm infants. Measurements were made by nearinfrared spectroscopy in 13 very preterm, extremely low birth weight infants (median gestation 25 weeks) during the first 3 days after birth. There was a negative correlation between cerebral oxygen delivery and OEF (n ¼ 13, r ¼ À0.5, P ¼ 0.03), which implies that when there is a reduction in cerebral oxygen delivery in sick preterm infants, increased cerebral oxygen extraction may be responsible for maintaining oxygen availability to the brain. During the first 3 days after birth CBF (n ¼ 13, r ¼ 0.7, P ¼ 0.01), oxygen delivery (n ¼ 13, r ¼ 0.5, P ¼ 0.03), and oxygen consumption (n ¼ 13, r ¼ 0.7, P ¼ 0.004) all increased. This increase in oxygen consumption indicates increased cerebral metabolic activity after birth, which is likely to be a normal adaptation to extrauterine life. The increases in blood flow and oxygen delivery may also be normal adaptations that facilitate this increase in metabolic activity. There was a decrease (P ¼ 0.04) in mean (7s.d.) cerebral OEF between day 1 (0.3770.10) and day 2 (0.2970.09), with no change between day 2 and day 3. Taking into account the negative correlation between OEF and oxygen delivery, this decrease in OEF may be because of increased oxygen delivery during this time.

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Section: Discussionsupporting

confidence: 55%

Cerebral Fractional Oxygen Extraction is Inversely Correlated with Oxygen Delivery in the Sick, Newborn, Preterm Infant

Kissack

Garr

Wardle

et al. 2005

J Cereb Blood Flow Metab

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“…The Hamamatsu NIRO 500 and a pulse oximeter in beat-to-beat mode (Datex-Ohmeda) with partial jugular venous occlusion was used to measure cerebral venous oxygen saturation (CSvO 2 ). The CSvO 2 value was the mean of five partial jugular venous occlusions made over a 5 to 10 min period and selected using preset criteria (8,18). Cerebral arterial oxygen saturation (CSaO 2 ) was assumed to be equal to peripheral arterial oxygen saturation.…”

Section: Methodsmentioning

confidence: 99%

“…Cerebral arterial oxygen saturation (CSaO 2 ) was assumed to be equal to peripheral arterial oxygen saturation. CFOE was calculated using the formula: CFOE ϭ CSaO 2 -CSvO 2 / CSaO 2 (8,18).…”

Section: Methodsmentioning

confidence: 99%

“…This effect of arterial carbon dioxide tension (PaCO 2 ) on the brain is likely to be mediated through its effect on cerebral blood flow, which is decreased by hypocarbia. In such a situation, cerebral fractional oxygen extraction (CFOE) would be expected to increase, as cerebral oxygen delivery is reduced (8). Decreased cerebral oxygen delivery would also be expected to be associated with reduced cerebral electrical activity.…”

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confidence: 99%

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Effect of carbon dioxide on background cerebral electrical activity and fractional oxygen extraction in very low birth weight infants just after birth

et al. 2005

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Decreased arterial carbon dioxide tension (PaCO 2 ) results in decreased cerebral blood flow, which is associated with diminished cerebral electrical activity. In such a situation, cerebral fractional oxygen extraction (CFOE) would be expected to increase to preserve cerebral oxygen delivery. This study aimed to determine whether changes in blood gases in infants less than 30 wk' gestation were associated with changes in background electroencephalograms (EEG) and CFOE. Thirty-two very low birth weight infants were studied daily for the first three days after birth. Digital EEG recordings were performed for 75 min each day. CFOE, mean blood pressure and arterial blood gases were measured midway through each recording. EEG was analysed by (a) spectral analysis and (b) manual calculation of interburst interval. Blood pressure, pH and PaCO 2 did not have any effect on the EEG. On day one, only PaCO 2 showed a relationship with the relative power of the delta frequency band (0.5-3.5 Hz) and the interburst interval. The relative power of the delta band remained within normal limits when PaCO 2 was between 24 and 55 mm Hg on day one. There was a negative association between PaCO 2 and CFOE. The associations between PaCO 2 and EEG measurements were strongest on day one, weaker on day two, and absent on day three. The slowing of EEG and increased CFOE at lower levels of PaCO 2 are likely to be due to decreased cerebral oxygen delivery induced by hypocarbia. When PaCO 2 was higher, there was suppression of the EEG. Periventricular leukomalacia is an important cause of neurologic morbidity in very low birth weight infants (1) and has been associated with severe hypocarbia during the first 24 h after birth. This effect of arterial carbon dioxide tension (PaCO 2 ) on the brain is likely to be mediated through its effect on cerebral blood flow, which is decreased by hypocarbia. In such a situation, cerebral fractional oxygen extraction (CFOE) would be expected to increase, as cerebral oxygen delivery is reduced (8). Decreased cerebral oxygen delivery would also be expected to be associated with reduced cerebral electrical activity. A positive relationship between cerebral blood flow and integrated amplitude of the EEG has been demonstrated on a group of infants between 27 and 33 wk' gestation (9). However, no studies have described the relationship between background cerebral electrical activity and PaCO 2 in very low birth weight infants.Electroencephalography provides a noninvasive technique for monitoring cerebral electrical activity. The normal EEG pattern of infants less than 30 wk' gestation is markedly discontinuous and consists of long isoelectric periods called interburst intervals, interspersed with bursts of high voltage and mixed frequency activity (10). Two separate studies have linked adverse neurologic outcome of such infants with an abnormal background EEG activity characterised by prolonged Received February 18, 2004; accepted November 16, 2004

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“…Conclusions are limited by the fact that cerebrovascular autoregulation can also be impaired due to illness or therapeutic interventions. Two studies found intact cerebrovascular autoregulation in all of the preterm infants studied, either undergoing high-frequency oscillatory ventilation [26] or treated for hypotension [27]. This was based on the absent relationship between CBF or cerebral fractional oxygen extraction (measured by NIRS) and ABP.…”

Section: Autoregulatory Capacitymentioning

confidence: 99%

Measuring cerebrovascular autoregulation in preterm infants using near-infrared spectroscopy: an overview of the literature

Kooi¹,

Verhagen

Elting

et al. 2017

Expert Review of Neurotherapeutics

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(2017) Measuring cerebrovascular autoregulation in preterm infants using near-infrared spectroscopy: an overview of the literature, Expert Review of Neurotherapeutics, 17:8, 801-818, DOI: 10.1080/14737175.2017 Introduction:The preterm born infant's ability to regulate its cerebral blood flow (CBF) is crucial in preventing secondary ischemic and hemorrhagic damage in the developing brain. The relationship between arterial blood pressure (ABP) and CBF estimates, such as regional cerebral oxygenation as measured by near-infrared spectroscopy (NIRS), is an attractive option for continuous non-invasive assessment of cerebrovascular autoregulation. Areas covered: The authors performed a literature search to provide an overview of the current literature on various current clinical practices and methods to measure cerebrovascular autoregulation in the preterm infant by NIRS. The authors focused on various aspects: Characteristics of patient cohorts, surrogate measures for cerebral perfusion pressure, NIRS devices and their accompanying parameters, definitions for impaired cerebrovascular autoregulation, methods of measurements and clinical implications. Expert commentary: Autoregulation research in preterm infants has reported many methods for measuring autoregulation using different mathematical models, signal processing and data requirements. At present, it remains unclear which NIRS signals and algorithms should be used that result in the most accurate and clinically relevant assessment of cerebrovascular autoregulation. Future studies should focus on optimizing strategies for cerebrovascular autoregulation assessment in preterm infants in order to develop autoregulation-based cerebral perfusion treatment strategies. ARTICLE HISTORY

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Determinants of Cerebral Fractional Oxygen Extraction Using Near Infrared Spectroscopy in Preterm Neonates

Cited by 122 publications

References 56 publications

Cerebral Fractional Oxygen Extraction is Inversely Correlated with Oxygen Delivery in the Sick, Newborn, Preterm Infant

Cerebral Fractional Oxygen Extraction is Inversely Correlated with Oxygen Delivery in the Sick, Newborn, Preterm Infant

Effect of carbon dioxide on background cerebral electrical activity and fractional oxygen extraction in very low birth weight infants just after birth

Measuring cerebrovascular autoregulation in preterm infants using near-infrared spectroscopy: an overview of the literature

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