Cerebral oxygenation and haemodynamics in the foetus and newborn infant

Wyatt, John

doi:10.1098/rstb.1997.0051

Cited by 16 publications

(22 citation statements)

References 31 publications

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“…Mean ⌬CBV changed from ϩ 0.006 mL/100 g (pretest) to ϩ 0.09 mL/100 g (in-test) and ϩ0.04 mL/100 g (posttest). To date the literature has described an increased ⌬CBV on visual stimulation (7,8) or hypoxicischemic brain injury (18,(31)(32)(33) or increasing P C02 (15). Pellicer et al (34) studied NIRS response to an i.v.…”

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confidence: 99%

Brain Auditory Activation Measured by Near-Infrared Spectroscopy (NIRS) in Neonates

et al. 2001

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This study presents a new measure of the hemodynamic changes to an auditory stimulus in newborns. Nineteen newborns born at 28-41 wk and aged 1 to 49 d were studied in waking and/or sleeping state, for a median time of 4 min 40 s before, 2 min 40 s during, and 3 min 5 s after an acustic stimulus (tonal sweep of frequency increasing from 2 to 4 kHz, intensity 90 dB SPL) originating 5 cm from the external auditory meatus. The emitter and detector optodes were placed over the left or right temporal region, corresponding to T3 or T4 EEG electrodes. Near-infrared transmission spectroscopy (NIRS) through tissue is made possible by the transparency of biologic tissue to light in the near-infrared region (750 -1000 nm). The noninvasive nature of the technique and the portability of the device, combined with the relative transparency of the neonatal head, explain the early applications of the machine in neonatal intensive care units, to the observation of hemodynamic brain responses. Our study presents a method for applying NIRS to the testing of central auditory response in newborns by using an acustic stimulus, a tonal sweep with a frequency increasing from 2 to 4 KHz. The incident near-infrared light from the transmitting optode is scattered through the tissues, and the reflected light is read by a receiving optode. The amount of the light that a compound absorbs is dependent upon the wavelength of the incident light upon it, and is described by the spectrum of a single compound. Brain absorption of the light is due to the main cerebral chromophores, oxyhemoglobin (HbO 2 ), deoxyhemoglobin (Hb), and oxidized cytochrome oxidase (CtOx) and is determined by the oxygenation status of the compound. Through NIRS we measured the loss of the intensity due to absorption of the incident photons by these solutes; this loss or attenuation is usually measured in units of OD (OD) and can be calculated using the Beer-Lambert law. For an absorbing compound dissolved in a nonabsorbing medium, the attenuation (A) is proportional to the concentration of the compound in the solution (c), the specific extinction coefficient of the compound (␣) and the optical path length (

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confidence: 99%

Brain Auditory Activation Measured by Near-Infrared Spectroscopy (NIRS) in Neonates

et al. 2001

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“…NIRS has been shown to be a useful non-invasive technique for monitoring cerebral oxygenation and haemodynamics in newborns [19,20] and adults [21][22][23][24][25].…”

Section: Discussionmentioning

confidence: 99%

Evaluation of potential factors affecting the measurement of cerebrovascular reactivity by near-infrared spectroscopy

TOTARO¹,

BARATTELLI²,

Quaresima³

et al. 1998

Clinical Science

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1.Near-infrared (IR) spectroscopy is based on the relative transparency of skin, skull and brain to the light in the near-IR region (700-1100 nm) and on the oxygen-dependent tissue absorption changes of haemoglobin.2. We evaluated the most relevant factors (reproducibility, venous return, age and sex) that might affect reliability of near-IR spectroscopy to test CO2 cerebrovascular reactivity.3.Thirty-four healthy volunteers were enrolled in the study. The protocol consisted of a 3-min baseline, a 3-min hypercapnia (5% CO2 in air) and a 2-min recovery. Transcranial Doppler sonography measurements were simultaneously performed. The CO2 reactivity test was repeated on 27 subjects after 1 h to assess reproducibility. CO2 reactivity was also evaluated at different body positions (supine, 35 degrees Trendelenburg and 35 degrees reverse Trendelenburg), and over a gradual increase of the inspired CO2.4. Changes in near-IR spectroscopy and transcranial Doppler sonography parameters were significantly correlated with variations of end-tidal CO2 (P<0.005). A significant correlation between the reactivity indexes of near-IR spectroscopy parameters and flow velocity was also found (P<0.01). A high reproducibility was also found for deoxyhaemoglobin (rI=0.76), oxyhaemoglobin (rI=0.68) and flow velocity (rI=0.60) reactivity indexes. No significant differences between the reactivity indexes of different body positions were found (P>0.05). The reactivity index of oxyhaemoglobin and deoxyhaemoglobin decreased (P<0.05) and increased (P<0.01) with age respectively.5. We found that near-IR spectroscopy is a reliable and reproducible method for the evaluation of cerebrovascular reactivity and might be considered, after appropriate validation, for the assessment of patients with cerebrovascular disease.

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“…NIR became popular after a publication by Jobsis in 1977, which showed its potential to monitor cerebral 29 Since then, NIR has been used as an investigative tool to assess cerebral and muscle perfusion in neonates and adults along with the determination of end points of resuscitation in trauma patients. 21,[30][31][32][33] Its capacity to accurately determine changes in blood volume, oxygenation, and hydration that occur deep within the tissue as a result of impaired circulation or ischemia has been well documented. [34][35][36][37][38][39][40][41][42][43] To date, very little work has been performed using NIR spectroscopy to determine burn depth.…”

Section: Discussionmentioning

confidence: 99%

Clinical utilization of near‐infrared spectroscopy devices for burn depth assessment

Cross

Leonardi

Payette

et al. 2007

Wound Repair Regeneration

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The diagnosis of burn depth is based on a visual assessment and can be subjective. Near-infrared (NIR) spectroscopic devices were used preclinically with positive results. The purpose of this study was to test the devices in a clinical setting using easily identifiable burn wounds. Adult patients with acute superficial and full-thickness burns were enrolled. NIR point spectroscopy and imaging devices were used to collect hemodynamic data from the burn site and an adjacent unburned control site. Oxy-hemoglobin and deoxy-hemoglobin concentrations were extracted from spectroscopic data and reported as oxygen saturation and total hemoglobin. Sixteen patients (n=16) were included in the study with equal numbers in both burn wound groups. Point spectroscopy data showed an increase in oxygen saturation (p<0.0095) and total hemoglobin (<0.0001) in comparison with the respective control areas for superficial burn wounds. The opposite was true for full-thickness burns, which showed a decrease in oxygenation (p<0.0001) and total hemoglobin (p<0.0147) in comparison with control areas. NIR imaging technology provides an estimate of hemodynamic parameters and could easily distinguish superficial and full-thickness burn wounds. These results confirm that NIR devices can successfully distinguish superficial and full-thickness burn injuries.

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Cerebral oxygenation and haemodynamics in the foetus and newborn infant

Cited by 16 publications

References 31 publications

Brain Auditory Activation Measured by Near-Infrared Spectroscopy (NIRS) in Neonates

Brain Auditory Activation Measured by Near-Infrared Spectroscopy (NIRS) in Neonates

Evaluation of potential factors affecting the measurement of cerebrovascular reactivity by near-infrared spectroscopy

Clinical utilization of near‐infrared spectroscopy devices for burn depth assessment

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