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D Azzopardi

Publications and source records attributed to D Azzopardi.

At least 19 recordsLinked to original sources
PubMed2006

Maturation of cerebral electrical activity and development of cortical folding in young very preterm infants.

OBJECTIVE: The aim of this study was to examine the relationship between cortical development and cerebral electrical activity at early gestational ages. METHODS: We obtained EEGs (7.2+/-3.8 days) and MR brain images (3.2+/-2.9 days) after birth in 17<30 week gestation infants without evidence of focal brain injury The EEGs were assessed for discontinuity and characteristic maturational features (delta brush, occipital and temporal sawtooth); cortical development was quantified from MR scans using a specially designed computer programme to measure cortical folding. RESULTS: The inter-burst interval shortened and cortical folding increased with increasing post-menstrual age (PMA). In contrast, the minimum duration of bursts was independent of PMA and cortical folding. Delta brush (8-20 Hz activities) was seen at all PMAs; temporal and occipital sawtooth activities were always more prominent than delta brush but were seen less frequently with increasing PMA and complexity of cortical folding. CONCLUSION: There was a positive correlation between some but not all maturational features of the preterm neonatal EEG and the complexity of whole brain cortical folding and PMA. These relationships were strong for the inter-burst interval, a global measure of maturation, but not strongly seen for regional features such as occipital and temporal sawtooth within this gestational age range. SIGNIFICANCE: Combining neurophysiological examination with detailed neuroimaging gives insights into developmental changes occurring in the very preterm brains and suggests further comparative studies focusing on measures of focal brain development at different gestational ages.

Cerebral Cortex↗
PubMed2001

Combined use of electroencephalogram and magnetic resonance imaging in full-term neonates with acute encephalopathy.

OBJECTIVE: The electroencephalogram (EEG) is widely used in full-term infants with acute neonatal encephalopathy, and its prognostic value has been confirmed by several studies. Magnetic resonance imaging (MRI) of the brain has also been applied in these patients, and increasing numbers of reports affirm its prognostic reliability. The aim of this study has been to investigate the correlation between an early EEG and MRI findings in infants with acute neonatal encephalopathy and to assess the prognostic value of a combination of EEG and MRI findings. PARTICIPANTS AND METHODS: Twenty-five full-term infants had an EEG recorded within the first 72 hours after birth and a neonatal brain MRI scan after the end of the first week. RESULTS: Both EEG and MRI were predictive of outcome. A normal MRI was always associated with normal EEG background activity and normal outcome and severe abnormalities on MRI with marked EEG abnormalities and an abnormal outcome. When the MRI showed moderate abnormalities, the EEG in all cases but one identified patients with normal and abnormal outcome.EEG, MRI, HIE, neurodevelopment.

Brain↗
PubMed2001

Comparison of findings on cranial ultrasound and magnetic resonance imaging in preterm infants.

OBJECTIVE: To compare findings on hard copies of cranial ultrasound (US) and magnetic resonance imaging (MRI) obtained between birth and term in a group of preterm infants. PARTICIPANTS AND METHODS: Infants born at or below a gestational age of 30 weeks who underwent cranial US scan and MRI on the same day were eligible for this study. Infants underwent, whenever possible, 3 scans between birth and term. We calculated the predictive probability (PP) of US findings as a predictor of findings on MRI. RESULTS: Sixty-two paired MRI and US studies were performed between birth and term in 32 infants born at a median gestational age of 27 (range: 23-30) weeks and a median birth weight of 918 (530-1710) grams. US predicted some MRI findings accurately: germinal layer hemorrhage (GLH) on US had a PP of 0.8 with a 95% confidence interval of (0.70-0.90) for the presence of GLH on MRI, intraventricular hemorrhage (IVH) on US had a PP of 0.85 (0.76-0.94) for the presence of IVH on MRI, and severe white matter (WM) echogenicity on US had a PP of 0.96 (0.92-1.0) for the presence of WM hemorrhagic parenchymal infarction on MRI. Other MRI changes were less well-predicted: mild or no WM echogenicity on US had a PP of 0.54 (0.41-0.66) for the presence of normal WM signal intensity on MRI, and moderate or severe WM echogenicity on US had a PP of 0.54 (0.42-0.66) for the presence of small petechial WM hemorrhage and/or diffuse excessive high-signal intensity (DEHSI) in the WM on T2-weighted images on MRI. However, mild/moderate or severe WM echogenicity on US scans performed at >/=7 days after birth had a PP of 0.72 (0.58-0.87) for the presence of WM hemorrhage and/or DEHSI on MRI. There were no cases of cystic periventricular leukomalacia. CONCLUSION: US accurately predicted the presence of GLH, IVH, and hemorrhagic parenchymal infarction on MRI. However, its ability to predict the presence of DEHSI and small petechial hemorrhages in the WM on T2 weighted images is not as good, but improves on scans performed at >/=7 days after birth. In addition, normal WM echogenicity on US is not a good predictor of normal WM signal intensity on MRI.

Brain↗
PubMed2000

Occipital sawtooth: a physiological EEG pattern in very premature infants.

OBJECTIVE: To evaluate EEG maturational features in preterm infants below 27 weeks postmenstrual age. METHODS: EEGs recorded from 5 preterm infants (postmenstrual age 24-26 weeks) were examined and selected maturational features were scored and quantified. The five infants also had serial cranial ultrasound scans (US) and magnetic resonance images of the brain within the first weeks after birth. RESULTS: Background activity was markedly discontinuous in all patients and very variable. Temporal sawtooths occurred but less frequently than in older preterm infants. All 5 infants also showed a particular novel feature, characterized by rhythmic, regularly shaped, medium-high amplitude 4-7 Hz activities, lasting 0.5-3 s and located in the occipital regions. This pattern was symmetrical but sometimes asynchronous. CONCLUSIONS: Occipital sawtooth, so called because it shares shape and frequency with temporal sawtooth but has an occipital localisation, constitutes a physiological EEG pattern characteristic of premature infants between 24 and 26 weeks of postmenstrual age.

Electroencephalography↗
PubMed2000

Randomized double-blind controlled trial comparing the effects of ibuprofen with indomethacin on cerebral hemodynamics in preterm infants with patent ductus arteriosus.

A prospective randomized controlled trial was performed to compare the effects of ibuprofen with indomethacin on cerebral hemodynamics measured using near infrared spectroscopy in preterm infants during treatment for patent ductus arteriosus. Infants were randomly assigned to three intravenous doses of either indomethacin (0.20-0.25 mg/kg, 12 hourly) or ibuprofen (5-10 mg/kg, 24 hourly) and also received a dose of saline. The primary end points of the study were the effects of the first dose on cerebral blood flow (CBF) and cerebral blood volume. Fifteen infants received indomethacin and 18 received ibuprofen. The group mean (SD) values for CBF (mL x 100 g(-1) x min(-1)) before and after the first dose of indomethacin were 13.6 (4.1) and 8.3 (3.1), respectively, the change being significant (p<0.001). In contrast, no significant changes in CBF were observed with the first dose of ibuprofen, the respective before and after values being 13.3 (3.2) and 14.9 (4.7) mL x 100 g(-1) x min(-1). The median (interquartile range) value for change in cerebral blood volume (mL/100 g) after the first dose in the indomethacin group was -0.4 (-0.3 to -0.6) and in the ibuprofen group was 0.0 (0.1 to -0.1), the difference between the two groups being significant (p<0.001). Cerebral oxygen delivery changed significantly after the first dose in the indomethacin group but not in the ibuprofen group. Significant reductions in CBF, cerebral blood volume, and cerebral oxygen delivery also occurred after the 24-h dose of indomethacin, but there were no significant changes after the 48-h dose of saline in the indomethacin group or after the 24- and 48-h doses of ibuprofen. The patent ductus arteriosus closure rates after indomethacin and ibuprofen were 93 and 78%, respectively. We conclude that ibuprofen, unlike indomethacin, has no adverse effects on cerebral hemodynamics and appears to mediate patent ductus arteriosus closure.

Brain↗
PubMed2000

International Guidelines for Neonatal Resuscitation: An excerpt from the Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care: International Consensus on Science. Contributors and Reviewers for the Neonatal Resuscitation Guidelines.

The International Guidelines 2000 Conference on Cardiopulmonary Resuscitation (CPR) and Emergency Cardiac Care (ECC) formulated new evidenced-based recommendations for neonatal resuscitation. These guidelines comprehensively update the last recommendations, published in 1992 after the Fifth National Conference on CPR and ECC. As a result of the evidence evaluation process, significant changes occurred in the recommended management routines for: * Meconium-stained amniotic fluid: If the newly born infant has absent or depressed respirations, heart rate <100 beats per minute (bpm), or poor muscle tone, direct tracheal suctioning should be performed to remove meconium from the airway. * Preventing heat loss: Hyperthermia should be avoided. * Oxygenation and ventilation: 100% oxygen is recommended for assisted ventilation; however, if supplemental oxygen is unavailable, positive-pressure ventilation should be initiated with room air. The laryngeal mask airway may serve as an effective alternative for establishing an airway if bag-mask ventilation is ineffective or attempts at intubation have failed. Exhaled CO(2) detection can be useful in the secondary confirmation of endotracheal intubation. * Chest compressions: Compressions should be administered if the heart rate is absent or remains <60 bpm despite adequate assisted ventilation for 30 seconds. The 2-thumb, encircling-hands method of chest compression is preferred, with a depth of compression one third the anterior-posterior diameter of the chest and sufficient to generate a palpable pulse. * Medications, volume expansion, and vascular access: Epinephrine in a dose of 0.01-0.03 mg/kg (0.1-0.3 mL/kg of 1:10,000 solution) should be administered if the heart rate remains <60 bpm after a minimum of 30 seconds of adequate ventilation and chest compressions. Emergency volume expansion may be accomplished with an isotonic crystalloid solution or O-negative red blood cells; albumin-containing solutions are no longer the fluid of choice for initial volume expansion. Intraosseous access can serve as an alternative route for medications/volume expansion if umbilical or other direct venous access is not readily available. * Noninitiation and discontinuation of resuscitation: There are circumstances (relating to gestational age, birth weight, known underlying condition, lack of response to interventions) in which noninitiation or discontinuation of resuscitation in the delivery room may be appropriate.

Blood Volume↗
PubMed2000

Pilot study of treatment with whole body hypothermia for neonatal encephalopathy.

BACKGROUND: There is extensive experimental evidence to support the investigation of treatment with mild hypothermia after birth asphyxia. However, clinical studies have been delayed by the difficulty in predicting long-term outcome very soon after birth and by concern about adverse effects of hypothermia. OBJECTIVES: The objectives of this study were to determine whether it is feasible to select infants with a bad neurological prognosis and to begin hypothermic therapy within 6 hours of birth, and to observe the effect of this therapy on relevant physiologic variables. METHODS: Sixteen newborn infants with clinical features of birth asphyxia (median cord blood pH: 6.74; range: 6.58-7.08) were assessed by amplitude integrated electroencephalography (aEEG), and mild whole body hypothermia was instituted within 6 hours of birth in the 10 infants with an aEEG prognostic of a bad outcome. Rectal temperature was maintained at 33.2 +/- (standard deviation).6 degrees C for 48 hours. Rectal and tympanic membrane temperature, blood pressure, heart rate, blood gases, blood lactate, full blood count, blood electrolytes, high and low shear rate viscosity, and coagulation studies were monitored during and after cooling. A preliminary assessment of neurological outcome was made by repeated magnetic resonance imaging (MRI) and neurological examination. RESULTS: All infants selected to receive hypothermia developed convulsions and a severe encephalopathy. During 48 hours of hypothermia infants had prolonged metabolic acidosis (median pH: 7.30; base excess: -6.3 mmol x L(-1), a high blood lactate (median lactate: 5.3 mmol x L(-1)) and low blood potassium levels (median value: 3.9 mmol x L(-1)) x Hypothermia was associated with lower heart rate and higher mean blood pressure. However, these changes did not seem to be clinically relevant and no significant complication of hypothermia was encountered. Blood viscosity and coagulation studies were similar during and after cooling. Unusual MRI findings were noted in 3 infants: transverse sinus thrombosis with subsequent small cerebellar infarct; probable thrombosis in the straight sinus; and hemorrhagic cerebral infarction. Six of the 10 cooled infants had minor abnormalities only or normal follow-up neurological examination; 3 infants died and 1 had major abnormalities. None of the 6 infants with a normal aEEG developed severe neonatal encephalopathy or neurological sequel. CONCLUSIONS: After birth asphyxia infants can be objectively selected by aEEG and hypothermia started within 6 hours of birth in infants at high risk of developing severe neonatal encephalopathy. Prolonged mild hypothermia to 33 degrees C to 34 degrees C is associated with minor physiologic abnormalities. Further studies of both the safety and efficacy of mild hypothermia, including further neuroimaging studies, are warranted.

Asphyxia Neonatorum↗
PubMed1999

Prediction of neurological outcome after birth asphyxia from early continuous two-channel electroencephalography.

OBJECTIVE: To determine whether two-channel continuous electroencephalography (EEG) applied within 12 h of birth can predict the severity of neurological complications and neurodevelopmental outcome following birth asphyxia. METHODS: A continuous two-channel EEG was performed within 12 h of birth in 22 infants suspected of having suffered birth asphyxia and 11 healthy control infants (22 infants at a general and 11 at a specialist paediatric unit). Criteria to categorise normal and abnormal EEG records were defined and compared with the severity of hypoxic/ischaemic encephalopathy (HIE) and with neurodevelopmental outcome, assessed at or after 12 months of age. RESULTS: EEG recordings were commenced at a median (range) of 2 h 50 min (1 h 45 min to 12 h) after birth. Technically satisfactory recordings were obtained in all but one infant. All control infants remained asymptomatic and had a normal EEG with discernible sleep/awake periods. 12 h after birth the EEG was normal in all 12 infants suspected of asphyxia who remained well or developed grade 1 HIE and was abnormal in six of nine infants with grade II or III HIE. Fifteen of 16 infants suspected of asphyxia with a normal neurodevelopmental outcome had a normal EEG at 12 h; transient abnormalities lasting not more than 8 h had been detected in three of these infants. All five infants who died or developed neurodevelopmental abnormalities had an abnormal EEG. At 12 h of age the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and likelihood ratio for predicting severe (grade II or III) HIE were: 67, 100, 100, 80% and infinity and for subsequent death or neurodevelopmental impairments: 100, 94, 83, 100 and 16%, respectively. Assessment of the EEG before 12 h of age altered prognostic accuracy: 4 h after birth the sensitivity, specificity, positive and negative predictive values and the likelihood ratio for poor neurodevelopmental outcome were 100, 71, 33%, 100 and 3.7%, respectively (16 infants). CONCLUSION: Continuous two-channel EEG is an accurate tool for assessing the severity of neurological insult soon after birth asphyxia.

Asphyxia Neonatorum↗
PubMed1999

Relation between proton magnetic resonance spectroscopy within 18 hours of birth asphyxia and neurodevelopment at 1 year of age.

The aim of the study was to test the hypotheses that elevated cerebral lactate, detected by proton spectroscopy performed within 18 hours of suspected birth asphyxia, is associated with adverse outcome, and that increased lactate can be used to predict adverse outcome. Thirty-one term infants suspected of having had birth asphyxia and seven control infants underwent proton magnetic resonance spectroscopy, using three-dimensional chemical shift imaging, within 18 hours of birth. Adverse outcome was defined as death or neurodevelopmental impairment at 1 year of age or more. Nine infants had an adverse outcome. The other 22 and all of the control infants remained normal. Median (range) lactate/creatine plus phosphocreatine (lactate/creatine) ratios in the abnormal, the normal, and the control group were 1.14 (0.17 to 3.81), 0.33 (0 to 1.51), and 0.05 (0 to 0.6) respectively (P=0.003). Lactate/creatine >1.0 predicted neurodevelopmental impairment at 1 year of age with sensitivity of 66% and specificity of 95%, positive and negative predictive values of 86% and 88%, and a likelihood ratio of 13.2. Elevated cerebral lactate/creatine within 18 hours of birth asphyxia predicts adverse outcome.

Asphyxia Neonatorum↗
PubMed1999

Cerebral intracellular lactic alkalosis persisting months after neonatal encephalopathy measured by magnetic resonance spectroscopy.

We have found that cerebral lactate can be detected later than 1 month of age after neonatal encephalopathy (NE) in infants with severe neurodevelopmental impairment at 1 y. Our hypothesis was that persisting lactate after NE is associated with alkalosis and a decreased cell phosphorylation potential. Forty-three infants with NE underwent proton and phosphorus-31 magnetic resonance spectroscopy at 0.2-56 wk postnatal age. Seventy-seven examinations were obtained: 25 aged <2 wk, 16 aged > or = 2 to < or = 4 wk, 25 aged > 4 to < or = 30 wk, and 11 aged > 30 wk. Neurodevelopmental outcome was assessed at 1 y of age: 17 infants had a normal outcome and 26 infants had an abnormal outcome. Using univariate linear regression, we determined that increased lactate/creatine plus phosphocreatine (Cr) was associated with an alkaline intracellular pH (pHi) (p < 0.001) and increased inorganic phosphate/phosphocreatine (Pi/PCr) (p < 0.001). This relationship was significant, irrespective of outcome group or age at time of study. Between outcome groups, there were significant differences for lactate/Cr measured at < 2 wk (p = 0.005) and > 4 to < or = 30 wk (p = 0.01); Pi/PCr measured at < 2 wk (p < 0.001); pHi measured at < 2 wk (p < 0.001), > or = 2 to < or = 4 wk (p = 0.02) and > 4 to < or = 30 wk (p = 0.03); and for N-acetylaspartate/Cr measured at > or = 2 to < or = 4 wk (p = 0.03) and > 4 to < or = 30 wk (p = 0.01). Possible mechanisms leading to this persisting cerebral lactic alkalosis are a prolonged change in redox state within neuronal cells, the presence of phagocytic cells, the proliferation of glial cells, or altered buffering mechanisms. These findings may have implications for therapeutic intervention.

Brain↗
PubMed1999

Early prognostic indicators of outcome in infants with neonatal cerebral infarction: a clinical, electroencephalogram, and magnetic resonance imaging study.

OBJECTIVE: The aim of this study was to identify prognostic factors in newborns with cerebral infarction. DESIGN: Antenatal and perinatal factors and early clinical, electroencephalogram (EEG), and magnetic resonance imaging (MRI) findings were compared with neurodevelopmental outcome in 24 children with evidence of cerebral infarction on neonatal MRI. RESULTS: Out of 24 infants, 19 had an infarction in the territory of a major cerebral vessel and 5 in the borderzone between cerebral arteries. Neuromotor outcome was normal in 17 and abnormal in 7 infants. Of these 7 infants, 5 infants showed a definite hemiplegia, whereas the other 2 showed some asymmetry of tone or function but no definite hemiplegia. None of the adverse antenatal or perinatal factors was significantly associated with abnormal outcome. Neonatal clinical examination was also not always predictive of the outcome. The extent of the lesion on MRI was a better predictor. In particular, it was the concomitant involvement of hemisphere, internal capsule and basal ganglia that was always associated with an abnormal outcome whereas the involvement of only one or two of the three tended to be associated with a normal outcome. EEG was also very helpful. Abnormal background activity either unilateral or bilateral was found in 6 infants and 5 out of 6 developed hemiplegia. In contrast, the presence of seizure activity in presence of a normal background was not related to abnormal outcome. CONCLUSIONS: Early MRI and EEG can help to identify the infants with cerebral infarction who are likely to develop hemiplegia.

Cerebral Infarction↗
PubMed1999

Assessment of neonatal encephalopathy by amplitude-integrated electroencephalography.

OBJECTIVE: To define normal and abnormal patterns, test interobserver variability, and the prognostic accuracy of amplitude-integrated electroencephalography (aEEG) soon after the onset of neonatal encephalopathy. METHODS: Consecutive cases of neonatal encephalopathy (n = 56; gestation median, 40; range, 35-42 weeks) and healthy infants (n = 14; gestation median, 40; range, 39-40 weeks) were studied. aEEG was recorded using a cerebral function monitor, at median, 0, range, 0-21 days of age. Of the infants, 24 of the 56 with encephalopathy and all of the normal infants were studied within 12 hours of birth (median, 5; range, 3-12 hours). Forty infants were suspected of having suffered birth asphyxia. Criteria for normal and abnormal patterns were defined and the interobserver variability of these classifications determined. Results were compared with neurodevelopmental outcome assessed at 18 to 24 months of age. aEEG also was compared with a standard EEG and with magnetic resonance imaging. RESULTS: The median upper margin of the widest band of aEEG activity in the control infants was 37.5 microV (range, 30-48 microV), and median lower margin was 8 microV (range, 6.5-11 microV). We classified the aEEG background activity as normal amplitude, the upper margin of band of aEEG activity >10 microV and the lower margin >5 microV; moderately abnormal amplitude, the upper margin of band of aEEG activity >10 microV and the lower margin </=5 microV; and suppressed amplitude, the upper margin of the band of aEEG activity <10 microV and lower margin <5 microV. Recordings were analyzed further for the presence of seizures, defined as periods of sudden increase in voltage accompanied by a narrowing of the band of aEEG activity. Tests of interobserver variability showed excellent agreement both for assessment of amplitude (kappa statistic = 0.85) and for identification of seizures (kappa statistic = 0.76) There was a close relationship between the aEEG and subsequent outcome: 19 of 21 infants with a normal aEEG finding were normal on follow-up at 18 to 24 months of age, whereas 27 of 35 infants with a moderately abnormal or suppressed aEEG and/or seizures died or developed neurologic abnormalities. Thus, aEEG predicted outcome with a sensitivity of 0. 93, a specificity of 0.70, positive predictive value of 0.77, negative predictive value of 0.90, and the likelihood ratio of a positive result of 3.1 and a negative result of 0.06. For the 24 infants studied within 12 hours of birth, the corresponding results were sensitivity, 1.0; specificity, 0.82; positive predictive value, 0.85; negative predictive value, 1; likelihood ratio of a positive result, 5.5; and likelihood ratio of a negative result, 0.18. CONCLUSION: The aEEG is a simple but accurate and reproducible clinical tool that could be useful in the assessment of infants with encephalopathy.

Asphyxia Neonatorum↗
PubMed1998

Neonatal cranial ultrasonographic findings in preterm twins complicated by severe fetofetal transfusion syndrome.

OBJECTIVE: To investigate cranial ultrasonographic findings in survivors of monochorionic pregnancies complicated by fetofetal transfusion syndrome. STUDY DESIGN: Case details of all monochorionic twin pregnancies complicated by fetofetal transfusion syndrome were obtained from the Centre for Fetal Care database for a 3-year period. Fetofetal transfusion syndrome was diagnosed according to ultrasonographic criteria. Eligible for entry were twin pregnancies resulting in live-born preterm infants and complicated by fetofetal transfusion syndrome severe enough to require amnioreduction. Cranial ultrasonographic scans performed within 48 hours of birth were reviewed for evidence of abnormality. RESULTS: Seventeen pregnancies were eligible for inclusion in the study. Median gestational age was 25 weeks (between 17 and 29 weeks) at diagnosis and 30 weeks (between 25 and 35 weeks) at delivery. Three infants died before ultrasonography could be performed. The remaining 31 twin infants received an early cranial ultrasonographic scan. One of the 31 had a major cerebral infarct; 10 others had evidence of other, more minor, antenatally acquired lesions. CONCLUSIONS: Both donor and recipient survivors from pregnancies complicated by fetofetal transfusion syndrome are at significant risk for antenatally acquired cerebral lesions. Long-term neurologic follow-up studies are indicated to determine the clinical significance of these lesions.

Brain↗
PubMed1998

Physiological stability of preterm infants during magnetic resonance imaging.

AIM: This study looked for evidence of physiological disturbance in preterm infants undergoing magnetic resonance imaging (MRI). METHODS: Intensive care was continued, as appropriate, throughout scanning in each infant. The heart rate, oxygen saturation (SaO2), temperature and mean arterial blood pressure (BP) was monitored during MRI in preterm infants, median gestational age at birth 27 (range 23-32) weeks and median postnatal age at initial MRI, 3 days (range 1-42). The acoustic noise level during imaging was also measured. RESULTS: 2087 min of data were obtained from 39 examinations in 23 infants. The median heart rate was 159 and no bradycardia < 100 or tachycardia > 200 bpm occurred. Although 42 episodes of desaturation < 90% were detected only three were < 80, and these occurred in one infant due to endotracheal tube blockage. The median axillary temperature was 36.9 degrees C (range 35.7-37.8) and median BP (n = 6) was 37 mmHg (24-48). The ambient noise level in the MR system during scanning was 67-72 dBA. CONCLUSION: In preterm infants who required intensive care during scanning, MRI could be performed without major physiological instability.

Blood Pressure↗
PubMed1998

Measurement of cerebral blood flow in newborn infants using near infrared spectroscopy with indocyanine green.

Cerebral blood flow (CBF) measurement by near infrared spectroscopy (NIRS) using oxyhemoglobin (HbO2) as a tracer (CBF-HbO2) needs rapid changes in arterial oxygen saturation (SaO2) which often cannot be achieved in many sick infants. An alternative method based on the same adaptation of the Fick principle using i.v. injection of the dye indocyanine green (ICG) is described (CBF-ICG). Six mechanically ventilated infants (age 26-38 wk, birth weight 0.885-3.730 kg) requiring supplementary oxygen therapy were studied within 72 h of birth. For CBF-ICG measurements, ICG (0.1 mg x kg-1 was injected via an umbilical venous catheter, and blood ICG concentration was measured by an optical umbilical artery catheter and brain ICG concentration was measured by NIRS. For CBF-HbO2 measurements the inspired oxygen concentration was rapidly increased, blood HbO2 concentration was calculated from SaO2 measured by pulse oximetry, and brain HbO2 concentration was measured by NIRS. A series of CBF measurements were performed using each method before and after altering the arterial carbon dioxide tension (PaCO2). Mean CBF values from repeated measurements by each method at any given PaCO2 were used to compare the methods. The SD of single measurements within an individual subject by CBF-ICG was 15%, and by CBF-HbO2, 24%. The relationship between the methods was mean CBF-ICG = (1.13 x mean CBF-HbO2) - 2.76 mL x 100 g-1 x min-1 HbO2 (r = 0.93, p < 0.001). The mean difference between the methods (CBF-ICG - CBF-HbO2) was -0.25 mL x 100 g-1 x min-1 (95% confidence interval 6.30 to -6.80). The methods were in good agreement, and the use of i.v. ICG permitted rapid and repeated CBF measurements in the sickest infants at greatest risk of cerebral injury.

Brain↗