PubMed Health⌕ Search

Biomedical subjects

Linda S de Vries

Publications and source records attributed to Linda S de Vries.

At least 19 recordsLinked to original sources
PubMed2006

Using cerebral ultrasound effectively in the newborn infant.

Cranial ultrasound is the most available and easily repeatable technique for imaging the neonatal brain. Its quality and diagnostic accuracy depend on various factors; the suitability of the ultrasound machine for neonatal cranial work, the use of optimal settings and probes, appropriate scanning protocols, the use of a variety of acoustic windows and, not least, the scanning experience of the examiner. Knowledge of normal anatomy and the echogenicities of different tissues in normal and pathological situations as well as familiarity with the physiological and pathological processes likely to be encountered is vital. This paper assesses the value and appropriate use, safety and diagnostic accuracy of modern, high-quality ultrasound in evaluating the brain of the preterm and term born infant. Issues of concern regarding teaching, supervision and experience of the examiner are also addressed.

Brain↗
PubMed2006

The role of cranial ultrasound and magnetic resonance imaging in the diagnosis of infections of the central nervous system.

Imaging data concerning infection of the central nervous system (CNS) in neonates are usually confined to small groups of infants. We have reviewed the imaging findings in 96 preterm and full-term infants admitted to our neonatal intensive care unit over a 15 year period. Neuro-imaging, especially cranial ultrasound (CUS) and magnetic resonance imaging (MRI) provided useful information; CUS allows the early and later detection of calcification, germinolytic and parenchymal cysts, ventricular dilatation and strands and ependymal abnormality; diffusion weighted imaging (DWI) is especially useful in the acute stage of bacterial and viral infections, while conventional MRI helps in the detection of neocortical dysplasia in CMV infection and defining cerebellar abnormality.

Central Nervous System Infections↗
PubMed2006

Development of an optimal lidocaine infusion strategy for neonatal seizures.

INTRODUCTION: Lidocaine is an effective drug for the treatment of neonatal convulsions not responding to traditional anticonvulsant therapy. However, one of the side-effects is a risk of cardiac arrhythmias. The aim of this study was to develop an optimal dosing strategy with minimal risk of cardiac arrhythmias. MATERIALS AND METHODS: As a first step, we studied 20 neonates during routine treatment of neonatal seizures with lidocaine. All were given a loading dose of 2 mg/kg in 10 min, followed by the continuous infusion of 6 mg/kg per hour for 12 h, 4 mg/kg per hour for 12 h and finally 2 mg/kg per hour for 12 h. Effectiveness, cardiac toxicity and lidocaine plasma concentrations were then determined. RESULTS: No cardiac arrhythmias were observed, and lidocaine was effective in 76% of the treatments. In most of the treatments (13 out of 20) maximal lidocaine plasma concentrations were >9 mg/L. Plasma levels >9 mg/L have been related to cardiac toxicity when used as an anti-arrhythmic drug in adults. It was of interest that all preterm infants showed high lidocaine plasma levels. Secondly, we developed the optimal dosing regimen, which was defined as an infusion regimen at which maximal lidocaine plasma concentrations are <9 mg/L. Simulations with the developed pharmacokinetic model indicated a reduction in the infusion duration of lidocaine at 6 mg/kg per hour from 12 to 6 h. Thirdly, the new lidocaine dosing regimen was evaluated. Fifteen neonates (16 treatments) were studied. No cardiac arrhythmias were observed, and lidocaine was effective in 78% of the treatments. In most of the treatments (11 out of 16) maximal lidocaine plasma concentrations were <9 mg/L. Again preterm infants showed relatively high lidocaine plasma levels. CONCLUSION: A new lidocaine dosing schedule was developed. This new regimen should have a lower risk of cardiac arrhythmias and appears to be as effective in term infants. For preterm infants the optimal regimen needs to be determined.

Anti-Arrhythmia Agents↗
PubMed2006

Amplitude integrated electroencephalography in the full-term newborn.

Amplitude-integrated electroencephalography (aEEG) is beginning to play an important role in the care of full-term infants who have neonatal encephalopathy. The three main features an aEEG provides include (1) the background pattern, showing the activity at admission to the neonatal intensive care unit and the rate of recovery during the first 24 to 48 hours after birth; (2) the presence or absence of sleep-wake cycling; and (3) the presence of most electrographic discharges.

Brain↗
PubMed2006

Pre-wallerian degeneration in the neonatal brain following perinatal cerebral hypoxia-ischemia demonstrated with MRI.

AIM: Pre-Wallerian degeneration was studied in term and near-term neonates with hypoxic-ischemic brain injury, and related to neurodevelopmental outcome. SUBJECTS: Thirty-nine surviving patients with hypoxic-ischemic encephalopathy or seizures and MRI-documented brain abnormalities were included. Patients were grouped according to the MRI findings: group 1 (n = 23), ischemic stroke or watershed infarcts; group 2 (n = 8), lesions of the basal ganglia; group 3 (n = 8), predominantly white matter lesions. METHODS: Cranial MRI, including diffusion-weighted MRI, was performed between 1 and 10 days after birth. ADC maps were created, and presence or absence of pre-Wallerian degeneration in the cerebral peduncles was assessed. RESULTS: Of the 15 neonates with pre-Wallerian degeneration, 14 had permanent abnormalities of motor development, whereas 1 had a transient asymmetry. Six neonates with a poor outcome had no pre-Wallerian degeneration, which may be contributed to the timing of the MRI in 2. Eighteen neonates had no pre-Wallerian degeneration and a normal motor development. CONCLUSION: Pre-Wallerian degeneration of the cerebral peduncles in neonates with hypoxia-ischemia is almost invariably associated with a poor motor development. In neonates with abnormalities of the basal ganglia or white matter and a poor outcome, pre-Wallerian degeneration is less common than in neonates with stroke or watershed infarcts and a poor motor outcome.

Diffusion Magnetic Resonance Imaging↗
PubMed2006

Neonatal hydrocortisone treatment related to 1H-MRS of the hippocampus and short-term memory at school age in preterm born children.

Animal studies have shown that corticosteroids (dexamethasone) cause neuronal loss in the hippocampus and deficits in short term memory. Proton magnetic resonance spectroscopy can measure brain metabolites in vivo and give an indication of neuronal integrity. We investigated whether prolonged administration of hydrocortisone during the neonatal period for bronchopulmonary dysplasia (BPD) in preterm born children changes the metabolism in the hippocampus, measured at school age. Secondly, we investigated whether hippocampal metabolism and short-term memory and neurodevelopmental outcome are related. In this observational study 37 preterm born children (< or = 32 wk (range 25.0-33.0) and/or a birth weight < or = 1500 g) underwent proton spectroscopy of the hippocampus at school age. Eighteen children were treated with hydrocortisone for BPD (starting dose 5 mg/kg/d tapered over a minimum period of 22 d, median duration 28 d) and 19 never received corticosteroids during the perinatal period. N-acetyl aspartate/ Choline + Creatine/phosphocreatine (NAA/(Cho + Cr)) ratios were determined. A 15-word recall memory test and an IQ measurement were obtained on the same day. Hydrocortisone treated children were younger, lighter and sicker than their nonsteroid treated counterparts. Mean NAA/(Cho + Cr) ratios in the hippocampus were not significantly different in the hydrocortisone group compared with the non-steroid group. Performance on the 15-word memory test and IQ were similar in the two groups. There was no relation between NAA/(Cho + Cr) ratios and memory nor between NAA/(Cho + Cr) ratios and IQ. We conclude that hydrocortisone in the mentioned dose, administered in the neonatal period for BPD, does not appear to have any long-term effects on memory and/or hippocampal metabolism.

Hippocampus↗
PubMed2005

Magnetic resonance angiography of cerebral arteries after neonatal venoarterial and venovenous extracorporeal membrane oxygenation.

BACKGROUND AND PURPOSE: In newborns with severe respiratory failure, extracorporeal membrane oxygenation (ECMO) has been proven to improve survival. With venoarterial ECMO, the right common carotid artery is ligated, whereas with venovenous ECMO, this carotid artery remains intact. The authors present the magnetic resonance angiography (MRA) evaluation of cerebral hemodynamics in a case of venoarterial and a case of venovenous ECMO. METHODS: With 2D phase-contrast MRA flow volume (mL/min), measurements are obtained of the brain feeding arteries and draining veins. Time-of-flight and flow-directional MRA are used to demonstrate the anatomy and flow patterns at the level of the circle of Willis. RESULTS: A total volume flow of 63 mL/min at the skull base and collateral flow via the anterior circle of Willis were measured in the infant after venoarterial ECMO, and a total volume flow of 86 mL/min and a fetal type configuration of the circle of Willis were observed in the infant after venovenous ECMO. CONCLUSION: MRA is a useful technique to quantify cerebral blood flow in neonates after venoarterial or venovenous ECMO and could be used to select neonates with insufficient collateral compensation after venoarterial ECMO, requiring revascularization surgery.

Carotid Arteries↗
PubMed2005

Early diffusion-weighted MRI and 1H-Magnetic Resonance Spectroscopy in asphyxiated full-term neonates.

AIM: To assess the predictive value of early MRI and proton MR spectroscopy ((1)H-MRS), 11 full-term neonates with severe perinatal asphyxia were studied within 48 h after birth. METHODS: T(1)- and T(2)-weighted MRI, diffusion-weighted MRI (DW-MRI), apparent diffusion coefficient of water (ADC) of the basal ganglia and parietal white matter, as well as (1)H-MRS of the basal ganglia were performed in a 1.5-Tesla magnetic field. Neurodevelopment was assessed in the survivors for at least 24 months. RESULTS: Nine of the 11 neonates had a poor outcome (7 died, 2 developed cerebral palsy). All examinations were normal in the 2 neonates with a good outcome. T(1)- and T(2)-weighted MRI were abnormal in 7, DWI was abnormal in 7, ADC was abnormal in 5, and elevated lactate/N-acetylaspartate ratios using (1)H-MRS were seen in 7 of the 9 neonates with a poor outcome. None of these 9 had completely normal MRI or (1)H-MRS findings. CONCLUSIONS: Using a combination of T(1)- and T(2)-weighted MRI, DW-MRI, ADC measurements and (1)H-MRS within 48 h after severe perinatal asphyxia, no abnormalities were seen with any of these techniques in both neonates with a good outcome.

Asphyxia Neonatorum↗
PubMed2005

Severe umbilical cord acidemia and neurological outcome in preterm and full-term neonates.

BACKGROUND: Severe intrauterine hypoxia-ischemia and acidemia may lead to a disturbed neurodevelopment. OBJECTIVES: To study the effects of acidemia at birth on neurodevelopment in preterm and full-term neonates. SUBJECTS AND METHODS: Short- and long-term outcome were studied retrospectively in 44 inborn preterms and 95 full-terms with severe acidemia at birth defined as a pH of the umbilical artery <7.00. Outcome was compared with 67 preterm and 90 full-term non-acidemic neonates (pH>7.15). Intraventricular hemorrhage (preterms) or seizures (both preterms and full-terms) were considered an adverse short-term outcome. Neonatal death, cerebral palsy or neurodevelopmental delay were considered an adverse long-term outcome. RESULTS: Severe intraventricular hemorrhage (IVH) occurred in 5 of the 44 (11%) acidemic preterms and in none of the 67 (0%) non-acidemic preterms (p<0.01). Seizures were observed in 9 of the 44 (20%) and 11 of the 95 (12%) acidemic preterms and full-terms, respectively, and in none of the 67 (0%) and 1 of the 90 (1%) non-acidemic preterms and full-terms, respectively (p<0.001 for preterms, p<0.01 for full-terms). Nine preterms (6 acidemic, 3 non-acidemic) and 2 full-terms (both acidemic) died in the neonatal period. Adverse long-term outcome occurred in 32% of the acidemic preterms, in 21% of the non-acidemic preterms, in 7% of the acidemic full-terms and in 7% of the non-acidemic full-terms. CONCLUSIONS: Acidemia at birth increased the occurrence of severe IVH in preterm neonates and seizures in both preterm and full-term neonates. However, no significant effect of acidemia on long-term outcome could be demonstrated.

Acidosis↗
PubMed2005

Postneonatal epilepsy following amplitude-integrated EEG-detected neonatal seizures.

To assess the incidence of postneonatal epilepsy in term infants treated with antiepileptic drugs for neonatal seizure discharges that were detected with amplitude-integrated electroencephalography (aEEG), 206 term infants were monitored using this modality. They received antiepileptic drugs for clinical as well as subclinical neonatal seizures. Follow-up data were analyzed for the development of postneonatal epilepsy and for their neurodevelopmental outcome, assessed at 3, 9, 18 months, and 3 and 5 years of age. A total of 169 (82%) neonates received two or more antiepileptic drugs. Overall mortality was 39% (n = 80). Forty-one of the 126 survivors (33%) were abnormal at follow-up, and 12 of them developed postneonatal epilepsy (9.4%). Eighty-four children survived after hypoxic-ischemic encephalopathy grade II (n = 92), and 6 (7%) developed postneonatal epilepsy. In this subgroup, no postneonatal epilepsy was observed if seizures were controlled within 48 hours after birth and when not more than two antiepileptic drugs were required. Twenty-four children survived after an intracranial hemorrhage (n = 28), and only 1 (4%) developed postneonatal epilepsy. Eleven children survived after perinatal arterial stroke (n = 13), and 2 (18%) developed postneonatal epilepsy. In conclusion, the incidence of postneonatal epilepsy after treatment of clinical and subclinical neonatal seizures detected with continuous amplitude-integrated electroencephalography was 9.4%; This figure is lower than previously reported in children who only received treatment for clinical seizures.

Anticonvulsants↗
PubMed2005

The internal capsule in neonatal imaging.

The internal capsule is highly visible on conventional magnetic resonance imaging (MRI). It is myelinating rapidly at term, and the time course of its maturation is well known. It carries the major motor and sensory pathways to and from the cortex and the spinal cord. Additionally, fibres from the thalamus pass through it connecting to most regions of the cortex. It is therefore of vital importance, and damage to it has severe consequences. Its abnormal appearance on conventional MRI is a good predictor of an abnormal motor outcome in different clinical situations encountered in perinatal medicine. Its normal appearance on conventional MR images at term age is usually associated with a relatively normal motor outcome. More recently, diffusion-weighted and diffusion tensor imaging have allowed a much more sophisticated assessment of its maturation and connectivity; this has already led to a better understanding of how its development is affected by preterm birth and by hypoxic-ischaemic brain injury. Future studies will assess the relevance of these findings not only for motor outcome but also for cognitive, visual and sensory abilities.

Cerebral Infarction↗
PubMed2005

Sleep-wake cycling on amplitude-integrated electroencephalography in term newborns with hypoxic-ischemic encephalopathy.

OBJECTIVE: The objective of this amplitude-integrated electroencephalography (aEEG) study was to evaluate the influence of perinatal hypoxia-ischemia on sleep-wake cycling (SWC) in term newborns and assess whether characteristics of SWC are of predictive value for neurodevelopmental outcome. METHODS: From a consecutive series of newborns born during a 10-year period, the aEEG tracings of 171 term newborns with hypoxic-ischemic encephalopathy were assessed for the presence, time of onset, and quality of SWC. SWC patterns were categorized with regard to the background pattern on which they presented, as normal or abnormal SWC. RESULTS: SWC was seen in 95.4% of the surviving newborns and in 8.1% of those who died. The median time intervals from birth to onset of SWC were significantly different in newborns with hypoxic-ischemic encephalopathy grades I, II, and III (7, 33, and 62 hours, respectively). Newborns with seizure discharges developed SWC with a delay of 30.5 hours. Good outcome was associated with earlier onset of SWC and normal SWC pattern. The difference in the median Griffiths' developmental quotients in newborns who started SWC before/after 36 hours was 8.5 points. The good/poor neurodevelopmental outcome was predicted correctly by the onset of SWC before/after 36 hours in 82% of newborns. CONCLUSIONS: The presence, time of onset, and quality of SWC reflected the severity of the hypoxic-ischemic insult to which newborns were exposed. The time of onset of SWC has a predictive value for neurodevelopmental outcome.

Activity Cycles↗
PubMed2005

Structural and functional brain development after hydrocortisone treatment for neonatal chronic lung disease.

OBJECTIVE: There is much concern about potential neurodevelopmental impairment after neonatal corticosteroid treatment for chronic lung disease. Dexamethasone is the corticosteroid most often used in this clinical setting, and it has been shown to impair cortical growth among preterm infants. This study evaluated long-term effects of prematurity itself and of neonatal hydrocortisone treatment on structural and functional brain development using three-dimensional MRI with advanced image-processing and neurocognitive assessments. METHODS: Sixty children born preterm, including 25 children treated with hydrocortisone and 35 children not treated with hydrocortisone, and 21 children born at term were evaluated, at a mean age of 8 years, with quantitative MRI and neurocognitive assessments (Wechsler Intelligence Scales for Children-Revised [WISC-R]). Automatic image segmentation was used to determine the tissue volumes of cerebral gray matter, white matter, and cerebrospinal fluid. In addition, the volume of the hippocampus was determined manually. WISC-R scores were recorded as mean intelligence scores at evaluation. Neonatal hydrocortisone treatment for chronic lung disease consisted of a starting dose of 5 mg/kg per day tapered over a minimum of 3 weeks. RESULTS: Cerebral gray matter volume was reduced among preterm children (regardless of hydrocortisone treatment), compared with children born at term (preterm: 649 +/- 4.4 mL; term: 666 +/- 7.3 mL). Birth weight was shown to correlate with gray matter volume at 8 years of age in the preterm group (r = 0.421). Cerebrospinal fluid volume was increased among children born preterm, compared with children born at term (preterm: 228 +/- 4.9 mL; term: 206 +/- 8.2 mL). Total hippocampal volume tended to be lower among children born preterm, with a more pronounced reduction of hippocampal volume among boys (preterm: 6.1 +/- 0.13 mL; term: 6.56 +/- 0.2 mL). The WISC-R score was lower for children born preterm, compared with children born at term (preterm: 99.4 +/- 12.4; term: 109.6 +/- 8.8). Children treated with neonatal hydrocortisone had very similar volumes of gray matter (preterm with hydrocortisone: 650 +/- 7.0 mL; preterm without hydrocortisone: 640 +/- 5.6 mL), white matter (preterm with hydrocortisone: 503 +/- 6.1 mL; preterm without hydrocortisone: 510 +/- 4.9 mL), and cerebrospinal fluid (preterm with hydrocortisone: 227 +/- 7.4 mL; preterm without hydrocortisone: 224 +/- 6.0 mL), compared with untreated infants. The hippocampal volumes were similar in the 2 groups (preterm with hydrocortisone: 5.92 +/- 0.15 mL; preterm without hydrocortisone: 5.81 +/- 0.12 mL). The WISC-R score assessments were within the normal range for both groups, with no difference between the groups (preterm with hydrocortisone: 100.8 +/- 13; preterm without hydrocortisone: 98.6 +/- 12.3). CONCLUSIONS: Prematurity is associated with mild brain structural differences that persist at 8 years of age, with associated lower scores in neurocognitive assessments. The data suggest that perinatal hydrocortisone given at the described dosage has no long-term effects on either neurostructural brain development or neurocognitive outcomes.

Anti-Inflammatory Agents↗
PubMed2004

Cardiac arrhythmias in neonates receiving lidocaine as anticonvulsive treatment.

UNLABELLED: Lidocaine has been used in neonates as an effective drug in controlling neonatal seizures not responding to traditional anticonvulsant therapy. Little is known about the effect of lidocaine on heart rate or occurrence of cardiac arrhythmias in neonates. The purpose of the present study was to assess the incidence of cardiac arrhythmias associated with lidocaine use for neonatal seizures. A retrospective review was performed in 207 neonates who received lidocaine for treatment of neonatal seizures. All were given a loading dose of 2 mg/kg in 10 min followed by a continuous infusion of 6 mg/kg per h, tailed off over the next 48 h. A total of ten (4,8%) infants developed cardiac arrhythmias during lidocaine infusion. In five infants a bradycardia developed, associated with a prolonged QRS complex in one. In one infant a tachycardia was seen following the bolus administration. In the other four an irregular heart rate was noted. In eight infants the arrhythmias disappeared immediately following discontinuation of lidocaine. In two infants, with severe encephalopathy, who died, the association was not so clear. CONCLUSION: The present study demonstrates that continuous cardiac monitoring of neonates who receive lidocaine for neonatal seizures is indicated, as there is a risk to develop cardiac arrhythmias. Lidocaine should be discontinued immediately when a cardiac arrhythmia occurs. Lidocaine should not be given to patients with a congenital heart disease and to infants who have already been treated with diphantoine.

Anticonvulsants↗
PubMed2004

Cerebral structure and metabolism and long-term outcome in small-for-gestational-age preterm neonates.

In the present study, we compared brain development and metabolism of small-for-gestational-age (SGA) and appropriate-for-gestational-age (AGA) infants using proton magnetic resonance spectroscopy ((1)H-MRS). We tested the hypothesis that intrauterine growth retardation caused by placental insufficiency is associated with changes in cerebral metabolism and is followed by an adverse neurodevelopmental outcome at the age of 2 y. Twenty-six AGA and 14 SGA (birth weight <P 2.3) preterm infants with no major ultrasound abnormalities were enrolled prospectively. At 32 and 41 wk postmenstrual age, (1)H-MRS and magnetic resonance imaging were performed. For (1)H-MRS, a volume of interest was placed in the basal ganglia and in the periventricular white matter. Using echo times of 31 and 144 ms N-acetylaspartate/choline (NAA/Cho), lactate/Cho, myo-inositol/Cho (mI/Cho), and glutamate-glutamine-gamma-aminobutyric acid/Cho (Glx/Cho) ratios were compared between AGA and SGA groups. Griffiths' developmental quotient (DQ) values were assessed at 24 mo corrected age. Griffiths' DQ (AGA, 104 +/- 10; SGA, 99 +/- 9) and brain development assessed using magnetic resonance imaging showed no significant differences between both AGA and SGA groups, and NAA/Cho, Lac/Cho, mI/Cho, and Glx/Cho ratios were not significantly different between the groups. NAA/Cho ratios increased from 32 to 41 wk, whereas mI/Cho ratios decreased in both groups. No differences in cerebral metabolism, brain development, and DQ values between AGA and severely SGA infants could be demonstrated.

Birth Weight↗
PubMed2004

Visual perceptual impairment in children at 5 years of age with perinatal haemorrhagic or ischaemic brain damage in relation to cerebral magnetic resonance imaging.

Children with perinatally acquired parenchymal haemorrhage are thought to have better visual perceptual skills than those with leukomalacia. We examined seven prematurely born children with parenchymal haemorrhage and 14 with grades 2-4 leukomalacia, at the age of 5 years. Clinical and magnetic resonance imaging parameters were related to visual perceptual performance assessed with the L94, using performance age. Belonging to the leukomalacia group, the inability to walk, a diminished peritrigonal white matter, a high degree of gliosis and cortical damage were associated with poorer visuo-perceptual skills. Enlarged lateral ventricles, confirming the findings of Melhelm (Radiology 214 (2000) 199), were associated with both cognitive, perceptual and motor problems and probably reflect the considerable extent of the brain damage. Specific factors protecting against visual perceptual impairment were a preserved volume of the right optical radiation and of the splenium of the corpus callosum. Children with leukomalacia are at considerable risk of visual perceptual impairment. Children with right-sided parenchymal haemorrhages also appear to be at risk although they function much better due to better motor and cognitive skills.

Birth Injuries↗
PubMed2004

Cerebral metabolism in severe neonatal hyperbilirubinemia.

The metabolism of the basal ganglia was examined by using proton magnetic resonance spectroscopy in 5 neonates with severe hyperbilirubinemia. A decreased N-acetylaspartate/choline ratio, indicating neuronal injury, and an abnormally high lactate/N-acetylaspartate ratio were found only in the neonate with neonatal magnetic resonance imaging abnormalities and subsequent cerebral palsy.

Aspartic Acid↗