Developmental change in carotid artery blood flow waveform by component analysis in children

The carotid artery blood flow waveform (CABFW) is regarded as a summation of cardiac impulse responses. These impulse responses are divided into several components through a two-dimensional autoregressive modelling approach. Using this approach, we determined the developmental change in CABFW in 94 normal subjects from the neonatal period to adolescence. Our analysis demonstrated that: (i) the total power of impulse response increased significantly with increasing age. The component of impulse response was divided into six groups according to the damping frequency: group I (0 Hz), group II (1–5 Hz), group III (5–8 Hz), group IV (8–13 Hz), group V (13–17 Hz) and group VI (> 17 Hz); (ii) the power-density and the damping time of group I and II impulse response increased significantly with increasing age; (iii) the power-density and percent power of group III impulse response and power-density of group IV impulse response increased significantly with increasing age. Our results indicated that CABFW contained some regular impulses and that group I, II, III and IV, which were influenced by several factors, including cardiac contraction and the compliance and frictional forces of the carotid artery, appeared to be important to the developmental change of CABFW in children.     

Electrocortical brain activity during hypoxia and hypotension in anesthetized newborn lambs.

Blood gas and blood pressure disturbances do influence cerebral blood flow in newborns. To what extent cerebral blood flow changes affect electrocortical brain activity remains uncertain. We studied the effect of severe hypoxia and hemorrhagic hypotension on carotid artery blood flow and electrocortical brain activity in newborn anesthetized lambs. During hypoxia carotid artery blood flow increased significantly, whereas electrocortical brain activity remained unchanged. The hemorrhagic hypotension study showed that the lower limit of the autoregulatory ability of the cerebral vascular bed was 60 mmHg. Electrocortical brain activity however remained stable until mean aortic pressure had dropped below 30 mmHg, carotid artery blood flow below 10.6 ml/kg/min, and cerebral oxygen delivery below 1.4 ml/kg/min.     

Cerebral Doppler measurements in risk newborn infants do not have a prognostic value]

PROBLEM: The prognostic value of cerebral doppler for the neonatal and the developmental prognosis was studied. METHODS: A prospective longitudinal study on 175 newborns at risk was performed. The blood flow velocities were recorded transcranially in the middle cerebral, posterior cerebral and internal carotid artery on day 1, 3-5 and 8-10 of life. Neonatal mortality and cerebral sonography gave the criteria for neonatal prognosis. Developmental prognosis was determined at a corrected age of 9 months by neurological examination and Griffth's test. RESULTS: In 60 neonates abnormal flow velocities were obtained at least at one recording. Ultrasound revealed cerebral hemorrhage in 20, hypoxic-ischemic encephalopathy in 5 children. 14 infants died during the neonatal period, 5 in the following months. Premature babies with birth weights below 1501 g and abnormal flow velocities presented more cerebral hemorrhages and deaths than those with normal flow velocities. At the age of 9 months a slight handicap was observed in 10, a severe handicap in 6 of the surviving 156 infants. The majority of infants with abnormal neonatal doppler-recording had a normal neurodevelopmental status. CONSEQUENCE: Cerebral doppler seems to be of little value to determine the prognosis of newborns at risk.     

Alterations of intracranial pressure and cerebral blood flow velocity in healthy neonates and their implication in the origin of perinatal brain damage

Intracranial pressure and cerebral blood flow velocity were recorded in term healthy neonates during the first 3 days of life using non-invasive methods (LADD-fontanometry and cw-Doppler sonography). Intracranial pressure increased from 4.0±2.7 cm H₂O to 5.8±2.7 cm H₂O and maximal cerebral blood flow velocity in the anterior cerebral artery (ACA) increased from 33 cm/s to 58 cm/s as calculated from a Doppler shift of 0.63 to 1.10 kHz and vascular resistance decreased between the 1st and 3rd day of life. These alterations could not be demonstrated in the femoral artery. This is in accordance with other registrations obtained by different methods and under various conditions. They allow an explanation of some well known physiological phenomena like alterations of cranial volume and the structure of the bony skull in the first days of life. Furthermore, these physiological variations may have implications for the origin of cerebral damage during the perinatal period, especially of hypoxic-ischaemic encephalopathies.Abbreviations ACA anterior cerebral artery - CA carotid artery - FA femoral artery - IP intracranial pressure - MFV mean flow velocity - PI pulsatility index (Pourcelot) - REM rapid eye movements sleep state - TAM time-average-mean - V cranial volume     

Noninvasive intracranial pressure measurement at the anterior fontanelle in the first days of life

A continuous registration of intracranial pressure by aplanation-tonometry on the anterior fontanelle was performed in 12 healthy term newborns during the night hours of the first 3 days. The median intracranial pressure of the first day was 4.01 +/- 2.74 cm H2O. There was a slight increase between the first and the second day of life and a significant increase between second and third day up to 5.84 +/- 2.66 cm H2O. In our interpretation this result is a sign for the active reconfiguration of the skull by increasing intracranial pressure, which may be a consequence of changing tonus of cerebral vessels.     

Foetal supraventricular tachycardia and cerebral complications

We report on two newborn infants with foetal tachycardia and cerebral lesions. Using foetal echocardiography, the diagnosis of supraventricular tachycardia in a structurally normal heart was made at 28 and 37 weeks of gestation, respectively. One infant had a 3 week period of foetal tachycardia and hydrops before successful pharmacological cardioversion. Even several weeks after a term birth he remained hypotonic and needed gavage feeding. A computed tomography (CT) scan demonstrated cerebral lesions indicating a vascular origin. A possible thrombus was found in the heart. The other infant converted to sinus rhythm during birth by Caesarean section on the day after diagnosis. He had convulsions at the second day of life. On CT scan an infarction was found. The observations of this report suggest that cerebrovascular complications to foetal arrhythmias are more common than previously observed and should be considered when managing cases of foetal tachycardia.     

Transient neonatal thyrotoxicosis: clinical presentation and treatment in 7 cases]

Neonatal thyrotoxicosis is a rare disease. The goal of this study was to analyse main neonatal symptoms, clinical complications and patient's care. MATERIAL AND METHODS: This retrospective study concerned the newborns admitted with neonatal thyrotoxicosis between 1992 and 2004 in the neonatal department of Bordeaux, Toulouse and Pau hospital. RESULTS: Seven of these patients were included in the study. All of the newborns had permanent tachycardia and 3 of them had respiratory failure. Two patients had potentially lethal clinical complications. The first had goitre with tracheal compression. The second developed global heart failure on his 13th day of life. The onset of antithyroid drug treatment was between the 3rd and the 18th day of life. Mean duration of treatment was 50 days. Occurring complications were neutropenia in 3 patients and hypothyroidism in 1 patient. The children were tracked during their first year, and all had normal growth and normal neurological development. CONCLUSION: The main prognostic factor is the early onset of antithyroid treatment. In our study, 2 patients had potentially lethal clinical complications. Adequate care depends on early spotting of high-risk newborn.     

Vibratory acoustic stimulation and the flow velocity waveform in the fetal internal carotid artery

Eleven healthy fetuses between 36 and 39 weeks of gestation were studied during the active sleep state to examine effects of a 5-s vibratory acoustic stimulus on the baseline fetal heart rate and flow velocity waveform in the fetal internal carotid artery. There was an immediate marked rise in baseline fetal heart rate with concomitant drop in pulsatility index in the flow velocity waveform of the fetal internal carotid artery, which persisted for at least 15 min after the stimulus. However, when the pulsatility index was standardized for a fetal heart rate of 140 beats/min this index remained virtually unaltered. These data suggest that in the healthy term fetus during active sleep state, a vibratory acoustic stimulus has no measurable effect on cerebral vascular resistance. Since virtually all reported studies on vibratory acoustic stimulation of the fetus were carried-out during the quiet sleep state, the data from the present study do not provide any information on the safety of this device when employed as a means of assessing of fetal well-being.     

Vitamin K in the newborn: influence of nutritional factors on acarboxy-prothrombin detectability and factor II and VII clotting activity

The incidence of acarboxy-prothrombin and the clotting activity of factors II and VII were evaluated on the fifth day of life in 183 healthy newborns, who had received no vitamin K prophylaxis. Acarboxy-prothrombin was detected in 93/183 newborns. All acarboxy-prothrombin-negative babies had factors II and VII clotting activities above 25% whereas a great variability was observed in acarboxy-prothrombin-positive babies: 21/93 had factor II and 14/93 had factor VII activities below 25%. Seventy-two of the acarboxyprothrombin-positive babies had normal factor II and VII clotting times on the fifth day of life. These babies must be suspected to have had vitamin K deficiency on one of the first 4 days, as acarboxy-prothrombin has a 50% disappearance rate of 50 h. Acarboxy-prothrombin ws mainly observed in breastfed infants (84/122) and only rarely detectable in infants receiving supplementary (7/44) or exclusive formula feeding (2/17). The type of milk feeding however might be less important for the babies' vitamin K supply than the actual milk intake. All acarboxy-prothrombin-positive babies had received small amounts of milk on the first 4 days of life. In those with low factor II and VII clotting activities the milk intake was low throughout the first 4 days of life, whereas babies with acarboxy-prothrombin and and normal clotting activities had increased their milk intake to more than 100 ml on the third and fourth day of life. Recommendations for vitamin K prophylaxis in newborns should be given with regard to the feeding on the first days of life.     

Flow velocity waveforms in the fetal internal carotid artery relative to fetal blood gas and acid-base measurements in normal pregnancy

Flow velocity waveforms in the fetal internal carotid artery during fetal behavioural state 2F were compared with blood gas and acid-base data from fetal scalp blood samples immediately following artificial rupture of the membranes in 17 normal term pregnancies. The pulsatility index in the fetal internal carotid artery was positively related to PO2 and base excess suggesting that also under physiological conditions fetal cerebral vascular resistance may respond to changes in fetal oxygenation.     

Normal neonatal values of ophthalmic and central retinal artery blood flow velocities

PURPOSE: To define standard values of blood flow velocities and indices in the ophthalmic and central retinal arteries in the neonatal period. METHODS: Forty-two healthy full-term neonates comprised the study population. A color Doppler with mechanical sector probe was used for measuring blood flow velocity in the ophthalmic and central retinal arteries. Systolic, end diastolic, and mean-enveloped velocities were measured, and the resistance index and pulsatility index were calculated. RESULTS: Ophthalmic artery Doppler velocities were similar on the first and third days of life, but increased significantly on the fifth and seventh days of life; resistance index significantly increased during the first week of life, whereas pulsatility index did not change significantly. Doppler velocities of the central retinal artery were similar on the first and third days; they show a delayed increase compared to the ophthalmic artery. Central retinal artery blood flow velocities increased significantly from the third to seventh postnatal day. Resistance index also increased between the first two days and on the fifth and seventh postnatal days, while pulsatility index did not change. CONCLUSION: These data constitute a starting point for studying the possible relationship between eye circulation and pathogenesis of retinopathy of prematurity.     

经颅多普勒超声对脑功能受损危重症患儿脑功能及预后评估的应用

目的：探讨在儿童危重症患者使用经颅多普勒超声( transcranial Doppler sonography, TCD)判断脑损伤情况的应用价值。方法对2014年11月至2015年3月期间所有入住本院重症医学科的首次格拉斯哥昏迷评分( GCS)小于13分并且明确存在脑损伤患儿进行TCD检查,根据脑血流频谱形态、血流速度分为低灌注组、基本正常组及相对异常组。收集第1、3、7天TCD检查大脑中动脉及颈内动脉颅内段的脑血流频谱形态、血流速度以及患儿第1、7天GCS评分,观察经治疗后脑灌注改善情况对GCS评分及预后的影响。结果共收集病例65例,低灌注组21例,脑灌注改善6例、未改善15例;相对异常组42例,脑灌注改善28例,未改善14例;基本正常组2例,脑灌注均改善。低灌注组脑灌注改善患儿第7天GCS评分明显大于未改善的患儿(12.33±4.63 vs.3.00±0.00,P<0.05);相对异常组其脑灌注改善患儿第7天GCS评分明显大于未改善的患儿(13.42±2.72 vs.3.50±1.09,P<0.05)。TCD监测提示脑灌注改善的患儿存活比例(34/36例)显著大于未改善的患儿(2/29例)(χ2＝49.82, P<0.05)。结论 TCD检查能够较准确评估脑功能、意识状态,在治疗脑功能受损患儿的过程中具有指导意义。     

Perinatal assessment of cerebral flow velocity wave forms in the human fetus and neonate.

The temporal relationship between changes in cerebral Doppler flow velocity wave forms, ductal patency, blood gases, and blood pressure during the transition from intrauterine to newborn life was assessed longitudinally in 16 healthy term fetuses and newborns. Doppler flow velocity wave forms were obtained from fetal cerebral arteries (anterior cerebral, internal carotid, and basilar) before birth, within 8 h after birth, and again at 24 and 48 h after birth. The resistance index was used as a measure of vascular resistance. The resistance index of the cerebral arteries studied increased significantly between the antenatal and 8-h study periods. This was followed by a significant decrease below fetal levels by the 24-h study period, with little change thereafter. We conclude that in the newborn human, as in the newborn lamb, the transition from fetal to immediate newborn life is associated with an increase in cerebral vascular resistance and thus a decrease in cerebral blood flow in response to the increase in arterial oxygenation. The subsequent decrease in the cerebral resistance index between 8 and 24 h of life cannot be explained by a loss of ductal shunting nor by associated changes in newborn blood gases or blood pressure, but may rather reflect a remodeling of the circulation due to impedance matching.     

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??Objective??To approach the performance of digital subtraction angiography??DSA?? in the early diagnosis and treatment with drug perfusion therapy in children with cerebral infarction after the congenital heart disease surgery??then assess the outcome. Methods??From January 2015 to December 2016??6 patients with cerebral infarction developed neurologic symptoms??including facial paralysis??physical activity disorders or convulsions within 12 hours to 3 days after surgery for congenital heart disease. After being diagnosed with ischemic cerebrovascular disease by initial magnetic resonance imaging??MRI???? patients were made a definite diagnosis through DSA and given intravenous infusion of internal carotid artery at the same time. Patients were treated to improve circulation??anticoagulation??intravenous thrombolysis and rehabilitation after DSA. Clinical symptoms were observed at 6 hours??1 day??3 days??1 week and 1 month after operation. Patients were followed up for 1 month to 3 months. Results??After successful DSA surgery and drug perfusion therapy??neurologic symptoms in patients were improved. Facial paralysis was improved in 5 of 6 patients at 6 h??1 d and 2 d of DSA??and limb muscle strength was also improved. Physical activity was gradually improved in 2 patients at the third day after DSA surgery. All cases had no signs of recurrence??serious complications or sequalae??no DSA perioperative bleeding??infection??cognitive dysfunction or physical disability?? in the follow-up??and muscle strength was significanthy improved. Conclusion??The early diagnosis is crucial to children with cerebral infarction after the surgery for congenital heart disease.     

Myocardial dysfunction and cerebral blood flow velocity following birth asphyxia

Birth asphyxia often leads to left ventricular myocardial dysfunction. To assess the effect of myocardial dysfunction on cerebral perfusion, we evaluated cardiac output and cerebral blood flow velocity in the anterior cerebral and internal carotid arteries in 20 asphyxiated term newborn infants during the first 4 days of life using 2-dimensional/pulsed Doppler ultrasound. In 8 infants with myocardial dysfunction cardiac output was reduced on days 1 and 2 and within normal limits thereafter. In these infants changes in mean cerebral blood flow velocity and pulsatility index were passively related to changes in mean arterial pressure and cardiac output. In 12 infants without myocardial dysfunction a stable cerebral blood flow velocity pattern was found, which was unaffected by changes in mean arterial pressure. We conclude that infants presenting with a reduced cardiac output after deliveries associated with severe asphyxia may be at risk for additional ischemic or hemorrhagic cerebral damage because of lack of autoregulation.     

Cerebral blood flow velocity in normal, full-term newborns is not related to ductal closure.

OBJECTIVE--To correlate changes in blood flow velocity in the anterior and middle cerebral arteries with closure of the ductus arteriosus in normal, full-term newborns during the first 2 days following delivery. DESIGN--Survey. SETTING--Large community hospital. PARTICIPANTS--Twenty-three normal, full-term neonates. SELECTION PROCEDURES--Volunteer sample. INTERVENTIONS--None. MEASUREMENTS AND RESULTS--We measured blood flow velocity in the anterior and middle cerebral arteries, cardiac output, and patency of the ductus arteriosus using pulsed Doppler, M-mode, and real-time ultrasound. The initial examination was performed at (mean +/- SD) 7.6 +/- 2 hours and the second examination was performed at 30 +/- 3 hours. The systolic, diastolic, and mean blood flow velocity in the anterior and middle cerebral arteries increased significantly from day 1 to day 2. Cardiac output did not change significantly (252 +/- 49 vs 279 +/- 69 cm3/kg per minute). Thirteen newborns on day 1, but only two newborns on day 2, had echocardiographic evidence of a patent ductus arteriosus. Newborns whose ductus was already closed on day 1 had similar increases in blood flow velocity in the anterior and middle cerebral arteries from day 1 to day 2 compared with newborns whose ductus had closed from day 1 to day 2. CONCLUSION--The normal increase in blood flow velocity in the anterior and middle cerebral arteries in the first 2 days following delivery is not related to changes in cardiac output or ductal closure.     

Symmetric cerebral blood flow in newborns who have undergone successful extracorporeal membrane oxygenation.

Cerebral blood flow (CBF) was measured with positron emission tomography in 23 newborns following extracorporeal membrane oxygenation. In 9 newborns the common carotid artery was reanastomosed after extracorporeal membrane oxygenation and in 14 newborns the common carotid artery remained ligated. The ratio of right/left hemispheric CBF was not significantly different in the newborns with reanastomosed or occluded common carotid arteries (right/left CBF ratio was 0.98 in both groups). The maximum asymmetry was 8% and was observed in 2 newborns. All 9 newborns with reanastomosis of the carotid artery are normal at follow-up at 1 year or longer. Three newborns with ligation of the common carotid artery were lost to follow-up and 1 newborn died. Eight of 10 remaining newborns are normal at follow-up; the 2 other infants have developmental quotients of 60 and 64, respectively, and no other deficits. The data indicate (1) that hemispheric CBF is symmetric in newborns who have undergone extracorporeal membrane oxygenation and have no evidence of brain injury, and (2) that reanastomosis of the common carotid artery does not alter hemispheric CBF in the newborn period.     

Cerebrovascular event, dilated cardiomyopathy, and pheochromocytoma

Cerebral infarction in children may be the result of various disease processes, including emboli from intracardiac sources, paradoxical emboli from the venous system, sickle cell disease, cyanotic heart disease, vasculitis affecting the carotid or cerebral vascular system, vascular anomalies, and prothrombotic states. We present a previously healthy adolescent who presented with the acute onset of hemiparesis. Work-up revealed a dilated cardiomyopathy with a left ventricular mural thrombus as the etiology of his cerebrovascular event. Although dilated cardiomyopathy (DCM) may predispose to the development of a mural thrombus and subsequent embolic events, there are no previous reports in pediatric-aged patients of the development of an embolic event as the presenting manifestation of DCM. Further investigation of the etiology of the DCM led to the diagnosis of a pheochromocytoma. Congestive heart failure and DCM as the presenting sign of pheochromocytoma has likewise not been reported in a pediatric-aged patient. We review this unlikely sequence of events, the diagnostic evaluation of such patients, and treatment options.     

血管内皮生长因子在重度子癎痫前期产妇新生儿脐血中的表达

目的 探讨血管内皮生长因子(VEGF)在重度子癎前期产妇分娩的新生儿脐静脉血、脐动脉血中的表达及其意义.方法 采用放射免疫分析法检测26例重度子癎前期产妇所分娩新生儿(重度子癎前期组)与30例健康产妇所分娩新生儿(对照组)的脐静脉血、脐动脉血VEGF水平.重度子癎前期组新生儿按照其出生体质量-胎龄分类分为小于胎龄儿15例(SGA组)和适于胎龄儿11例(AGA组).结果 (1)重度子癎前期组脐静脉血、脐动脉血VEGF水平[(15.26±5.28)pg/ml、(19.334±4.45)pg/ml]均显著高于对照组[(12.78±3.21)pg/ml、(14.55±2.90)pg/ml](t=2.16,P<0.05;t=4.82,P<0.01).(2)对照组和重度子癎前期组的脐动脉血VEGF水平均显著高于脐静脉血VEGF水平(t=2.24,P<0.05;t=3.00,P<0.01).(3)对照组和重度子癎前期组脐静脉血和脐动脉血VEGF水平与新生儿胎龄或出生体质量均无明显相关性.(4)重度子癎前期SGA组的脐动脉血VEGF水平(21.38±3.68pg/ml)显著高于AGA组(16.53±3.96pg/ml)和对照组(t=3.22,P<0.01;t=6.80,P<0.01).结论 重度子癎前期产妇新生儿脐静脉血和脐动脉血VEGF水平均较健康产妇新生儿明显升高;脐动脉血VEGF水平在一定程度上可反映妊娠期高血压疾病产妇的新生儿宫内损伤程度.     

Myocardial Dysfunction and Cerebral Blood Flow Velocity Following Birth Asphyxia

ABSTRACT. Birth asphyxia often leads to left ventricular myocardial dysfunction. To assess the effect of myocardial dysfunction on cerebral perfusion, we evaluated cardiac output and cerebral blood flow velocity in the anterior cerebral and internal carotid arteries in 20 asphyxiated term newborn infants during the first 4 days of life using 2-dimensional/pulsed Doppler ultrasound. In 8 infants with myocardial dysfunction cardiac output was reduced on days 1 and 2 and within normal limits thereafter. In these infants changes in mean cerebral blood flow velocity and pulsatility index were passively related to changes in mean arterial pressure and cardiac output. In 12 infants without myocardial dysfunction a stable cerebral blood flow velocity pattern was found, which was unaffected by changes in mean arterial pressure. We conclude that infants presenting with a reduced cardiac output after deliveries associated with severe asphyxia may be at risk for additional ischemic or hemorrhagic cerebral damage because of lack of autoregulation.