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Biomedical subjects

G Duc

Publications and source records attributed to G Duc.

At least 19 recordsLinked to original sources
PubMed1999

Cerebral blood flow and neurological outcome in the preterm infant.

UNLABELLED: Cerebral blood flow (CBF) studies have provided some insight into pathophysiological mechanisms of cerebral damage in newborn children; their value in predicting brain damage, however, remains elusive. The purpose of our study was to evaluate the role of CBF measurements in predicting developmental outcome in preterm neonates at 18 months. Preterm babies with a gestational age of less than 34 weeks and a birth weight of less than 1500 g (n = 71) were enrolled in the study. CBF was measured by the noninvasive intravenous 133Xe method on three different occasions. We classified our measurements into three groups: depending on the time when performed group 1: between 2 and 36 h (n = 52); group 2: between 36 and 108 h (n = 44); group 3: between 108 and 240 h (n = 41). At the age of 18 months neurodevelopment testing was performed according to the Bayley mental and motor scales. Surviving infants had a higher mean CBF over the three groups than non surviving children (15.2 +/- 3.5 ml/100 g brain tissue/min vs 13.0 +/- 2.1 ml/100 g brain tissue/min, P < 0.05). There was no correlation of CBF with mental or motor development in our study population in either of the three groups. CONCLUSION: In preterm infants basal CBF is higher in surviving than in non surviving infants, but there is no correlation of resting CBF and later neurological outcome.

Aging↗
PubMed1998

Sleep state changes associated with cerebral blood volume changes in healthy term newborn infants.

In order to assess the possible effects of sleep states on cerebral haemodynamics in healthy term infants, we measured cerebral oxyhaemoglobin, deoxyhaemoglobin and total haemoglobin concentration using near infrared spectroscopy. Thirty-seven sleep state changes in seventeen infants (gestational age: 37 to 41 4/7 weeks), aged between two and eight days were continuously registrated during 1-3 h. Transcutaneous PaO2, PaCO2, arterial O2 saturation and heart rate were simultaneously recorded and sleep states were clinically defined. There was a close relationship between sleep state changes and changes in total cerebral haemoglobin concentration, which increased from active to quiet sleep and decreased from quiet to active sleep. Changes in total cerebral haemoglobin were due, in the most part, to changes in the cerebral oxyhaemoglobin concentration. In conclusion, sleep states influence the cerebral haemoglobin concentration. Studies on cerebral haemodynamics should take sleep state into account in term newborn infants.

Blood Volume↗
PubMed1997

Continuous noninvasive measurement of cerebral arterial and venous oxygen saturation at the bedside in mechanically ventilated neonates.

OBJECTIVES: To test the practicablity of a new spectrophotometric method using pulse oximetric techniques in combination with special filters for the noninvasive determination of cerebral arterial and venous oxygen saturation and oxygen extraction in neonatal intensive care unit patients. The spectrophotometer used three different wavelengths at a sampling rate of 100 Hz. DESIGN: Clinical evaluation of a new method and comparison with previously published data. SETTING: Design and construction of the special spectrophotometer at the Biomedical Engineering Laboratory of the Swiss Federal Institute of Technology. Measurements in the neonatal intensive care unit of the University Hospital, Zurich, Switzerland. PATIENTS: Convenience sample of 15 clinically stable newborn infants, who were mechanically ventilated and receiving supplemental oxygen. Median gestational age was 29 5/7 wks (range 26 3/ 7 to 36 0/7), median birth weight was 1555 g (720 to 2500), median postnatal age was 4 days (1 to 10). INTERVENTIONS: The emitter and receiver were placed on the forehead near the sagittal sinus, between 2 and 2.8 cm apart, and the pulsating light attenuations (arterial and venous pulse waves) were recorded. MEASUREMENTS AND MAIN RESULTS: Arterial and venous pulse waves were satisfactory in 10 of 15 infants. Mean cerebral arterial oxygen saturation was 89.9 +/- 5.4% (SD), mean cerebral venous oxygen saturation was 73.0 +/- 8.9%, and mean cerebral oxygen extraction was 16.9 +/- 11.7%. A linear regression analysis demonstrated a significant correlation between mean PCO2 and venous oxygen saturation (slope 1.0%/torr, p < .05) and between mean PCO2 and cerebral oxygen extraction (slope -1.3%/torr, p < .05). CONCLUSION: This new method has the potential for monitoring continuously, noninvasively, and simultaneously cerebral arterial and venous oxygen saturation and oxygen extraction in mechanically ventilated preterm infants.

Blood Gas Analysis↗
PubMed1997

Body proportionality in growth-retarded VLBW infants.

The aim of this study was to investigate how intrauterine growth retardation affects body proportions in VLBW infants. The cohort consisted of 135 surviving and 80 deceased preterm infants weighing less than 1250 grams at birth. Gestational age varied between 24 and 36 weeks (mean age 29.7 and 27.5 weeks, respectively). Birth weight was more than 2 SD below the mean birth standard values in 32% of the surviving, and in 27% of the deceased infants. Reduction of weight, length and head circumference at birth was analysed using Z scores based on Swedish birth standards. Z scores of weight, length and head circumference were highly correlated in the surviving and the deceased infants (r = 0.78 to 0.94 and 0.65 to 0.97, respectively). Length was significantly more affected by growth retardation than weight. Weight and head circumference were proportionately reduced. Intrauterine growth retardation influences body proportions in VLBW infants differently than in larger preterm and term infants.

Body Constitution↗
PubMed1997

Effect of nursing in the head elevated tilt position (15 degrees) on the incidence of bradycardic and hypoxemic episodes in preterm infants.

OBJECTIVE: We investigated whether nursing in the head elevated tilt position (HETP), compared with the horizontal position, has any effect on the incidence of bradycardic and hypoxemic episodes in preterm infants. METHODS: Twelve spontaneously breathing preterm infants with idiopathic recurrent apnea were studied in a randomized controlled crossover trial. Nine infants were treated with aminophylline. Each spent a total of 24 hours in the horizontal prone position and a total of 24 hours in HETP (prone, 15 degrees). The position was changed in random order every 6 hours. Thoracic impedance, heart rate, and arterial oxygen saturation were recorded continuously. The frequency of isolated hypoxemia (arterial saturation <80%), of isolated bradycardia (heart rate <90 beats per minute), and of mixed events was analyzed and compared without knowledge of the allocated position. RESULTS: In total, there were significantly fewer bradycardic and/or hypoxemic episodes (28.2%) in HETP compared with the horizontal position (mean difference, 13.35 episodes/24 hours; 95% confidence interval [CI]: 5.9- 20.8). The decrease was largest for isolated hypoxemic episodes (48.5%; mean difference, 11.74 episodes/24 hours; 95% CI: 6.1-17.4). Isolated bradycardic episodes (mean difference, 2.27 episodes/24 hours; 95% CI: -0.78-5.31) and mixed events were not decreased significantly in HETP. CONCLUSIONS: Nursing in a moderately tilted position (15 degrees) reduces hypoxemic events in preterm infants. This intervention is easy to apply, quickly reversible, and can be combined with drugs such as aminophylline.

Apnea↗
PubMed1996

[Prenatal and perinatal infections--problems for the practicing pediatrician: group B streptococci, varicella, toxoplasmosis].

A practical approach is reported for the care of the neonate born to a mother infected/colonized during pregnancy by group B streptococcus, varicella-zoster virus or Toxoplasma gondii. Starting from clinical situations, an attempt is made to work out evidence based recommendations using an overview of the current literature. GROUP B STREPTOCOCCI: Relevant factors for the treatment of infants born to colonized mothers are clinical symptoms, gestational age, additional risk factors (such as premature rupture of membranes or maternal fever) and intrapartum antibiotics. Postnatal antibiotic prophylaxis and laboratory screens failed the test of controlled trials. Transfer to a neonatology unit is recommended for symptomatic term and all preterm infants. Asymptomatic term infants should be carefully monitored during the first 48 hours for signs of respiratory, circulatory or thermoregulatory compromise. VARICELLA: In the case of maternal varicella near term, delaying delivery for one week will lower the risk of severe neonatal varicella. The postnatal administration of varicella-zoster-immunoglobulin to the neonate is supported by some (if limited) evidence from the literature in the case of maternal eruption between 7 days before and 2 days after delivery. In newborns of mothers with eruption appearing later immunoglobulin is often recommended, though no supporting clinical evidence is available. There are no data to justify the use of immunoglobulin after exposure during pregnancy in order to prevent pneumonia in the pregnant patient, but there are preliminary indications that its application could lower the risk of congenital varicella syndrome (2% between 13 and 20 weeks). The use of immunoglobulin in very low birth weight infants after nosocomial exposure is generally recommended but efficacy data are lacking. TOXOPLASMOSIS: The practical approach depends on clinical findings in the newborn and laboratory results during pregnancy and after birth. Examination of the newborn should include fundoscopy, cranial sonography and, in cases of documented infection, lumbar puncture. Serology from cord blood comprises assays for IgG, IgM and if possible IgA/IgE. If available, demonstration of the parasite by culture or PCR can be helpful. All infants with documented congenital toxoplasmosis should be treated for a minimum of 12 months. In the case of suspected toxoplasmosis the child should be treated as long as the suspicion persists. The prognosis after consequential therapy is less bleak than previously reported for untreated children even in seriously symptomatic patients.

Chickenpox↗
PubMed1996

Diagnostic and prognostic value of cerebral 31P magnetic resonance spectroscopy in neonates with perinatal asphyxia.

The impact of depressed neonatal cerebral oxidative phosphorylation for diagnosing the severity of perinatal asphyxia was estimated by correlating the concentrations of phosphocreatine (PCr) and ATP as determined by magnetic resonance spectroscopy with the degree of hypoxic-ischemic encephalopathy (HIE) in 23 asphyxiated term neonates. Ten healthy age-matched neonates served as controls. In patients, the mean concentrations +/- SD of PCr and ATP were 0.99 +/- 0.46 mmol/L (1.6 +/- 0.2 mmol/L) and 0.99 +/- 0.35 mmol/L (1.7 +/- 0.2 mmol/L), respectively (normal values in parentheses). [PCr] and [ATP] correlated significantly with the severity of HIE (r = 0.85 and 0.9, respectively, p < 0.001), indicating that the neonatal encephalopathy is the clinical manifestation of a marred brain energy metabolism. Neurodevelopmental outcome was evaluated in 21 children at 3, 9, and 18 mo. Seven infants had multiple impairments, five were moderately handicapped, five had only mild symptoms, and four were normal. There was a significant correlation between the cerebral concentrations of PCr or ATP at birth and outcome (r = 0.8, p < 0.001) and between the degree of neonatal neurologic depression and outcome (r = 0.7). More important, the outcome of neonates with moderate HIE could better be predicted with information from quantitative 31P magnetic resonance spectroscopy than from neurologic examinations. In general, the accuracy of outcome predictability could significantly be increased by adding results from 31P magnetic resonance spectroscopy to the neonatal neurologic score, but not vice versa. No correlation with outcome was found for other perinatal risk factors, including Apgar score.

Asphyxia Neonatorum↗
PubMed1995

Regional differences of cerebral blood flow in the preterm infant.

The purpose of our study was to evaluate the regional distribution of the resting cerebral blood flow (CBF) pattern in preterm neonates. Sixty-eight preterm babies with a gestational age of less than 34 weeks and a birth weight of less than 1500 g were enrolled into the study. The CBF was measured by the noninvasive intravenous 133Xenon method at three different times. Depending on the age we classified our measurements into three groups. Group 1: measurement between 2-36 h (n = 46). Group 2: measurement between 36-108 h (n = 39). Group 3: measurement between 108-240 h (n = 41). In all three groups CBF was significantly lower in the occipital region than in the frontal and parietal regions (group 1: frontal region 12.8 +/- 3.5 ml/100 g/min, parietal region 12.8 +/- 3.9 ml/100 mg/min, and occipital region 11.6 +/- 3.18 ml/100 g/min; group 2: frontal region 15.4 +/- 4.2 ml/100 g/min, parietal region 15.3 +/- 4.1 ml/100 g/min, and occipital region 13.4 +/- 3.5 ml/100 g/min; group 3: frontal region 14.6 +/- 3.6 ml/100 g/min, parietal region 14.6 +/- 3.2 ml/100 g/min, and occipital region 12.8 +/- 2.7 ml/100 g/min.). CBF did not differ between the left and the right hemispheres in either of the three measured regions. No gradient was found in infants between 108 h and 240 h of age with periventricular leukomalacia and periventricular haemorrhage. CONCLUSION. In preterm neonates the antero-posterior gradient of CBF is already present. Periventricular leukomalacia as well as periventricular haemorrhage may affect the regional regulation of CBF.

Age Factors↗
PubMed1995

Randomized controlled trial of Ringer solution versus serum for partial exchange transfusion in neonatal polycythaemia.

UNLABELLED: We tested whether crystalliod solutions could be used instead of colloid solutions for partial exchange transfusions (PET) in polycythaemic neonates because crystalloid solutions are cheap, carry no risk of anaphylactic reactions and can be sterilized. We randomly assigned 20 term neonates with venous haematocrit (Hct) > 0.65 l/l to PET with either a serum preparation (BISEKO) or Ringer solution. Plasma volume (PV) was measured with Evans blue dilution. Blood volume (BV) and red cell mass were calculated from PV and venous Hct. Before PET both serum and Ringer groups had the same Hct (0.69 (0.66-0.76) vs 0.69 (0.66-0.71) l/l; median (range)) and BV (108 (81-116) versus 96 (68-121) ml/kg. During PET an equivalent amount of blood was withdrawn stepwise (19 (14-26) versus 17 (13-25) ml/kg and replaced by either serum or Ringer solution. More of the Ringer solution (median 77%) than of the serum (median 36%) given left the intravascular space within 4 h after PET (P = 0.016); but there was no significant difference in Hct after Ringer-PET compared to serum-PET (median 0.58 vs 0.56 l/l). No infant required repeat PET. Ringer-PET reduced BV from high to normal values (from median 96 to 83 ml/kg; P = 0.005), whereas after serum-PET BV remained high (from median 108 to 98 ml/kg; not significant). CONCLUSION: PET with Ringer solution resulted in a haemodilution comparable to PET with serum and a correction of hypervolaemia.

Blood Component Transfusion↗