Changes in cerebral blood volume during endotracheal suctioning.
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Biomedical subjects
Publications and source records attributed to G Duc.
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The recommendations of the American Academy of Pediatrics for eye examinations of premature infants are based on the following criteria: an age of gestation less than 35 weeks for infants having received oxygen or a birthweight under 1300 g with or without supplemental oxygen. The first examination should take place between the 5th and the 7th week of extra-uterine life, or prior to discharge of the hospital and repeated according to the first observations. It is specified that the examination must be done by a person experienced in neonatal ophthalmology and indirect ophthalmoscopy. In Zurich, following these recommendations, the criteria of the CRYO-ROP study, and our experience, we examine the infants with following features: (1) all premature infants with birthweight less than 1500 g independently of oxygen exposure, (2) neonates who have less than 35 gestational weeks and who were exposed in a FIO2 > 0.4 during more than 24 h. And (3) the first eye examination is done between the 5th and the 6th weeks of extra-uterine life. The follow-up of these children will depend on the primary state. The infants with ROP will be followed by the neonatal ophthalmologist as long as retinal complications can persist. Afterwards these infants will be controlled by the general ophthalmologist for the amblyopie prophylaxis (by anisomyopia or strabismus). Two controls during the first year, then one per year are advised in these cases. For children who had a cryocoagulation or an retinal detachment operation, the follow-up will be assured by the general ophthalmologist for the prevention of the amblyopia and by the neonatal ophthalmologist for the retina.
Estimations of cerebral blood flow were performed by both near infrared spectroscopy and 133xenon clearance on 12 occasions in nine critically ill premature infants (26-29 gestational wk) who required mechanical ventilation and supplemental oxygen. For each study, one determination of cerebral blood flow by 133xenon was compared with the mean of two to five measurements by near infrared done within 1-19 (median 5) h. 133Xenon measurements ranged from 9.6-16.9 mL/100 g/min, and mean near infrared measurements ranged from 8.6-25.0 mL/100 g/min. There was a significant correlation between the two sets of measurements (r = 0.80, p < 0.001). The mean difference between the methods was 1.6 mL/100 g/min, and the 95% limits of agreement were -0.5-3.8 mL/100 g/min. This study showed that cerebral blood flow can be measured noninvasively in critically ill premature infants at the cotside by near infrared spectroscopy and by the 133xenon clearance technique. The methods give comparable results.
To determine the incidence of multiple births and associated morbidity and mortality, we collected in a retrospective study all the multiple births (twins excluded) in Switzerland from 1985 to 1988. In all we followed 77 sets of triplets and 9 sets of quadruplets, representing an annual incidence of 1/3968 births for the triplets and 1/33,947 births for the quadruplets. The incidence of induced pregnancies increased in the period 1985 to 1988. The principal complications were premature contractions and preeclampsia. Only 56% of the children were born in a hospital with a neonatal intensive care unit. The mean gestational age was 33 0/7 weeks (ranging from 25 0/7 to 38 5/7) for the triplets, and 30 5/7 weeks (ranging from 27 5/7 to 36 3/7) for the quadruplets. The mean birthweight was 1787 g (ranging from 560 to 3000 g) for the triplets and 1189 g (ranging from 590 to 1980 g) for the quadruplets. RDS was found to be the principal neonatal pathology (65.5% of triplets and 85.2% of quadruplets) with 18.8% of triplets and 61.8% of quadruplets requiring ventilation. The mortality rate in our study was 8.9% for triplets and 14.7% for quadruplets.
Three mitochondrial plasmids (1704, 1695 and 1478 bp) were isolated from sterile cytoplasms of Vicia faba L. and cloned into a bacterial plasmid vector. Their nucleotide sequence was found to be 99 to 100% homologous to their counterparts isolated from a fertile cytoplasm (J.A. Wahleithner and D.R. Wolstenholme, Curr Genet 12 (1987) 55-76). Several overlapping transcripts were localized in the region which is unique to each of the three plasmids. S1 nuclease mapping indicated for all of them several 3' termini but a unique 5' boundary which was located downstream of the consensus sequence CNTAAGTGANNNNNGAA also found at the transcript 5' boundary of other plant mitochondrial plasmids. Southern blot hybridization with nuclear DNA indicated the presence of nuclear sequences homologous to each plasmid.
Intrauterine growth retardation, microcephaly, and developmental delay in two first cousins lead to the recognition of phenylketonuria (PKU) in their mothers, 24- and 23 year-old sisters with blood phenylalanine concentrations of approx. 1.2 mmol/l who had never been treated and had no overt mental retardation. Both mothers were shown to be homozygous for a point mutation leading to an Arg-to-Gln substitution at codon 261 of the phenylalanine hydroxylase gene, a mutation which has been recently identified and tentatively associated with a mild variant of PKU. Our observation suggests that homozygosity for the Arg-261-Gln mutation can indeed result in "mild" PKU with little or perhaps no mental retardation, but also indicates that in such women, who may go unrecognized if not screened for, blood phenylalanine is elevated enough to cause the maternal PKU syndrome in their offspring.
The development of fine motor and adaptive skills during the first 2 years of life is reported in 97 high-risk preterm children and 94 healthy term children. Most stages of fine motor and adaptive development were found to occur at slightly later ages among preterm children. Neurological development was significantly correlated with fine motor and adaptive development in preterm children only. No significant influence of prenatal, perinatal and postnatal variables on fine motor and adaptive development was noted. No significant sex differences were observed in both the term and preterm group. The strongest predictors of later intellectual functioning were fine motor performance at 9 months and fine motor and adaptive skills at 18 to 24 months.
Switzerland has one of the lowest neonatal mortalities in the world (5%) which has barely decreased during the last 10 years. The aim of care for newborn infants has therefore shifted from reducing mortality to reducing morbidity and increasing quality of life. Diseases which were frequent and severe some twenty years ago, such as rubella embryopathy and rhesus incompatibility, have almost disappeared today due to general prophylaxis. On the other hand, new, partly iatrogenic diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia, considerably affect present morbidity of newborn infants. Due to newly developed imaging techniques and genetic, biochemical and immunological methods for screening of risk groups or all pregnant women or newborns, more and more diseases are detected earlier. Therefore the optimal procedure has to be settled early and on an interdisciplinary basis, and include prenatal investigation and possibly treatment, planning of delivery, and early and late postnatal diagnostic and therapeutic measures. The consequence of this development is close cooperation between obstetricians, neonatologists, and pediatric specialists, and a rapidly increasing need for neonatal beds, especially for intensive care. In spite of identification and centralization of women with high risk pregnancy before delivery, every newborn may develop sudden, unpredictable problems of adaptation which need immediate action. Therefore, at every delivery in a clinic or at home the necessary equipment and skilled staff must be available in order to cope with acute problems during adaptation from intrauterine to extrauterine life.
We performed a multicenter prospective randomized controlled trial to determine the efficacy and safety of the surfactant preparation, Survanta (Abbott Laboratories, Chicago, USA), for 750-1750 g infants with idiopathic respiratory distress syndrome, (IRDS) receiving assisted ventilation with 40% or more oxygen. One hundred and six eligible infants from the eight participating centers were randomly assigned between March 1986 and June 1987 to receive either surfactant (100 mg phospholipid/kg, 4 ml/kg) or air (4 ml/kg) administered into the trachea within 8 h of birth (median time of treatment 6.2 h, range 3.2-9.1 h). The study was stopped before enrollment was completed at the request of the United States Food and Drug Administration when significant differences were observed in incidence of periventricular-intraventricular hemorrhage (PIH), between the surfactant treated and control infants. Surfactant treated infants had larger average increases in the arterial-alveolar oxygen ratio, (a/A ratio) (P less than 0.0001), and larger average decreases in FiO2 (P less than 0.0001) and mean airway pressure, (MAP) (P less than 0.017) than controls over the 48 h following treatment. The magnitude of the differences between the surfactant and control groups were 0.19 (SE = 0.03) for a/A ratio, -0.28 (SE = 0.04) for FiO2 and -1.7 cm H2O (SE = 0.70) for MAP. The clinical status on days 7 and 28 after treatment was classified using four predefined ordered categories: (1) no respiratory support; (2) supplemental O2 with or without continuous positive airway pressure (CPAP); (3) intermittent mandatory ventilation; and (4) death. There were no statistically significant differences in the status categories on days 7 or 28 between surfactant and control infants.(ABSTRACT TRUNCATED AT 250 WORDS)
Neurological development in preterm children with birth weight appropriate for gestational age is reported in two separate groups: a longitudinal study of 97 preterm children and 93 term children as a control group and a cross-sectional study of 249 preterm children. Both preterm groups were regarded as high risk with respect to number of outborns, distribution of gestational age and perinatal risk factors. Neurological outcome at 5-6 years of age in the majority of the preterm children was comparable to that of the term children. However, 15% of boys and 9% of girls in the preterm group were diagnosed as having cerebral palsy. Mild diplegia was most frequently observed; 4% of the children were severely impaired. Fourteen percent of the preterm vs 2% of the term boys and 6-9% of the preterm vs none of the term girls received motor therapy during early school age. There was a small but consistent sex difference in neurological outcome in favour of the term and preterm girls. Effects of drop out rate and of incompleteness of ascertainment are reported in detail.
Intellectual development, speech and school performance of preterm infants with birth weight appropriate for gestational age are reported in two separate investigations: a longitudinal study of 97 preterm children and 93 term children as a control group, and a cross-sectional study of 249 preterm children. Both preterm groups were regarded as high risk groups with respect to number of outborns, distribution of gestational age and perinatal risk factors. Intellectual outcome at 5 and 7 years of age in the majority of the preterm children was comparable to that of the term children. However, 8% of the preterm boys and 2% of the preterm girls achieved lower IQ scores than any of the term children. Between 15% and 17% of the preterm boys and 9%-12% of the preterm girls did not attend school at grade level, compared to 4% and 2% in the term group, respectively. Intellectual and neurological development and school performance were higher interrelated in the preterm than in the term children. Articulation defects, stuttering and dysgrammatism occurred more frequently in the preterm than in the term children and in boys more so than in girls.
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A serological survey over a 1-year period of 1416 mothers at delivery and their 1434 offspring for the presence of anti-Borrelia burgdorferi antibodies revealed a prevalence of 0.85%. Clinically active Lyme disease during pregnancy was found in 1 of these 12 women with elevated titres and the child was born with a ventricular septal defect. Of six affected children, two had hyperbilirubinaemia, one muscular hypotonia, one was underweight for gestational age, one was macrocephalic, and one had supraventricular extrasystoles. Anomalous findings could not be attributed to B. burgdorferi due to a lack of serological evidence of intrauterine infection. Our data do not imply the need for serological screening in pregnancy, however, the importance of recognition and treatment of Lyme disease in pregnancy is emphasized.
The effects of prenatal, perinatal and postnatal events on developmental outcome at five to seven years of preterm infants with birthweights appropriate for gestational age were investigated in two separate cohorts: one a longitudinal study of 97 infants, the other a cross-sectional study of 249 infants. Among the prenatal variables, the number of minor congenital anomalies was negatively correlated with neurological development, as was the deformation score. The pregnancy optimality score was not significantly related to outcome. Among the perinatal variables, gestational age and birthweight had some significant correlations with development, but birth and neonatal optimality scores were only inconsistently significant in relation to outcome. Socio-economic status was strongly related to language and intellectual development. Infants with gestations of 32 to 36 weeks had a more favourable neurological and intellectual outcome than those born before 32 weeks: however, the former group comprised about 80 per cent of the population studied, so the majority of children with lower function were found in that group.
Low cerebral blood flow (CBF) is thought to cause ischaemic brain lesions in premature infants, but a normal outcome has also been observed. Low oxygen affinity of haemoglobin and high arterial oxygen content, independently, reduce CBF under normal, physiological conditions. Transfusions lower the amount of fetal haemoglobin [HbF] and therefore the oxygen affinity of premature babies. In 47 premature babies (range of gestational age 25-34 weeks, birthweight 740-1370 g), CBF was measured with the i.v. Xenon 133 method on days 1, 3 and 7. The relative amount of fetal haemoglobin [HbF] was used as a marker of oxygen affinity of haemoglobin and the haematocrit as representing the arterial oxygen content. A significant influence of [HbF] on CBF was found on days 1, 3 and 7 in ultrasonographically normal babies (n = 13). In babies with subependymal and/or intraventricular haemorrhage (n = 15), this correlation was significant only on day 3 and in those with abnormal intraparenchymal echodensities (n = 19) only on day 7. The correlation between haemoglobin concentration and CBF was not significant. Multiple regression analysis showed a significant influence of [HbF] on CBF independent of haematocrit, pCO2 and blood pressure. It appears that, after blood transfusion, normal babies, and to a lesser extent those with haemorrhages are able to lower their CBF according to the actual oxygen affinity of blood. However, low CBF (less than 10 ml/100 g/min) in non-transfused babies was often associated with later development of cystic periventricular leukomalacia.)
With use of a modified surface coil technique, the authors recorded phosphorus-31 magnetic resonance (MR) spectra of the brains of 40 neonates and infants (48 examinations) ranging from 33 weeks postconceptional age to 6 years of age. Signals of phosphorus metabolites were collected in the frontotemporal region of the brain, and various P-31 MR spectral variables were compared at different times during postnatal life. The ratio of the phosphomonoester signal to the phosphodiester signal, which is related to phospholipid synthesis, decreases within the first 6 months of life; during the same time period, the ratio of the phosphocreatine (PCr) signal to the beta-adenosine triphosphate (ATP) signal increases. In addition, a difference was observed between the areas under the alpha- and beta-ATP peaks. This difference increases with age and correlates with the PCr/beta-ATP signal ratio. The variation of the alpha-ATP peak with age might be explained by overlap of the signals of nicotinamide adenine dinucleotide (NAD) and alpha-ATP.
Pulse oximetry has been proposed as a noninvasive continuous method for transcutaneous monitoring of arterial oxygen saturation of hemoglobin (tcSO2) in the newborn infant. The reliability of this technique in detecting hyperoxemia is controversial, because small changes in saturation greater than 90% are associated with relatively large changes in arterial oxygen tension (PaO2). The purpose of this study was to assess the reliability of pulse oximetry using an alarm limit of 95% tcSO2 in detecting hyperoxemia (defined as PaO2 greater than 90 mm Hg) and to examine the effect of varying the alarm limit on reliability. Two types of pulse oximeter were studied alternately in 50 newborn infants who were mechanically ventilated with indwelling arterial lines. Three arterial blood samples were drawn from every infant during routine increase of inspired oxygen before intratracheal suction, and PaO2 was compared with tcSO2. The Nellcor N-100 pulse oximeter identified all 26 hyperoxemic instances correctly (sensitivity 100%) and alarmed falsely in 25 of 49 nonhyperoxemic instances (specificity 49%). The Ohmeda Biox 3700 pulse oximeter detected 13 of 35 hyperoxemic instances (sensitivity 37%) and alarmed falsely in 7 of 40 nonhyperoxemic instances (specificity 83%). The optimal alarm limit, defined as a sensitivity of 95% or more associated with maximal specificity, was determined for Nellcor N-100 at 96% tcSO2 (specificity 38%) and for Ohmeda Biox 3700 at 89% tcSO2 (specificity 52%). It was concluded that pulse oximeters can be highly sensitive in detecting hyperoxemia provided that type-specific alarm limits are set and a low specificity is accepted.