Early treatment with nasal-CPAP.
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Humans↗
Biomedical subjects
G Greisen
Publications and source records attributed to G Greisen.
ROP in three follow-up studies from Rigshospitalet during the period 1976-1987.
Three studies of late outcome in groups of consecutively admitted very low birthweight or very pre-term infants have recently been reported from Rigshospitalet, Copenhagen. The periods were 1976-78, 1980-82, and 1984-87. The incidences of blindness due to retinopathy of prematurity (ROP) and of motor deficit due to cerebral palsy (CP) are analysed in this report. For the present purpose selection within the three groups made them more, although not entirely, comparable. In spite of marked changes in the use of mechanical ventilation, and in survival rate, the incidences of ROP as well as CP remained constant, at about 5% and 10% of the survivors, respectively. The actual numbers are too small for clearcut conclusions but the analysis supports two previously formed notions: 1) According to monitoring of blood gases deviating oxygen and carbon dioxide tensions do not appear as prime factors in inducing neither ROP nor CP, and 2) a very preterm infant of given size and maturity has become less exposed to ROP and CP over the years.
Blindness↗
Estimation of cerebral venous saturation in newborn infants by near infrared spectroscopy.
The purpose of the study was to evaluate the near infrared spectroscopy technique for determination of the cerebral venous oxygen saturation. By tilting the patient's head down 15 degrees, changes in OD may be caused by changes in cerebral blood volume. On the assumption that increases in cerebral blood volume consist of venous blood only, cerebral venous oxygen saturation can be calculated as the measured change in oxygenated Hb divided by the change in total Hb. Two groups of mechanically ventilated, newborn infants were investigated: 10 asphyxiated, term infants and another 22 preterm infants with respiratory distress syndrome. All were monitored by near infrared spectroscopy during tilting, and cerebral blood flow was estimated by the 133Xe clearance technique immediately before tilting. Cerebral venous oxygen saturation could not be calculated in 13 preterm infants, as the blood volume remained constant during tilting. In the remaining 19, cerebral venous oxygen saturation averaged 0.67 (SD = 0.09) in asphyxiated infants and 0.53 (SD = 0.15) in preterm infants (p = 0.03). The corresponding values of cerebral blood flow were closely and inversely related to oxygen extraction calculated from cerebral venous saturation as estimated by near infrared spectroscopy.
Asphyxia Neonatorum↗
Very pre-term birth and visual impairment. A retrospective investigation of 411 infants of gestational age 30 weeks or less, 1983-89 Rigshospitalet, Copenhagen.
In a group of infants and children of very preterm delivery (gestational age 30 weeks or less, n = 411, Rigshospitalet Copenhagen 1983-89) 13 got blind due to retinopathy of prematurity (3.2%) while another 13 with sequelae retained useful vision of at least one eye. One child later acquired bilateral retinoblastoma, with a free interval of one year from a protracted course of ROP stage 2-3 eventually to regress. The 411 surviving subjects being recruited from a total of 515 of a similarly low gestational age, the survival rate in the 7-year period under study was just below 80%. No doubt, the high survival rate in this very pre-term group is of importance for the risk of developing retinopathy of prematurity, but the role of the ophthalmologist in controlling the infants is also emphasized. Generally, stricter observation schemes are recommended. Probably, the ROP frequency in the sample of 23.6% is an underestimate.
Blindness↗
[Surfactant treatment of newborn infants with respiratory distress syndrome primarily treated with nasal continuous positive air pressure. A pilot study].
In this pilot study, Curosurf (200 mg/kg) was administrated to 34 patients with the respiratory distress syndrome in nasal-CPAP therapy with FiO2 requirements greater than 0.60 and/or TcPCO2 greater than 8 kPa. The surfactant was instilled during a short period of intubation or in a few cases via an intratracheal catheter (Ch. 6). The age of the patients on surfactant treatment ranged from two to 72 hours. Eighteen patients could be maintained on nasal-CPAP after treatment with Curosurf and only a few complications were seen in these infants. The other 16 patients subsequently required artificial ventilation and had a higher incidence of pulmonary and extrapulmonary complications. On the basis of these observations, we plan a randomized trial to investigate whether, administration of surfactant reduces the need for ventilator treatment and improves the odds for uneventful recovery in this category of patients.
Biological Products↗
Judging fetal growth from body proportions at birth.
Fetal growth velocity from 27 weeks until birth was calculated in 378 infants born after high risk pregnancies from at least three ultrasound measurements of estimated fetal weight and the weight at birth. Anthropometric measurements at birth (weight, head circumference, length, ponderal index and skinfolds), after correction for differences in gestational age, were significantly related to fetal growth velocity. The relation between fetal growth velocity and ponderal index was significant (correlation coefficient = 0.34, P < 0.001). However, the correlations between fetal growth velocity and each of the anthropometric measures disappeared when birth weight relative to gestational age was accounted for. This means that given the birth weight and the gestational age of a newborn infant, body proportions, e.g. ponderal index or skinfold thickness, do not contribute further to the judgment about fetal growth rate.
Anthropometry↗
Acute changes in cerebral oxygenation and cerebral blood volume in preterm infants during surfactant treatment.
Following administration of surfactant a marked depression in aEEG activity occurs for about 10 minutes; the mechanism of this depression is unknown. In view of this, twenty-nine preterm infants were investigated with near infrared spectroscopy (NIRS) to evaluate rapid changes in total cerebral haemoglobin concentration and cerebral oxyhaemoglobin concentration during rescue treatment with natural surfactant. During surfactant instillation there was a short-lasting hypoxaemia as demonstrated by pulseoximetry as well as a considerable fall in arterial blood pressure. With NIRS, tissue hypoxia was demonstrated by a drop in cerebral oxyhaemoglobin concentration. The marked drop in arterial blood pressure occurring immediately following surfactant was not matched by a drop in total cerebral haemoglobin concentration. This suggests that cerebral blood volume and hence cerebral blood flow was maintained. In the following minutes there was an improvement in cerebral oxygenation as indicated by the rise in cerebral oxyhaemoglobin concentration in nearly all the infants.
Birth Weight↗
Detection of small-for-gestational-age fetuses by ultrasound screening in a high risk population: a randomized controlled study.
OBJECTIVE: To assess the value of fetal weight estimation during routine third trimester ultrasound examinations for the identification of small-for-gestational-age (SGA) fetuses, to promote active pregnancy management and so reduce perinatal morbidity. DESIGN: A prospective controlled randomized study. SETTING: Outpatient clinic at the Department of Obstetrics, Herlev University Hospital, Denmark. SUBJECTS: One thousand pregnant women considered at risk were selected consecutively from April 1985 to September 1987 and randomized to either a revealed-results group or a withheld-results group. INTERVENTION: All the women had an early ultrasound examination for estimation of gestational age. Both groups had routine ultrasound estimates of fetal weight after 28 weeks and then every third week until delivery. The results were available for clinical use only in the revealed group. MAIN OUTCOME MEASURES: Number of interventions during pregnancy (admission to hospital, elective delivery), emergency intervention during labour, and fetal outcome. RESULTS: Revealing the results of ultrasound estimates of fetal weight for gestational age during the third trimester resulted in statistically significantly increased diagnosis of SGA fetuses, of elective deliveries based on this diagnosis, and of healthy preterm babies admitted to the neonatal care unit, but no detectable overall improvement in weight for gestational age at birth, or in neonatal morbidity or mortality. CONCLUSION: This method of screening improved the diagnosis of SGA fetuses, but this was not followed by improved fetal outcome.
Birth Weight↗
Changes in cerebral oxygenation and cerebral blood volume during endotracheal suctioning in ventilated neonates.
The effect of endotracheal suctioning on cerebral haemodynamics was investigated in 29 newborn infants with a mean gestational age of 31 weeks (range 25-40 weeks). Prior to one of two suctioning procedures, the inspiratory fraction of oxygen was increased by 10%. Brain oxygenation and total haemoglobin concentration were estimated continuously by near infrared spectroscopy. Mean arterial blood pressure, arterial blood oxygen saturation and carbon dioxide tension were recorded simultaneously. Brain oxygenation decreased in parallel with arterial oxygen saturation during suctioning. Preoxygenation ameliorated the decrease in brain oxygenation and arterial oxygen saturation whereas there was no benefit with regard to the changes in total haemoglobin concentration, carbon dioxide tension or mean arterial pressure. Changes in total haemoglobin concentration were related closely to concomitant changes in carbon dioxide tension (p less than 0.0001) but unrelated to changes in mean arterial pressure or arterial oxygen saturation. Our findings suggest that cerebral blood volume may react to changes in carbon dioxide tension during endotracheal suctioning in mechanically ventilated neonates. Apparently, preoxygenation prior to suctioning does not ameliorate the stress in normoxic infants.
Blood Pressure↗
Effect of cerebral blood flow and cerebrovascular autoregulation on the distribution, type and extent of cerebral injury.
Global cerebral blood flow (GCBF) is low in the human neonate compared to the adult. It is even lower in mechanically ventilated, preterm infants: 10-12 ml/100 g/minute, a level associated with brain infarction in adults. The reactivity, however, of global CBF to changes in cerebral metabolism, PaCO2, and arterial blood pressure is normal, except following severe birth asphyxia, or in mechanically ventilated preterm infants, who subsequently develop major germinal layer hemorrhage. The low level of cerebral blood flow (CBF) matches a low cerebral metabolism of glucose and a relatively small number of cortical synapses in the perinatal period. It has not been possible to define a threshold for GCBF below which electrical dysfunction or brain damage occurs (such as white matter and thalamic-basal ganglia necrosis). Three explanations for the lack of clear relation between GCBF and electrical brain activity of the preterm infant must be examined more closely: 1) low levels of CBF are adequate; 2) GCBF does not adequately reflect critically low perfusion of the white matter, and 3) acute white matter ischemia does not result in electrical silence. Two clinical patterns of brain damage following asphyxia may be explained by changes in the blood flow distribution induced by asphyxia: brainstem sparing and parasagittal cerebral injury. Hours to days after severe asphyxia, a state of marked global hyperperfusion may prevail. It is associated with poor neurological outcome and may be an entry point for trials of interventions aiming sat blocking the translation of asphyctic injury to cellular death and tissue damage.
Brain Ischemia↗
Estimation of fetal weight by ultrasound.
Estimation of fetal size by ultrasound has supported two recent concepts of fetal growth. Firstly, the normal weight gain is constant from 28 weeks of gestation until several weeks after term; about 27 g/day. Secondly, the average weight of fetuses born preterm is lower than the average weight of fetuses of the same gestational age who remain in utero. This means that up to 40% of infants born at 28-30 weeks of gestation are small-for-gestational age, when related to the biological optimum. Unfortunately, the test-retest variation of fetal weight estimation is as much as 50% of the standard deviation of the gestational-age-specific fetal weight distribution. This means that fetal growth has to be followed for many weeks to document statistically significant deviations. No study has, as yet, demonstrated the value of this approach to distinguish between intrauterine growth retardation and growth along low centiles by fetuses of reduced growth potential.
Birth Weight↗
Surfactant administration and the cerebral circulation.
We have used two main techniques to investigate the effect of surfactant therapy on the cerebral circulation in 34 babies. Twenty-one babies were studied using near infrared spectroscopy and 13 had cerebral blood flow measured using a xenon clearance technique. Other measures recorded included amplitude integrated EEG, mean arterial blood pressure and central venous or oesophageal pressure. There was a marked depression in EEG activity lasting for 10-20 min after surfactant administration. Cerebral blood volume and cerebral blood flow were maintained in most infants in spite of a fall in mean arterial blood pressure. We conclude that factors other than cerebral ischaemia cause the transient disturbance in electrophysiologic activity.
Biological Products↗
Ischaemia of the preterm brain.
Much has been learned about the diagnosis and prognosis of periventricalar leucomalacia during the past 10 years. The understanding of its causation, however, has not advanced much. Still, the candidate for the principal role is focal ischaemia in the particularly vulnerable regions of the brain. It has been difficult to provide direct supportive evidence for this hypothesis. It has not been possible to define a threshold for (global) cerebral blood flow (CBF) under which brain damage or electrical dysfunction occurs. Three hypothetical explanations for the lack of clear relation between global CBF and electrical brain activity of the preterm infant must be examined more closely: (1) the very low levels of CBF are adequate, (2) global CBF does not reflect the perfusion of the white matter, or (3) acute white-matter ischaemia does not result in cerebro-electrical dysfunction. In view of the practical importance, more research is indicated.
Brain↗
Cerebroelectrical depression following surfactant treatment in preterm neonates.
During surfactant treatment of respiratory distress syndrome, 23 premature newborns were investigated with continuous amplitude-integrated electroencephalography (cerebral function monitors). Simultaneously, arterial blood pressure and transcutaneous blood gas values were recorded. A short (less than 10 minutes) but significant decrease in cerebral activity was seen in almost all neonates immediately after the surfactant instillation, in spite of an improved pulmonary function. In 21 of 23 neonates, a transient fall in mean arterial blood pressure of 9.3 mm Hg (mean) occurred coincidently with the cerebral reaction. Neonates in whom intraventricular hemorrhage developed tended to have lower presurfactant mean arterial blood pressure (P greater than .05), but they had a significantly lower mean arterial blood pressure after surfactant instillation (P less than .05). No other differences were found between neonates in whom intraventricular hemorrhage developed and those without intraventricular hemorrhage. The present findings demonstrate that an acute cerebral dysfunction may occur after surfactant instillation. In some vulnerable neonates with arterial hypotension and severe pulmonary immaturity, the fall in mean arterial blood pressure may increase the risk of cerebral complications and could be related to an unchanged rate of intraventricular hemorrhage after surfactant treatment.
Biological Products↗
[The relationship between low pH in the umbilical cord artery in neonates and later development of cerebral paresis].
Routine determination of the pH in umbilical arterial blood immediately after delivery is a commonly employed variable for assessing the risk of subsequent cerebral paresis caused by hypoxia. Opinions differ regarding the lower limit for normal NS-pH (acidosis limit) and this is due mainly to variable conceptions of what a normal delivery is. Lower limits from 7.04 to 7.14 are thus observed if the limit -2 SD is chosen. Even if the limit of 7.04 is chosen, only very few of the infants who are acidotic on delivery subsequently develop cerebral paresis. The most important reason for this is that the prevalence of cerebral paresis developed as a result of hypoxia during delivery is very low and that a low NS-pH value most probably originates from a neonate who recovers without cerebral paresis. Another reason is that the relationship between the pH value and the degree of hypoxia is far from perfect and this holds also true for the relationship between the degree of hypoxia and cerebral paresis. It is therefore concluded that in connection with cerebral paresis, NS-pH does not fulfill the requirements of a diagnostic test. Determination of NS-pH may, on the other hand, be of significance for neonatal treatment as the combination of a low Apgar score and NS-pH is a reasonable predictor for the neonatal morbidity.
Cerebral Palsy↗
The relation between perinatal conditions and developmental outcome in low birthweight infants. Comparison of two cohorts.
We have compared the relations between perinatal conditions and developmental outcomes at age four years for two cohorts of children with birthweights 2,300 g or less, who did not develop cerebral palsy--one from Southeastern Wisconsin (children born 1975-76) and the other from Copenhagen (children born 1980-82). We examined the general effects of parental education and socioeconomic status, the use of Cesarean section, the degree of prematurity and neonatal complications on outcome. The methods of latent path structural analysis were used to form two models among 15 latent variables: one for children from Copenhagen and a similar model for children from Wisconsin. The impact of parental education and socioeconomic status was somewhat greater in Wisconsin. Several neonatal complications were related to outcome in Wisconsin: the early condition of the infant, use of a respirator, pneumothorax, and anemia/apnea. The only neonatal complication with a significant relation to outcome in Copenhagen was pneumothorax and to a much lesser degree major germinal layer haemorrhage. The degree of prematurity per se had a greater impact in Copenhagen. The use of Cesarean section and mechanical ventilation in the smallest infants was much more frequent in Denmark, but no association could be shown between this increased use and improved developmental outcome.
Child Development↗
Estimating cerebral blood flow in newborn infants: comparison of near infrared spectroscopy and 133Xe clearance.
A new method of measuring cerebral blood flow (CBF) in newborn infants by means of near infrared spectroscopy (CBFnirs) was compared with the i.v. 133Xe clearance technique (CBFxe). Forty CBFnirs measurements were obtained during 19 133Xe measurements in 16 infants; 79 other CBFnirs data sets were discarded because the assumptions for their use were not fulfilled. The test-retest variation of repeated near infrared-measurements during each 133Xe clearance was 17.5%. CBFnirs was closely related to CBFxe (r2 = 0.84, p less than 0.0001), with a slope of 0.75 (SEM = 0.064) and a intercept of 1.58 mL/100 g/min (SEM = 0.51). The difference between the measurements obtained by the two methods (CBFnirs-CBFxe) was negative in the high range of CBF, whereas the difference was close to zero in the low range. We conclude that CBF measured with near infrared spectroscopy was in good agreement with the CBF measured with the 133Xe method. The near infrared spectroscopy method has the advantage of being noninvasive, and it does not involve ionizing radiation. Because of methodologic constraints, however, it may underestimate CBF in the high range of flow, and it may have limitations of application in clinical research.
Blood Flow Velocity↗
Normal fetal growth evaluated by longitudinal ultrasound examinations.
Fetal weight estimation was evaluated using the equations of Warsof, Shepard and Hadlock in 192 patients, less than 3 days before delivery. Warsof's and Hadlock's equations resulted in significantly better weight estimates compared to Shepard's equation. No systematic error was found below 2500 g by use of Warsof's equation, whereas Shepard's and Hadlocks's equations resulted in significant over-estimation in the low weight group. In a study of 5 fetuses, of 27-38 weeks gestational age, the intra-observer variation was calculated to 4.6%, whereas the coefficient of variation among observer means was 2.9%. The mixed intra- and inter-observer coefficient of variation was 6.5%. Thirty-five low-risk, uncomplicated pregnancies with reliable last menstrual dates were investigated longitudinally with ultrasound measurements of fetal weight. Population growth curves of fetal weight, fetal femur length, abdominal circumference and biparietal diameter were constructed by weighted polynomial regression. After 27 weeks of gestational age the weight growth curve showed only insignificant non-linearity. Compared to a Danish growth curve based on birth weights, significant higher mean weight was found, especially before 31 weeks of gestational age. The 10th and 90th percentiles for the individual percentage deviation change was +/- 4.4% per 28 days.
Body Weight↗