ABSTRACT. Objective. To prospectively investigate the development of amplitude-integrated electroencephalographic (aEEG) activity during the first 2 weeks of life in neurologically normal and clinically stable preterm infants <30 weeks' gestational age (GA).Patients and Methods. Infants with a GA of <30 weeks admitted to the neonatal intensive care unit of the Vienna University Children's Hospital (Vienna, Austria) were studied prospectively by using aEEG and cranial ultrasound. Clinically stable infants without clinical or sonographic evidence of neurologic abnormalities were eligible for inclusion in the reference group. The distribution of 3 background aEEG activity patterns (discontinuous low-voltage, discontinuous high-voltage, and continuous), presence of sleep-wake cycles, and number of bursts per hour in the reference group were determined by visual analysis.Results. Seventy-five infants (median GA: 27 weeks; range: 23-29 weeks) were eligible for inclusion in the reference group and had aEEG recordings during the first 2 weeks of life available. Analysis of aEEG background activity showed that with higher GA the relative amount of continuous activity increased while discontinuous patterns decreased. The number of bursts per hour decreased with increasing GA. Cyclical changes in aEEG background activity resembling early sleep-wake cycles were observed in all infants.Conclusions. Normal values for aEEG background activity were determined in preterm infants <30 weeks' GA. Clinically stable and neurologically normal preterm infants exhibit at least 2 different patterns of aEEG activity. There is a correlation between the GA and the relative duration of continuous aEEG activity. A dvances in neonatal intensive care during the last decades have led to an increased survival rate of extremely low birth weight infants. However, neurologic and developmental disability is still common among survivors. 1 Prevention of brain injury in these patients has become one of the main goals of modern neonatology. Continuous monitoring of neonatal brain function may aid in the identification of risk factors and patients at increased risk for neurologic morbidity. Early recognition and modification of potentially harmful environmental factors may prevent secondary brain injury.Conventional electroencephalography (EEG) is one of the most useful tools for intermittent and continuous assessment of brain function and prediction of neurologic outcome in term infants and children. 2-4 However, conventional EEG has limitations in its application for extremely low birth weight infants. Registration and interpretation of conventional EEG in this age group are difficult because of the electrical interferences on the neonatal intensive care unit, the large volume of data generated during a longer recording, and the need for 24-hour availability of a skilled examiner experienced in EEG of preterm infants. Further, data on normal EEG patterns in extremely premature infants are still limited. 5,6 Recently, amplitude-integrated EEG (aEEG) pro...
This study investigated the influence of temperature or glutamate antagonism on the immediate outcome of perinatal asphyxia. Perinatal asphyxia was produced by water immersion of fetus-containing uterus horns removed by cesarean section from ready to deliver rats. The uterus horns were kept in a water bath for different time periods, before the pups were delivered and stimulated to breathe. After delivery, the pups were assessed for behavior and for systemic glutamate, aspartate, lactate and pyruvate levels measured with in vivo microdialysis, or ex vivo for energy-rich phosphates, including adenosine triphosphate (ATP), in brain, heart and kidney. In a series of experiments, asphyxia was initiated in a water bath at 37 degrees C, before the pup-containing uterus horns were moved for different time intervals to a 15 degrees C bath. In another series of experiments, the mothers were treated with N-methyl-D-aspartate (NMDA) antagonist, dizocilpine (MK-801), or alpha-amino-3-hydroxy-methylisoxazole-4-propionic acid (AMPA) antagonist,2,3-dihydroxy-6-nitro-7-sulfamoyl benzo(f) quinoxalin NBQX) 1 h before hysterectomy and asphyxia at 37 degrees C. The rate of survival rapidly decreased following exposure to more than 16 min of asphyxia, and no survival could be observed after 22 min of asphyxia. An LD50 was estimated to occur at approximately 19 min of asphyxia. The outcome was paralleled by a decrease in ATP in kidney, followed by a decrease in heart and brain. A maximal decrease in ATP was observed after 20 min of asphyxia in all tissues. Systemic microdialysis revealed that glutamate, aspartate and pyruvate levels were increased with a peak after 5 min of asphyxia. In contrast, lactate levels increased along with the length of the insult. Survival was increased when the pup-containing uterus horns were moved from a 37 degrees C to a 15 degrees C bath, at 15 min of asphyxia (the LD50 was thus increased to 30 min). If the shift occurred at 10 or 5 min of asphyxia, the LD50 increased to 80 or 110 min, respectively. The effect of glutamate antagonism was minor compared to hypothermia; the best effect (an increase in the LD50 to approximately 22 min) was observed after combining AMPA and NMDA antagonists.
We previously reported on a series of 27 newborn infants treated for posthemorrhagic hydrocephalus with external ventricular drainage during 1984 to 1989. In the present study we continued to evaluate this technique during the subsequent 8 years (37 patients; mean birthweight 1251+/-478 g; mean gestational age 29+/-2.9 weeks; 51 drains), and we now report on the long-term experience with this method, complications, and neurodevelopmental outcome of the survivors. The mean age at drain insertion was 21 days, and the mean duration of drainage 23 days. Eight infants died of causes unrelated to external ventricular drainage. Eleven of the survivors did not require a permanent shunt. Two patients experienced ventriculitis, resulting in an infection rate of 5.4% per patient and 3.9% per drain. The neurodevelopmental outcome was mainly dependent on the extent of the pre-existing parenchymal injury. We conclude that external ventricular drainage is a safe and effective technique for the management of preterm infants with posthemorrhagic hydrocephalus.
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