Outcome of neonatal stroke in full-term infants without significant birth asphyxia

Seven children with neonatal stroke were identified and six were followed for 13 months to 5 years (mean 28 months). Gestational age ranged between 39 and 42 weeks and none had hypoxic ischaemic encephalopathy. Focal clonic seizures were the presenting feature in six, and one presented with apnoea. The age of the first seizure ranged between 8 and 48 h (mean 26). The total number of seizures ranged between 3 and 10 (mean 5), and all seizures resolved by day 3 in all cases. CT scan showed an ischaemic infarct in six cases, and one child had a haemorrhagic infarct in the right anterior cerebral artery distribution. Phenobarbital was maintained for 3 weeks to 6 months (mean 11 weeks). None had recurrent seizures beyond the 3rd day of life and all were developing normally with no significant focal neurological deficits on follow up assessment.

CONCLUSIONS

Full-term infants with neonatal stroke unrelated to significant birth asphyxia have a favourable neurological outcome. Seizures appear to be restricted to the first 3 days of life. We recommend short-term treatment with anticonvulsants.

Perinatal outcome of singleton term breech deliveries

OBJECTIVE

To assess neonatal morbidity and mortality in singleton term infants delivered in breech presentation and to find a possible correlation between outcome and mode of delivery.

STUDY DESIGN

Case study of 306 singleton, term (37-42 weeks), breech deliveries, that took place between 1989 and 1994 in one perinatal centre.

RESULTS

170 infants were delivered vaginally, 72 by elective and 64 by secondary cesarean section. Even after application of strict selection criteria -- i.e. prior pelvic assessment by staff obstetricians, an estimated birth weight of 2500-4000 g -- and with staff supervision, vaginal delivery turned out to be associated with a significantly higher incidence of low umbilical artery pH values and neonatal care unit admissions as compared to elective cesarean section. Five infants suffered mechanical trauma. One neonatal death occurred in the vaginal delivery group.

CONCLUSION

The results of this retrospective study of 306 singleton term breech deliveries imply that even after strict selection of patients, vaginal delivery is associated with increased neonatal morbidity in comparison to elective cesarean section.

Hypoxia-ischaemia model in the 7-day-old rat: possibilities and shortcomings

The Levene model in 7-day-old rats is the most often used model of hypoxia-ischaemia (HI) in immature animals. The rat central nervous system is immature at birth and corresponds neurodevelopmentally to the term human infant during the second postnatal week. The Levene model of HI differs from clinical asphyxia with respect to the unilateral distribution of brain injury and lack of multi-organ dysfunction. Furthermore, it does not allow cardiovascular monitoring or repeated blood sampling. On the other hand, the progressive nature of HI bears many similarities to birth asphyxia with regard to blood flow changes and cellular metabolic derangements. The model is well characterized, easy to carry out and the low cost allows inclusion of a sufficient number of animals for dose-response evaluation of neuroprotective agents. In addition, it provides the unique opportunity of long-term evaluation of neuropathological and functional outcome.

Magnesium attenuates a striatal dopamine increase induced by anoxia in the neonatal rat brain: an in vivo microdialysis study

We evaluated the effects of magnesium on extracellular dopamine (DA) and its metabolites in the striatum of 5-d-old rats submitted to 16 min of anoxia using microdialysis and HPLC. Rat pups were divided into three groups and received either 1) intrastriatal perfusion (IS) of MgSO4, 2) intraperitoneal injection (IP) of MgSO4, and 3) NaCl and Ringer's solution, respectively in place of MgSO4. After stabilization, Mg2+, saline, and Ringer's solution were administered; then, 114 animals were exposed to 100% nitrogen for 16 min. Anoxia induced a DA surge, an acutely marked increase of DA, in both the control and the IP group. In contrast, the DA surge was significantly suppressed in the IS group (p < 0.01, analysis of variance). During anoxia, the plasma Mg2+ in the IP group, but not in the IS group, maintained a significantly higher level compared with the basal level. On the other hand, Mg2+ in the perfusates in the IS group, but not in the IP group, maintained a significantly high level during anoxia. Alterations induced by anoxia in other metabolites, 3,4-dihydroxyphenylacetic acid, homovanillic acid, norepinephrine, and 5-hydroxyindole-3-acetic acid, did not significantly differ among the three groups. We propose that elevated levels of Mg2+ in the striatum had inhibitory effects on the DA surge during anoxia.

Clinicopathological correlations in postasphyxial organ damage: a donor organ perspective

OBJECTIVES

1) To assess pathology in the heart, kidneys, lungs, liver, and intestine in babies dying of postasphyxial hypoxic ischemic encephalopathy (HIE), and their suitability for organ transplantation. 2) To analyze the correlation between in vivo clinical markers of collateral organ damage and autopsy findings.

STUDY DESIGN

Retrospective cohort study of 58 infants who died of postasphyxial HIE and had autopsies during 1985 to 1994. Collateral organ damage was evaluated clinically and pathologically, and the results compared.

RESULTS

Severe pathological changes were observed in 6% to 62% of the five organs studied; 59% of the four major organs had either minor or no pathology. The sensitivity of the clinical predictors ranged from 69% to 100%, and specificity from 50% to 97%.

CONCLUSIONS

The organs of newborns dying of severe HIE may be suitable for use as donor organs; predictions of their suitability were most accurate for liver, kidney, and lungs, and least accurate for the heart.

Proton magnetic resonance spectroscopy of the brain during acute hypoxia-ischemia and delayed cerebral energy failure in the newborn piglet

Studies of the brains of severely birth-asphyxiated infants using proton (1H) magnetic resonance spectroscopy (MRS) have shown changes indicating a rise in cerebral lactate (Lac) and a fall in N-acetylaspartate (Naa). The aim of this study was to test two hypotheses: 1) that these changes can be reproduced in the newborn piglet after transient reversed cerebral hypoxiaischemia, and their time course determined; and 2) that changes in Lac peak-area ratios are related to changes in phosphorylation potential as determined by phosphorus (31P) MRS. Eighteen piglets aged < 24 h were anesthetized and ventilated. Twelve underwent temporary occlusion of the carotid arteries and hypoxemia, and six served as sham-operated controls. 1H and 31P spectra were acquired alternately, both during the insult and for the next 48 h, using a 7-tesla spectrometer. During hypoxiaischemia, the median Lac/total creatine (Cr) peak-area ratio rose from a baseline of 0.14 (interquartile range 0.07-0.27), to a maximum of 4.34 (3.33-7.45). After resuscitation, Lac/Cr fell to 0.75 (0.45-1.64) by 2 h, and then increased again to 2.43 (1.13-3.08) by 48 h. At all stages after resuscitation Lac/Cr remained significantly above baseline and control values. Naa/Cr was significantly reduced below baseline and control values by 48 h after resuscitation. The increases in the Lac peak-area ratios were concomitant with the falls in the [phosphocreatine (PCr)*]/ [inorganic phosphate (Pi)] ratio, during both acute hypoxiaischemia and delayed energy failure. The maximum Lac/Naa during delayed energy failure correlated strongly with the minimum [nucleotide triphosphate (NTP)]/[exchangeable phosphate pool (EPP)] (r = -0.94, p < 0.0001). We conclude that both hypotheses have been confirmed.