The authors examined the involvement of platelet-activating factor (PAF) in mediating leukocyte adherence to brain postcapillary pial venules and altering blood-brain barrier (BBB) permeability during basal conditions and during reoxygenation after asphyxia in newborn piglets. Intravital epifluorescence videomicroscopy, closed cranial windows, and labeling of leukocytes with rhodamine 6G allowed us to obtain serial measurements of adherent leukocytes within postcapillary venules. Blood-brain barrier breakdown was determined by optical measures of cortical extravascular fluorescence intensity after intravenous sodium fluorescein. Superfusion of PAF over the cortex induced a dose-dependent increase in leukocyte adherence to cerebral venules and leakage of fluorescein; with 1 micromol/L PAF, the magnitude of adherence and BBB breakdown was similar to that seen during reoxygenation after 9 minutes of asphyxia. Both adherence and loss of BBB integrity resulting from either exogenous PAF or asphyxia-reoxygenation could be significantly attenuated by intravenous administration of WEB 2086, a PAF receptor antagonist. Window superfusion of superoxide dismutase with PAF attenuated PAF-induced increases in adherence and associated fluorescein leakage. These findings indicate that PAF exhibits proinflammatory effects in piglet brain and that PAF contributes to leukocyte adherence and BBB breakdown after cerebral ischemia. These PAF effects are mediated by increases in superoxide radical generation. (+info)
Intraosseous lines in preterm and full term neonates.
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AIM: To evaluate the use of intraosseous lines for rapid vascular access in primary resuscitation of preterm and full term neonates. METHODS: Thirty intraosseous lines were placed in 27 newborns, in whom conventional venous access had failed. RESULTS: All the neonates survived the resuscitation procedure, with no long term side effects. CONCLUSION: Intraosseous infusion is quick, safe, and effective in compromised neonates. (+info)
Outcome of very severe birth asphyxia.
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The aim of this study was to establish the outcome of very severe birth asphyxia in a group of babies intensively resuscitated at birth. 48 infants, born between 1966 and 1971 inclusive, were selected; 15 were apparently stillborn and 33 had not established spontaneous respirations by 20 minutes after birth. One-half of them died, but 3 to 7 years later three-quarters of the survivors are apparently normal. Later handicap was associated with factors leading to prolonged partial intrapartum asphyxia, while acute periods of more complete asphyxia were not necessarily harmful. (+info)
Amplitude integrated EEG 3 and 6 hours after birth in full term neonates with hypoxic-ischaemic encephalopathy.
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AIM: To assess the prognostic value of amplitude integrated EEG (aEEG) 3 and 6 hours after birth. METHODS: Seventy three term, asphyxiated infants were studied (from two different centres), using the Cerebral Function Monitor (CFM Lectromed). The different aEEG tracings were compared using pattern recognition (flat tracing mainly isoelectric (FT); continuous extremely low voltage (CLV); burst-suppression (BS); discontinuous normal voltage (DNV); continuous normal voltage (CNV)) with subsequent outcome. RESULTS: Sixty eight infants were followed up for more than 12 months (range 12 months to 6 years). Twenty one out of 68 infants (31%) showed a change in pattern from 3 to 6 hours, but this was only significant in five cases (24%). In three this changed from BS to CNV with a normal outcome. One infant showed a change in pattern from CNV to FT and had a major handicap at follow up. Another infant showed a change in pattern from DNV to BS, and developed a major handicap at follow up. The other 16 infants did not have any significant changes in pattern: 11 infants had CLV, BS, or FT at 3 and 6 hours and died (n = 9) in the neonatal period or developed a major handicap (n = 2). Five infants had a CNV or DNV pattern at 3 and 6 hours, with a normal outcome. The sensitivity and specificity of BS, together with FT and CLV, for poor outcome at 3 hours was 0.85 and 0.77, respectively; at 6 hours 0.91 and 0.86, respectively. The positive predictive value (PPV) was 78% and the negative predictive value (NPV) 84% 3 hours after birth. At 6 hours the PPV was 86% and the NPV was 91%. CONCLUSION: aEEG could be very useful for selecting those infants who might benefit from intervention after birth asphyxia. (+info)
Measurement of the urinary lactate:creatinine ratio for the early identification of newborn infants at risk for hypoxic-ischemic encephalopathy.
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BACKGROUND: Newborn infants with perinatal asphyxia are prone to the development of hypoxic-ischemic encephalopathy. There are no reliable methods for identifying infants at risk for this disorder. METHODS: We measured the ratio of lactate to creatinine in urine by proton nuclear magnetic resonance spectroscopy within 6 hours and again 48 to 72 hours after birth in 58 normal infants and 40 infants with asphyxia. The results were correlated with the subsequent presence or absence of hypoxic-ischemic encephalopathy. RESULTS: Hypoxic-ischemic encephalopathy did not develop in any of the normal newborns but did develop in 16 of the 40 newborns with asphyxia. Within six hours after birth, the mean (+/-SD) ratio of urinary lactate to creatinine was 16.75+/-27.38 in the infants who subsequently had hypoxic-ischemic encephalopathy, as compared with 0.09+/-0.02 in the normal infants (P<0.001) and 0.19+/-0.12 in the infants with asphyxia in whom hypoxic-ischemic encephalopathy did not develop (P<0.001). A ratio of 0.64 or higher within six hours after birth had a sensitivity of 94 percent and a specificity of 100 percent for predicting the development of hypoxic-ischemic encephalopathy. The sensitivity and specificity of measurements obtained 48 to 72 hours after birth were much lower. The mean ratio of urinary lactate to creatinine was significantly higher in the infants who had adverse outcomes at one year (25.36+/-32.02) than in the infants with favorable outcomes (0.63+/-1.50) (P<0.001). CONCLUSIONS: Measurement of the urinary lactate: creatinine ratio soon after birth may help identify infants at high risk for hypoxic-ischemic encephalopathy. (+info)
Abnormal cerebral haemodynamics in perinatally asphyxiated neonates related to outcome.
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AIM: To measure changes in cerebral haemodynamics during the first 24 hours of life following perinatal asphyxia, and relate them to outcome. METHODS: Cerebral blood volume (CBV), its response (CBVR) to changes in arterial carbon dioxide tension (PaCO(2)), and cerebral blood flow (CBF) were measured using near infrared spectroscopy (NIRS) in 27 term newborn infants with clinical and/or biochemical evidence consistent with perinatal asphyxia. RESULTS: Both CBF and CBV were higher on the first day of life in the infants with adverse outcomes, and a CBV outside the normal range had a sensitivity of 86% for predicting death or disability. The mean (SD) CBVR on the first day of life was 0.13 (0.12) ml/100 g/1/kPa, which, in 71% of infants, was below the lower 95% confidence limit for normal subjects. CONCLUSION: An increase in CBV on the first day of life is a sensitive predictor of adverse outcome. A reduction in CBVR is almost universally seen following asphyxia, but is not significantly correlated with severity of adverse outcome. (+info)
Effects of the AMPA receptor antagonist NBQX on outcome of newborn pigs after asphyxic cardiac arrest.
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In neonates, asphyxia is a common cause of neuronal injury and often results in seizures. The authors evaluated whether blockade of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors during asphyxia and early recovery with 2,3-dihydroxy-6-nitro-7-sulfamoylbenzo-(F)-quinoxaline (NBQX) ameliorates neurologic deficit and histopathology in 1-week-old piglets. Anesthetized piglets were exposed to a sequence of 30 minutes of hypoxia, 5 minutes of room air ventilation, 7 minutes of airway occlusion, and cardiopulmonary resuscitation. Vehicle or NBQX was administered intravenously before asphyxia (30 mg/kg) and during the first 4 hours of recovery (15 mg/kg/h). Neuropathologic findings were evaluated at 96 hours of recovery by light microscopic and cytochrome oxidase histochemical study. Cardiac arrest occurred at 5 to 6 minutes of airway occlusion, and cardiopulmonary resuscitation restored spontaneous circulation independent of treatment modalities in about 2 to 3 minutes. Neurologic deficit over the 96-hour recovery period was not ameliorated by NBQX. Seizure activity began after 24 to 48 hours in 7 of 10 animals with vehicle and in 9 of 10 of animals with NBQX. In each group, four animals died in status epilepticus. Neuropathologic outcomes were not improved by NBQX. The density of remaining viable neurons was decreased in parietal cortex and putamen by NBQX treatment. Metabolic defects in cytochrome oxidase activity were worsened by NBQX treatment. Seizure activity during recovery was associated with reduced neuronal viability in neocortex and striatum in piglets from both groups that survived for 96 hours. This neonatal model of asphyxic cardiac arrest and resuscitation generates neurologic deficits, clinical seizure activity, and selective damage in regions of basal ganglia and sensorimotor cortex. In contrast to other studies in mature brain, AMPA receptor blockade with NBQX failed to protect against neurologic damage in the immature piglet and worsened postasphyxic histopathologic outcome in neocortex and putamen. (+info)
Reproducibility and accuracy of MR imaging of the brain after severe birth asphyxia.
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BACKGROUND AND PURPOSE: MR imaging of the brain can be used to detect cerebral damage after suspected hypoxic-ischemic injury. This study examines the reproducibility and accuracy of MR imaging soon after severe birth asphyxia. METHODS: During a 48-month period, full-term newborn neonates, who died within the first week as a result of severe hypoxic ischemic encephalopathy, were included in the study if they had undergone early (<5 days old) MR imaging and postmortem neuropathologic studies. Two trained observers assessed reproducibility by examining multiple brain regions independently with current criteria and then defining and applying improved criteria. Accuracy of MR findings was tested by comparing the brain regions about which the two imaging raters agreed to those regions about which the two pathologists agreed. RESULTS: Eight neonates, with a median gestational age of 40 weeks (range, 38-40 weeks) and who suffered severe birth asphyxia, were included in the study. In the reproducibility study, MR imaging agreement was moderate when current criteria were used (k = .44). Using the improved criteria, agreement increased considerably (k = .62). Much of this improvement was due to limiting the analyses to the posterior limb of the internal capsule, thalamus, parietal cortex, hippocampus, and medulla. The posterior limb of the internal capsule was the most reliable region analyzed. MR imaging agreement was similar to that achieved by two experienced pathologists reviewing the histologic sections (k = .66). In the accuracy study, MR imaging abnormality was predictive of pathologic abnormality with a sensitivity of .79 and a positive predictive value of 1.0. The predictive value of a single MR imaging abnormality was .79 (95% confidence interval, .61-.96). CONCLUSION: Criteria that provide substantial reproducibility and accuracy for the interpretation of MR imaging findings very early after birth asphyxia can be derived. (+info)