University college london institute for womens health – academia.edu what is anoxic encephalopathy

We have developed a method to estimate the critical closing pressure (crcp) of the cerebral circulation based on the intrinsic variability of arterial blood pressure (BP) around stable values of mean arterial pressure (MAP). A consecutive cohort of 33 premature newborns was studied at 6, 12, 24, 48 and 72 hours of age. Cerebral blood flow velocity (CBFV) was measured with doppler ultrasound in the middle cerebral artery and BP was recorded in the abdominal aorta or in a peripheral artery. Continuous measurements lasting five minutes were recorded on digital magnetic tape and signals were digitized at a rate of 200 samples/seconds for processing on a digital computer.


Mean values of BP (mbp) and CBFV (mbv) were computed for each cardiac cycle and crcp was determined as the pressure axis intercept of the regression line of mbv as a function of mbp using 100 sequential heart beats.What is anoxic encephalopathy the resistance-area product (RAP) was obtained from the slope of the regression line. For 57 records (30 patients) the mean +/- SD values of crcp and RAP were 23.9 +/- 11.6 mmhg and 4.07 +/- 1.83 x 10(4) kg.M-2.S-1, respectively. CrCP has a highly significant correlation with mean arterial pressure (p lt; 0.001) but RAP has not. Neither crcp nor RAP are significantly correlated (p gt; 0.05) with PO2, PCO2, ph, haematocrit, gestational age, birthweight, postnatal age, heart rate on pourcelot#39;s resistance index. Our results suggest that cerebral perfusion pressure should be defined as MAP-crcp for normal values of intracranial pressure.

ABSTRACT background moderate therapeutic hypothermia improves outcome in babies with hypoxic ischaemic encephalopathy by reducing neuronal damage during the reperfusion stage at which time seizures often commence.What is anoxic encephalopathy some evidence suggests seizures may cause additional damage beyond the original insult via excitotoxic effects. We used continuous electroencephalography (EEG) to compare the seizure burden in a group of hypothermic (HT) babies against a normothermic (NT) group to examine the effects of cooling on seizure burden.Methods continuous video-EEG was started as soon after birth as possible and recorded for a minimum of 20 h. Two experienced encephalographers marked the beginning and end of each seizure and the number of seconds of seizure/hour was calculated.ResultsA total of 31 babies with seizures were recorded, 15 NT and 16 HT. Recordings were started earlier and recorded for longer in the HT group, despite this increased facility to record seizures, the seizure burden was significantly lower in the HT group than the NT group who had shorter seizures for less time.What is anoxic encephalopathy the median seizure burden during the entire EEG period in the HT group was 60 (39–224) min compared to 203 (141–206) min in the NT group.Conclusion there is a reduced seizure burden in babies with HIE who are cooled. The beneficial effects of therapeutic hypothermia may in part be mediated via a reduction in the excitotoxic effects of seizures.

To investigate any possible effect of cooling on seizure burden, the authors quantified the recorded electrographic seizure burden based on multichannel video-EEG recordings in term neonates with hypoxic-ischaemic encephalopathy (HIE) who received cooling and in those who did not. Retrospective observational study. Neonates amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;37 weeks gestation born between 2003 and 2010 in two hospitals.What is anoxic encephalopathy off-line analysis of prolonged continuous multichannel video-EEG recordings was performed independently by two experienced encephalographers. Comparison between the recorded electrographic seizure burden in non-cooled and cooled neonates was assessed. Data were treated as non-parametric and expressed as medians with interquartile ranges (IQR). One hundred and seven neonates with HIE underwent prolonged continuous multichannel EEG monitoring. Thirty-seven neonates had electrographic seizures, of whom 31 had EEG recordings that were suitable for the analysis (16 non-cooled and 15 cooled). Compared with non-cooled neonates, multichannel EEG monitoring commenced at an earlier postnatal age in cooled neonates (6 (3-9) vs 15 (5-20) h)and continued for longer (88 (75-101) vs 55 (41-60) h).What is anoxic encephalopathy despite this increased opportunity to capture seizures in cooled neonates, the recorded electrographic seizure burden in the cooled group was significantly lower than in the non-cooled group (60 (39-224) vs 203 (141-406) min). Further exploratory analysis showed that the recorded electrographic seizure burden was only significantly reduced in cooled neonates with moderate HIE (49 (26-89) vs 162 (97-262) min). A decreased seizure burden was seen in neonates with moderate HIE who received cooling. This finding may explain some of the therapeutic benefits of cooling seen in term neonates with moderate HIE.

This study aims to determine the accuracy of post-mortem magnetic resonance imaging (MRI) and autopsy for confirmation of sonographically detected fetal ventriculomegaly.What is anoxic encephalopathy this study uses retrospective review of fetuses with sonographically diagnosed ventriculomegaly, where the pregnancy was terminated and post-mortem examination was performed during a period in which post-mortem MRI was being offered. Sixteen cases were identified. In nine (56%), autopsy and/or post-mortem MRI confirmed the prenatal findings. In the other seven, both autopsy and post-mortem MRI demonstrated no ventriculomegaly, but antenatal MRI confirmed the ultrasound findings in 6/7 cases where it had been performed. Post-mortem investigations confirmed antenatal findings in 8/9 cases with severe ventriculomegaly (posterior horn measurement amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;15 mm), whereas only 2/7 in which ventriculomegaly was not confirmed had severe ventriculomegaly.What is anoxic encephalopathy post-mortem examination, both by traditional neuropathological examination, and post-mortem MRI may fail to confirm prenatal ventriculomegaly in around half of cases. The post-mortem MRI findings indicate that this is due to resolution of ventriculomegaly rather than autopsy artefact, and is presumably a consequence of post-mortem fluid redistribution. Parents should be advised before termination of pregnancy that post-mortem confirmation of ventriculomegaly, especially in mild cases, may not be possible. Antenatal MRI may be a better approach for confirming prenatal ultrasound findings.

There are many pathological conditions leading to an elevated unconjugated bilirubin level (hyperbilirubinaemia) in neonates.What is anoxic encephalopathy currently the standard therapies for unconjugated hyperbilirubinaemia include phototherapy and exchange transfusion. In addition to phototherapy, clofibrate has been studied as a treatment for hyperbilirubinaemia in several countries. To determine the efficacy and safety of clofibrate in combination with phototherapy versus phototherapy alone in unconjugated neonatal hyperbilirubinaemia. Randomised controlled trials were identified by searching MEDLINE (1950 to april 2012) before being translated for use in the cochrane library, EMBASE 1980 to april 2012 and CINAHL databases. All searches were re-run on 2 april 2012. We included trials where neonates with hyperbilirubinaemia received either clofibrate in combination with phototherapy or phototherapy alone or placebo in combination with phototherapy.What is anoxic encephalopathy data were extracted and analysed independently by two review…

Preclinical data suggest that the loop-diuretic bumetanide might be an effective treatment for neonatal seizures. We aimed to assess dose and feasibility of intravenous bumetanide as an add-on to phenobarbital for treatment of neonatal seizures. In this open-label, dose finding, and feasibility phase 1/2 trial, we recruited full-term infants younger than 48 h who had hypoxic ischaemic encephalopathy and electrographic seizures not responding to a loading-dose of phenobarbital from eight neonatal intensive care units across europe. Newborn babies were allocated to receive an additional dose of phenobarbital and one of four bumetanide dose levels by use of a bivariate bayesian sequential dose-escalation design to assess safety and efficacy.What is anoxic encephalopathy we assessed adverse events, pharmacokinetics, and seizure burden during 48 h continuous electroencephalogram (EEG) monitoring. The primary efficacy endpoint was a reduction in electrographic seizure burden of more than 80% without the need for resc…

The objective of this study was to validate the performance of a seizure detection algorithm (SDA) developed by our group, on previously unseen, prolonged, unedited EEG recordings from 70 babies from 2 centres. EEGs of 70 babies (35 seizure, 35 non-seizure) were annotated for seizures by experts as the gold standard. The SDA was tested on the eegs at a range of sensitivity settings. Annotations from the expert and SDA were compared using event and epoch based metrics.What is anoxic encephalopathy the effect of seizure duration on SDA performance was also analysed. Between sensitivity settings of 0.5 and 0.3, the algorithm achieved seizure detection rates of 52.6-75.0%, with false detection (FD) rates of 0.04-0.36FD/h for event based analysis, which was deemed to be acceptable in a clinical environment. Time based comparison of expert and SDA annotations using cohenamp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s kappa index revealed a best performing SDA threshold of 0.4 (kappa 0.630). The SDA showed improved detection performance with longer seizures. The SDA achieved promising performance and warrants further testing in a live clinical evaluation. The SDA has the potential to improve seizure detection and provide a robust tool for comparing treatment regimens.What is anoxic encephalopathy