Search

The most important forms of brain injury in premature infants are partly caused by disturbances in cerebral autoregulation. As changes in cerebral intravascular oxygenation (HbD), regional cerebral oxygen saturation (rSO2), and cerebral tissue oxygenation (TOI) reflect changes in cerebral blood flow (CBF), impaired autoregulation can be measured by studying the concordance between HbD/rSO2/TOI and the mean arterial blood pressure (MABP), assuming no changes in oxygen consumption, arterial oxygen saturation (SaO2), and in blood volume. We investigated the performance of the partial coherence (PCOH) method, and compared it with the coherence method (COH). The PCOH method allows the elimination of the influence of SaO2 on HbD/rSO2/TOI in a linear way. We started from long-term recordings measured in the first days of life simultaneously in 30 infants from three medical centres. We then compared the COH and PCOH results with patient clinical characteristics and outcomes, and concluded that PCOH might be a better method for assessing impaired autoregulation.

Cerebral autoregulation is normally controlled via three different mechanisms, namely: the myogenic, the metabolic, and the neurogenic one. The myogenic mechanism responds efficiently to slow changes in mean arterial blood pressure (MABP) while the metabolic one is more efficient with fast changes. The neurogenic mechanism is not yet well understood. As changes in cerebral intravascular oxygenation (HbD), measured with near-infrared spectroscopy (NIRS), reflect changes in cerebral blood flow, the myogenic influence in the cerebral autoregulation can be assessed by analysis of HbD and MABP; the metabolic influence can be assessed by analysis of the HbD and the partial pressure of carbon dioxide (pCO2). We performed a transfer function analysis in order to calculate the gain and phase of the HbD/MABP and HbD/PCO2 subsystems. Due to the fact that cerebral autoregulation may be absent in sick premature infants, we then investigated how well these parameters could predict clinical outcome in this population.

1 juni 2011, Promotor : Groot, R. de Co-promotores : Heijst, A.F.J. van, Liem, K.D., Vandenbussche, F.P.H.A., Hoeven, J.G. van der, Tibboel, D., Naulaers, G., Contains fulltext : 87183.pdf (publisher's version ) (Open Access)

The concordance between the change in the Mean Arterial Blood Pressure (MABP) and the Cerebral Blood Flow (CBF) is studied using the Correlation, Coherence and Partial Coherence methods in order to detect Impaired Cerebral Autoregulation in Neonates. The presence of impaired autoregulation is assessed by the use of the Critical Percentage of Recording Time (CPRT). The changes in CBF are reflected by the measurement of changes in cerebral intravascular oxygenation (HbD), regional cerebral oxygen saturation (rSO(2)), and cerebral tissue oxygenation (TOI), as measured by Near-Infrared Spectroscopy (NIRS) (INVOS4100 and NIRO300). The relation between impaired autoregulation and long term clinical outcomes in premature infants is studied.

1 februari 2010, Contains fulltext : 88747.pdf (publisher's version ) (Closed access), OBJECTIVES: The goals were to investigate how many subclinical seizures in full-term neonates with hypoxic-ischemic encephalopathy (HIE) would be missed without continuous amplitude-integrated electroencephalography (aEEG) and whether immediate treatment of both clinical and subclinical seizures would result in a reduction in the total duration of seizures and a decrease in brain injury, as seen on MRI scans. METHODS: In this multicenter, randomized, controlled trial, term infants with moderate to severe HIE and subclinical seizures were assigned randomly to either treatment of both clinical seizures and subclinical seizure patterns (group A) or blinding of the aEEG registration and treatment of clinical seizures only (group B). All recordings were reviewed with respect to the duration of seizure patterns and the use of antiepileptic drugs (AEDs). MRI scans were scored for the severity of brain injury. RESULTS: Nineteen infants in group A and 14 infants in group B were available for comparison. The median duration of seizure patterns in group A was 196 minutes, compared with 503 minutes in group B (not statistically significant). No significant differences in the number of AEDs were seen. Five infants in group B received AEDs when no seizure discharges were seen on aEEG traces. Six of 19 infants in group A and 7 of 14 infants in group B died during the neonatal period. A significant correlation between the duration of seizure patterns and the severity of brain injury in the blinded group, as well as in the whole group, was found. CONCLUSIONS: In this small group of infants with neonatal HIE and seizures, there was a trend for a reduction in seizure duration when clinical and subclinical seizures were treated. The severity of brain injury seen on MRI scans was associated with a longer duration of seizure patterns.

Several studies of peripheral measurements with near infrared spectroscopy (NIRS) and venous or arterial occlusion have been performed in neonates. Results have been variable. Reasons include differences in patient populations, technical aspects of the devices used or the way measurements were made. It is therefore important that there should be common elements for measurement protocols. This statement proposes a standardised approach to allow comparison between different study populations and devices Udgivelsesdato: 2008

Clinical pharmacology intends to predict drug-specific effects and side effects based on pharmacokinetics (i.e. absorption, distribution, metabolism and elimination) and pharmacodynamics (i.e. dose/effect relationship). Developmental pharmacology focuses on the maturational aspects of these phenomena during perinatal life and later stages of infancy. In general, phenotypic variation in drug metabolism is based on constitutional, environmental and genetic factors but in early neonatal life, it mainly reflects ontogeny. Although the major site of drug metabolism is the liver, the gastrointestinal tract, blood cells and other organs like kidneys or lungs might also be involved in drug metabolism. Important alterations in hepatic drug metabolism occur in early neonatal life. These alterations are of relevance when age-dependent aspects of pharmacokinetics, -dynamics or toxicology are considered. Age dependent maturation of various phase I and II processe

Objectives: To document pain expression characteristics in former preterm infants in the first year of life in whom systematic evaluation and treatment of pain was provided. Methods: Data on the Modified Behavioral Pain Scale (MBPS), Visual Analogue Scale (VAS, crying time and heart rate were collected during immunization. The effect of clinical characteristics {postconception and gestational age [PCA], surgery, ventilation, fentanyl, length of stay (LOS)} on bio-behavioral parameters was evaluated. Results: 121 procedures were recorded in 49 infants. GA was 28 (25-32) weeks. PCA was 60 (34-90) weeks. Median MBPS was 8 (2-10), median crying time 44 (0-112) s. Median pre-procedural heart rate was 144 (103-201) and increased to 184 (147-220) afterwards, resulting in a relative increase of 29 (5-99)%. Median VAS score was 7 (1-10).

Item does not contain fulltext, Our objective was a retrospective evaluation of cranial US in survivors of twin pregnancy with feto-fetal transfusion syndrome (FFTS), with knowledge of prenatal treatment and neonatal/postnatal clinical data. In 18 pregnancies with FFTS (January 1996 to May 2000), pregnancy management and outcome, and neonatal clinical/neurological data and follow-up (age of 3-7 months) were documented when available. Postnatal cranial US abnormalities were differentiated in prenatal and peri/postnatal lesions, respectively, in "donor" and "recipient." The statistical analysis used was Mann Whitney U test and Fisher's exact test. Overall pregnancy survival rate was 19 of 36 (53%); mors in utero occurred in five twin members. Gestational age at birth was significantly lower in FFTS after laser coagulation (13 of 18; p<0.05). Initial (

A recent study 1 suggests that, under certain circumstances, concordant changes in cerebral intravascular oxygenation and mean arterial blood pressure reflect impaired cerebrovascular autoregulation. In this paper, we propose a new measure to quantitate this concordance, derived front the common subspace of these signals. The method is compared to correlation and conference analysis with respect to our application, but it is also suited for other biomedical signals. Furthermore, this model-based approach is not restricted to applications involving only 2 signals., Papers from the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society, October 25-28, 2001, held in Istanbul, Turkey. See also ADM001351 for entire conference on cd-rom.