Libros
URI permanente para esta colección
Examinar
Examinando Libros por Autor "Alderliesten, Thomas"
Mostrando1 - 3 de 3
Resultados por página
Opciones de clasificación
- ÍtemSolo MetadatosA New Framework for the Assessment of Cerebral Hemodynamics Regulation in Neonates Using NIRS(2016) Caicedo Dorado, Alexander; Alderliesten, Thomas; Naulaers, Gunnar; Lemmers, Petra; Van Bel, Frank; Van Huffel, SabineWe present a new framework for the assessment of cerebral hemodynamics regulation (CHR) in neonates using near-infrared spectroscopy (NIRS). In premature infants, NIRS measurements have been used as surrogate variables for cerebral blood flow (CBF) in the assessment of cerebral autoregulation (CA). However, NIRS measurements only reflect changes in CBF under constant changes in arterial oxygen saturation (SaO2). This condition is unlikely to be met at the bedside in the NICU. Additionally, CA is just one of the different highly coupled mechanisms that regulate brain hemodynamics. Traditional methods for the assessment of CA do not take into account the multivariate nature of CHR, producing inconclusive results. In this study we propose a newly developed multivariate methodology for the assessment of CHR. This method is able to effectively decouple the influences of SaO2 from the NIRS measurements, and at the same time, produces scores indicating the strength of the coupling between the systemic variables and NIRS recordings. We explore the use of this method, and its derived scores, for the monitoring of CHR using data from premature infants who developed a grade III-IV intra-ventricular hemorrhage during the first 3 days of life.
- ÍtemSolo MetadatosEffect of Maternal use of Labetalol on the Cerebral Autoregulation in Premature Infants(2013-06-04) Caicedo Dorado, Alexander; Alderliesten, Thomas; Naulaers, Gunnar; Lemmers, Petra; Van Bel, Frank; Van Huffel, SabineHypertensive disorders of pregnancy (HDP) are normally treated to avoid maternal complications. In this study we aimed to investigate if there was an effect of maternal HDP treatment on the cerebral autoregulation of the neonates by analysing measurements of mean arterial blood pressure (MABP) and rScO2 by means of correlation, coherence, and transfer function analysis. We found that these infants presented higher values of transfer function gain, which indicates impaired cerebral autoregulation, with a decreasing trend towards normality. We hypothesised that this trend was due to a vasodilation effect of the maternal use of labetalol due to accumulation, which disappeared by the third day after birth. Therefore, we investigated the values of pulse pressure in order to find evidence for a vasodilatory effect. We found that lower values of pulse pressure were present in these infants when compared with a control population, which, together with increased transfer function gain values, suggests an effect of the drug on the cerebral autoregulation.
- ÍtemSolo MetadatosInfluence of the Maternal Use of Labetalol on the Neurogenic Mechanism for Cerebral Autoregulation Assessed by Means of NIRS(2014-03-22) Caicedo Dorado, Alexander; Alderliesten, Thomas; Naulaers, Gunnar; Lemmers, Petra; Van Bel, Frank; Van Huffel, SabineLabetalol is a drug used in the treatment of hypertensive disorders of pregnancy (HDP). In a previous study we investigated the influence of the maternal use of labetalol on the cerebral autoregulation (CA) mechanism of neonates. In that study, we found that labetalol induces impaired CA during the first day of life, with CA returning to a normal status by the third day after birth. This effect was hypothesized to be caused by labetalol-induced vasodilation. However, no strong evidence for this claim was found. In this study we aim to find stronger evidence for the vasodilation effect caused by labetalol, by investigating its effect on the neurogenic mechanism (NM) involved in CA. The status of the NM was assessed by means of transfer function analysis between the low frequency content of the autonomic control activity (LFA), obtained by processing of the heart rate (HR), and the regional cerebral oxygen saturation (rScO2). We found that neonates from mothers treated with labetalol presented a lower LFA and an impaired NM response during the first day of life, with values returning to normal by the end of the third day. These results reflect a vasodilation effect caused by labetalol, and indicate that the impaired CA observed in the previous study is caused by vasodilation.