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Aim: After preterm birth, supine head midline position is supported for stable cerebral blood flow (CBF) and prevention of intraventricular haemorrhage (IVH), while prone position supports respiratory function and enables skin-to-skin care. The prone compared to supine position could lead to a change in near-infrared derived cerebral tissue oxygen saturation (rScO2), which is a surrogate for cerebral blood flow (CBF). By monitoring rScO2 neonatologists aim to stabilise CBF during intensive care and prevent brain injury. In this systematic review and meta-analysis, we investigate the effect of the body position on rScO2., Methods: A comprehensive literature search was performed to identify all trials that included preterm infants in the first 2 weeks after birth and compared rScO2 in the prone versus supine head in midline position of the infant. A meta-analysis, including two subgroup analyses based on postnatal age (PNA) and gestational age (GA), was performed., Results: Six observational cohort studies were included. In the second, but not the first week after birth, a significant higher rScO2 in the prone position was found with a mean difference of 1.97% (95% CI 0.87-3.07). No rScO2 difference was observed between positions in the extremely preterm nor the preterm group., Conclusion: No consistent evidence was found that body position influences rScO2 in the first 2 weeks after preterm birth. Subgroup analysis suggests that in the second week after birth, the prone position might result in higher cerebral rScO2 than the supine position with head in midline. Multiple factors determine the best body position in preterms., (© 2022 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.)

This study investigates the relationship between brain oxygenation, assessed by means of near infrared spectroscopy (NIRS), and brain function, assessed by means of electroencephalography (EEG). Using NIRS signals measuring the regional cerebral oxygen saturation (rScO 2 ) and computing the fractional tissue oxygen extraction (FTOE), we compared how these variables relate to different features extracted from the EEG, such as the inter-burst interval (IBI) duration and amplitude, the amplitude of the EEG, and the amplitude of the burst. A cohort of 22 neonates undergoing sedation by propofol was studied and a regression of the NIRS-derived values to the different EEG features was made. We found that higher values of FTOE were related to higher values of EEG amplitude. These results might be of used in the monitoring of proper brain function in neonates.

Brain function is supported by an appropriate balance between the metabolic demand and the supply of nutrients and oxygen. However, the physiological principles behind the regulation of brain metabolism and demand in premature infants are unknown. Some studies found that changes in hemodynamic variables in this population precede changes in EEG activity; however, these studies only used descriptive statistics. This paper describes the relationship between changes in cerebral oxygenation, assessed by means of near-infrared spectroscopy (NIRS), and changes in EEG, using mathematical methods taken from information dynamics. In a cohort of 35 neonates subjected to sedation by propofol, we quantified the direction of information transfer between brain oxygenation and EEG. The results obtained indicate that, as reported in other studies, changes in NIRS are likely to precede changes in EEG activity.

The microvasculature and macrovasculature undergo extensive, organ-specific perinatal maturation. Multiple studies show associations between low birth weight and subsequent cardiovascular dysfunction in adulthood, suggesting that extreme preterm birth interferes with this maturation process. Therefore, we designed PREMATCH (PREMATurity as predictor of Cardiovascular-renal Health) to phenotype the microcirculation and macrocirculation during childhood in former preterm infants. A well-characterized cohort of former extreme preterm birth survivors and gender- and age-matched controls (aged 8-13 years) will be investigated for microvascular and macrovascular structure and function. In addition to cognitive performance and anthropometrics, we will investigate (i) the microvascular structure and function by endothelial function (photoplethysmography), sublingual capillary glycocalyx function (sidestream dark field imaging) and retinal structure (diameters of arterioles and venules); and (ii) the macrovascular phenotype by cardiac and renal ultrasound, repeated blood pressure measurements and arterial pulse-wave recordings. The PREMATCH study is unique in its design, and ongoing recruitment demonstrates excellent feasibility. The expectation is that the results of this study will identify risk factors during childhood for subsequent cardiovascular-renal disease in the adult life of former preterm infants, while further analysis on mediators in neonatal life of this cardiovascular-renal outcome may provide new information on perinatal risk factors.

Background: Indomethacin has vasoactive properties in cerebral and systemic vascular beds, and it improves cerebral autoregulatory ability. We speculated that tocolytic indomethacin will improve cerebral autoregulatory ability in the very preterm infant in early postnatal life., Methods: Eighteen stable preterm infants gestational age (GA) 25.3-29.6 weeks, birth weight (BW) 660-1430 grams), whose mothers had received 50-150 mg of tocolytic indomethacin within 24 h before birth, and 18 individually matched controls (GA 25.0-29.7 weeks, BW 700-1390 grams) were studied four times for 15 min in the first 24 h of life. Autoregulation was assessed by determining correlations between mean arterial blood pressure (MABP (mm Hg)) and near-infrared spectroscopy-monitored cerebral oxygenation (rScO2)., Results: MABPs were significantly higher in the indomethacin infants than in the control infants (p=0.03). A decreased ability to autoregulate was found in four of the indomethacin infants, and in six of the control infants, which is not significantly different., Conclusions: Prenatally administered indomethacin, given as a tocolytic in doses of 50-150 mg per day, improved transitional circulation in very preterm infants by significantly raising the MABP. It did not have an effect on the ability to autoregulate the cerebral circulation. In this study, no differences in short-term outcomes, like haemorrhagic or ischaemic cerebral lesions, were observed.

Hypertensive 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.