Publications by authors named "Michael Weindling"

Monitoring patent ductus arteriosus (PDA) in premature infants is currently performed intermittently using echocardiography which requires considerable expertise. The aim of this pilot study was to investigate whether PDA status could be assessed from standard neonatal intensive care monitoring. Electrocardiography (ECG) and blood pressure (BP) waveforms were acquired from extremely preterm infants using standard neonatal monitors.

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Infants below 28 weeks' gestation have low thyroid hormone plasma levels compared with more mature infants and this may contribute to their risk of developmental disability. We aimed at determining the effect of supplementation with levothyroxine (LT4) for extremely premature infants born below 28 weeks' gestations on neurodevelopmental outcomes at 42 months. An explanatory double-blind, randomized, placebo-controlled trial consecutively recruited 153 infants below 28 weeks' gestation from 5 neonatal units in the United Kingdom.

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Background: In early pregnancy, maternal transfer of thyroxine (T4) significantly contributes to the foetal T4 requirements. Interruption of the maternal transfer of T4 may lead to inadequate T4 exposure, potentially leading to neurodevelopmental deficits.

Aim: To determine if maternal factors are associated with the thyroid hormone status of extremely premature infants during the first five days of life.

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The aim of this study is to compare a two-wavelength light emitting diode-based tissue oximeter (INVOS), which is designed to show trends in tissue oxygenation, with a four-wavelength laser-based oximeter (FORE-SIGHT), designed to deliver absolute values of tissue oxygenation. Simultaneous values of cerebral tissue oxygenation (StO2) are measured using both devices in 15 term and 15 preterm clinically stable newborns on the first and third day of life. Values are recorded simultaneously in two periods between which oximeter sensor positions are switched to the contralateral side.

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Aim: The major advantage of salivary cortisol sampling is that it is considerably less invasive than taking a blood sample. However, previous methods of obtaining saliva in premature infants have been poorly tolerated and inaccurate. We describe a simple, non-distressing technique for obtaining saliva samples to assess extremely premature infants' salivary cortisol status.

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The mechanisms for the adequate provision of oxygen to the peripheral tissues are complex. They involve control of the microcirculation and peripheral blood flow, the position of the oxygen dissociation curve including the proportion of fetal and adult haemoglobin, blood gases and viscosity. Systemic blood pressure appears to have little effect, at least in the non-shocked state.

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Unlabelled: Recent brain imaging and outcome studies of infants born at very early gestation have cast new light on brain development at a vulnerable stage. Some of these new developments are reviewed in this editorial.

Conclusion: The anatomical differences between the brains of babies born extremely prematurely and those born at term appear to translate into disturbances of function.

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Peripheral haemodynamics refers to blood flow, which determines oxygen and nutrient delivery to the tissues. Peripheral blood flow is affected by vascular resistance and blood pressure, which in turn varies with cardiac function. Arterial oxygen content depends on the blood haemoglobin concentration (Hb) and arterial pO2; tissue oxygen delivery depends on the position of the oxygen-dissociation curve, which is determined by temperature and the amount of adult or fetal haemoglobin.

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Background: Perinatal mortality remains high among infants of mothers with type 1 and type 2 diabetes mellitus. Although high glucose levels have been implicated, the mechanism is not well understood.

Aims: 1) to identify the causes of stillbirth and neonatal death in infants of women with type 1 and type 2 diabetes; 2) to determine whether the causes of perinatal mortality are the same for women with type 1 and type 2 diabetes; and 3) to ascertain the relationship between perinatal mortality and maternal glycemic control.

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In spite of clinicians apparently appreciating the risks of maternal diabetes to the baby, babies of mothers with diabetes are still at increased risk compared to those of non-diabetic women. The rate of prematurity in infants of diabetic mothers is five times that of the general population. Women with pre-gestational diabetes give birth to larger babies.

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This study examined the relationship between blood pressure, peripheral blood flow (PBF), and peripheral fractional oxygen extraction (FOE). Variables that may influence PBF and peripheral FOE were also measured. Measurements of PBF by near infrared spectroscopy and fractional shortening by echocardiography were made within 12 h of birth in 24 infants less than 32 wk gestation.

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Background: Gaps between research knowledge and practice have been consistently reported. Traditional ways of communicating information have limited impact on practice changes. Strategies to disseminate information need to be more interactive and based on techniques reported in systematic reviews of implementation of changes.

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Objective: To evaluate the relation between cerebral tissue oxygenation index (TOI), measured with spatially resolved spectroscopy (SRS), and the different oxygenation parameters. To evaluate the relation between a new parameter named fractional tissue oxygen extraction (FTOE) and the cerebral fractional oxygen extraction (FOE).

Methods: Six newborn piglets were measured at 33, 35, and 37 degrees C and in hypocapnia.

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Cardiac output is a determinant of systemic blood flow and its measurement may therefore be a useful indicator of abnormal hemodynamics and tissue oxygen delivery. The purpose of this study was to investigate in very premature newborn infants the relationships between cardiac output (left and right ventricular outputs), systemic blood pressure, peripheral blood flow (PBF) and two indicators of cerebral oxygen delivery (cerebral electrical activity and cerebral fractional oxygen extraction (CFOE)). This was a prospective observational study performed on 40 infants of less than 30 wk gestation.

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There is uncertainty about the level of systemic blood pressure required to maintain adequate cerebral oxygen delivery and organ integrity. This prospective, observational study on 35 very low birth weight infants aimed to determine the mean blood pressure (MBP) below which cerebral electrical activity, peripheral blood flow (PBF), and cerebral fractional oxygen extraction (CFOE) are abnormal. Digital EEG, recorded every day on the first 4 d after birth, were analyzed a) by automatic spectral analysis, b) by manual measurement of interburst interval, and c) qualitatively.

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Objective: To identify variations in standards of neonatal care in the first week of life that might have contributed to deaths in infants who were born at 27 and 28 weeks' gestation.

Methods: A case-control study was conducted of infants who were born at 27 and 28 weeks' gestation in England, Wales, and Northern Ireland during a 2-year period. Cases were neonatal deaths; control subjects were randomly selected survivors at day 28.

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The paper by Dannevig et al. in this issue of Acta Paediatrica carefully compares the agreement between blood pressure measurements made by three non-invasive blood pressure monitors with those made from an indwelling intra-arterial catheter. Non-invasive blood pressure monitoring is not particularly accurate for making measurements in neonates and generally overestimates the blood pressure as observed by others.

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Cerebral blood flow (CBF) is known to be low in newborn infants, but this has not been shown to be damaging. The purpose of this study was to investigate the relationships between cerebral haemoglobin flow, blood flow, oxygen delivery, oxygen consumption, venous saturation, and fractional oxygen extraction (OEF) in newborn, preterm infants. Measurements were made by near-infrared spectroscopy in 13 very preterm, extremely low birth weight infants (median gestation 25 weeks) during the first 3 days after birth.

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Continuous EEG monitoring has not been used widely in neonatal intensive care, especially in the care of extremely premature infants, probably in part because of a lack of a reliable quantitative method. The purpose of this study was to quantify the EEG of the very premature infants just after birth by using spectral analysis and to describe the characteristics of the spectral signal when infants were clinically stable. Digital EEG recordings were performed on 53 infants who were < or =30 wk gestation for 75 min each day during the first 4 d after birth.

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Fluctuations in cerebral hemodynamics have been implicated in the pathogenesis of acquired brain damage in babies born prematurely. This study examined the changes in cerebral fractional oxygen extraction (FOE) over the first 3 d after birth in 25 very-low-birth-weight preterm infants. Twelve infants had no major cerebral injury and 13 had acquired brain injury; cystic periventricular leukomalacia (PVL) was present in 4 and intraventricular hemorrhage (IVH) in 9, of whom 2 also had hemorrhagic parenchymal infarction (HPI).

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This study examined the relationships between cerebral fractional oxygen extraction (FOE), mean arterial blood pressure (MABP), left ventricular output (LVO), blood gases, and other physiologic variables in 36 very-low-birth-weight preterm infants during the first 3 d after birth. There was a decrease in cerebral FOE (p = 0.008), and rises in LVO (p < 0.

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