Clinical events relating to intraventricular haemorrhage in the newborn.

Fujimura, Masanori; Salisbury, D M; Robinson, Richard O.; Howat, P; Emerson, PaulineM.; Keeling, J. W.; Tizard, Jack

doi:10.1136/adc.54.6.409

Cited by 86 publications

(14 citation statements)

References 20 publications

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“…In this population, low postnatal BP has been linked to the development of intraventricular hemorrhage (IVH) (1)(2)(3)(4)(5)(6)(7)(8), ischemic cerebral lesions (3), adverse neurodevelopmental outcome (7,9,10), and neonatal mortality (3,4,7,10). BP regulation in preterm infants is complex and poorly understood, and several perinatal factors have been shown to influence postnatal BP in preterm infants.…”

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Early Postnatal Blood Pressure in Preterm Infants: Effects of Chorioamnionitis and Timing of Antenatal Steroids

et al. 2009

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Previous studies suggest postnatal blood pressure in preterm infants to be decreased by chorioamnionitis and increased by antenatal steroids (AS). We examined the adjusted effects of both antenatal modulators on postnatal blood pressure (BP), with separate effects reported for histologic chorioamnionitis with or without fetal involvement and timing of AS. General characteristics, BP, and heart rate values during the first 72 h after birth were obtained from 271 infants with gestational age Յ32.0 wk. In unadjusted analyses, chorioamnionitis was associated with lower BP, most prominently so in infants with fetal involvement, without an effect on hypotension incidence. AS increased BP and decreased the incidence of hypotension when administered within 7 d before birth. In a multivariable mixed model analysis, the AS effect remained significant, whereas chorioamnionitis was not independently predictive of postnatal BP. Other variables associated with increased postnatal BP were gestational age and umbilical artery pH, whereas hemolysis, elevated liver enzymes, low platelets syndrome was associated with decreased BP.

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Early Postnatal Blood Pressure in Preterm Infants: Effects of Chorioamnionitis and Timing of Antenatal Steroids

et al. 2009

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“…Accordingly, periventricular hemorrhage may result from abrupt hyperperfusion whereas periventricular leukomalacia has been related to ischemia (1)(2)(3)(4)(5)(6)(7)(8)(9).…”

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Cerebral Pressure Autoregulation and Vasoreactivity in the Newborn Rat

et al. 2005

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Perinatal brain injury has been associated with impaired cerebral blood flow (CBF) pressure autoregulation. The brain of 3-to 5-d-old rat pups is immature and similar to that of a preterm infant, and therefore we tested cerebral vasoreactivity in that animal. CBF pressure autoregulation was tested in 20 Wistar pups during normocapnia and hypercapnia, respectively. Hypotension was induced by hemorrhage and cerebral perfusion was monitored with laser Doppler flowmetry and near-infrared spectroscopy. Systolic blood pressure was measured noninvasively from the tail. During normocapnia, the autoregulatory plateau was narrow. Resting systolic blood pressure (SBP) was 39.2 mm Hg and CBF remained constant until SBP decreased below 36.0 mm Hg (SE 0.8). Below the lower limit, CBF declined by a mean of 2.7% per mm Hg [95% confidence interval (CI), 2.4 -3.0%], and hemoglobin difference (HbD) and total hemoglobin (HbT) changed proportionally to CBF. After inhalation of carbon dioxide, CBF increased significantly by a mean of 17.7% (95% CI, 13.7-22.8%). The CBF-CO 2 reactivity was estimated to 13.4% per kPa (95% CI, 2-24.8%), p ϭ 0.026. Over the range of SBP (6 -54 mm Hg), a linear relationship between CBF and SBP was found during hypercapnia, indicating abolished pressure autoregulation. A linear correlation between CBF and HbD was found (r ϭ 0.80). CBF pressure autoregulation and reactivity to CO 2 operate in the newborn rat. This model may be useful for future investigations concerning perinatal pathophysiology in the immature brain. In very preterm infants, brain injury has been associated with impaired pressure autoregulation of CBF. Accordingly, periventricular hemorrhage may result from abrupt hyperperfusion whereas periventricular leukomalacia has been related to ischemia (1-9).Cerebral pressure autoregulation refers to vascular mechanisms whereby CBF is held within constant levels during variations in perfusion pressure. Perfusion is thus maintained over a range of pressures by appropriate alterations in the diameter of precapillary arterioles. However, the lower limit of autoregulation is reached when the vessels become fully dilated and, beyond that point, any further decrease in pressure results in proportional drops in CBF. Several conditions may affect the autoregulatory plateau and increased CBF as well as complete pressure passiveness secondary to vasodilatation is observed during hypercapnia, hypoglycaemia, hypoxia, and seizure (10 -13).Cerebral pressure autoregulation has been documented in several newborn animals such as piglets, lambs, and puppies (14 -19). Most of these animals have rather mature brains at birth, and to compare vascular physiology with that of a preterm infant, the newborn rat pup served as a model (20,21). Because we could not control ventilation in this immature animal, we evaluated the cerebrovascular response to hemorrhagic hypotension during normocapnia and carbon dioxide inhalation. The hypothesis was that pressure autoregulation operates normally in the healthy immature brain. METH...

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“…TSIANTOS et al [21] routinely labeled erythrocytes of neonates with Chromium 51 within the first few hours of life and found that 60% of the hemorrhages took place between 15 and 48 hours of age. FUJIMURA et al [9] using hemoglobin as a marker, observed that infants less than 28 week's gestation were more likely to sustain PIVH in the first 24 hours of life than infants of greater gestational age. The authors concluded that these early hemorrhages are common in very low birth weight infants and that they are probably related to adverse parinatal factors.…”

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confidence: 99%