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Background: Fetal growth restriction (FGR) is associated with an increased risk for kidney disease in later life. Studies reporting on early signs of renal disturbances in FGR are sparse and mostly include invasive measurements, which limit the possibility for early identification and prevention. We aim to investigate whether renal tissue oxygen saturation (rSO2) measured with near-infrared spectroscopy (NIRS) and the derived value fractional tissue oxygen extraction (FTOE) differ between premature FGR and control neonates in the first three days after birth. Methods: Nine FGR and seven control neonates born <32 weeks of gestation were included. FGR was defined as biometry 2 was measured continuously with NIRS for 72 hours. FTOE was calculated as: (arterial saturation-rSO2)/arterial saturation. Renal artery blood flow (pulsatility and resistance index) was measured within 24 hours after birth. A linear mixed model approach was used (intercept ± slope = r) to analyze the NIRS parameters. Results: Renal rSO2 was higher in FGR neonates compared to controls (94% vs. 83%; pgroup = 0.002). During the first three days after birth, renal rSO2 decreased in FGR neonates and increased in controls (r = -0.25 vs. r = 0.03; pinteraction = 0.001). Renal FTOE was lower in FGR neonates (0.02 vs. 0.14; pgroup = 0.01) and increased slightly during three days after birth, while it remained stable in controls (r = 0.003 vs. r = -0.0001; pinteraction = 0.001). Renal artery blood flow was similar between groups. Conclusions: FGR neonate kidneys showed higher rSO2 as measured with NIRS and lower derived values of FTOE in the first three days after birth. We speculate that this was caused by either a reduced oxygen consumption due to impaired renal maturation or increased renal oxygen supply. How these observations correlate with short- and long-term renal function needs further investigation before renal NIRS can be implemented in screening and prevention in clinical practice. [ABSTRACT FROM AUTHOR]

Although near-infrared spectroscopy is increasingly being used to monitor cerebral oxygenation in neonates, it has a limited penetration depth. The T2-prepared Blood Imaging of Oxygen Saturation (T2-BIOS) magnetic resonance sequence provides an oxygen saturation estimate on a voxel-by-voxel basis, without needing a respiratory calibration experiment. In 15 neonates, oxygen saturation measured by T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy were compared. In addition, these measures were compared to cerebral blood flow and venous oxygen saturation in the sagittal sinus. A strong linear relation was found between the oxygen saturation measured by magnetic resonance imaging and the oxygen saturation measured by near-infrared spectroscopy (R2 = 0.64, p < 0.001). Strong linear correlations were found between near-infrared spectroscopy oxygen saturation, and magnetic resonance imaging measures of frontal cerebral blood flow, whole brain cerebral blood flow and venous oxygen saturation in the sagittal sinus (R2 = 0.71, 0.50, 0.65; p < 0.01). The oxygen saturation obtained by T2-prepared blood imaging of oxygen saturation correlated with venous oxygen saturation in the sagittal sinus (R2 = 0.49, p = 0.023), but no significant correlations could be demonstrated with frontal and whole brain cerebral blood flow. These results suggest that measuring oxygen saturation by T2-prepared blood imaging of oxygen saturation is feasible, even in neonates. Strong correlations between the various methods work as a cross validation for near-infrared spectroscopy and T2-prepared blood imaging of oxygen saturation, confirming the validity of using of these techniques for determining cerebral oxygenation. [ABSTRACT FROM AUTHOR]

Background: In the clinical setting, episodes of desaturation in newborn infants are often treated by increasing the fraction of inspired oxygen (FiO2). Objectives: To study the effect of an increase in FiO2 on cerebral oxygenation during recovery from desaturation, as measured by near-infrared spectroscopy (NIRS). Methods: Peripheral arterial saturation (SaO2), NIRS-monitored cerebral saturation (rScO2), and fractional cerebral oxygen extraction (cFTOE) were analyzed in the first 3 days of life during 6 episodes of desaturation (SaO2 <75%, >30 s) in each of 24 otherwise stable spontaneously breathing preterm infants (gestational age 29.8 ± 1.5 weeks, birth weight 1,215 ± 280 g; mean ± SD), during 3 episodes without and 3 episodes with increased FiO2 during recovery from desaturation. Results: Post-recovery SaO2 with increased FiO2 was significantly higher than post-recovery SaO2 without increased FiO2. Post-recovery SaO2 and rScO2 were significantly increased over baseline saturations when FiO2 was increased. Post-recovery rScO2 was very high for several minutes in some cases, while cFTOE was highly suggestive of oxygen delivery that exceeded consumption. Conclusions: Assuming that NIRS-measured rScO2 is an indicator of cerebral oxygen content, an increase in FiO2 to assist recovery from desaturation may cause hyperoxygenation of the brain in relatively stable preterm infants. This procedure may be particularly harmful in the sick very preterm infant with limited regulation of brain circulation and poorly developed antioxidant defenses. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

OBJECTIVES. A hemodynamically important patent ductus arteriosus is a common problem in the first week of life in the preterm infant. Although patent ductus arteriosus induces alterations in organ perfusion, scarce information is available of the impact of patent ductus arteriosus and its subsequent treatment on the oxygen supply and oxygen extraction of the brain. We investigated the impact of patent ductus arteriosus and its treatment with indomethacin on regional cerebral oxygen saturation and fractional tissue oxygen extraction by using near-infrared spectroscopy. PATIENTS AND METHODS. Twenty infants with patent ductus arteriosus (gestational age: <32 weeks), subsequently treated with indomethacin, were monitored for mean arterial blood pressure, arterial oxygen saturation, near-infrared spectroscopy-determined regional cerebral oxygen saturation, and fractional tissue oxygen extraction ([arterial oxygen saturation -- regional cerebral oxygen saturation] /arterial oxygen saturation). Ten-minute periods were selected and averaged during patent ductus arteriosus, at 10, 20, 30, 60, and 120 minutes, and at 6, 12, 24, and 36 hours after starting indomethacin treatment (to ductal closure) for mean arterial blood pressure, arterial oxygen saturation, regional cerebral oxygen saturation, and fractional tissue oxygen extraction. The patients with patent ductus arteriosus were matched for gestational age, birth weight, postnatal age, and severity of respiratory distress syndrome with infants without patent ductus arteriosus, who served as control subjects. RESULTS. Mean arterial blood pressure and regional cerebral oxygen saturation were significantly lower and fractional tissue oxygen extraction significantly higher compared with the control infants during patent ductus arteriosus (mean arterial blood pressure: 33 ± 5 vs 38 ± 6 mm Hg; regional cerebral oxygen saturation: 62% ± 9% vs 72% ± 10%; fractional tissue oxygen extraction: 0.34 ± 0.1 vs 0.25 ± 0.1, respectively). Regional cerebral oxygen saturation and fractional tissue oxygen extraction were lower and higher, respectively, up to 24 hours after the start of indomethacin but normalized to control values afterward. Indomethacin had no additional negative effect on cerebral oxygenation. CONCLUSIONS. A hemodynamically significant patent ductus arteriosus has a negative effect on cerebral oxygenation in the premature infant. Subsequent and adequate treatment of a patent ductus arteriosus may prevent diminished cerebral perfusion and subsequent decreased oxygen delivery, which reduces the change of damage to the vulnerable immature brain. [ABSTRACT FROM AUTHOR]