Saneyuki Yasuda

Functional imaging of the brain in sedated newborn infants using near infrared topography during passive knee movement.

Near infrared topography was used for functional imaging of the sensorimotor cortex of newborn infants during passive knee movement under sedated sleep. Contralateral knee movement caused a marked increase in oxyhemoglobin and total hemoglobin from the baseline values at almost all locations in the primary sensorimotor area of all neonates and a decrease in local deoxyhemoglobin in six of seven neonates. During ipsilateral knee movement, oxyhemoglobin and total hemoglobin showed slighter changes at a few locations, equal to 30% (mean) and 29% (mean) of the changes that occurred with contralateral stimulation, respectively. The mean times corresponding to maximal changes were 11.9 s for oxyhemoglobin and 19.1 s for deoxyhemoglobin, demonstrating that oxyhemoglobin has a much faster response than does deoxyhemoglobin.

New transcutaneous jaundice device with two optical paths.

Abstract Objectives: To confirm the accuracy and precision of transcutaneous bilirubin (TcB) values measured by a new device with two optical paths (JM-103) and the value of total serum bilirubin (TSB) level in clinical units of measurement. Methods: For comparison of the levels of accuracy and precision of JM-103 and the old device (JM-102), serum samples were collected from 77 Japanese infants in three different hospitals including 24 preterm infants and 53 term infants. Measurement of TcB by JM-103 and JM- 102 were performed on the forehead of each infant within 30 min before or after blood sampling. Results: The range of TSB was limited to 19.6 mg/dL and to 17 mg/dL for preterm infants. The correlation coefficients for all subjects (r = 0.94) and for term and preterm subjects between TcB measured by JM-103 and TSB was higher than that between TcB measured by JM-102 and TSB. The regression line in term infants between TcB measured by JM-103 and TcB was similar to that in preterm infants. The error distribution of TcB measured by JM-102 and TSB for all subjects (0.00±2.21) and for term and preterm subjects was larger than that of TcB measured by JM-103 and TSB (all subjects, 0.30±1.55).

Estimation of Regional Cerebral Blood Flow Distribution in Infants by Near-Infrared Topography Using Indocyanine Green

Near-infrared topography with indocyanine green was used to measure regional cerebral blood flow (rCBF) in the temporal lobes of infants. The mean rCBF in infants without neural abnormality was 14.5 +/- 3.1 ml/100 g/min, and the rCBFs in the fronto-temporal, temporal, and occipito-temporal regions were 15.1 +/- 3.9, 15.4 +/- 3.3, and 14.6 +/- 3.3 ml/100 g/min, respectively. Moreover, in one asphyxiated infant with infarction and one infant with subdural and intracerebellar hemorrhage, it was demonstrated that the area of defective blood flow could be detected as well as it can by SPECT. This technique makes it possible to estimate rCBF distribution in infants at the bedside. Thus, in the future, evaluation of various neonatal illnesses should be feasible.

Changes in cerebral hemoglobin concentration and oxygen saturation immediately after birth in the human neonate using full-spectrum near infrared spectroscopy

Using full-spectrum near infrared spectroscopy (fsNIRS), we measured changes in oxy- and deoxyhemoglobin (HbO2 and Hb), total hemoglobin (T-Hb) concentration, and hemoglobin oxygen saturation (SbO2) in the brain tissue of seven neonates immediately following birth. It was found that HbO2 rose rapidly within 2-3 min after birth. During the same time, there was a transient increase in T-Hb concentration, after which it decreased together with Hb. SbO2 increased rapidly after birth, from 18% at 1.5 min to about 55% at 5-6 min, followed by a gradual increase of about 10%. Oxygenation in the brain occurred much sooner in three subjects given oxygen for a short time immediately after birth than in those who did not receive oxygen. This preliminary study indicated that dynamic changes occur in cerebral circulation and oxygenation as part of the physiological changes taking place soon after birth.

Measurement of cerebral oxygenation in neonates after vaginal delivery and cesarean section using full-spectrum near infrared spectroscopy ☆

To investigate whether or not the mode of delivery produces differences in cerebral oxygenation, cerebral hemoglobin oxygen saturation was measured using full-spectrum near infrared spectroscopy in 26 healthy term newborn infants immediately after birth. Infants in group 1 (n=20) were delivered vaginally, and those in group 2 (n=6) by elective cesarean section. Arterial oxygen saturation in the right hand was also measured simultaneously using a pulse oximeter. Changes in arterial oxygen saturation showed no significant difference between the two groups. The mean+/-S.D. of cerebral hemoglobin oxygen saturation in group 1 increased rapidly after birth, from 29+/-17% at 2 min to 68+/-6% at 8.5 min, followed by an almost constant value (66+/-7% at 15 min). In comparison, cerebral hemoglobin oxygen saturation in group 2 also increased rapidly until 8.5 min, but after this time decreased significantly to 57+/-5% at 15 min after birth. This indicates that the mode of delivery has a marked influence on cerebral oxygenation immediately after birth.

Quantification of cerebral oxygenation by full-spectrum near-infrared spectroscopy using a two-point method.

The aim of this study was to quantify the relative concentrations of oxyhemoglobin and deoxyhemoglobin within the light path of the brain and to estimate cerebral hemoglobin (Hb) oxygen saturation using full-spectrum near-infrared spectroscopy (fsNIRS). For this purpose, we developed a novel exponential correction equation as well as a two-point spectroscopy method to estimate the relative concentrations of Hb and Hb oxygen saturation in biological tissues. The results of evaluation of measurements using an in vitro model indicated that our fsNIRS method enables accurate and non-invasive measurements of Hb content and saturation in a highly scattered medium such as the human brain. According to the results of analysis using a hypoxic piglet model, the mean cerebral Hb oxygen saturation (SbO(2)) of newborn piglets at an inspired oxygen gas concentration of 0.21 was estimated to be 63+/-4% (mean+/-S.D.). Umbilical arterial and left internal jugular venous Hb oxygen saturation were simultaneously estimated to be 96+/-2% and 52+/-11%, respectively. SbO(2) and arterial Hb oxygen saturation values had a linear relationship. The average oxygenation state of cerebral tissue is comparable with that of the cerebral vein. The results of this study showed that our method can be used to monitor Hb oxygen saturation in the neonatal brain at the bedside in an intensive care unit.

Functional lateralization of sensorimotor cortex in infants measured using multichannel near-infrared spectroscopy.

Multichannel near-infrared spectroscopy (MNIRS) was used for the functional imaging of the sensorimotor cortex of newborn infants during passive knee and elbow movement under sedated sleep. Contralateral knee and elbow movement caused a marked increase in the concentration of oxyhemoglobin ([oxyHb]) from the baseline values at site within the sensorimotor area in all infants. During ipsilateral knee and elbow movement, [oxyHb] showed smaller changes, equivalent to 64 ± 23 and 66 ± 28% of the changes that occurred with contralateral stimulation, respectively. The mean times corresponding to maximal changes in [oxyHb] were 16.1 ± 3.3 s for contralateral knee movement and 17.9 ± 5.7 s for contralateral elbow movement. No significant difference was noted between the mean latencies showing the maximal changes in [oxyHb] between contralateral and ipsilateral movement. There was a significant difference in the area and degree of response between the contralateral and ipsilateral movement. MNIRS could be a useful tool to understand the pathophysiology of the developing brain and monitor cortical responses in various clinical situations.

Influence of Glucuronosyl Bilirubin and (EZ)-Cyclobilirubin on Determination of Serum Unbound Bilirubin by UB-Analyser

Background In the enzyme reaction for the determination of the unbound (free) bilirubin concentration by glucose oxidase and peroxidase, materials with low affinity for serum protein are reactive. The influence of these materials on the determination of serum unbound bilirubin was investigated. Methods Serum samples from patients with neonatal hyperbilirubinaemia were analysed by high-performance liquid chromatography for total glucuronosyl bilirubin concentration (TGC) and (E2)-cyclobilirubin concentration [(EZ)-C]. Based on these measurements, the samples were classified into three groups: group I [13 samples, TGC < 2 μmol/L and (EZ)-C < 2·5 μmol/L]; group II [four samples, TGC < 2 μmol/L and (EZ)-C ≥ 2·5 μmol/L]; and group III (five samples, TGC ≥ 2 μmol/L). The concentrations of total bilirubin and unbound bilirubin were measured in these same samples with a UB-analyser. When the absorbance at 460 nm was monitored, the decrease in absorbance was non-linear (concave curve). The degree of concavity was estimated (D15 value) as the deviation from linearity at 15 s. Results The D15 value was significantly higher in groups II and III than in group I. D15 value correlated significantly with TGC, (EZ)-C and unbound bilirubin concentration, and the unbound bilirubin concentration correlated significantly with TGC and (EZ)-C. Conclusion These results indicated that determination of serum unbound bilirubin concentration using the UB-analyser could be positively skewed by high concentrations of TGC and (EZ)-C.

Estimation of circulating blood volume in infants using the pulse dye densitometry method

Background:  Estimation of hemodynamics is important for critically ill infants. Pulse dye densitometry (PDD) using indocyanine green (ICG), which enables measurements of circulating blood volume at the bedside, has recently been developed for adults.

Current incidence of clinical kernicterus in preterm infants in Japan.

Clinical kernicterus in preterm infants has recently been reported in Japan, diagnosed on the basis of clinical findings during the neonatal and infancy periods. We investigated the incidence of clinical kernicterus in preterm infants <30 weeks gestational age (GA) based on a nationwide survey conducted in 233 certified educational facilities for neonatologists. The numbers of infants admitted and infants who died within 14 days after birth during 2011, and the number of infants who subsequently developed clinical kernicterus, were recorded. A total of 2720 infants were analyzed, representing 59% (2720/4623) of all preterm live births <30 weeks GA in Japan in 2011. Of these, 159 (5.8%) died within 14 days after birth, similar to the national rate. Five infants developed clinical kernicterus in infancy (5/2720, 0.18%). The current incidence of clinical kernicterus in Japan is therefore estimated at 1.8 per 1000 live births <30 weeks GA.