Beyond plasma bilirubin: the effects of phototherapy and albumin on brain bilirubin levels in Gunn rats.

BACKGROUND & AIMS: Severe unconjugated hyperbilirubinemia, as occurs in Crigler-Najjar disease and neonatal jaundice, carries the risk of neurotoxicity. This neurotoxicity is related to the increased passage of free bilirubin (UCB(free)), the fraction of bilirubin that is not bound to plasma proteins, into the brain. We hypothesized that albumin treatment would lower the UCB(free) fraction, and thus decrease bilirubin accumulation in the brain. METHODS: We treated chronic (e.g., as a model for Crigler-Najjar disease) and acute hemolytic (e.g., as a model for neonatal jaundice) moderate hyperbilirubinemic Gunn rats with phototherapy, human serum albumin (HSA) or phototherapy+HSA. RESULTS: In the chronic model, adjunct HSA increased the efficacy of phototherapy; it decreased plasma UCB(free) and brain bilirubin by 88% and 67%, respectively (p<0.001). In the acute model, adjunct HSA also increased the efficacy of phototherapy; it decreased plasma UCB(free) by 76% (p<0.001) and completely prevented the hemolysis-induced deposition of bilirubin in the brain. Phototherapy alone failed to prevent the deposition of bilirubin in the brain during acute hemolytic jaundice. CONCLUSIONS: We showed that adjunct HSA treatment decreases brain bilirubin levels in phototherapy-treated Gunn rats. We hypothesize that HSA decreases these levels by lowering UCB(free) in the plasma. Our results support the feasibility of adjunct albumin treatment in patients with Crigler-Najjar disease or neonatal jaundice.

Measurements of neonatal bilirubin and albumin concentrations: a need for improvement and quality control.

Accurate and precise bilirubin and albumin measurements are essential for proper management of jaundiced neonates. Data hereon are lacking for Dutch laboratories. We aimed to determine variability of measurements of bilirubin and albumin concentrations typical for (preterm) neonates. Aqueous, human serum albumin-based samples with different concentrations of bilirubin (100, 200, 300, 400, and 500 µmol/L) and albumin (0, 10, 15, 20, 25, and 30 g/L) were sent to laboratories of all Dutch neonatal intensive care units (n = 10). Bilirubin and albumin recoveries of the specimens were measured using locally available routine analytical methods. The mean, standard deviation, and coefficients of variations (CV) were calculated per sample. Bilirubin concentrations were underestimated in the absence of albumin (maximal CV 26.0%). When the albumin concentration was 10 or 20 g/L, the bilirubin concentrations of the samples were overestimated (maximal CV 14.1% and 9.2%, respectively). Variability increased with higher weighed-in bilirubin concentrations. Measured albumin levels were ~10% lower than albumin levels of manufactured samples. Bilirubin concentration did not influence albumin measurements. The maximal CV was 6.8%. In conclusion, interlaboratory variability of bilirubin and albumin measurements is high. Recalibration and introduction of a specific quality assessment scheme for neonatal samples is recommended to ensure exchangeability of bilirubin and albumin measurements among laboratories and to control the observed large variability.

Should transcutaneous bilirubin be measured in preterm infants receiving phototherapy? The relationship between transcutaneous and total serum bilirubin in preterm infants with and without phototherapy.

Our objective was to analyze the relationship between transcutaneous bilirubin (TcB) measured on an unexposed area of skin and total serum bilirubin (TSB) in preterm infants before, during, and after phototherapy (PT). For this purpose paired TSB and TcB levels were measured daily during the first ten days after birth in preterm infants of less than 32 weeks' gestation. TcB was measured with a Dräger Jaundice Meter JM-103 on the covered hipbone. Agreement between TSB and TcB levels was assessed before, during, and after PT. True negative and corresponding false negative percentages were calculated using different TcB cut-off levels. Data are presented as mean (±SD). We obtained 856 paired TcB and TSB levels in 109 preterm infants (66 boys, gestational age 29.4 ± 1.6 weeks and birth weight 1282 g ± 316 g). We found that the difference between TSB and TcB before PT was significantly lower, 44 (±36) µmol/L, than the difference during and after PT, 61 (±29) µmol/L and 63 (±25) µmol/L, respectively; P < 0.01. Blood sampling could be reduced by 42%, with 2% false negatives, when 50 µmol/L was added to the TcB level at 70% of the PT threshold. Our conclusion is that phototherapy enhances underestimation of TSB by TcB in preterms, even if measured on unexposed skin. The use of specific TcB cut-off levels substantially reduces the need for TSB measurements.

The Ages and Stages Questionnaire and Neurodevelopmental Impairment in Two-Year-Old Preterm-Born Children.

OBJECTIVE: To test the ability of the Ages and Stages Questionnaire, Third Edition (ASQ3) to help identify or exclude neurodevelopmental impairment (NDI) in very preterm-born children at the corrected age of two. METHODS: We studied the test results of 224 children, born at <32 postmenstrual weeks, who had scores on ASQ3 and Bayley Scales of Infant and Toddler Development, Third Edition (BSIDIII) and neurological examination at 22-26 months' corrected age. We defined NDI as a score of <70 on the cognitive--or motor composite scale of BSIDIII, or impairment on neurological examination or audiovisual screening. We compared NDI with abnormal ASQ3 scores, i.e., < -2SDs on any domain, and with ASQ3 total scores. To correct for possible overestimation of BSIDIII, we also analyzed the adjusted BSIDIII thresholds for NDI, i.e., scores <80 and <85. RESULTS: We found 61 (27%) children with abnormal ASQ3 scores, and 10 (4.5%) children who had NDI with original BSIDIII thresholds (<70). Twelve children had NDI at BSIDIII thresholds at <80, and 15 had <85. None of the 163 (73%) children who passed ASQ3 had NDI. The sensitivity of ASQ3 to detect NDI was excellent (100%), its specificity was acceptable (76%), and its negative predictive value (NPV) was 100%. Sensitivity and NPV remained high with the adjusted BSIDIII thresholds. CONCLUSION: The Ages and Stages Questionnaire is a simple, valid and cost-effective screening tool to help identify and exclude NDI in very preterm-born children at the corrected age of two years.

The bilirubin albumin ratio in the management of hyperbilirubinemia in preterm infants to improve neurodevelopmental outcome: a randomized controlled trial--BARTrial.

BACKGROUND AND OBJECTIVE: High bilirubin/albumin (B/A) ratios increase the risk of bilirubin neurotoxicity. The B/A ratio may be a valuable measure, in addition to the total serum bilirubin (TSB), in the management of hyperbilirubinemia. We aimed to assess whether the additional use of B/A ratios in the management of hyperbilirubinemia in preterm infants improved neurodevelopmental outcome. METHODS: In a prospective, randomized controlled trial, 615 preterm infants of 32 weeks' gestation or less were randomly assigned to treatment based on either B/A ratio and TSB thresholds (consensus-based), whichever threshold was crossed first, or on the TSB thresholds only. The primary outcome was neurodevelopment at 18 to 24 months' corrected age as assessed with the Bayley Scales of Infant Development III by investigators unaware of treatment allocation. Secondary outcomes included complications of preterm birth and death. RESULTS: Composite motor (100 ± 13 vs. 101 ± 12) and cognitive (101 ± 12 vs. 101 ± 11) scores did not differ between the B/A ratio and TSB groups. Demographic characteristics, maximal TSB levels, B/A ratios, and other secondary outcomes were similar. The rates of death and/or severe neurodevelopmental impairment for the B/A ratio versus TSB groups were 15.4% versus 15.5% (P = 1.0) and 2.8% versus 1.4% (P = 0.62) for birth weights ≤ 1000 g and 1.8% versus 5.8% (P = 0.03) and 4.1% versus 2.0% (P = 0.26) for birth weights of >1000 g. CONCLUSIONS: The additional use of B/A ratio in the management of hyperbilirubinemia in preterm infants did not improve their neurodevelopmental outcome. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN74465643.

High variability and low irradiance of phototherapy devices in Dutch NICUs.

OBJECTIVE: To evaluate phototherapy practices by measuring the irradiance levels of phototherapy (PT) devices. DESIGN: Prospective study. SETTING: Tertiary neonatal intensive care units. PATIENTS: None. INTERVENTIONS: Irradiance levels of PT devices used in the 10 Dutch Neonatal Intensive Care Units (NICUs) were measured according to the local PT practice patterns. The irradiance levels of all overhead and fibre-optic PT devices were measured with a radiometer using an infant silhouette model. RESULTS: Eight different PT devices were used in the 10 NICUs; five were overhead devices and three fibre-optic pads. The median (range) irradiance level for overhead PT devices was 9.7 (4.3-32.6) µW/cm(2)/nm and for fibre-optic pads 6.8 (0.8-15.6) µW/cm(2)/nm. Approximately 50% of PT devices failed to meet the minimal recommended irradiance level of 10 µW/cm(2)/nm. Maximal irradiance levels for overhead PT spot lights were inversely related to the distance between device and infant model (R2=0.33). The distances ranged from 37 cm to 65 cm. CONCLUSIONS: PT devices in the Dutch NICUs show considerable variability with often too low irradiance levels. These results indicate that suboptimal PT is frequently applied and may even be ineffective towards reducing total serum bilirubin levels. These results underline the need for greater awareness among all healthcare workers towards the requirements for effective PT including measurements of irradiance and distance.

[Uniform intervention criteria for jaundice in hyperbilirubinemia in preterm infants]. / Uniforme bilirubinegrenzen voor de behandeling van icterische premature neonaten.

OBJECTIVE: To compare the guidelines of the 10 Dutch neonatal intensive care units (NICUs) for the treatment of preterm infants with hyperbilirubinemia, in order to develop uniform threshold levels for the total serum concentration of bilirubin (TSB) above which treatment with phototherapy or exchange transfusion is indicated. DESIGN: Survey. METHODS: Guidelines for hyperbilirubinemia in preterm infants (gestational age < 32 weeks) from all 10 Dutch NICUs were obtained and compared with each other and with international guidelines. RESULTS: All 10 NICUs used intervention criteria based on TSB. 9 NICUs used TSB thresholds based on birth weight (1 used gestational age) with 2, 3 or 5 categories. 6 NICUs used age-specific TSB thresholds and 4 NICUs used a constant TSB threshold. The maximum range in TSB thresholds was 170 micromol/l for phototherapy and 125 micromol/l for exchange transfusion. Acidosis, sepsis, asphyxia, active haemolysis and intraventricular haemorrhage were the risk factors most frequently used. During a consensus meeting with representatives of the 10 NICUs, a guideline was agreed upon that will now be used for all neonates with a gestational age < 35 weeks. CONCLUSION: There was considerable variation in the TSB thresholds used to date by the 10 NICUs. Now in the Netherlands, in addition to guideline 'Hyperbilirubinemia' for children with a gestational age >or= 35 weeks, 'uniform yellow thresholds' shall be used for jaundiced preterm infants with a gestational age < 35 weeks.