Action spectrum of phototherapy in hyperbilirubinemic neonates.

BACKGROUND: Phototherapy with blue light matching plasma absorption spectrum of the bilirubin-albumin complex with peak at 460 nm is standard treatment of neonatal hyperbilirubinemia. AIM: To demonstrate clinically the action (efficacy) spectrum of phototherapy in hyperbilirubinemic neonates, through determination of the fraction of total serum bilirubin (TSB) decreased by phototherapy with peak emission wavelengths ≥478 nm (blue-green) compared with that of light of 459/452 nm (blue). METHODS: TSB values were compiled from three earlier trials, in which hyperbilirubinemic neonates were randomized to receive 24 h of either blue-green light (478/490/497 nm) (intervention groups) or blue light (459/452/459 nm) (control groups) with equal irradiance and exposed body surface areas. Ratios (efficacy) between the decrease in TSB between intervention and control groups were calculated and graphed versus peak wavelengths, demonstrating the course of the action spectrum. RESULTS: Calculated efficacy ratios were 1.31, 1.18, and 1.04 for light with peak wavelengths of 478, 490, and 497 nm, respectively. The action spectrum increases from 452/459 to maximum at 478 nm, from where it decreases to 1.18 and finally to 1.04. CONCLUSION: For optimal phototherapeutic treatment, neonates need to be exposed to light with peak wavelength some 20 nm longer than is presently used. IMPACT: The action (efficacy) spectrum of phototherapy for hyperbilirubinemic neonates has its peak wavelength at 478 nm. The peak wavelength of this action spectrum is 20 nm longer than the wavelength presently believed to be most efficient. The peak is also different from the peak found in vitro. For optimal phototherapeutic effect, neonates need to be treated with light of wavelengths some 20 nm longer than are presently used.

The impact of hemoglobin on the efficacy of phototherapy in hyperbilirubinemic infants.

BackgroundPhototherapy is the routine treatment for neonatal hyperbilirubinemia. Absorption of light in the skin transforms the native Z,Z-bilirubin to photobilirubins. This study investigates whether the hemoglobin concentration has an impact on efficacy of phototherapy, expressed by the decline of total serum bilirubin concentration (TsB).MethodsA trial was conducted on 93 infants, gestational age ≥33 weeks, with uncomplicated hyperbilirubinemia. The infants were treated with conventional phototherapy using LED light for 24 h. The median light irradiance was 66.8 µW/cm2/nm.ResultsThe median decrease in TsB after 24 h was 121 (57-199) µmol/l; the median hemoglobin was 12.0 (7.0-14.7) mmol/l. There was a significant effect of hemoglobin concentration on the decrease in TsB of -3.61 µmol/mmol hemoglobin (P=0.022), after adjusting for initial TsB and postnatal age. That is, assuming the same initial TsB and postnatal age, for each mmol/l increase in hemoglobin, the decrease in TsB was 3.61 µmol/l smaller. In our hemoglobin range, the decrease in TsB is reduced by 28 µmol/l (23%).ConclusionIncreasing hemoglobin levels led to a decrease in the efficacy of phototherapy. Our data provide additional support for the conclusion that the transformation of bilirubin to photobilirubins takes place mainly in the superficial capillaries of the skin.

Effect of phototherapy with turquoise vs. blue LED light of equal irradiance in jaundiced neonates.

BACKGROUND: Blue light with peak emission around 460 nm is the preferred treatment of neonatal hyperbilirubinemia. However, studies using fluorescent light tubes have suggested that turquoise light with peak emission at 490 nm may be more efficient. At present, the predominant light source for phototherapy is light emitting diodes (LEDs). Hence, the aim of this study was to compare the bilirubin-reducing effect in jaundiced neonates treated either with turquoise or with blue LED light with peak emission at 497 or 459 nm, respectively, with equal irradiance on the infants. METHODS: Infants with gestational age ≥33 wk and uncomplicated hyperbilirubinemia were randomized to either turquoise or blue LED light and were treated for 24 h. The mean irradiance footprint at skin level was 5.2 × 10(15) and 5.1 × 10(15) photons/cm(2)/s, respectively. RESULTS: Forty-six infants received turquoise light and 45 received blue light. The median (95% confidence interval) decrease of total serum bilirubin was 35.3% (32.5; 37.3) and 33.1% (27.1; 36.8) for infants treated with turquoise and blue lights, respectively. The difference was nonsignificant (P = 0.53). The decrease was positively correlated to postnatal age and negatively to birth weight. CONCLUSION: Using LED light of equal irradiance, turquoise and blue lights had equal bilirubin-reducing effect on hyperbilirubinemia of neonates.

Bilirubin isomer distribution in jaundiced neonates during phototherapy with LED light centered at 497 nm (turquoise) vs. 459 nm (blue).

BACKGROUND: Phototherapy using blue light is the treatment of choice worldwide for neonatal hyperbilirubinemia. However, treatment with turquoise light may be a desirable alternative. Therefore, the aim of this randomized, controlled study was to compare the bilirubin isomer distribution in serum of jaundiced neonates after 24 h of therapy with narrow-band (LED) light centered at 497 nm (turquoise) vs. 459 nm (blue), of essentially equal irradiance. MATERIALS: Eighty-three neonates (≥33 wk gestational age) with uncomplicated hyperbilirubinemia were included in the study. Forty neonates were exposed to light centered at 497 nm and 43 infants with light centered at 459 nm. Irradiances were 5.2 × 10(15) and 5.1 × 10(15) photons/cm(2)/s, respectively. RESULTS: After 24 h of treatment no significant differences in serum concentrations of total bilirubin isomers and Z,Z-bilirubin were observed between the 2 groups. Interestingly, concentrations of Z,E-bilirubin, and thus also total bilirubin isomers formed during therapy, were highest for infants receiving light centered at 459 nm, while the concentration of E,Z-bilirubin was highest for those receiving light centered at 497 nm. No significant difference was found between concentrations of E,Z-lumirubin. CONCLUSION: Therapy with LED light centered at 497 nm vs. 459 nm, applied with equal irradiance on the infants, resulted in a different distribution of bilirubin isomers in serum.

Relation between serum bilirubin levels ≥450 µmol/L and bilirubin encephalopathy; a Danish population-based study.

AIM: Describe the relation between levels of total serum bilirubin (TsB) ≥450 µmol/L and acute intermediate, acute advanced and chronic bilirubin encephalopathy. MATERIAL AND METHODS: All infants born at gestational age ≥35 weeks in Denmark between 2000 and 2007 with a TsB ≥450 µmol/L according to the national laboratory information system. Infants diagnosed with bilirubin encephalopathy were found in the Danish National Registry of Patients. RESULTS: 502,766 infants at gestational age ≥35 weeks were identified. Two hundred twenty-four developed a TsB ≥450 µmol/L, equivalent to an incidence of 45/100,000/year, and it increased during the period. Incidence of infants with peak TsB of 450-499, 500-599 and 600-1000 µmol/L were 29.6, 12.7 and 2.2 per 100,000, respectively. Three infants had acute advanced bilirubin encephalopathy and got severe sequelae, whereas the two infants with acute intermediate encephalopathy developed normally. Their peak TsB was ≥544 µmol/L. Having a peak TsB 600-1000 µmol/L, the risk of acute advanced and chronic bilirubin encephalopathy was 27% (95% CI 6;61), and the incidence of these conditions was 0.6 (95% CI 0.1;1.7) per 100,000. CONCLUSION: The incidence of infants with TsB ≥450 µmol/L was 45/100,000/year. Infants with a TsB ≥600 µmol/L had a substantial risk of developing acute advanced and chronic bilirubin encephalopathy, and the incidence of these conditions was 0.6 per 100,000.

Comparison of the transcutaneous bilirubinometers BiliCheck and Minolta JM-103 in preterm neonates.

AIM: To investigate the trueness and uncertainty of two transcutaneous bilirubinometers BiliCheck and Minolta JM-103 in preterm infants; establish cut-off values for the transcutaneous bilirubin (TcB) level, indicating the need for total serum bilirubin (TsB) measurement; and estimate how many blood samples could be saved. METHODS: In 133 neonates with gestational ages 28(+0) -34(+6) weeks, 239 measurements of TcB by BiliCheck (TcB(B)) and JM-103 (TcB(M)) and of TsB were performed. RESULTS: Median TsB of the first samples was 160 (range, 53-293) µmol/L, whereas median TcB(B) was 12 µmol/L (8%) lower and TcB(M) 67 µmol/L (40%) lower. TcB(B) underestimated TsB for TsB ≥180µmol/L. All TcB(M) values, except one, underestimated TsB. The underestimation increased with increasing TsB. Multiple regression analysis showed that post-natal age and ethnicity were confounding factors for TcB(M); none were found for TcB(B). The uncertainty was the same for the two instruments. By using cut-off values of 70% of the phototherapy limit for TcB(B) and 35% for TcB(M), the sensitivity of the screening would be 95% and 97%, and 36% and 24% of the blood samples could be saved, respectively. CONCLUSION: TcB determined with JM-103 gave values much lower than those obtained with BiliCheck. The underestimation of TsB increased with increasing concentrations. By using transcutaneous bilirubinometers in preterm neonates, 24-36% of the blood samples could be saved.

The effectiveness of phototherapy using blue-green light for neonatal hyperbilirubinemia - Danish clinical trials.

The effectiveness of phototherapy for neonatal hyperbilirubinemia based on Danish clinical trials is presented. Randomized controlled trials on the quality of light showed that blue-green fluorescent light (peak emission at 490 nm) was more efficient than blue fluorescent light (peak emission at 452 nm); blue-green light-emitting diode (LED) light (peak emission at 478 nm) was more efficient than blue LED light (peak emission at 459 nm); and blue-green LED light (peak emission at 497 nm) was equivalent to blue LED light (peak emission at 459 nm). Bilirubin-reducing effects correlated with irradiance, dependent on hemoglobin concentration, and independent of rotating infants. Phototherapy from both above and below was more efficient than therapy applied only from above at high levels of irradiance. In conclusion, we estimate and recommend the use of blue-green LED light (peak emission at 480 nm) rather than blue light (peak emission at 460 nm) for treating of neonatal hyperbilirubinemia.