Phototherapy is proved to be a strong candidate for the most common therapeutic modality in NICU infants. However, in the light of reported toxicity in the smallest, most vulnerable infants, we recommend increased emphasis on quality control.
Intermediate-to-advanced stage acute bilirubin encephalopathy may occasionally be reversible. These cases provide a strong argument in favour of rapid and aggressive intervention in infants presenting with extreme jaundice and neurological symptoms.
Neonatal jaundice is usually treated with phototherapy that converts bilirubin to more polar stereoisomers. These should theoretically be less able to cross the blood-brain barrier. The rates of photoisomer formation and concentrations accumulating in the circulation may have a bearing on the risk of kernicterus. The purpose of this study was to determine the rate of appearance of the major 4Z, 15E photoisomer of bilirubin during the early stages of phototherapy. Twenty jaundiced neonates were treated with phototherapy, and blood samples were drawn before and at approximately 15, 30, 60, and 120 min (10 infants) or at approximately 15, 60, 120, and 240 min (10 infants) after beginning phototherapy. Blood samples were analyzed for total serum bilirubin (TSB) and the 4Z, 15E photoisomer of bilirubin. Significant (p<0.0001) formation of the 4Z, 15E photoisomer was detectable within 15 min. The change in TSB from time 0 was insignificant at 120 min but reached significance at 240 min (p<0.001). The 4Z, 15E bilirubin constituted up to 20-25% of TSB at 2 h and may not have peaked by 4 h. Further studies are needed to determine whether this early shift in balance between bilirubin isomers with different polarities may impact the risk of bilirubin encephalopathy even before TSB starts to fall.
There were considerable variations in phototherapy practices among Norwegian NICUs. In particular, the significant variations in duration need to be addressed.
Background:In neonatal jaundice, phototherapy converts bilirubin to more polar photoisomers which can be excreted without conjugation. We measured changes in the concentration of bilirubin Z,E-photoisomer during the first 4 h of intensive phototherapy using single fluorescent lights as a reference, compared to double fluorescent lights, and a single unit of photodiodes. Methods: Neonates (N = 42; birth weight: 1,200-4,690 g; gestational age: 28-42 wk) were studied during phototherapy. Infants were randomized to: (i) single, or (ii) double fluorescent phototherapy; or (iii) single unit photodiodes. Irradiance was measured. Serum bilirubin (by cooximetry) and Z,E bilirubin (by high-pressure liquid chromatography) were measured at 0,15, 30, 60, 120, and 240 min after the start of phototherapy. Data were analyzed with a linear mixed model. results: There was a highly significant increase of Z,E-bilirubin over time (P < 0.0001), starting at 15 min. Photoisomers reached ~25% of total bilirubin concentration after 4 h. However, there were no significant differences between the three randomized groups in spite of significantly higher irradiance using double fluorescent lights vs. single fluorescent or photodiodes. conclusion: Formation of bilirubin photoisomers is rapid, and occurs early during intensive phototherapy for neonatal jaundice. The rate and level of photoisomerization was not influenced by irradiance and light source. P hototherapy is the standard treatment for hyperbilirubinemia in newborns, and is administered to prevent kernicterus and other sequelae of bilirubin neurotoxicity (1).It is effective and considered safe. However, a recent report suggests that "aggressive" phototherapy in the smallest infants of birth weight 501-750 g may be associated with increased risk of death (2).When native bilirubin IXα (Z,Z) in neonates is exposed to light, a rapid photochemical reaction produces water-soluble configurational (4Z,15E; 4E,15Z; 4E,15E) and structural (Z-lumirubin; E-lumirubin) isomers (3,4). Photooxidation may also occur (5,6). Due to increased polarity, these isomers can be excreted in bile and urine, bypassing the need for conjugation. It has recently been suggested that these isomers, because of their polarity, should be less able to cross the bloodbrain barrier (1,7). If this is correct, photoisomer formation might be directly neuroprotective, irrespective of the effect on excretion. Experimental data suggest that bilirubin photoisomers are less toxic than the native IX α (Z,Z), but there are methodological weaknesses in these studies (1). Thus, experimental proof of the hypothesized direct neuroprotective effects of photoisomerization is still needed. Both different light qualities and variable light irradiance are commonly employed in practical phototherapy. Herein we have investigated whether such factors may impact on photoisomer formation.The common light sources used in phototherapy are either fluorescent, or tungsten-halogen lamps with wide emission spectrum, or light-emitting diodes (LEDs) wi...
1348 Figure 1 Study GroupsFormation of PI reached 25% at 4h, anddid not appear to have plateaued. Conclusions Formation of PI is rapid during intensive phototherapy. However, increasing irradiance or chancing the character of thelight source did not significantly improve the rate or level of PI formation. TREATING INFANTS OF VITAMIN D DEFICIENT MOTHERS -IS ROUTINE SUPPLEMENTATION Background and AimsInfants with maternal vitamin D deficiency are at increased risk of low vitamin D levels. Cholecalciferol is the usual treatment for such infants. We wanted to see whether routine vitamin supplementation with Abidec alone was enough to normalize vitamin D levels in such infants. Methods All infants infants with maternal vitamin D deficiency, after August 2011 were given 0.6ml Abidec which provides 400IU of vitamin D2. Vitamin D levels were done at birth and infants with borderline (10-20ng/dl) or deficient(< 10ng/dl) vitamin D levels had repeat test at follow-up. Records of all such infants, from August to November 2011 were reviewed. The results were also compared to the period when cholecaciferol was used. Results Total 64 patients were identified. Initial vitamin D results were obtained for 60 infants of which 16 infants were deficient (range 3.1 to 9.1 ng/dl), 20 had borderline (range 10.3-19.8 ng/dl), 10 had suboptimal (range 20.6-29.7ng/dl) and 14 infants had normal vitamin D levels.Post treatment levels were available for 17 out of 36 infants with low or borderline levels. Of the 5 infants with initially deficient levels, 3 had normal, 1 had suboptimal and 1 had borderline vitamin D post treatment levels. 8 of the 12 infants with borderline vitamin D levels had normalized and 4 had suboptimal vitamin D levels post treatment.These results were comparable to the period when cholecaliferol was used.
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