Phototherapy and photo-oxidation in premature neonates
Michael Kaplan1, Vadim Gold, Cathy Hammerman
1Department of Neonatology, Shaare Zedek Medical Center, Jerusalem, Israel. kaplan@cc.huji.ac.il
Insights
Phototherapy effectively reduces total plasma bilirubin in premature infants. Short-term treatment showed no significant signs of photo-oxidation, ensuring infant safety during jaundice treatment.
Area of Science:
- Neonatal Medicine
- Biochemistry
- Photobiology
Background:
- Neonatal jaundice is common, often treated with phototherapy.
- Phototherapy involves exposing infants to light to reduce bilirubin levels.
- Concerns exist regarding potential photo-oxidative stress during treatment.
Purpose of the Study:
- To assess the risk of photo-oxidation in premature neonates undergoing phototherapy.
- To measure specific biomarkers indicative of oxidative damage.
Main Methods:
- Blood samples collected from premature infants before and after phototherapy (4 and 24 hours).
- Measured total plasma bilirubin (TPB), carboxyhemoglobin (COHbc), thiobarbituric acid reacting substances (TBARS), and plasma protein carbonyls.
- Analyzed data for the overall group and by birthweight subgroups (<1.5 kg and >=1.5 kg).
Main Results:
- Phototherapy significantly reduced TPB levels in premature infants.
- No significant increases in COHbc, TBARS, or protein carbonyls were observed, indicating no widespread photo-oxidation.
- A minor increase in COHbc in the smallest infants (<1.5 kg) was noted but not associated with other oxidative markers.
Conclusions:
- Short-term phototherapy is effective in lowering bilirubin in premature infants.
- The treatment does not appear to cause significant photo-oxidation.
- COHbc changes in the smallest infants warrant consideration but do not indicate systemic oxidative damage from phototherapy.
Objective:
The potential for photo-oxidation during phototherapy in premature neonates was assessed by measuring parameters reflective of photo-oxidation.
Methods:
Blood was sampled from premature neonates prior to, and after 4 and 24 h of phototherapy, respectively. Total plasma bilirubin (TPB), blood carboxyhemoglobin corrected for inspired carbon monoxide (COHbc) (a sensitive index of heme catabolism), blood thiobarbituric acid reacting substances (TBARS) (a measure of lipid peroxidation), and plasma protein carbonyls (representative of protein oxidation) were determined. Study measurements were compared with baseline values both for the entire study group, and also individually for subgroups < and > or = 1.5 kg birthweight, respectively. The percentage difference (%delta) between baseline and the 24-hour measurement was calculated for each parameter.
Results:
Forty-one premature neonates (mean [+/- SD] gestational age 30.5 +/- 2.7 weeks and birthweight 1,499 +/- 448 g) were studied. Mean TPB values decreased from a baseline of 9.1 +/- 2.3 to one of 7.2 +/- 2.8 mg/dl, p < 0.01, during the first 24 h of phototherapy. For the entire patient sample, neither COHbc, TBARS or protein carbonyl values increased significantly over baseline measurements: COHbc: 0.90 +/- 0.26% vs. 0.92 +/- 0.32%; TBARS: 19.0 +/- 5.6 vs. 18.0 +/- 4.5 nmol/ml, and protein carbonyls 7.73 +/- 3.78 vs. 7.63 +/- 3.56 U/ml (baseline and 24-hour samples only are shown in the abstract). Similarly, for the entire group, %delta (mean, interquartile range) were not significantly different between COHbc [-3.77 (-15.89-17.65)%], TBARS [-7.47 (-17.37-7.38)%], and protein carbonyls [-1.47 (-28.51-43.48)%], respectively. For subgroup analysis of neonates < or > or = 1.5 kg birthweight, respectively, no significant increases in COHbc, TBARS or protein carbonyls were documented. A significant increase in %delta for COHbc in the <1.5 kg birthweight subgroup compared with those > or =1.5 kg, possibly indicative of hemolysis, was not matched by similar changes in %delta for TBARS or protein carbonyls, and may therefore not be a result of photo-oxidation.
Conclusions:
Except for changes in %delta in COHbc alone and in the smallest babies only, overall, short term phototherapy in premature infants was effective in reducing TPB concentrations without associated evidence reflective of photo-oxidation.
