Evaluation of Serum Endothelin-1 (ET-1) and Nitric Oxide (NO) Levels in Unconjugated Hyperbilirubinemic Neonates

Background: Neonatal hyperbilirubinemia is the most common cause of admission in NICU. Phototherapy is the golden standerd therapy long time ago, which shows efficacy and safety but its side effects should be studied in depth. Both endotheline 1 (ET-1) and nitric Oxide (NO) are potent vasoconstrictor and vasodilator respectively and they are affected by phototherapy. Objectives: This study aimed to investigate the impact of phototherapy on the level of ET-1 and NO in fullterm and preterm as well as studying their effect on hemodynamic stability in treated newborns. Subjects and Methods: This study included 120 newborn infants who were classified into two groups. 60 patients (30 term infants and 30 preterm infants 30 weeks) with unconjugated hyperbilirubinemia indicated for phototherapy and not indicated for exchange transfusion and the onset of jaundice from 2nd to 4th day. In addition, to 60 apparently healthy newborns as control group with matched age, sex, weight and gestational age. Results: There was significant increase in both endothelin-1 and nitric oxide in both fullterm and preterm groups after phototherapy. For fullterm group, ET-1 levels were 53.20 ± 6.17, 55.94 ± 6.30 Pg/ml and 65.42 ± 6.36 Pg/ml before, 12 hour and 24 hour after phototherapy respectively (p-v alue = 0.048 and 0.013 respectively). Nitric oxide levels among fullterm group were 54.56 ± 6.95, 59.77 ± 5.03 \u0026 62.23 ± 5.26 umol/L before, 12 hour and 24 hour after phototherapy respectively (p-value = 0.042 and 0.012 respectively). The means heart rate changes among fullterm group were 134.50 ± 1.73 and 135.73 ± 3.96 beat/min before and 24 hours after photothearpy (p-value = 0.05). Conclusion: There was significant increase in both endothelin-1 and nitric oxide in both fullterm and preterm groups after treatment with photo-therapy. In addition, a significant increase in mean heart rate and a significant decrease in mean blood pressure among preterm and fullterm groups befor and after phototherapy and before phototherapy versus controls.