Photooxidant injury to glucose-6-phosphate dehydrogenase-deficient erythrocytes with bilirubin as the sensitizer--an in vitro study

Neonatal jaundice in very low birth weight babies

Very low birth weight (VLBW) neonates born between January 1995 to December 1998, who survived for > 2 days, were studied for the incidence, causes and interventions required for neonatal jaundice. Significant neonatal jaundice was defined as the total serum bilirubin (TSB) level beyond which baby required intervention (phototherapy and/or exchange transfusion) for neonatal jaundice. The incidence of significant neonatal jaundice (NNJ) was 76.6% and 37.3% required exchange transfusion. It was 82.9% at gestational age < or = 28 weeks reduced whereas to 56.9% at gestational age of 35-36 weeks. The incidence was 75.3%, 78.5% and 76.7% in the birth weight group of 750-799 grams, 1000-1249 grams and 1250-1499 grams respectively. Glucose 6 phosphatase dehydrogenase (G-6-PD) deficiency (12.1%) was the commonest cause of jaundice. There is a need for evaluation of prophylactic therapies that enhances liver function or decreases production of bilirubin, which would prevent the rise of TSB to dangerous levels and thus would decrease the need for exchange transfusions.

Oxidative stress, phototherapy and the neonate

Phototherapy is the most widely used form of therapy for unconjugated hyperbilirubinaemia. Its non-invasive nature and few side effects reported earlier have led to the assumption that it is innocuous. Recent research has revealed that phototherapy is a photodynamic stress and can induce lipid peroxidation. There is increasing evidence that many severe diseases of the neonate are caused by oxidative injury and lipid peroxidation. In the present communique, we review the oxidative susceptibility of the neonate and the evidence now available that phototherapy induces oxidative stress. Although intensive phototherapy (up to 40 mwatt/cm2/nm) has been reported to be increasingly effective, a little caution, we believe is warranted, till more definite data in the human neonate, help resolve the issue.