Literature Review: Neonatal Jaundice

REVIEW OF LITERATURE
Introduction
Neonatal jaundice is one of the most common clinical entity encountered by the neonatologists. It is natural phenomenon occurring in the major proportion of full term neonates and virtually in all preterm neonates11. Neonatal jaundice is transitional phenomenon, usually having benign course and have physiologic role in development. Bilirubin outside the circulation can be dangerous, such as its accumulation in the brain, contributing to neurologic dysfunction and, sometimes permanent injury like kernicterus. The neonatal hyperbilirubinemia results from an imbalance between bilirubin production and bilirubin elimination, which is temporarily exacerbated during the transition after birth.1,

. When compared to traditional methods like HPLC, diazo methods, TSB measurement by a point-of-care (POC) direct spectrophotometric method has the advantages of smaller blood sample requirement and more rapid turnaround time. The direct spectrophotometric test is work on the principle of the absorbance of bilirubin at 454 nm; by contrast, hemoglobin absorbs equally at both 454 and 528 nm. Subtraction of the absorbance at 528 nm from that at 454 nm removes the effect of hemolysis and yields a value that can be attributed primarily to bilirubin.
Diazo method
Non-invasive methods
Visual assessment Kramer described this first noninvasive method in 1969 for jaundice assessment, that the level of skin discolouration correlated with the serum bilirubin but it was easy to miss infants with high levels of bilirubin. Kramers noted that with raising levels of bilirubin there is cephalo-caudal progression of jaundice and he developed scale which maps out estimated bilirubin levels for different body parts. Although this scale was developed there were wide bilirubin ranges for each zone13. Colour scale (icterometer)
Icterometer having a strip with different shades of yellow with estimated bilirubin corresponding to intensity of shadows was developed to which the infants’ skin colour was compared to estimate

The mean gestational age was 31 week and mean birth weight was 1728 ± 60 g. 30 percent of neonates were clinically ill. The mean value obtained by TSB was 8.8 mg/dl and for frontal TcB was 8.2mg/dl and for sternal TcB was 7.4mg/dl. There were good correlation between TBS and TcB and the maximum correlation were seen in 33-37 weeks of gestation and birth weight more than 2500 g with forehead TcB measurement. Healthy preterm infants had significant correlation of TSB and TcB (r=0.56, P<0.001. The correlation between TBS and TcB with and without phototherapy was r=0.66, P=0.000 and r=0.69, P=0.000 respectively. Although TcB measurement may underestimate TBS but there is significant correlation between TcB and TBS in preterm cases even in ill neonate or who receiving phototherapy. This method can be used for determination of bilirbin level in preterm neonate and reduces the number of blood