METHODOLOGY
This prospective cohort study was conducted in the Pediatrics department of a tertiary care teaching institution of central India from December 2014 to June 2015. Prior approval from the institutional ethics committee was obtained and informed consent was taken from the parents/ legal guardians. All healthy, full term, appropriate for date (completed 37-42 weeks) neonates, admitted during study period with jaundice and serum bilirubin > 12 mg/dL were included in the study. Premature or post-term, low birth weight, small for date, IUGR babies and those with hypoglycemia, perinatal asphyxia, neonatal sepsis, seizures, metabolic disorders, hypothyroidism or congenital malformations affecting the neurodevelopmental outcome were excluded from the study.
Gestational age (completed 37-42 weeks) was assessed using last menstrual period and available ultrasonography scans. Gestational age was confirmed by Ballard scoring in neonates of age less than 7 days. Anthropometric measurements were taken of all enrolled neonates. Appropriate for date (as per Fenton’s Charts) newborns with serum bilirubin >12 mg/dL were included in the study as physiological jaundice rarely exceeds 12 mg/dL in full-term neonates and 15 mg/dL in preterm neonates [2].
The thorough clinical examination was done to assess the extent of Icterus (Kramer’s Rule) and neurological status. Blood sample collection was done by Venepuncture under all aseptic precautions at the time of admission. Serum was separated by centrifugation and then serum bilirubin estimation was done using Modified Jendrassic and Grof’s Method kit [5]. Other investigations including Blood group, Glucose-6-phosphate dehydrogenase (G6PD), Direct Coomb’s Test ( DCT ), Thyroid Profile, Liver Function test, Haematocrit, C-Reactive Protein were also done. Serum bilirubin estimation was done 12 hourly [1] and the peak serum bilirubin level was considered.
Newborns with hyperbilirubinemia were managed as per the guidelines for phototherapy and exchange transfusion published by American Academy of Pediatrics Subcommittee on Hyperbilirubinemia [6]. Infant once discharged was then followed up fortnightly till 3 months of age and then monthly till 6 months of age. In each follow-up visit, a thorough clinical examination was done and neurodevelopment was assessed using Denver Development Screening Test II. The test was applied as per instructions given in manual and results were plotted on the form provided. Individual items in the test were interpreted as advanced, normal, caution, delayed or no opportunity. The test subjects were interpreted as normal with no delay or one caution, as suspects with two or more cautions and/or one or more delays and as untestables with one or more refusal scores. In each visit, the results were analyzed and in a case of caution, early follow-up was done within 1-2 weeks.
BERA [7] was planned in both ears at 3 months of age. The machine used was RMS EMG EP MARK II and the test was carried out in Department of Physiology at the same institution. Infants were sedated using Syrup chloral hydrate at a dose of 20 mg/kg. Middle ear examination for wax impaction or any other ear defects was done. The guidelines published by Joint Committee on Infant Hearing [8] were followed. Increased latencies of waves as per the age limits and increased threshold in either ear were considered to be abnormal.
The study population was divided into 3 groups according to serum bilirubin levels viz. group 1 (bilirubin 12-15 mg/dl), group 2 (15-20 mg/dl) and group 3 (>20 mg/dl). Outcome was compared between these groups. Statistical analysis was done using appropriate tests including Chi square test, and t test. Statistical significance was tested at 95% confidence level, found significant if p<0.05. All the statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) software version 20.0 (IBM corporation, NY, USA).