INVESTIGATING THE PHOTOTHERAPY THRESHOLDS IN PRETERM INFANTS

Abstract

Abstract BACKGROUND Currently there are limited guidelines for the management of hyperbilirubinemia in preterm infants. Current guidelines are limited to individual sites and are consensus-based opinions. The current decrease in chronic bilirubin encephalopathy in preterm infants is a result of liberal use of phototherapy that are not based on evidence from a large dataset of preterm infants. The pattern of bilirubin levels in preterm is unclear and currently based on clinical judgement. Nomograms in term infants has been proven to be beneficial and effective in reducing unnecessary treatment of hyperbilirubinemia. A nomogram designed for preterm infants would allow health professionals to quantify risk based on evidence based methods and reduce the number of test done on preterm infants. OBJECTIVES The objectives of this study are 1) To determine photherapy thresholds in preterm infants and 2) To determine the normative pattern of bilirubin values in preterm infants. DESIGN/METHODS A multi-site retrospective chart review of preterm infants ≤ 35 weeks gestation born between January 2012- November 2017 was conducted. The following data was collected; all TSB, postnatal hours of age, duration of phototherapy, infant characteristics (gestational age, birth weight, outcomes) and maternal history (inter and anter partum medication). TSB samples prior to the initiation of phototherapy were analyzed per hour and stratified by gestational age groups. RESULTS A total of 330 preterm infants were included in the retrospective review (50 24-28 weeks gestation, 100 29-32 weeks gestation, and 180 33–35 weeks gestation). The mean peak bilirubin in infants 33-35 week gestation was 198 umol/L at 4 days. These infants were started on phototherapy at a mean age of 89 hours. At 24 hours of age these infants’ bilirubin was 104 umol/L (72-189umol/L). The mean peak bilirubin in infants 29–32 weeks gestation was 181umol/L at 5 days. At 24 hours of age the mean bilirubin was 109 umol/L. Finally in infants 24–28 weeks gestation the mean peak bilirubin was 127 umol/L at 4 days. These infants were started on phototherapy at 44 hours of age. CONCLUSION Bilirubin values in preterm infants is hetergenous across gestional ages. Phototherapy treatment thresholds are lower in preterm infants between 24–28 weeks gestation. A nomogram for preterm infants maybe possible in infants between 29–35 weeks. Further research is required to determine hour specific bilirubin levels in preterm infants.