141 Total bilirubin rate of rise of in moderate preterm neonates: impact of gestational age

Abstract

Background

As compared to term neonates, those < 35 weeks gestation (wks GA) are at greater risk for both acute and chronic bilirubin encephalopathy (ABE, CBE). Among these with postnatal total bilirubin rate of rise, (TB ROR) at age 0 to 72 hours has been observed because of either loss placental elimination system or increased postnatal production due to hemolysis. The ranges are known to vary > 8.5 umol/L/h in neonates with Rh disease to >3.4 umol/L/h at the 95th percentile track of the hour-specific nomogram. TB ROR in healthy term neonates is <3.4 umol/L/h.

Objectives

To determine the GA ranges on TB ROR to explore predictive TB ROR in preterm neonates who are more vulnerable with each <35 wks GA.

Design/Methods

A multi-site observational study to quantify TB ROR in preterm infants between 28 to 35 weeks. 1804 infants born between January 2013- March 2018 at 28–35 wks GA from three canadian perinatal centres were included and those with Rh disease were excluded. Analysis included infants >27 weeks with at least one TB prior to the initiation of treatment for severe hyperbilirubinemia treatment. Feeding patterns, birth history and maternal health conditions were documented.

Results

The TB ROR were compared by two prematurity GA groups (28–31 weeks and 32–35 weeks) then per individual gestational age in four time periods in hours, 0–24, 24–48, 48–96, and 96 -120 in 1049 preterm infants using 3065 TB samples. Infants <28 weeks GA were excluded since they represented a more diverse population. TB ROR by prematurity groups over all was higher in 32–35 weeks group at 0–12 hours (3.85 umol/L/h) and 25–36 hours (2.81umol/L/h) and decreased at 49–72 hours (0.24umol/L/h) time period as compared to the less mature group.

Conclusion

Though TB ROR were of similar patterns between prematurity groups (28–31 weeks and 32–35 weeks) it was at higher rate of rise between 13–36 hours and decreasing from 36–72 hours, with a plateau after 72 hours of age. There was a significant difference in the magnitude of TB ROR between prematurity groups at 0–24 hours. Additional research into the clinical care impact on the TB ROR should be conducted to study impact of production and elimination.

Table 1:

Total Bilirubin Rate of Rise Between 0–96 hours of age by Gestational Age.

	Postnatal Age (h) TB ROR (umol/l/h)
GA (weeks)	0 to 12h	13-24h	25 to 36h	37-48h	49-72h	73-96h
28–31	0.27	2.26	2.53	1.13	1.33	0.18
32–35	3.85	1.88	2.81	1.77	1.07	0.24