Transient bilirubin encephalopathy and apnea of prematurity in 28 to 32 weeks gestational age infants.

Department of Pediatrics, Division of Neonatology, University of Maryland, Baltimore, 21201, USA.
Journal of Perinatology (Impact Factor: 2.35). 06/2005; 25(6):386-90. DOI: 10.1038/
Source: PubMed

ABSTRACT Apnea of prematurity (AoP) is, in part, a reflection of brainstem-mediated respiratory control system maturation. We previously demonstrated changes in brainstem function in relation to hyperbilirubinemia (bilirubin encephalopathy, (BE)) as evaluated by auditory brainstem evoked responses (ABR) in infants 28 to 32 weeks gestational age (GA). We hypothesized that in this population, as bilirubin increases and causes auditory brainstem dysfunction, respiratory control system may also be adversely affected leading to increased frequency of AoP.
We studied 100, 28 to 32 weeks GA infants and identified 66 with normal and 34 with abnormal ABR progression in temporal relation to hyperbilirubinemia (BE). The abnormal ABR progression was associated with elevated bilirubin, specifically elevated unbound bilirubin levels. A blinded, retrospective chart review quantified the amount of weekly apnea and bradycardia events during the hospital stay, total duration of methylxanthine treatment, total duration of mechanical ventilation, CPAP, and/or nasal cannula, and risk factors for apnea (sepsis, IVH grade >II, asphyxia). Since mechanical ventilation confounds the identification of apnea, infants requiring mechanical ventilation were excluded from further review (n = 60; 21 with BE and 39 with normal ABR progression). Data from the remaining 40 infants were analyzed. Student's t-test was used to analyze continuous variables if the distribution was normal otherwise Wilcoxon-ranked-sum test was used. chi(2) was used to analyze nominal variables. A p < or =0.05 was considered significant.
There was no difference in risk factors between infants with and without BE. BE was identified on day 3 (median; range 1 to 6 days). Patients with BE had significantly more apneic events (15 vs 2, p = 0.0009), bradycardic events (14 vs 1, p = 0.02), and required more prolonged treatment with CPAP (2.2 vs 0.5 days, p = 0.007), nasal cannula (6.6 vs 2.2 days, p = 0.02), and methylxanthines (9.5 vs. 1.9 days, p = 0.002) than those with normal ABR progression. The difference in the incidence of apnea and bradycardia between infants with and without BE was most pronounced during the first week.
Premature infants with transient bilirubin encephalopathy as defined by abnormal ABR progression in relation to hyperbilirubinemia have more concurrent apneic events and require more prolonged respiratory support and medications.

  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate whether jaundice, indexed by unbound bilirubin (UB), is associated with central apnea in premature infants. A prospective observational study was performed with 27-33 weeks' gestational age infants who were not requiring either mechanical ventilation or noninvasive ventilation with continuous positive airway pressure beyond 24 hours after birth. Infants with congenital infections, chromosomal disorders, craniofacial anomalies, and/or family history of hearing loss were excluded. Total serum bilirubin and UB were measured twice daily during the first postnatal week and then when clinically indicated. Central apnea was evaluated by visual inspection of continuous, electronic cardiorespiratory recordings until 2 weeks of age. One hundred infants were subdivided into 2 groups via median peak UB level: the high UB group (greater than median) and low UB group (less than median). The high UB group had an increased frequency of apnea events during the first 2 weeks compared with infants in the low UB group. After we controlled for confounders, the high UB group had more events of apnea during the first 2 postnatal weeks compared with the low UB group (incidence rate ratio: 1.9, 95% CI 1.2-3.2). Our findings suggest that jaundice, as indexed by UB, is associated with central apnea in premature infants. Copyright © 2015 Elsevier Inc. All rights reserved.
    Journal of Pediatrics 01/2015; 166(3). DOI:10.1016/j.jpeds.2014.12.003 · 3.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Central apnea, defined as cessation of breathing for ≥20s, is frequent in premature infants born at <34 weeks׳ gestation but uncommon among healthy late preterm (34(0/7)-36(6/7) weeks׳ gestation) and term (≥37 weeks׳ gestation) infants, where it is usually a clinical manifestation of a neurological or metabolic problem. There is growing evidence that marked unconjugated hyperbilirubinemia is associated with central apnea in neonates. This article explores the reported association between acute bilirubin encephalopathy and symptomatic apneic events in newborns and the possible mechanisms involved in the pathogenesis of this phenomenon. The prevalence of symptomatic apneic events in reports of acute bilirubin encephalopathy suggests this clinical finding should be considered a sign of bilirubin neurotoxicity.
    Seminars in Perinatology 09/2014; 38(7). DOI:10.1053/j.semperi.2014.08.003 · 2.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To meet external financial reporting requirements, fixed (i.e., capacity related) manufacturing overhead costs are typically applied to inventory via the use of a predetermined overhead application rate. However, textbooks do not consider all appropriate conceptual issues regarding the setting of the overhead application rate nor how these issues influence the causes of misapplied capacity costs (under/over-applied fixed manufacturing overhead) typically reported as the Production Volume Variance. Specifically, discussion is lacking related to those misapplied capacity costs potentially caused variously by the presence of capacity that is not explicitly planned to be used, capacity that is currently unused but in the longer-term is planned to be used (due to anticipated growth), and capacity that is currently unused but in the shorter term is planned to be used due to seasonality. Determining if any of these three causes are contributing to misapplied capacity costs is critical, as there are important managerial accounting and financial accounting reporting implications associated with each. And while the relevant literature to be discussed offers support for these causal constructs, this paper extends this literature by developing a parsimonious and conceptually-based approach to permit a simultaneous partitioning of misapplied capacity costs into these causal categories. Further, this paper will identify the important conceptual differences among these three causes, how these differences warrant unique approaches for the managerial and financial reporting of information related to capacity costs and utilization, and needed changes to Generally Accepted Accounting Principles to facilitate more appropriate financial reporting in this area.
    Journal of Accounting Education 06/2010; 28(2):85-102. DOI:10.1016/j.jaccedu.2011.02.001

Full-text (2 Sources)

Available from
May 22, 2014