Total serum bilirubin exceeding exchange transfusion thresholds in the setting of universal screening

Exchange transfusion safety and outcomes in neonatal hyperbilirubinemia

OBJECTIVE

To characterize the prevalence of exchange transfusion (ET), clinical characteristics of infants receiving ET, and ET-associated morbidity and mortality.

STUDY DESIGN

We conducted a multicenter cohort study of infants ≥23 weeks of gestational age (GA) with hyperbilirubinemia who underwent ET within 30 days of birth from 1997 to 2016. We examined clinical characteristics and adverse events after ET. We used multivariable logistic regression to examine the association between clinical risk factors and death.

RESULT

A total of 1252 infants were included; 4% died within 7 days of ET and 6% died before discharge. Compared with infants ≥37 weeks of GA, infants ≤29 weeks of GA had greater odds of death (adjusted odds ratio [95% confidence interval] = 20.08 [7.32, 55.07]).

CONCLUSIONS

Infants ≤ 29 weeks of GA had greater odds of death following ET compared with term infants. These data will support clinicians in evaluating risks and prognosis for infants who require ET.

High unbound bilirubin for age: a neurotoxin with major effects on the developing brain

Neonatal hyperbilirubinemia is one of the most frequent diagnoses made in neonates. A high level of unconjugated bilirubin that is unbound to albumin is neurotoxic when the level exceeds age-specific thresholds or at lower levels in neonates with neurotoxic risk factors. Lower range of unbound bilirubin results in apoptosis, while moderate-to-high levels result in neuronal necrosis. Basal ganglia and various brain stem nuclei are more susceptible to bilirubin toxicity. Proposed mechanisms of bilirubin-induced neurotoxicity include excessive release of glutamate, mitochondrial energy failure, release of proinflammatory cytokines, and increased intracellular calcium concentration. These mechanisms are similar to the events that occur following hypoxic-ischemic insult in neonates. Severe hyperbilirubinemia in term neonates has been shown to be associated with increased risk for autism spectrum disorders. The neuropathological finding of bilirubin-induced neurotoxicity also includes cerebellar injury with a decreased number of Purkinje cells, and disruption of multisensory feedback loop between cerebellum and cortical neurons which may explain the clinical characteristics of autism spectrum disorders. Severe hyperbilirubinemia occurs more frequently in infants from low- and middle-income countries (LMIC). Simple devices to measure bilirubin, and timely treatment are essential to reduce neurotoxicity, and improve outcomes for thousands of neonates around the world.

Burden of severe neonatal jaundice: a systematic review and meta-analysis

CONTEXT

To assess the global burden of late and/or poor management of severe neonatal jaundice (SNJ), a common problem worldwide, which may result in death or irreversible brain damage with disabilities in survivors. Population-based data establishing the global burden of SNJ has not been previously reported.

OBJECTIVE

Determine the burden of SNJ in all WHO regions, as defined by clinical jaundice associated with clinical outcomes including acute bilirubin encephalopathy/kernicterus and/or exchange transfusion (ET) and/or jaundice-related death.

DATA SOURCES

PubMed, Scopus and other health databases were searched, without language restrictions, from 1990 to 2017 for studies reporting the incidence of SNJ.

STUDY SELECTION/DATA EXTRACTION

Stratification was performed for WHO regions and results were pooled using random effects model and meta-regression.

RESULTS

Of 416 articles including at least one marker of SNJ, only 21 reported estimates from population-based studies, with 76% (16/21) of them conducted in high-income countries. The African region has the highest incidence of SNJ per 10 000 live births at 667.8 (95% CI 603.4 to 738.5), followed by Southeast Asian, Eastern Mediterranean, Western Pacific, Americas and European regions at 251.3 (132.0 to 473.2), 165.7 (114.6 to 238.9), 9.4 (0.1 to 755.9), 4.4 (1.8 to 10.5) and 3.7 (1.7 to 8.0), respectively. The incidence of ET per 10 000 live births was significantly higher for Africa and Southeast Asian regions at 186.5 (153.2 to 226.8) and 107.1 (102.0 to 112.5) and lower in Eastern Mediterranean (17.8 (5.7 to 54.9)), Americas (0.38 (0.21 to 0.67)), European (0.35 (0.20 to 0.60)) and Western Pacific regions (0.19 (0.12 to 0.31). Only 2 studies provided estimates of clear jaundice-related deaths in infants with significant jaundice [UK (2.8%) and India (30.8%).

CONCLUSIONS

Limited but compelling evidence demonstrates that SNJ is associated with a significant health burden especially in low-income and middle-income countries.

Prophylactic intravenous calcium therapy for exchange blood transfusion in the newborn

BACKGROUND

Exchange blood transfusion (EBT) is a form of whole blood transfusion in which the total blood volume is replaced within a few hours. In perinatal and neonatal medicine, EBT is most often used in the management of severe anaemia or severe hyperbilirubinaemia in the first week of life. Hypocalcaemia, one of the common morbidities associated with EBT, is thought to arise from the chelating effects of the citrate commonly used as an anticoagulant in the donor's blood. This disorder manifests with muscular and nervous irritability and cardiac arrhythmias.

OBJECTIVES

To determine whether the use of prophylactic calcium reduces the risk of hypocalcaemia-related morbidities and death among newborn infants receiving EBT.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 5), MEDLINE via PubMed (1966 to 29 June 2016), Embase (1980 to 29 June 2016), and CINAHL (1982 to 29 June 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

All randomised and quasi-randomised trials of prophylactic intravenous calcium in EBT for newborns.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed and extracted data on methods, participants, interventions, and outcomes (mean total and ionised serum calcium before and after EBT and the presence of adverse events such as hypoglycaemia, apnoea, cardiac arrest, and death immediately after EBT). We reported results as means difference (MD) with 95% confidence intervals (CI) for continuous outcomes and risk ratio (RR) and risk differences (RD) and 95% CIs for dichotomous outcomes. We assessed quality using the Cochrane 'Risk of bias' assessment tool and the GRADE system.

MAIN RESULTS

We found only one quasi-randomised trial with 30 participants that met our inclusion criteria. In the small trial, total and ionised serum calcium levels were measured immediately before and immediately after EBT. All the participants were included in the final analysis and all the important outcomes were reported. Primary outcomesThere was one death in each group (RR 1.00, 95% CI 0.07 to 14.55; RD 0.00, 95% CI -0.18 to 0.18; participants = 30; studies = 1). The study did not report the presence of cardiac arrhythmias within one week of EBT and the number of infants with serum calcium levels (total less than 8 mg/dL (2 mmol/L) or ionised less than 4.4 mg/dL (1.1 mmol/L)).Pair-wise comparison of EBT with intravenous 10% calcium gluconate versus EBT without intravenous calcium (change from baseline) showed mean total serum calcium was raised in the intervention group compared to the control group (MD -0.46, 95% CI -0.81 to -0.11; participants = 30; studies = 1). Very low-quality evidence also indicated an increase in the levels of mean ionised serum calcium in the intervention group compared to the control group (MD -0.22, 95% CI -0.33 to -0.11; participants = 30; studies = 1). Secondary outcomesAdverse reactions to intravenous calcium therapy included cardiac arrest in one neonate in the intervention arm (RR 3.00, 95% CI 0.13 to 68.26; RD 0.07, 95% CI -0.10 to 0.23; participants = 30; studies = 1). There was apnoea and hypoglycaemia (RR 1.00, 95% CI 0.07 to 14.55; RD 0.00, 95% CI -0.18 to 0.18; participants = 30; studies = 1) in the two neonates who died. Data were not available for other major secondary outcomes such as the number of infants with reduced serum magnesium, reduced parathormone, increased calcitonin, presence of seizures, carpopedal spasm, jitteriness and prolonged QTc interval on electrocardiography within one week of EBT.

AUTHORS' CONCLUSIONS

Very low-quality data from one quasi-randomised controlled trial suggested that the mean serum total and ionised calcium increased in the study group but decreased in the control group immediately after EBT. However, the mean values of total and ionised calcium in both arms of studies remained within international reference ranges. Unfortunately, data were not available to assess the trend of total and ionised serum calcium to the end of the first week after EBT. Therefore, due to the very low quality of evidence available, it is difficult to support or reject the continual use of prophylactic intravenous calcium in newborn infants receiving EBT. Researchers are encouraged to conduct more robustly designed trials with larger numbers of participants, and particularly, addressing the pattern of differences based on gestational age of participants, type of anticoagulant used, and the volume of blood used.

A single heterochronic blood exchange reveals rapid inhibition of multiple tissues by old blood

Heterochronic parabiosis rejuvenates the performance of old tissue stem cells at some expense to the young, but whether this is through shared circulation or shared organs is unclear. Here we show that heterochronic blood exchange between young and old mice without sharing other organs, affects tissues within a few days, and leads to different outcomes than heterochronic parabiosis. Investigating muscle, liver and brain hippocampus, in the presence or absence of muscle injury, we find that, in many cases, the inhibitory effects of old blood are more pronounced than the benefits of young, and that peripheral tissue injury compounds the negative effects. We also explore mechanistic explanations, including the role of B2M and TGF-beta. We conclude that, compared with heterochronic parabiosis, heterochronic blood exchange in small animals is less invasive and enables better-controlled studies with more immediate translation to therapies for humans.

Joining the circulatory system of an old with a young animal has been shown to rejuvenate old tissues. Here the authors describe a comparatively simple blood infusion system that allows for the controlled exchange of blood between two animals, and study the effects of a single exchange on various tissues.

A pediatrician's practical guide to diagnosing and treating hereditary spherocytosis in neonates

Newborn infants who have hereditary spherocytosis (HS) can develop anemia and hyperbilirubinemia. Bilirubin-induced neurologic dysfunction is less likely in these neonates if the diagnosis of HS is recognized and appropriate treatment provided. Among neonates listed in the USA Kernicterus Registry, HS was the third most common underlying hemolytic condition after glucose-6-phosphate dehydrogenase deficiency and ABO hemolytic disease. HS is the leading cause of direct antiglobulin test (direct Coombs) negative hemolytic anemia requiring erythrocyte transfusion in the first months of life. We anticipate that as physicians become more familiar with diagnosing HS in the newborn period, fewer neonates with HS will develop hazardous hyperbilirubinemia or present to emergency departments with unanticipated symptomatic anemia. We predict that early suspicion, prompt diagnosis and treatment, and anticipatory guidance will prevent adverse outcomes in neonates with HS. The purpose of this article was to review the neonatal presentation of HS and to provide practical and up-to-date means of diagnosing and treating HS in neonates.

Factors Determining δ-Bilirubin Levels in Infants With Biliary Atresia

OBJECTIVES

δ-Bilirubin (Bδ) forms when bilirubin conjugates covalently bind to albumin by way of nonenzymatic transesterification in patients with cholestasis. Infants with cholestasis with biliary atresia form Bδ. The aim of the present study was to investigate the factors determining serum Bδ concentrations in infants with biliary atresia.

METHODS

Study patients were infants enrolled in a prospective study (PROBE: Clinicaltrials.gov NCT00061828) of biliary atresia. We acquired data of concurrently measured serum bilirubin analytes (total bilirubin [TB], conjugated bilirubin [Bc], and unconjugated bilirubin) and applied graphical methods and linear mixed effects model to study factors contributing to Bδ variability.

RESULTS

Bδ level increased with increasing levels of Bc and TB. In addition, the length of time cholestasis persisted partially determined the level of Bδ. An increase of 1 mg/dL in Bc is related to approximately 0.36 mg/dL increase in Bδ (P < 0.0001); every 100 days of cholestasis is associated with an approximately 1.0 mg/dL increase in Bδ (P < 0.0001) given the same level of Bc. Serum albumin levels are not significantly related to Bδ (P = 0.89).

CONCLUSIONS

Bδ levels in infants with biliary atresia increase with increasing levels of Bc and longer duration of cholestasis. Understanding the relation among Bδ, Bc, TB, and direct-reacting bilirubin levels can help in interpretation of the clinical extent of cholestasis in infants and children with biliary atresia, assisting in the diagnosis and management of these infants.

Transcutaneous bilirubinometry

Although the modern era of transcutaneous bilirubin monitoring (TcB) began only about 35 years ago, this screening tool is now widely used in newborn nurseries and outpatient clinics, offices, and emergency departments to obtain a rapid and non-invasive estimate of the degree of hyperbilirubinemia. TcB devices have become more sophisticated, and major breakthroughs include the following: (a) ability to report a bilirubin value rather than an index value, (b) enhanced correction for chromophores other than bilirubin, and (c) technologic improvements including interface with electronic medical records. Good agreement with laboratory bilirubin measurement has been demonstrated, and the ability of TcB screening to predict and decrease the incidence of subsequent hyperbilirubinemia has been well-documented. To date, it has not been shown that this screening results in improved long-term outcomes.

Neonatal death suspected to be from sepsis was found to be kernicterus with G6PD deficiency

We cared for a term male infant born to Burmese immigrants. At about 24 hours a total serum bilirubin (TSB) was 9.3 mg/dL, and phototherapy was begun. It was stopped 48 hours later, with a TSB of 10.9 mg/dL, and he was discharged from the hospital with an appointment for a repeat TSB check 48 hours later. A few hours before the appointment he became listless and apneic, and his parents took him to the emergency department of the regional children's hospital, where sepsis was suspected. The TSB was 41 mg/dL. He died 4 hours later, despite intensive care efforts, with opisthotonus and refractory hypotension. Blood drawn before the exchange transfusion had low glucose-6-phosphate dehydrogenase (G6PD) enzymatic activity, and sequencing of the G6PD gene revealed the G6PD Mahidol mutation (c.487G>A). Cultures and postmortem examination did not demonstrate an infectious process, but kernicterus was present. Acute kernicterus can mimic septic shock.

Unexplained extreme hyperbilirubinemia among neonates in a multihospital healthcare system

We report a series of neonates who developed a total serum bilirubin (TSB) >20mg/dL during a recent ten-year period in a multihospital healthcare system. The incidence of a TSB >20mg/dL fell after instituting a pre-hospital discharge bilirubin screening program in 2003/2004 (91.3 cases/10,000 births before vs. 72.4/10,000 after), but the incidence has subsequently remained unchanged. No specific cause for the hyperbilirubinemia was identified in 66% of (n=32) cases with a TSB >30 mg/dL or in 76% of (n=112) cases with a TSB 25.0-29.9 mg/dL. We hypothesized that hemolysis was a common contributing mechanism, but our review of hospital records indicated that in most instances these infants were not evaluated sufficiently to test this hypothesis. Records review showed maternal and neonatal blood types and direct antiglobulin testing were performed in >95% cases, but rarely were other tests for hemolysis obtained. In the ten-year period reviewed there were zero instances where erythrocyte morphology from a blood film examination or Heinz body evaluation by a pediatric hematologist or pathologist were performed. In 3% of cases pyruvate kinase was tested, 3% were evaluated by hemoglobin electrophoresis, 3% had a haptoglobin measurement, and 16% were tested for G6PD deficiency. Thus, determining the cause for hyperbilirubinemia in neonates remains a problem at Intermountain Healthcare and, we submit, elsewhere. As a result, the majority of infants with a TSB >25mg/dL have no specific causation identified. We speculate that most of these cases involve hemolysis and that the etiology could be identified if searched for more systematically. With this in mind, we propose a "consistent approach" to evaluating the cause(s) of hyperbilirubinemia among neonates with a TSB >25mg/dL.