Hemolysis and hyperbilirubinemia in antiglobulin positive, direct ABO blood group heterospecific neonates

The association of oxidative stress of neonatal hyperbilirubinemia and vitamin E supplementation

Aim of the study

Jaundice in newborns is a sign of skin and sclera pigmentation. Hyperbilirubinemia and these phenomena do, however, have a relationship. According to many clinical studies, elevated blood bilirubin and low vitamin E (VE) levels in newborns are associated. The aim of the study was to investigate the association of oxidative stress of neonatal hyperbilirubinemia in patients who underwent phototherapy with additional vitamin E supplementation (25 mg/kg/day over the course of three days) and patients without additional vitamin E.

Material and methods

A set of 100 neonatal indirect hyperbilirubinemia patients was enrolled at neonatal intensive care units (NICUs) of the pediatric departments at Al Azhar University Hospitals during the period from February 2021 to October 2022 after obtaining signed written informed consent of all neonates' parents with an explanation of the aim of study.

Results

Significant differences were found between the studied groups regarding serum bilirubin on the third day of admission (p = 0.039). Patients who were treated with vitamin E had lower serum bilirubin on the third day of admission (8.25 ±3.41) than the control group (11.66 ±3.22). Also, among the VE group, serum bilirubin was significantly decreased on the third day of admission (8.25 ±3.41) compared to zero days of admission (14.10 ±4.39) (p = 0.041).

Conclusions

Vitamin E supplementation has an important role in treatment of indirect hyperbilirubinemia in neonates. Early administration of vitamin E in preterm neonates resulted in a significant decrease of serum bilirubin and increased total antioxidant capacity. Vitamin E supplementation in full term decreased the duration of phototherapy.

Novel Two-Infusion Pump Technique for Exchange Transfusion in a Hyperbilirubinemic Neonate

Neonatal hyperbilirubinemia is a common concern in newborns, with ABO blood group incompatibility serving as a significant risk factor for severe jaundice. This case report outlines the successful management of a 2.5 kg female infant born to a primigravida mother with ABO incompatibility-induced hyperbilirubinemia. The neonate, born at 38.4 weeks via lower segment cesarean section, exhibited signs of jaundice at 91 hours of life, prompting screening and subsequent confirmation of serum bilirubin levels 26.4. The decision was made using the American Academy of Pediatrics (AAP) and categorized the child under high risk according to age and bilirubin level to implement a complete exchange transfusion using a novel approach with two infusion pumps. The unique aspect of this case lies in introducing a two-infusion pump technique, one to infuse and one to extract blood by inserting the IV set in opposite directions in the infusion pump to perform the exchange transfusion, aiming to minimize complications associated with traditional methods. Careful handling of umbilical venous and arterial lines, coupled with aseptic precautions, sought to mitigate the risk of sepsis. The procedure, conducted over two hours, demonstrated stability in vital signs and was monitored with a transcutaneous bilirubinometer. Post-transfusion, repeat serum bilirubin tests showed a decrease in bilirubin of 10.1, indicating the success of the novel exchange transfusion method. The infant was discharged after a five-day hospital stay, showcasing this innovative approach's potential efficacy and safety. This case contributes to the evolving strategies in neonatal care and emphasizes the importance of tailored interventions in managing hyperbilirubinemia associated with ABO incompatibility.

Neonatal hemolytic disease: How should we use indirect and direct antiglobulin tests?

BACKGROUND

In newborns with hemolysis, the direct antiglobulin test (DAT) and indirect antiglobulin test (IAT) play a key role in demonstrating the presence of an immune cause. We aimed to emphasize the importance of IAT in mothers of DAT-positive babies.

METHODS

DAT was performed with forward blood grouping on cord blood in term babies who were born between September 2020 and September 2022. IAT was performed in the mothers of the babies who were found to have a positive DAT and antibody identification was performed in the mothers who were found to have a positive IAT. Specific antibodies detected and identified were associated with the clinical course.

RESULTS

The study included 2769 babies and their mothers. The prevalence of DAT positivity was found to be 3.3% (87 of 2661). In DAT-positive babies, the rate of ABO incompatibility was 45.9%, the rate of RhD incompatibility was 5.7% and the rate of RhD and ABO incompatibility in association was 10.3%. The rate of subgroup incompatibility and other red blood cell antibodies was 18.3%. Phototherapy was applied because of indirect hyperbilirubinemia in 16.6% of the DAT-negative babies and in 51.5% of the DAT-positive babies. The need for phototherapy was significantly higher in DAT-positive infants (p < 0.01). Severe hemolytic disease of the newborn, bilirubin level, duration of phototherapy and use of intravenous immunoglobulin were found to be significantly higher in the babies whose mothers were IAT positive compared with the babies whose mothers were IAT negative (p < 0.01).

CONCLUSIONS

IAT should be performed on all pregnant women. When screening with IAT is not performed during pregnancy, performing DAT in the baby plays a key role. We showed that the clinical course was more severe when mothers of DAT-positive babies were IAT positive.

Does strengths of a positive direct antiglobulin test predicts the need for phototherapy and duration of phototherapy? - a single center, retrospective study

BACKGROUND

Use of Direct Antiglobulin test (DAT) in management of neonatal hyperbilirubinemia is conflicting.

OBJECTIVE

whether strength of positive DAT predicts the need for phototherapy, duration of phototherapy and need for major interventions.

METHODS

We retrospectively collected data on all DAT positive neonates with birth gestational age ≥32 weeks over six years (2014-2019). Data regarding blood group, DAT and clinical details were obtained from a hospital database. We also collected data on serial hemoglobin and other relevant laboratory parameters. We also collected data on infants receiving major interventions such as exchange transfusion, in-utero transfusion, immunoglobulins, and postnatal transfusion for the duration of the study period. All of these infants were electronically followed up for a period of 6 weeks. This study was approved by institutional audit authority. All the statistics were performed using SPSS software.

RESULTS

Out of 1285 DAT tests performed, only 91 infants were positive (7%), and 78 DAT positive infants were available for analysis. There were 54 infants with DAT (1+), 15 infants with DAT (2+), 7 infants with DAT (3+) and 2 infants with DAT (4+). There was no significant statistical difference in terms of need for phototherapy, duration of phototherapy, need for major interventions and hemoglobin levels at different time points between the groups (DAT 1+ Vs DAT ≥2+; DAT ≤2+ Vs DAT >2). A Total of 10 infants received major intervention, with one infant receiving all three interventions (DAT 3+ with significant maternal antibodies), 2 additional infants (both DAT1+) received exchange transfusion, 6 additional infants received immunoglobulin (2 infants: DAT 2+; 4 infants: DAT 1+) and one additional infant (DAT 1+) with significant maternal antibodies received a postnatal transfusion.

CONCLUSION

Strength of a DAT did not predict the need for phototherapy, duration of phototherapy, and the need for major hemolysis related intervention in the first 6 weeks of life.

Clinical value of combination detection of direct antiglobulin test and serum albumin globulin ratio in severe hyperbilirubinemia caused by ABO hemolytic disease of the newborn

Background To explore of a combination of antiglobulin test(DAT) and albumin globulin ratio(AGR) could predict the severity of ABO hemolytic disease of the newborn(ABO-HDN).Methods The measurement of DAT, AGR and combination detection of DAT and AGR was done to predict severe ABO-HDN hyperbilirubinemia in 270 full-term infants based on whether the infants received transfusions of blood components. The infants were divided into three groups according to the results of DAT and ARG and compared the differences of phototherapy day and hospitalization day of the three groups.Results Of the 270 cases enrolled in this study, 69 infants were DAT positive. Peak total bilirubin, AGR, and positive DAT were independently associated with the need for blood components transfusion. ROC curve analysis for blood components transfusion showed that DAT cutoff value >± with a sensitivity of 39.4% and a specificity of 83.9%, AGR cutoff value <2.05 with a sensitivity of 54.1% and a specificity of 85.7%, and combination detection of DAT and ARG with a sensitivity of 62.1% and a specificity of 91.2%. The AUCs for DAT, AGR, and combination detection of DAT and AGR were .621, .740, and .750 respectively. The phototherapy day and hospitalization day were significantly longer in group of AGR <2.05 and DAT >± than that of a group of AGR <2.05 and group of DAT >±.Conclusions DAT and ARG could be early predictors for the severity ABO-HDN hyperbilirubinemia and combination detection of DAT and AGR could further increase its predictive value.

Effectiveness and safety of prophylactic phototherapy to prevent jaundice in premature newborns: Systematic review and meta-analysis

To determine the effectiveness and safety of prophylactic phototherapy compared with conventional phototherapy for the prevention of neonatal jaundice. We included clinical trials comparing prophylactic phototherapy to conventional phototherapy to prevent jaundice in premature newborns. We searched Embase, MEDLINE, LILACS, Central, and others. The statistical analysis was performed in RevMan (Review Manager 5.3). Outcomes were analyzed according to the type of variable: risk difference (RD) and mean difference (MD). A random effects model was used due to heterogeneity. We reported results in forest plots. Risk of bias was evaluated, and a sensitivity analysis was made. 1127 articles were found, and six studies (2332 patients) were included in the meta-analysis. Five studies evaluated the need for exchange transfusion as the primary outcome RD -0.01, 95% CI [-0.05 to 0.03]. One study evaluated bilirubin encephalopathy RD -0.04, 95% CI [-0.09 to 0.00]. Five studies evaluated the duration of phototherapy, MD 38.47, 95% CI [1.28 to 55.67]. Four studies evaluated levels of bilirubin (MD -1.23, 95% CI [-2.25 to -0.21]. Two studies evaluated mortality, RD 0.01, 95% CI [-0.03 to 0.04]. As a conclusion, compared to conventional phototherapy, prophylactic phototherapy decreases the last measured level of bilirubin, as well as the probability of neurodevelopmental disturbances. However, it increases phototherapy duration.

A retrospective comparison of phototherapy need in O-B versus O-A incompatibility in a single Saudi institution

BACKGROUND

ABO incompatibility is a major risk factor for neonatal indirect hyperbilirubinemia (NIH), requiring treatment. It has been shown that there are racial differences in direct antiglobulin test (DAT) positivity and phototherapy need in the O--B versus (vs) O--A incompatibility. The comparison between the O--B and O--A incompatibility is not well studied in Saudi Arabia.

AIMS

We aimed to compare DAT positivity and phototherapy need in O-B vs O-A incompatibility in Saudi Arabia.

METHODS

This retrospective cohort study was conducted in one Saudi hospital. We included a convenience sample of neonates born between 01 January 2013 and 31 December 2021. We included healthy neonates admitted to the nursery care unit only, born at≥38 weeks gestation, and had normal G6PD levels. Neonates that had no G6PD level measurement or lost follow-up post-discharge were excluded. The data span was the first 14 days of life.

RESULTS

A total of 611 neonates met our inclusion criteria. Positive DAT was more prevalent in the O-B than the O-A incompatibility [43.5% vs 29.2%, p <  0.001). A greater odd of phototherapy need was observed in the O--B vs O-A incompatibility across various strata. Readmission for NIH, use of 360° exposure phototherapy, or intravenous immunoglobulin administration was more prevalent in the O-B than the O-A incompatibility (13.2% vs 5.0%, p <  0.001). A logistic regression analysis revealed that the O-B incompatibility modified the association between DAT positivity and phototherapy need.

CONCLUSIONS

The O-B incompatibility had a mediator effect on the relationship between DAT positivity and the need for phototherapy in the study population, which emphasizes that the O-B and O-A are not the same from the NIH point of view.

ABO hemolytic disease of the newborn: a need for clarity and consistency in diagnosis

The diagnosis of ABO hemolytic disease of the newborn (ABO HDN) has been the subject of considerable debate and clinical confusion. Its use as an overarching default diagnosis for hyperbilirubinemia in all ABO incompatible neonates regardless of serological findings is problematic and lacks diagnostic precision. Data on hemolysis indexed by carbon monoxide (CO) levels in expired air (ETCOc) and blood (COHbc) support an essential role for a positive direct antiglobulin test (DAT) in making a more precise diagnosis of ABO HDN. A working definition that includes ABO incompatibility, significant neonatal hyperbilirubinemia, and a positive DAT is needed to gain clarity and consistency in the diagnosis of ABO HDN. Absent a positive DAT, the diagnosis of ABO HDN is suspect. Instead, a negative DAT in a severely hyperbilirubinemic ABO incompatible neonate should trigger an exhaustive search for an alternative cause, a search that may require the use of targeted gene panels.

Sixth-Hour Trancutaneous Bilirubin and Need for Phototherapy in DAT Positive Newborns

OBJECTIVES

To characterize the outcomes of ABO incompatible direct antiglobulin test (DAT) positive newborns and determine the predictive ability of a sixth-hour transcutaneous bilirubin (TcB for needing phototherapy ≤24 hours of age.

METHODS

Retrospective, cross-sectional study from May 2013 to March 2017. Of 10 942 consecutive newborns ≥35 weeks estimated gestational age, 829 were ABO incompatible and DAT positive. After excluding for antibodies other than ABO (51), missing data (4), miscategorization of blood type O (1), and duplicate record (1), 772 newborns remained. Of 772, a subsample of 346 newborns with both TcB and total serum bilirubin (TSB) tests within 1 hour of the sixth hour was analyzed to determine the predictive ability.

RESULTS

Phototherapy was required in 281 of 772 (36.4%); 156 (20.2%) in the first 24 hours. There were 10 (1.3%) admissions for hyperbilirubinemia to the NICU for intravenous immunoglobin. Birth weight, infant blood type B, TSB, reticulocyte count, and TcB were all significantly associated with phototherapy ≤24 hours. On multivariate analysis, significant predictors of phototherapy ≤24 hours were TSB and reticulocyte count if no TcB was done and TcB alone if no blood tests were done. TcB was highly predictive (odds ratio 3.1, 95% confidence interval: 2.4-4.0) and nearly as accurate as the TSB and reticulocyte count (area under the curve, 0.90 and 0.96, respectively). Low (<3.0 mg/dL) and high (≥5.3 mg/dL) risk TcB cutoffs demonstrated a negative predictive value of 98% and positive predictive value of 85%, respectively.

CONCLUSIONS

Among high-risk ABO incompatible DAT positive newborns, the sixth-hour TcB is highly predictive of the need for phototherapy ≤24 hours.

Clinical Factors Influencing Endogenous Carbon Monoxide Production and Carboxyhemoglobin Levels in Neonates

Carboxyhemoglobin (COHb) is an index of endogenous carbon monoxide formation during the hem degradation process and could be used to confirm hemolysis in neonates. The influence of other clinical factors on COHb values in neonates has not been fully investigated. We aimed to evaluate the influence of hemolysis, sepsis, respiratory distress, and postnatal age on COHb values. We retrospectively analyzed COHb measurements determined with a carbon monoxide-oximeter in 4 groups of term neonates: A-sepsis, B-respiratory distress, C-hemolysis, and D-healthy neonates. The mean COHb values were 1.41% (SD: 0.26), 1.32% (SD: 0.27), 2.5% (SD: 0.69), and 1.27% (SD: 0.19) (P<0.001) in groups A (n=8), B (n=37), C (n=16), and D (n=76), respectively. COHb in group C was significantly higher than in the other groups. There was a negative correlation between postnatal age and COHb in healthy neonates. A cut-off level of 1.7% had 93% (95% confidence interval [CI]: 89%-97%) sensitivity and 94% (95% CI: 90%-98%) specificity for diagnosis of hemolysis. COHb values were higher during the first days of life. We found that COHb levels in neonates with hemolysis were significantly higher and that the influence of sepsis and respiratory distress on COHb values was insignificant.

Laboratory Monitoring of Mother, Fetus, and Newborn in Hemolytic Disease of Fetus and Newborn

Background

Laboratory monitoring of mother, fetus, and newborn in hemolytic disease of fetus and newborn (HDFN) aims to guide clinicians and the immunized women to focus on the most serious problems of alloimmunization and thus minimize the consequences of HDFN in general and of anti-D in particular. Here, we present the current approach of laboratory screening and testing for prevention and monitoring of HDFN at the Copenhagen University Hospital in Denmark.

Summary

All pregnant women are typed and screened in the 1st trimester. This serves to identify the RhD-negative pregnant women who at gestational age (GA) of 25 weeks are offered a second screen test and a non-invasive fetal RhD prediction. At GA 29 weeks, and again after delivery, non-immunized RhD-negative women carrying an RhD-positive fetus are offered Rh immunoglobulin. If the 1st trimester screen reveals an alloantibody, antenatal investigation is initiated. This also includes RhD-positive women with alloantibodies. Specificity and titer are determined, the fetal phenotype is predicted by non-invasive genotyping based on cell-free DNA (RhD, K, Rhc, RhC, RhE, ABO), and serial monitoring of titer commences. Based on titers and specificity, monitoring with serial peak systolic velocity measurements in the fetal middle cerebral artery to detect anemia will take place. Intrauterine transfusion is given when fetal anemia is suspected. Monitoring of the newborn by titer and survival of fetal red blood cells by flow cytometry will help predict the length of the recovery of the newborn.

ABO haemolytic disease of the newborn: Improved prediction by novel integration of causative and protective factors in newborn and mother

BACKGROUND AND OBJECTIVES

Prediction of haemolytic disease of the foetus and newborn (HDFN) caused by maternal anti-A/-B enables timely therapy, thereby preventing the development of kernicterus spectrum disorder. However, previous efforts to establish accurate prediction methods have been only modestly successful.

MATERIALS AND METHODS

In a case-control study, we examined 76 samples from mothers and 76 samples from their newborns; 38 with and 38 without haemolysis. The IgG subclass profile of maternal anti-A and anti-B was determined by flow cytometry. Samples from newborns were genetically analysed for the A² subgroup, secretor and FcγRIIa receptor alleles.

RESULTS

Surprisingly, we found a correlation between the newborn secretor allele and haemolysis (p = 0.034). No correlation was found for FcγRIIa alleles. The A² subgroup was found only in newborns without haemolysis. Unexpectedly, different reaction patterns were found for maternal anti-A and anti-B; consequently, the results were treated separately. For the prediction of haemolysis in A-newborns, the maternal IgG1 subclass determination resulted in an accuracy of 83% at birth. For B-newborns, an accuracy of 91% was achieved by the maternal IgG2 subclass determination.

CONCLUSION

We improved the prediction of ABO-HDFN by characterizing maternal anti-A and anti-B by flow cytometry and we presented genetic traits in newborns with correlation to haemolysis. We propose a new understanding of A- and B-substances as immunogens that enhance the maternal immune response and protect the newborn, and we suggest that the development of ABO-HDFN is different when caused by maternal anti-A compared to maternal anti-B.

From A to AB: A Caucasian Mother with High Anti-B Titer Causing Hemolytic Disease of the Newborn

We report on a term infant with clinically significant hemolysis and hyperbilirubinemia. Testing revealed ABO incompatibility between maternal type A and infant type AB. The maternal alloantibody screen was negative. The infant's direct antiglobulin test was positive, and anti-B IgG was eluted off the infant's red blood cells (RBCs). Testing of the mother's plasma revealed a high anti-B titer. The infant was successfully treated with phototherapy and intravenous immunoglobulin. The bilirubin and hematocrit stabilized, and the infant was discharged home. This case was unusual because of its severity and unusual ABO constellation. Furthermore, this report is an exemplary educational case study on how effective collaboration between the clinical team and the blood bank laboratory is critical in reaching the correct diagnosis. In summary, the differential diagnosis of more unusual and atypical ABO-incompatible constellations must be considered when an infant presents with unexplained hemolysis.

Prediction of ABO hemolytic disease of the newborn using pre- and perinatal quantification of maternal anti-A/anti-B IgG titer

BACKGROUND

Hemolysis in fetus/newborns is often caused by maternal antibodies. There are currently no established screening procedures for maternal ABO antibodies harmful to fetus/newborn. We investigated the clinical significance, and predictive value of maternal anti-A/B titer for hyperbilirubinemia in ABO-incompatible newborns.

METHODS

We conducted a case-control study of blood group O mothers and their ABO-compatible (O) vs. -incompatible (A/B) newborns receiving phototherapy, and of ABO-incompatible newborns receiving phototherapy vs. no phototherapy. Newborn data and treatment modalities were recorded, and total serum bilirubin and hemoglobin were measured. Maternal anti-A/B immunoglobulin-γ (IgG) titers were measured prenatally and perinatally, and negative and positive predictive values (NPV, PPV) were calculated to assess the risk of developing hyperbilirubinemia requiring phototherapy.

RESULTS

We found a significantly higher maternal IgG antibody titer in the case group (p < 0.001). Maternal anti-A/B titers at first trimester had modest predictive values: NPV = 0.82 and PPV = 0.65 for neonatal hyperbilirubinemia; titers at birth improved the predictive values: NPV = 0.93 and PPV = 0.73. Newborn hemoglobin was significantly lower in incompatibles compared to compatibles (p = 0.034). Furthermore, increased anti-A/B IgG production during pregnancy was associated with hyperbilirubinemia and hemolysis in incompatible newborns.

CONCLUSIONS

There was a significant association between maternal anti-A/B IgG titer and hyperbilirubinemia requiring treatment.

IMPACT

Maternal anti-A/B IgG titer in the first trimester and at birth is predictive of hemolytic disease of the ABO-incompatible newborn. Increased IgG anti-A/B production throughout pregnancy in mothers to ABO-incompatible newborns developing hyperbilirubinemia contrasts a constant or reduced production in mothers to newborns not developing hyperbilirubinemia. Screening tools available in most immunohematology laboratories can identify clinically important IgG anti-A/B. Use of maternal samples taken at birth yielded NPV = 0.93 and PPV = 0.73.

Maternal Blood Group and Routine Direct Antiglobulin Testing in Neonates: Is There a Role for Selective Neonatal Testing?

Recommendations for the screening of hemolytic disease of the newborn (HDN) advise taking a selective approach in using the direct antiglobulin test (DAT) for mothers with blood group O or RhD-negative. This study assessed the relation of DAT results to maternal and neonatal blood groups and evaluated the risk of HDN. A retrospective analysis of all healthy newborns admitted during 2018 was performed. Of 1463 newborns, 4.4% had a positive DAT. There were 541 (37%) maternal–neonatal pairs with ABO incompatibility, most commonly born to mothers with blood group O. The cohort of neonates born to mothers with blood group O was divided into three groups: the O-A and O-B groups and the O-O group as a control. The DAT was positive in 59 (8.3%) neonates; most were in the O-B group (49.2%), whereas 13.6% were in the control group (p < 0.01). While the neonates in the O-B group were more likely to require phototherapy (p = 0.03), this finding was not related to DAT results. We found that selective testing of mothers with blood group O, mothers with blood group O or RhD-negative, neonates with blood group B, and neonates with blood group B born to mothers with blood group O or RhD-negative was ineffective in detecting phototherapy requirements. Our results indicate no difference regarding the need for phototherapy in neonates born to mothers with different blood types regardless of the DAT results.

G6PD Deficiency Prevalence as a Cause of Neonatal Jaundice in a Neonatal Ward in Dohuk, Iraq

OBJECTIVE

The current study initiated to address the effect of glucose-6-phosphate dehydrogenase (G6PD) deficiency on the pathogenesis and the severity of neonatal hyperbilirubinemia (NHB).

STUDY DESIGN

A total of 100 newborns with moderate to severe indirect hyperbilirubinemia and 50 normal neonates without hyperbilirubinemia had been enrolled in the current case-control study. All enrolled neonates had been tested for ABO and Rh(D) blood grouping, Total serum bilirubin measurement, complete blood count, morphology, reticulocyte counts, direct Coombs' test, and G6PD enzyme assay.

RESULTS

From all enrolled hyperbilirubinemic neonates, 16% were G6PD deficient and this displays a statistically significant difference in comparison to controls (only 6% were G6PD deficient). Also, significant difference was found in the level of serum indirect bilirubin among G6PD-deficient neonate in comparison to G6PD nondeficient neonates which had contributed significantly to the difference in the duration of phototherapy and hospitalization among deficient neonate. Despite this, no significant difference found in the onset of presentation, reticulocytes count, and age of neonates between the two groups (G6PD-deficient and G6PD nondeficient neonates).

CONCLUSION

The current study augments the etiological role of G6PD in the causation and severity of NHB in the region; however, in the absence of significant difference in the reticulocytes and the hemoglobin level, the underlying mechanism cannot be backed to the excess hemolysis alone.

Neonatal hyperbilirubinemia management: Clinical assessment of bilirubin production

The predominant cause of elevated total/plasma bilirubin (TB) levels is from an increase in bilirubin production primarily because of ongoing hemolysis. If undiagnosed or untreated, the risk for developing extreme neonatal hyperbilirubinemia and possibly bilirubin-induced neurological dysfunction (BIND) is increased. Since carbon monoxide (CO) and bilirubin are produced in equimolar amounts during the heme catabolic process, measurements of end-tidal CO levels, corrected for ambient CO (ETCOc) can be used as a direct indicator of ongoing hemolysis. A newly developed point-of-care ETCOc device has been shown to be a useful for identifying hemolysis-associated hyperbilirubinemia in newborns. This review summarizes the biology of bilirubin production, the clinical utility of a novel device to identify neonates undergoing hemolysis, and a brief introduction on the use of ETCOc measurements in a cohort of neonates in China.

Neonatal Indirect Hyperbilirubinemia

Neonatal indirect hyperbilirubinemia (IHB) is caused by an imbalance in bilirubin production and elimination. Approximately 60% of term and 80% of preterm infants develop jaundice in the first week of age. This review seeks to provide the reader with a thorough understanding of the physiology of bilirubin, etiology of IHB, and management of severe IHB. Phototherapy and exchange transfusion remain the mainstays of treatment for severe IHB. Noninvasive screening tools, innovative treatments, and a better understanding of how prematurity and genetics contribute to severe IHB have improved our understanding of IHB and may help eliminate the hazards associated with severe IHB, including kernicterus spectrum disorder.

Rate of rise of total serum bilirubin in very low birth weight preterm infants

BACKGROUND

To assess the postnatal rate of rise (ROR) of total serum bilirubin (TSB) in very low birth weight (VLBW) preterm infants, to determine risk factors associated with a rapid rise (>90th percentile), and to compare ROR and hour-specific TSB at postnatal 12-48 h with data of term infants retrieved from the literature.

METHODS

Retrospective analysis of 2430 routine TSB concentrations obtained between birth and initiation of phototherapy in 483 VLBW infants.

RESULTS

TSB increased by a median (interquartile range) ROR of 0.15 (0.11-0.19) mg/dL/h. The 50th percentile of TSB was below the 40th percentile of (near-)term counterparts at 12-48 h. TSB ROR correlated with the age at initiation (R_S = -0.687; p < 0.001) and the duration (R_S = 0.444; p < 0.001) of phototherapy. ROR >90th percentile (>0.25 mg/dL/h) was associated with lower gestational ages [27.2 (25.4-29.3) vs. 28.4 (26.4-30.4) weeks], lower birth weights [978 (665-1120) vs. 1045 (814-1300) g], and lower 5-min Apgar scores [7 (7-8) vs. 8 (7-9)].

CONCLUSION

ROR of TSB is an indicator for early and prolonged phototherapy. While hour-specific TSB and ROR at 12-48 h are lower than those reported for (near-)term infants, TSB appears to rise more rapidly in infants with low gestational age, low birth weight, and low 5-min Apgar score.

A Neglected and Promising Predictor of Severe Hyperbilirubinemia Due to Hemolysis: Carboxyhemoglobin

Aims: We investigated the relationship between total serum bilirubin (TSB) and carboxyhemoglobin (COHb) in term neonates with detected and treated hemolysis within a particular time frame with the aim of augmenting the case for early diagnosis and prevention of morbidity in hemolysis. Materials and Methods: The study group comprised term newborns who were above the 95th percentile for TSB, underwent intravenous immunoglobulin (IVIG) or applied total exchange transfusion due to hemolysis. Newborns without hemolysis who were above the 95th TSB percentile and required phototherapy comprised the control group. Results: At a cutoff COHb value of 2.2%, 80.8% sensitivity, 95.5% specificity, 18.1 likelihood ratio, positive predictive value of 94.7%, and negative predictive value of 83.2% were identified. Conclusion: We found that COHb is a sensitive and specific method for detecting hemolysis, and it can be used in the early diagnosis of hemolytic diseases causing early and severe hyperbilirubinemia.

Prevalence of neonatal hyperbilirubinaemia and its association with glucose-6-phosphate dehydrogenase deficiency and blood-type incompatibility in sub-Saharan Africa: a systematic review and meta-analysis

BACKGROUND

Hyperbilirubinaemia is a silent cause of newborn disease and death worldwide. However, studies of the disease in sub-Saharan Africa are highly variable with respect to its prevalence. Hence, this study aimed to estimate the overall magnitude of neonatal hyperbilirubinaemia and its association with glucose-6-phosphate dehydrogenase (G6PD) deficiency and blood-type incompatibility in sub-Saharan Africa.

METHODS

PubMed, Scopus, Google Scholar and the Cochrane Review were systematically searched online to retrieve hyperbilirubinaemia-related articles. All observational studies reported the prevalence of hyperbilirubinaemia in sub-Saharan Africa were included for analysis and excluded if the study failed to determine the desired outcome. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Heterogeneity across the included studies was evaluated using the inconsistency index (I²). Subgroup and meta- regression analysis were also done. Publication bias was examined by funnel plot and the Egger's regression test. The random-effect model was fitted to estimate the pooled prevalence of neonatal hyperbilirubinaemia. The meta-analysis was performed using the STATA V.14 software.

RESULTS

A total of 30 486 studies were collected from the different databases and 10 articles were included for the final analysis. The overall magnitude of neonatal hyperbilirubinaemia was 28.08% (95% CI20.23 to 35.94, I²=83.2) in sub-Saharan Africa. Neonates with G6PD deficiency (OR 2.42, 95% CI 1.64 to 3.56, I²=37%) and neonates that had a blood type that was incompatible with their mother's (OR 3.3, (95% CI 1.96 to 5.72, I²=84%) were more likely to develop hyperbilirubinaemia.

CONCLUSION

The failure to prevent and screen G6PD deficiency and blood-type incompatibility with their mother's results in high burden of neonatal hyperbilirubinaemia in sub-Saharan Africa. Therefore, early identification and care strategies should be developed to the affected neonates with G6PD deficiency and blood-type incompatibility with their mother's to address long-term medical and scholastic damages among those exposed to hyperbilirubinaemia.

Examining the Role of Complement in Predicting, Preventing, and Treating Hemolytic Transfusion Reactions

Red blood cell (RBC) transfusion is a critical component of optimal management for a broad range of conditions. Regardless of the indication, pretransfusion testing is required to appropriately match RBC donors and recipients to provide immunologically compatible blood. Although this approach is effective in the vast majority of situations, occasionally, patients will inadvertently receive an incompatible RBC transfusion, which can result in a hemolytic transfusion reaction (HTR). In addition, patients with life-threatening anemia and a complex alloantibody profile, which precludes rapid procurement of compatible RBCs, may also receive incompatible RBCs, placing them at risk for an HTR. Despite the rarity of these clinical situations, when incompatible blood transfusion results in an HTR, the consequences can be devastating. In this review, we will explore the challenges associated with actively preventing and treating acute HTRs following incompatible RBC transfusion. In doing so, we will focus primarily on the role of complement, not only as a key player in HTRs, but also as a potential target for the prevention and treatment of HTRs.

Characteristics of Bilirubin According to the Results of the Direct Antiglobulin Test and Its Impact in Hemolytic Disease of the Newborn

BACKGROUND

Hyperbilirubinemia, which is a sign of hemolytic disease of the newborn (HDN), can irreversibly damage the central nervous system.

OBJECTIVES

To determine the etiology of HDN in affected patients and characterize the changing pattern of bilirubin using direct antiglobulin testing (DAT).

METHODS

We collected clinical data from newborns who underwent perinatal DAT and from their mothers, between August 2008 and July 2017.

RESULTS

Among 303 neonates, 37 (12.2%) showed positive DAT results. The positive predictive values (PPVs) and negative predictive values (NPVs) based on DAT results were 75.7% and 28.9%, respectively, for starting phototherapy. Bilirubin levels increased more rapidly in the DAT-positive group, compared with the DAT-negative group. The initial bilirubin level differed significantly according to the etiology of hyperbilirubinemia. Further, neonates with anti-D showed higher delta bilirubin per day than neonates with other antibodies.

CONCLUSION

Our results may help to determine the measurement period for bilirubin according to DAT results and etiology.

Elevated blood carboxyhemoglobin levels as an early predictor of phototherapy requirement in moderate and late preterm infants

Objective: Preterm infants are prone to increased bilirubin burden and display adverse outcomes if left unmonitored; therefore, predicting an increased bilirubin production is of paramount importance.Methods: We aimed to evaluate carboxyhemoglobin (COHb) levels in moderate (GA: 32^0/7-33^6/7) and late preterm (GA: 34^0/7-36^6/7) infants to assess whether this molecule could be used as an early predictor of phototherapy requirement.Results: A total of 221 infants were enrolled in the study. On admission, carboxyhemoglobin levels of infants who received phototherapy were significantly higher than that of infants who did not require this treatment, and this difference persisted in the consecutive hours (median (min-max): 1.2% (0.3-1.7) versus 0.8% (0.4-1.1); p < .001). The initial and consecutive COHb levels showed positive correlation (r = 0.77, p < .001). In the post-hoc analysis, direct antiglobulin test positivity significantly affected phototherapy requirement (p < .001). Receiver operating characteristics analysis showed that a COHb level of ≥0.95% was found to have a sensitivity of 90% and a specificity of 88%. Multinomial logistic regression analysis demonstrated that high COHb levels on admission significantly increased the likelihood of phototherapy requirement when adjusted for covariants (adjusted odds ratio: 2.2; 95% confidence interval: 1.4-3.5; p < .001).Conclusion: Carboxyhemoglobin measurement can be simply used to predict preterm infants who will require phototherapy.

Iron-mediated oxidative cell death is a potential contributor to neuronal dysfunction induced by neonatal hemolytic hyperbilirubinemia

The review article discusses current knowledge of iron-mediated oxidative cell death (ferroptosis) and its potential role in the pathogenesis of neuronal dysfunction induced by neonatal hemolytic hyperbilirubinemia. The connection between metabolic conditions related to hemolysis (iron and bilirubin overload) and iron-induced lipid peroxidation is highlighted. Neurotoxicity of iron and bilirubin is associated with their release from destructed erythrocytes in response to hemolytic disease. Iron overload initiates lipid peroxidation through the reactive oxygen species production resulting to oxidative damage to cells. Excessive loading of immature brain cells by iron-induced formation of reactive oxygen species contributes to the development of various neurodevelopmental disorders. The causal relationship between iron overload and susceptibility of brain cells to oxidative damage by ferroptosis appears to be associated not only with the amount of redox-active iron involved in oxidative cell damage but also with the degree of maturity of the neonatal brain. Neuronal dysfunction induced by neonatal hemolytic disease can represent a specific model of ferroptosis. The mechanism by which iron overload triggers ferroptosis is not completely explained. However, hemolysis of neonatal red blood cells appears to be a determining factor. Potential therapeutic strategy with iron-chelating agents to inhibit ferroptosis has a promising future in postnatal care.

ABO hemolytic disease of the fetus and newborn: thirteen years of data after implementing a universal bilirubin screening and management program

OBJECTIVE

ABO hemolytic disease occurs among neonates with blood groups A or B delivered to group O women. Extreme neonatal hyperbilirubinemia due to ABO disease has been reported, but its frequency is not well known. We sought to determine the odds of developing severe ABO hemolytic disease in the 13 years since adopting universal bilirubin screening/management in the Intermountain Healthcare system.

STUDY DESIGN

We conducted a retrospective analysis of neonates born between 2004 and 2016, defining "severe hemolytic disease" as; (1) total serum bilirubin (TSB) >25 mg/dL, or (2) hospital readmission for jaundice, or (3) bilirubin encephalopathy. Neonates born to group O (+) mothers were included and considered either; (1) Controls (not at risk for ABO disease because they were group O), (2) Study subjects (at risk for ABO disease because they were group A or B).

RESULTS

Of 400,531 live births, 47% were to group O women; 86% of whom were group O (+). Overall, 42,529 (27%) neonates born to group O (+) women had their blood group determined; 29,729 (68%) were O, 10,682 (25%) A, and 3109 (7%) B. Peak TSBs during the first 10 days were higher in group A (11.0 ± 4.2 mg/dL) and B (11.5 ± 4.3) than group O neonates (10.3 ± 4.1). However the relative risks of a TSB ≥25 mg/dL, readmission for jaundice, or kernicterus, were the same in the control vs. study groups.

CONCLUSIONS

In our health system, severe hemolytic disease in neonates born to group O (+) woman is not more likely in group A or B neonates than in controls (group O). We recognize that in other practices, particularly those who do not have a universal bilirubin screening/management program, ABO hemolytic disease severity might be different than in our system.

Carboxyhemoglobin - the forgotten parameter of neonatal hyperbilirubinemia

BACKGROUND

Neonatal hyperbilirubinemia is influenced by a wide variety of factors, one of which is hemolysis. Serious hyperbilirubinemia may lead to a kernicterus with detrimental neurologic sequelae. Patients suffering from hemolytic disease have a higher risk of developing kernicterus. Carbon monoxide (CO), a byproduct of hemolysis or heme degradation, was described by Sjöstrand in the 1960s. It is transported as carboxyhemoglobin (COHb) and exhaled through the lungs. We were interested in a potential correlation between COHb and total serum bilirubin (TSB) and the time course of both parameters.

MATERIALS AND METHODS

We used a point of care (POC) blood gas analyzer and did a retrospective analysis of bilirubin and COHb data collected over a 60-day period.

RESULTS

An arbitrary cut-off point set at 2% COHb identified four patients with hemolytic disease of different origins who required phototherapy. In one patient with atypical hemolytic uremic syndrome (aHUS), COHb preceded the rise in bilirubin by about 2 days. Despite this displacement, there was a moderately good correlation of COHb with TSB levels <15 mg/dL (257 μmol/L) (r2: 0.80) and direct bilirubin (r2: 0.78) in the first patient. For all the four patients and all time points the correlation was slightly lower (r2: 0.59).

CONCLUSIONS

COHb might be useful as a marker for high hemoglobin turnover to allow an earlier identification of newborns at risk to a rapid rise in bilirubin.

Indication of Mild Hemolytic Reaction Among Preterm Infants With ABO Incompatibility

BACKGROUND

Among term infants, ABO incompatibility is a leading cause of hemolytic disease and neonatal jaundice. With respect to preterm infants, data are lacking.

OBJECTIVE

To evaluate the incidence and severity of ABO incompatibility hemolytic disease among preterm infants with respect to hemolytic and jaundice parameters.

DESIGN

Clinical and laboratory data were collected retrospectively from the medical records of 118 ABO-incompatible preterms born at gestational age (GA) 29-34 weeks, as well as 118 controls matched for GA, birth weight, and multiplicity. All infants were born at the Sheba Medical Center Tel-Hashomer between 2009 and 2012.

RESULTS

The study and control groups were similar on all maternal and neonatal outcome parameters. No differences between the groups were recorded throughout hospitalization regarding hematocrit levels or the need for blood transfusion. Bilirubin levels were higher among the study (ABO-incompatible) group during the first 10 days of life; however, no significant differences were found regarding the need for phototherapy. Upon evaluating subgroups divided by GA, we found no differences on any hematological and jaundice factors among preterms of 29-31 weeks, whereas among preterms of 32-34 weeks higher positive direct antiglobulin test (DAT) results (7% vs. 0% in the control, P = 0.014) as well as higher bilirubin levels were documented.

CONCLUSIONS

Among ABO-incompatible preterm infants with GA 29-34 weeks, there is no evidence of significant hemolytic reaction derived from placental transfer of antibodies. With increasing GA, antibody transfer becomes more significant, resulting in more positive DAT results and greater incidence of neonatal jaundice.

Post-test probability for neonatal hyperbilirubinemia based on umbilical cord blood bilirubin, direct antiglobulin test, and ABO compatibility results

Many hospitals opt for early postnatal discharge of newborns with a potential risk of readmission for neonatal hyperbilirubinemia. Assays/algorithms with the possibility to improve prediction of significant neonatal hyperbilirubinemia are needed to optimize screening protocols and safe discharge of neonates. This study investigated the predictive value of umbilical cord blood (UCB) testing for significant hyperbilirubinemia. Neonatal UCB bilirubin, UCB direct antiglobulin test (DAT), and blood group were determined, as well as the maternal blood group and the red blood cell antibody status. Moreover, in newborns with clinically apparent jaundice after visual assessment, plasma total bilirubin (TB) was measured. Clinical factors positively associated with UCB bilirubin were ABO incompatibility, positive DAT, presence of maternal red cell antibodies, alarming visual assessment and significant hyperbilirubinemia in the first 6 days of life. UCB bilirubin performed clinically well with an area under the receiver-operating characteristic curve (AUC) of 0.82 (95 % CI 0.80-0.84). The combined UCB bilirubin, DAT, and blood group analysis outperformed results of these parameters considered separately to detect significant hyperbilirubinemia and correlated exponentially with hyperbilirubinemia post-test probability.

CONCLUSION

Post-test probabilities for neonatal hyperbilirubinemia can be calculated using exponential functions defined by UCB bilirubin, DAT, and ABO compatibility results.

WHAT IS KNOWN

• The diagnostic value of the triad umbilical cord blood bilirubin measurement, direct antiglobulin testing and blood group analysis for neonatal hyperbilirubinemia remains unclear in literature. • Currently no guideline recommends screening for hyperbilirubinemia using umbilical cord blood. What is New: • Post-test probability for hyperbilirubinemia correlated exponentially with umbilical cord blood bilirubin in different risk groups defined by direct antiglobulin test and ABO blood group compatibility results. • Exponential functions can be used to calculate hyperbilirubinemia probability.

Carboxyhemoglobin levels as a predictor of risk for significant hyperbilirubinemia in African-American DAT(+) infants

OBJECTIVES

To compare the degree of hemolysis in a group of direct antiglobulin test (DAT) positive (pos) African-American (AA) infants as measured by carboxyhemoglobin corrected (COHbc) for carbon monoxide in ambient air to a similar group of DAT negative (neg) ABO incompatible infants and a group without blood group incompatibility. To determine if COHbc is a better predictor of significant hyperbilirubinemia than DAT status.

STUDY DESIGN

A prospective study of 180 AA infants from the Well-Baby Nursery of an inner city community hospital, all of whose mothers were type O pos. Infants (60) were ABO incompatible DAT pos, 60 were ABO incompatible DAT neg and 60 were type O(+). Blood for COHbc was drawn at the time of the infants' initial bilirubin and the infants' precise percentile on the Bhutani nomogram was calculated.

RESULT

Mean COHbc of type O(+) infants was 0.76±0.21 and 0.78±0.24% for ABO incompatible DAT neg infants (P=0.63). Mean CoHbc for the ABO incompatible DAT pos infants was 1.03±0.41% (P<0.0001 compared with both type O and DAT neg infants). Optimal cutoff on the receiver operating characteristic curve for COHbc to determine the risk for being in the Bhutani curve high risk zone was COHbc >0.90% (area under the curve(AUC) 0.8113). This was similar to the AUC of the receiver operating characteristic curve using any titer strength of DAT pos as a cutoff (0.7960).

CONCLUSION

Although not greatly superior to the titer strength of DAT pos, COHbc is useful in determining if the etiology of severe hyperbilirubinemia is a hemolytic process.

Neonatal BO Incompatibility Is Associated With a Positive Cord Blood Direct Antiglobulin Test in Infants of Black Ethnicity

ABO hemolytic disease of the newborn occurs almost exclusively in infants of blood group A and B who are born to group O mothers. Positive Direct Antiglobulin Test (DAT) can identify those infants who are at risk of developing the ABO hemolytic disease. Earlier studies have suggested that BO incompatibility is associated with a positive DAT in black infants. In this study we sought to determine whether ABO incompatibility type could be associated with a higher rate of DAT positivity or clinical hemolytic disease. We reviewed the electronic medical records of all ABO-incompatible births over a 2-year period. There were 1537 ABO-incompatible births during the study period. DAT was more commonly positive among BO incompatible (21.5% in BO vs. 14.8% in AO, P=0.001) and black (18.8% in blacks vs. 10.8% in nonblacks, P=0.003) infants. DAT positivity was significantly associated with both severe hyperbilirubinemia (P=0.028) and hemolytic anemia (P<0.001). BO incompatibility was significantly associated with hemolytic anemia, but not severe hyperbilirubinemia, in the infants tested.

Importance of Direct Antiglobulin Test (DAT) in Cord Blood: Causes of DAT (+) in a Cohort Study

BACKGROUND

The direct antiglobulin test (DAT) is the cornerstone of the diagnosis of hemolytic disease of the newborn (HDN). The aim of this study was to review the incidence and causes of positive DAT in cord blood in relation to development of HDN.

METHODS

We retrospectively reviewed all results of DAT, which is routinely performed in cord blood samples, along with the laboratory and infants' medical records.

RESULTS

DAT was positive in 70/2695 (2.59%) cases. In 64/70 (91.43%) cases, DAT positivity was attributed to ABO incompatibility. There were 50/218 (22.93%) DAT (+) cases in the A/O group and 13/97 (13.40%) cases in the B/O group (p = 0.0664). Two DAT (+) cases were attributed to maternal alloimmunization (anti-Fya and anti-JKb, respectively), and one to maternal IgG autoantibodies that developed after methyldopa treatment. Among the 70 DAT (+) cases, 30 (42.86%) cases required phototherapy with no difference between the A/O and B/O groups. The duration of phototherapy in the B/O group was significantly longer than in the A/O group (p = 0.024). There was a trend of correlation of increasing strength of DAT positivity with phototherapy need. No false positive DAT case was detected.

CONCLUSIONS

Although ABO incompatibility remains the main reason of DAT (+), other causes (e.g., alloimmunization, drugs) should also be explored. The relevant impact of DAT (+) on HDN development should be considered.

Common hematologic problems in the newborn nursery

"Common red blood cell disorders encountered in the normal newborn nursery include hemolytic disease of the newborn and resultant hyperbilirubinemia, anemia, and polycythemia. A less frequent clinically relevant hematologic issue in newborns to be covered herein is thrombocytopenia."

The role of carboxyhemoglobin measured with CO-oximetry in the detection of hemolysis in newborns with ABO alloimmunization

OBJECTIVES

To evaluate carboxyhemoglobin (COHb) values measured with a CO-oximeter (Roche-cobas b 221) in jaundiced newborns with or without hemolysis and healthy controls in order to assess whether COHb measurement determined with a CO-oximeter could be used as an indicator of hemolysis in newborns with ABO alloimmunization.

METHODS

A total of 86 term newborn infants were prospectively studied. The study cohort consisted of three subgroups: 18 infants with ABO HDN, 21 infants with hyperbilirubinemia without hemolytic disease who required phototherapy, and 47 healthy controls. The COHb, bilirubin, and Hb levels were measured.

RESULTS

The three subgroups did not differ significantly with respect to birth weight, gestational age, gender, Apgar score, or mode of delivery. The ABO HDN infants had significantly higher COHb values than the healthy controls (median 2.4% versus 1.3%, p < 0.0005) and the group with hyperbilirubinemia without hemolytic disease (median 2.4% versus 1.3%, p < 0.0005), although the infants with hyperbilirubinemia without hemolytic disease did not have significantly higher COHb values compared with the healthy controls. The cut-off value of 1.7% COHb had 72% sensitivity and 97% specificity for confirming hemolysis in ABO alloimmunization.

CONCLUSIONS

Our data show that COHb values determined with CO-oximeters are higher in newborns with hemolysis than in those without hemolysis. COHb measured with CO-oximeters could be used to confirm hemolysis in infants with ABO alloimmunization.

Direct antiglobulin titer strength and hyperbilirubinemia

BACKGROUND AND OBJECTIVES

We recently demonstrated that direct antiglobulin titer (DAT) positive, blood group A or B newborns born to group O mothers had a high incidence of hyperbilirubinemia, attributable to increased hemolysis. We reanalyzed our data asking whether increasing DAT strength plays a modulating role in the pathophysiology of the hemolysis and hyperbilirubinemia.

METHODS

Data from previously published DAT-positive, ABO-heterospecific neonates were analyzed for hyperbilirubinemia and hemolysis according to strength of DAT. DAT was measured by using a gel agglutination technique and reported as values ranging from DAT ± to DAT ++++. Hemolysis was evaluated by blood carboxyhemoglobin corrected for inspired, ambient CO (COHbc), and expressed as percent total hemoglobin (tHb). Hyperbilirubinemia was defined as any plasma total bilirubin value >95th percentile on the hour-specific nomogram.

RESULTS

Hyperbilirubinemia was more prevalent in those with DAT ++ readings (16 of 20, 80%) than those both DAT ± (37 of 87 [42.5%], relative risk: 1.88, 95% confidence interval: 1.35-2.61) and DAT + (32 of 56 [57.1%], relative risk: 1.40, 95% confidence interval: 1.02-1.92). COHbc values were higher for those with DAT ++ (1.45 ± 0.49% tHb [mean ± SD]) than those DAT ± (1.20 ± 0.37% tHb, P = .01) or DAT + (1.22 ± 0.37% tHb, P = .02).

CONCLUSIONS

DAT ++ readings were associated with a higher incidence of hyperbilirubinemia and higher COHbc values than DAT ± or DAT + counterparts. Increasing DAT strength may be a modulator of hemolysis and hyperbilirubinemia in ABO-heterospecific neonates. DAT strength, and not merely DAT presence or absence, should be taken into consideration in the management of ABO-heterospecific newborns.

Hyperbilirubinemia, hemolysis, and increased bilirubin neurotoxicity

Increased hemolysis in the presence of severe neonatal hyperbilirubinemia appears to augment the risk of bilirubin neurotoxicity. The mechanism of this intensifying effect is uncertain. In direct antiglobulin titer (DAT) positive, isoimmune hemolytic disease, the bilirubin threshold at which neurotoxicity occurs appears to be lower than in DAT-negative hyperbilirubinemia. In other hemolytic conditions, the hemolysis may simply facilitate the development of extremely high serum bilirubin levels. Whether the hemolytic process per se exerts an independent effect or whether a very rapid rise in serum bilirubin might lead to greater penetration of the blood-brain barrier is unclear. In this review, we survey the synergistic role of hemolysis associated with severe hyperbilirubinemia in the potentiation of bilirubin-induced neurotoxicity and suggest methods of identifying at-risk babies with increased hemolysis to allow for their increased surveillance.

Sixth hour transcutaneous bilirubin predicting significant hyperbilirubinemia in ABO incompatible neonates

BACKGROUND

Neonates with ABO hemolytic disease are at greater risk for developing significant hyperbilirubinemia. We aimed to determine whether sixth hour transcutaneous bilirubin (TcB) could predict such a risk.

METHODS

TcB measurements were obtained at the 6th hour of life in blood group A or B neonates born to blood group O, rhesus factor compatible mothers. Subsequent hyperbilirubinemia was monitored and considered significant if a neonate required phototherapy/exchange transfusion. The predictive role of sixth hour TcB was estimated.

RESULTS

Of 144 ABO incompatible neonates, 41(OA, 24; O-B, 17) had significant hyperbilirubinemia. Mean sixth hour TcB was significantly higher among neonates who developed significant hyperbilirubinemia than those who did not (5.83±1.35 mg/dL vs. 3.65±0.96 mg/dL, P<0.001). Sixth hour TcB value >4 mg/dL had the highest sensitivity of 93.5% and >6 mg/dL had the highest specificity of 99%. Area under receiver operating characteristic curve was 0.898.

CONCLUSION

Sixth hour TcB predicts subsequent significant hyperbilirubinemia in ABO incompatible neonates.

Potential risks of hemolysis after short-term administration of analgesics in children with glucose-6-phosphate dehydrogenase deficiency

OBJECTIVE

To evaluate the risk of hemolysis in children with glucose-6-phosphate dehydrogenase (G6PD) deficiency after short-term administration of analgesics, such as paracetamol, ibuprofen, tramadol, sufentanil, and parecoxib.

STUDY DESIGN

This was a prospective study of children with G6PD deficiency who were treated with analgesics for 3 days after undergoing surgery. Hemoglobin (Hb) concentration, reticulocyte count, unconjugated bilirubin level, lactate dehydrogenase level, and the presence of Heinz bodies on blood smear microscopy were assessed at baseline and after analgesic treatment. Telephone interviews and clinical reviews were provided during a 7-day study period. The primary outcome was evidence of hemolysis. Statistical analyses were done using the paired Student t test or Wilcoxon signed-rank test as appropriate.

RESULTS

Ten male infants (mean age, 4.3 ± 1.3 years) completed the study. The mean decrease in (Hb) concentration was -0.2 g/dL (P, not significant). The mean reticulocyte count increased by 0.1% (95% CI, 0.08%-0.2%; P = .001). However, the change in reticulocyte count was not correlated with the changes in Hb concentration or other laboratory results and was not accompanied by the clinical signs and symptoms of hemolysis.

CONCLUSION

Short-term administration of paracetamol, ibuprofen, tramadol, sufentanil, and parecoxib in therapeutic dosages did not increase the risk of hemolysis in children with G6PD deficiency.

'Haptoglobin concentrations in preterm and term newborns'

OBJECTIVE

To measure systemic haptoglobin (HPT) concentrations from birth in preterm (PT) and T newborns. To compare HPT in newborns without hemolysis or infection with values in bacteremic newborns.

STUDY DESIGN

HPT was measured using enzyme-linked immunosorbent assay in 30 PT and 28 T newborns without hemolysis or infection at birth (cord blood), on days of life 2 to 4, and at 1 to 2 weeks of life. Concentrations were measured in eight additional newborns with bacteremia. Wilcoxon-Mann-Whitney test was used for comparisons.

RESULT

HPT concentrations were consistently measurable from birth in PT and T neonates. Values were significantly greater in 2- to 4-day-old PT and T newborns than in newborns at birth (P<0.01). Bacteremic newborns had higher HPT concentrations than newborns without infection (P=0.033).

CONCLUSION

HPT is detectable from birth in PT and T newborns. HPT concentrations increase in bacteremic newborns. HPT levels may have clinical utility in the evaluation of neonatal sepsis.

Bilirubin production and the risk of bilirubin neurotoxicity

Neonatal jaundice usually occurs in the transitional period after birth, presenting as an elevation of circulating bilirubin. Bilirubin neurotoxicity can occur if the levels of bilirubin become excessive (hyperbilirubinemia). This pathologic phenotype of newborn jaundice can develop because of excessive bilirubin production or impaired conjugation, with the risk for developing bilirubin-induced neurologic dysfunction, depending on the degree of the resultant bilirubin load. The plasma bilirubin level thus can be used to assess an infant's risk for developing bilirubin neurotoxicity relative to an infant's age in hours. Because all infants have an impaired conjugation ability, infants at greatest risk are those who have increased bilirubin production rates, because of hemolysis, for example. Therefore, developing potential preventive strategies as well as noninvasive technologies to treat and to identify infants with increased bilirubin production rates, respectively, are tantamount to reducing the incidence of bilirubin-induced neurologic dysfunction.