Red blood cell transfusion in preterm infants: restrictive versus liberal policy

Stored RBC transfusions leads to the systemic inflammatory response syndrome in anemic murine neonates

OBJECTIVE

RBC transfusions (RBCT) are life-saving treatment for premature and critically ill infants. However, the procedure has been associated with the development of systemic inflammatory response syndrome (SIRS) and potentially multiple organ dysfunction syndrome (MODS) in neonates. The present study aimed to investigate the mechanisms of RBCT-related SIRS in severely anemic murine neonates.

METHODS

C57BL/6 (WT), TLR4-/- and myeloid-specific triggered myeloid receptor-1 (trem1)-/- mouse pups were studied in 4 groups (n = 6 each): (1) naïve controls, (2) transfused control, (3) anemic (hematocrit 20-24%) and (4) anemic with RBC transfused using our established murine model of phlebotomy-induced anemia (PIA) and RBC transfusion. Plasma was measured for quantifying inflammatory cytokines (IFN-γ, IL-1β, TNF-α, IL-6, MIP-1α, MIP-1β, MIP2 and LIX) using a Luminex assay. In vitro studies included (i) sensitization by exposing the cells to a low level of lipopolysaccharide (LPS; 500 ng/ml) and (ii) trem1-siRNA transfection with/without plasma supernatant from stored RBC to assess the acute inflammatory response through trem1 by qRT-PCR and immunoblotting.

RESULTS

Anemic murine pups developed cytokine storm within 2 h of receiving stored RBCs, which increased until 6 h post-transfusion, as compared to non-anemic mice receiving stored RBCTs ("transfusion controls"), in a TLR4-independent fashion. Nonetheless, severely anemic pups had elevated circulating endotoxin levels, thereby sensitizing circulating monocytes to presynthesize proinflammatory cytokines (IFN-γ, IL-1β, TNF-α, IL-6, MIP-1α, MIP-1β, MIP2, LIX) and express trem1. Silencing trem1 expression in Raw264.7 cells mitigated both endotoxin-associated presynthesis of proinflammatory cytokines and the RBCT-induced release of inflammatory cytokines. Indeed, myeloid-specific trem1-/- murine pups had significantly reduced evidence of SIRS following RBCTs.

CONCLUSION

Severe anemia-associated low-grade inflammation sensitizes monocytes to enhance the synthesis of proinflammatory cytokines and trem1. In this setting, RBCTs further activate these monocytes, thereby inducing SIRS. Inhibiting trem1 in myeloid cells, including monocytes, alleviates the inflammatory response associated with the combined effects of anemia and RBCTs in murine neonates.

Restrictive versus liberal transfusion thresholds in very low birth weight infants: A systematic review with meta-analysis

BACKGROUND

To assess the efficacy and safety of restrictive versus liberal red blood cell transfusion thresholds in very low birth weight infants.

METHODS

We searched MEDLINE, EMBASE, and Cochrane database without any language restrictions. The last search was conducted in August 15, 2020. All randomized controlled trials comparing the use of restrictive versus liberal red blood cell transfusion thresholds in very low birth weight (VLBW) infants were selected. Pooled risk ratio (RR) for dichotomous variable with 95% confidence intervals were assessed by a random-effects model. The primary outcome was all-cause mortality.

RESULTS

Overall, this meta-analysis included 6 randomized controlled trials comprising 3,483 participants. Restrictive transfusion does not increase the risk of all-cause mortality (RR, 0.99; 95% CI, 0.84 to 1.17; I2 = 0%; high-quality evidence), and does not increase the composite outcome of death or neurodevelopmental impairment (RR, 1.01, 95% CI, 0.93-1.09; I2 = 7%; high-quality evidence) or other serious adverse events. Results were similar in subgroup analyses of all-cause mortality by weight of infants, gestational age, male infants, and transfusion volume.

CONCLUSIONS

In very low birth weight infants, a restrictive threshold for red blood cell transfusion was not associated with increased risk of all-cause mortality, in either short term or long term.

Transfusion rates and disease spectrum in neonates treated with blood transfusion in China

This study aimed to investigate blood transfusion rates and spectrum of diseases in hospitalized neonates treated with blood transfusion in China to provide supporting data for future studies on neonatal blood transfusion.Data on hospitalized neonates were obtained from more than 100 experts from the Department of Neonatology of 55 hospitals in China between January 1, 2012 and December 31, 2016, using a standardized survey. A statistical analysis was conducted to evaluate the data collected, including the blood transfusion rates, blood component transfused, spectrum of diseases, and spectrum of major diseases.Between 2012 and 2016, 541,128 neonates were hospitalized in the 55 hospitals surveyed. There were 70,433 neonates who received blood transfusion, with an average transfusion rate of 13.02%. The rates of red blood cell transfusion, platelet transfusion, and plasma transfusion were 9.44%, 0.66%, and 4.77%, respectively. The neonatal blood transfusion rate was 17.99% in Northeast China, 9.74% in Northwest China, and between 10.60% and 16.22% in other regions. The neonatal blood transfusion rate was 12.3% in general hospitals and 13.8% in women and children's hospitals. The top 10 diseases identified in hospitalized neonates treated by blood transfusion were, in rank order, as follows:prematurity,pneumonia, hyperbilirubinemia, bacterial sepsis, respiratory distress syndrome, anemia, hemolytic disease, asphyxia, hemorrhage, and necrotizing enterocolitis.The neonatal blood transfusion rate in China is 13.03%.The rank order in the disease spectrum of the hospitalized neonates and that in hospitalized neonates treated with blood transfusion are different.

Association between anemia and postoperative complications in infants undergoing pyloromyotomy

BACKGROUND

Although preoperative anemia has been suggested to predict postsurgical morbidity and mortality among infants <1 year of age, the data were drawn from heterogeneous patient cohorts including severely ill infants undergoing complex, high-risk procedures. We aimed to determine whether untreated preoperative anemia was associated with increased risk of postoperative complications in infants <1 year of age who underwent pyloromyotomy, a common and relatively simple surgery.

METHODS

Infants <1 year of age undergoing pyloromyotomy were identified from the American College of Surgeons (ACS) National Surgical Quality Improvement Program-Pediatric database. Preoperative anemia was defined as a hematocrit ≤40% for infants 0-30 days of age and ≤30% for infants more than 30 days of age. Patients who received pre- or postoperative blood transfusions were excluded.

RESULTS

We identified 2948 patients who met our inclusion criteria, of whom 843 were anemic (29%). The overall rate of complications in this cohort was 6%. The most common postoperative complications were readmission (97 cases), surgical site infection (43), reoperation (39), prolonged hospital stay (24), urinary tract infection (3), 30-day mortality (3) and cardiac arrest (2). We found no differences in the incidence of complications in anemic versus nonanemic patients on bivariate analysis or multivariable logistic regression (adjusted odds ratio = 1.2; 95% confidence interval: 0.8-1.7; P = 0.319).

CONCLUSIONS

In relatively healthy infants undergoing pyloromyotomy, untreated preoperative anemia was not associated with postoperative compilations and should not be considered a significant risk factor. Level of evidence III.

Association between hemoglobin concentrations at discharge from the neonatal intensive care unit with markers of neurodevelopmental outcomes in premature neonates

BACKGROUND

Premature neonates are often subjected to multiple transfusions with red blood cells during their hospitalization in the neonatal intensive care unit (NICU). The hemoglobin threshold for transfusion prior to discharge from the NICU varies significantly among different centers. The aim of the present study is to investigate the association between hemoglobin concentration at discharge with neurodevelopmental outcomes in premature neonates.

METHODS

Retrospective observation study with regression analysis was performed with follow up assessment in the neuro-developmental outpatient clinic at 30 months of adjusted age.

RESULTS

Data from 357 neonates born at less than 37 weeks' gestation were analyzed. Sensory and motor neurodevelopment at 30 months of adjusted age, were not associated with the hemoglobin concentration at discharge (p=0.5891 and p=0.4575, respectively). There was no association between the hemoglobin concentration at discharge with fine or gross motor development (p=0.1582 and p=0.3805, respectively). Hemoglobin concentration at discharge was not associated with poor neurodevelopmental outcomes up until 30 months of adjusted age.

CONCLUSIONS

The data of the present study indicate that the hemoglobin concentration of premature neonates at the time of discharge is not associated with poorer markers of neurodevelopmental outcomes at 30 months of adjusted age. Comorbidities such as BPD and IVH that are present to premature neonates were identified as potential risk factors for certain aspects of the neurodevelopment.

Evaluation of serum ischemia-modified albumin levels in anemia of prematurity

PURPOSE

Ischemia-modified albumin (IMA) is used to determine tissue hypoxia. We aimed to evaluate the serum IMA levels in preterm infants requiring transfusion due to anemia of prematurity, a clinical condition to cause tissue hypoxia.

MATERIALS AND METHODS

This prospective study was performed in Etlik Zubeyde Hanim Hospital, Turkey. Preterm infants with birth weight less than 1500 g and born between 25 and 32 weeks were included during assessment for anemia of prematurity. The transfused infants with anemia of prematurity formed the "transfusion group", the control group consisted of gender, gestational and postnatal age-matched infants without transfusion requirement. Serum samples of control group and pre-transfusion and post-transfusion samples of transfusion group were analyzed for IMA (ABS unit). Serum IMA levels were compared between control group and pre-transfusion samples of transfusion group and were also evaluated for the significance of change after transfusion.

RESULTS

Sixty-two infants were included (transfusion group: 31, control group: 31). The pretransfusion serum IMA levels were higher than that of infants in the control group [ABS unit; transfusion group; pre-transfusion: 1.00 (0.76-1.09) and control group: 0.81 (0.52?1.04); p = .03]. Serum IMA levels decreased significantly to 0.79 (0.59-0.95) after transfusion; p = .007. Infants with hematocrit higher than 30% had lower IMA levels [0.69 (0.54-0.96)] than infants with lower hematocrit [0.96 (0.75-1.05)]; p = .002.

CONCLUSIONS

Clinicians may bear in mind that serum IMA levels could be utilized as a marker in deciding on erythrocyte transfusion in premature anemia.

Association between anemia and bronchopulmonary dysplasia in preterm infants

Anemia is commonly seen in preterm infants. It may reduce the capacity of hemoglobin to transport oxygen throughout the body and may result in tissue and organ dysfunction. This study aimed to investigate the effect of anemia on the development of bronchopulmonary dysplasia (BPD) in preterm infants. 243 infants who were admitted to BaYi Children’s Hospital Affiliated to Clinical Medical College in Beijing Military General Hospital with gestational age (GA) less than 32 weeks from February, 2014 to February, 2015 were included in the study. Maternal and infant data were recorded. Multivarariate logistic regression analysis was performed to determine the association between anemia and BPD. Of 243 preterm infants, the incidence of anemia was higher in BPD patients than non-BPD patients (p < 0.001). Mean Hct in BPD patients was lower than non-BPD patients at different time points in 1d, 7d, 14d, and 21d. Controlling for other confounding factors, early anemia was associated with an increased risk of BPD. Number of transfusions is also a significant risk factor for BPD (p = 0.001). Therefore, prevention and treatment of early anemia is necessary and reducing number of transfusions may reduce the incidence of BPD in preterm infants.