Red blood cell transfusions increase fecal calprotectin levels in premature infants

Blood Donor Sex and Outcomes in Transfused Infants

Red blood cell transfusion is common in neonatal intensive care. Multiple trials have evaluated different thresholds for when to administer red blood cell transfusion. In contrast, there has been less focus on studies of the characteristics of red blood cells transfused into neonates. In this review, the authors summarize the emerging literature on the potential impact of the sex of blood donors on outcomes in transfused neonates using a systematic search strategy. The authors review the uncertainty generated from studies with conflicting findings and discuss considerations regarding the impact of blood donor sex and other characteristics on neonatal outcomes.

Development of necrotizing enterocolitis after blood transfusion in very premature neonates

BACKGROUND

Prior studies report conflicting evidence on the association between packed red blood cell (PRBC) transfusions and necrotizing enterocolitis (NEC), especially in early weeks of life where transfusions are frequent and spontaneous intestinal perforation can mimic NEC. The primary objective of this study was to evaluate the association between PRBC transfusions and NEC after day of life (DOL) 14 in very premature neonates.

METHODS

A retrospective cohort analysis of very premature neonates was conducted to investigate association between PRBC transfusions and NEC after DOL 14. Primary endpoints were PRBC transfusions after DOL 14 until the date of NEC diagnosis, discharge, or death. Wilcoxon ranked-sum and Fisher's exact tests, Cox proportional hazards regression, and Kaplan-Meier curves were used to analyze data.

RESULTS

Of 549 premature neonates, 186 (34%) received transfusions after DOL 14 and nine (2%) developed NEC (median DOL = 38; interquartile range = 32-46). Of the nine with NEC after DOL 14, all were previously transfused (P < 0.001); therefore, hazard of NEC could not be estimated. Post hoc analysis of patients from DOL 10 onward included five additional patients who developed NEC between DOL 10 and DOL 14, and the hazard of NEC increased by a factor of nearly six after PRBC transfusion (hazard ratio = 5.76, 95% confidence interval = 1.02-32.7; P = 0.048).

CONCLUSIONS

Transfusions were strongly associated with NEC after DOL 14. Prospective studies are needed to determine if restrictive transfusion practices can decrease incidence of NEC after DOL 14.

Trends of fecal calprotectin levels and associations with early life experience in preterm infants

Background

Preterm infants are at risk for severe infections due to their immature immune systems. Factors such as early life pain/stress experiences and feeding may influence immune activation and maturation of immune systems. However, the underlying mechanism remains unclear. Fecal calprotectin (FCP) is a noninvasive surrogate biomarker of mucosal inflammation in the gastrointestinal tract and has been used in detecting intestinal inflammation in specific pediatric gastrointestinal disorders.

Objective

To describe the longitudinal trajectory of FCP levels in preterm infants and investigate the contributing factors that are associated with FCP levels.

Design

A longitudinal study design was used.

Settings

Preterm infants were recruited from 2 neonatal intensive care units (NICU) of a children's medical center in the North-eastern US.

Methods

Preterm infants were followed during their first 4 weeks of NICU hospitalization. Stool samples were collected twice per week to quantify the FCP levels. Cumulative pain/stress experiences and feeding types were measured daily. A linear mixed-effect model was used to examine the associations between FCP levels and demographic and clinical characteristics, cumulative pain/stress, and feeding over time.

Results

Forty-nine preterm infants were included in the study. Infants' FCP levels varied largely with a mean of 268.7±261.3 µg/g and increased over time. Preterm infants experienced an average of 7.5±5.0 acute painful procedures and 15.3±20.8 hours of chronic painful procedures per day during their NICU stay. The mean percentage of mother's own milk increased from the first week (57.1±36.5%) to the fourth week (60.7±38.9%) after birth. Elevated FCP concentration was associated with acute and cumulative (chronic) pain/stress levels, mother's own milk, non-White race, and higher severity of illness score.

Conclusions

FCP levels were elevated in preterm infants with wide interindividual and intraindividual variations. Cumulative pain/stress during the NICU hospitalization, feeding, race, and health status may influence FCP concentrations in early life that may be associated with inflammatory gut processes.

Immunologic effects of red blood cell and platelet transfusions in neonates

PURPOSE OF REVIEW

Premature neonates are frequently transfused red blood cells (RBCs) or platelets to raise hemoglobin or platelet counts. However, these transfusions may have unintended effects on the immune system. This review will summarize the newest discoveries on the immunologic effects of RBC and platelet transfusions in neonates, and their potential impact on neonatal outcomes.

RECENT FINDINGS

Neonatal RBC transfusions are associated with increases in plasma pro-inflammatory cytokines, but recent findings suggest sex-specific differential responses. At least one cytokine (monocyte chemoattractant protein-1) rises in females receiving RBC transfusions, but not in males. These inflammatory responses correlate with poorer neurodevelopmental outcomes in heavily transfused female infants, while preterm male infants seem to be more sensitive to severe anemia. Platelet transfusions in preterm neonates are associated with increased neonatal mortality and morbidity. The underlying mechanisms are unknown, but likely related to the immune/inflammatory effects of transfused platelets. Adult platelets are different from neonatal platelets, with the potential to be more pro-inflammatory. Early preclinical data suggest that platelet transfusions alter the neonatal systemic inflammatory response and enhance immune cell migration.

SUMMARY

RBC and platelet transfusions alter neonatal immune and inflammatory responses. Their pro-inflammatory effects might worsen neonatal disease or affect neurodevelopmental outcomes.

Changes in urinary kidney injury molecule-1 levels after blood transfusions in preterm infants

Literature supports an association between transfusions and gut injury in preterm infants. We hypothesized that packed red blood (PRBC) transfusions are associated with kidney inflammation marked by a rise in urinary levels of Kidney Injury Molecule 1 (KIM-1). Prospectively, KIM-1 levels were measured before and then at 6, 12 and 24 h after a PRBC transfusion. Results are presented as mean (± SD) and median (IQR). Thirty-four infants, birth weight 865 (± 375) g, had higher pretransfusion KIM-1 levels of 2270 (830, 3250) pg/mg than what is normal for age. These were not associated with hematocrit levels. KIM-1 levels peaked between 6 and 12 h after the transfusion. Levels peaked to 3300 (1990, 6830) pg/mg; levels returned to pretransfusion levels of 2240 (1240, 3870) pg/mg by 24 h, p < 0.01. The 24-h post-transfusion KIM-1 levels were similar to pretransfusion levels, p = 0.63. PRBC transfusions in preterm infants are associated with an elevation in urinary KIM-1 levels. The mechanism of this association may be important in studying transfusion associated organ injury. KIM-1, as an inflammatory marker, may be helpful in assessing the effect of different transfusion volumes or in evaluating operational thresholds of anemia in premature infants.

The development of intestinal dysbiosis in anemic preterm infants

OBJECTIVE

Anemia and Proteobacteria-dominant intestinal dysbiosis in very low birth weight (VLBW) infants have been linked to necrotizing enterocolitis, a severe gut inflammatory disease. We hypothesize that anemia of prematurity is related to the development of intestinal dysbiosis.

STUDY DESIGN

Three hundred and forty-two weekly stool samples collected prospectively from 80 VLBW infants were analyzed for bacterial microbiomes (with 16S rRNA). Linear mixed-effects model was used to determine the relationships between the onsets of anemia and intestinal dysbiosis.

RESULTS

Hematocrit was associated with intestinal microbiomes, with lower Hct occurring with increased Proteobacteria and decreased Firmicutes. Infants with a hematocrit <30% had intestinal microbiomes that diverged toward Proteobacteria dominance and low diversity after the first postnatal month. The microbiome changes were also related to the severity of anemia.

CONCLUSIONS

This finding supports a potential microbiological explanation for anemia as a risk factor for intestinal dysbiosis in preterm infants.

Epidemiology of Necrotizing Enterocolitis: New Considerations Regarding the Influence of Red Blood Cell Transfusions and Anemia

This article summarizes available evidence on the relationship between red blood cell transfusion and anemia, and necrotizing enterocolitis (NEC). We review recent studies that highlight the uncertainty of the effect of red blood cell transfusion on NEC and the potential role of anemia. We also discuss potential pathophysiologic effects of both red blood cell transfusion and anemia and highlight strategies to prevent anemia and red blood cell transfusion. We also discuss ongoing randomized trials that are likely to provide important new evidence to guide red blood cell transfusion practices.

Reference intervals for stool calprotectin in preterm neonates and their utility for the diagnosis of necrotizing enterocolitis

OBJECTIVE

Calprotectin is an antimicrobial protein found in stool when released by granulocytes. We sought to create stool calprotectin reference ranges in preterm neonates and to evaluate whether levels exceeding the upper reference interval are diagnostic for necrotizing enterocolitis (NEC).

STUDY DESIGN

Stool calprotectin was measured in premature neonates without gastrointestinal pathology to create reference intervals. For comparison, levels from infants undergoing "rule out NEC" evaluations were plotted on these reference intervals.

RESULTS

Stool calprotectin reference intervals were created according to gestational age at birth and corrected gestational age. Levels during "rule out NEC" evaluations were more often above the upper reference interval with NEC vs. those without NEC.

CONCLUSIONS

Stools from preterm neonates have a higher range of calprotectin than stools from healthy term neonates. In evaluating preterm neonates for NEC with stool calprotectin, a calprotectin upper reference interval that incorporates corrected gestational age best predicts the diagnosis of NEC.

Anemia, red blood cell transfusions, and necrotizing enterocolitis

In the past 15 years, multiple clinical studies have identified a temporal association between red blood cell (RBC) transfusions and necrotizing enterocolitis (NEC). With some variability, most of these studies indicate that up to one-third of all cases of NEC involving very low-birth weight infants may occur within 24-48h after receiving a RBC transfusion. There is also evidence that the risk of such transfusion-associated NEC may be higher in infants transfused with the greatest severity of anemia. In this article, we summarize the clinical evidence pertaining to these issues; specifically, the contribution of RBC transfusions, and the contribution of severity of underlying anemia, to the pathogenesis of a type of NEC potentially termed, "transfusion/anemia-associated NEC."

The relationship of red blood cell transfusion to intestinal mucosal injury in premature infants

OBJECTIVE

To determine the incidence of intestinal mucosal injury before and after transfusions in premature infants.

STUDY DESIGN

Urine was collected throughout the hospital stay of 62 premature infants and specimens obtained within 24h before and after transfusion were assayed for intestinal fatty acid binding protein (iFABP). A urinary iFABP:creatinine ratio (iFABP_u:Cr_u) of 2.0pg/nmol was considered elevated.

RESULT

Forty-nine infants were transfused. iFABPu:Cru was elevated following 71 (75.6%) of 94 transfusions for which urine was available. In 51 (71.8%) of these, iFABPu:Cru was also elevated prior to the transfusion. Among four cases of transfusion-associated NEC, iFABP_u was elevated following every sentinel transfusion and prior to three of them.

CONCLUSION

Subclinical intestinal mucosal injury is frequent following blood transfusions in premature infants and, when present, usually precedes transfusion. This suggests that transfusion may not be a primary mediator of intestinal injury so much as anemia and its associated conditions.

LEVEL OF EVIDENCE

Prognosis study/level 3.

Transient effects of transfusion and feeding advances (volumetric and caloric) on necrotizing enterocolitis development: A case-crossover study

Objective

To evaluate the short-term effects of feed fortification, feed volume increase, and PRBC transfusion on the odds of developing NEC.

Study design

Case-crossover study of neonatal intensive care infants born at ≤ 32 weeks’ gestation who were admitted to 5 central Ohio intensive care units from January 2012-July 2016 and developed NEC Bell Stage ≥2. Each patient served as their own control, with exposure during the 48-hour period just prior to NEC onset (hazard period) being compared to a preceding 48-hour control period, thus eliminating confounding by patient factors fixed between both intervals. NEC onset was determined by chart review as the earliest occurrence of one of the following within 24 hours of confirmatory x-ray: (1) antibiotic initiation, (2) enteral feeding cessation, (3) physician first notified of abdominal concerns, or (4) abdominal x-ray ordered. Conditional logistic regression compared exposures to feed volume increase, fortification, and PRBC transfusion during the 48-hour period prior to NEC onset to those during a preceding 48-hour control period. Analyses were stratified by gestational age and anemia (defined: hemoglobin ≤ 9.3 g/dL within 7 days of NEC onset).

Results

We included 63 infants with confirmed NEC. Acute exposure to fortification (odds ratio [OR]: 1.67, 95% confidence interval [CI]: 0.61, 4.59), feed volume increase (OR: 0.63, 95% CI: 0.28, 1.38), and PRBC transfusion (OR: 1.80, 95% CI: 0.60, 5.37) was not associated with the onset of NEC. Gestational age and anemia did not significantly modify the associations. Sensitivity testing substituting 24- and 72-hour hazard and control periods produced similar results.

Conclusion

Using a case-crossover design, we did not detect an association between NEC development and feed fortification, feed volume increase, or PRBC transfusion within 48-hours prior to NEC-onset. Replication in a larger set of cases is needed.

A critical question for NEC researchers: Can we create a consensus definition of NEC that facilitates research progress?

In the last decades the reported incidence of preterm necrotizing enterocolitis (NEC) has been declining in large part due to implementing comprehensive NEC prevention initiatives, including breast milk feeding, standardized feeding protocols, transfusion guidelines, and antibiotic stewardship and improving the rigor with which non-NEC cases are excluded from NEC data. However, after more than 60 years of NEC research in animal models, the promise of a "magic bullet" to prevent NEC has yet to materialize. There are also serious issues involving clinical NEC research. There is a lack of a common, comprehensive definition of NEC. National datasets have their own unique definition and staging definitions. Even within academia, randomized trials and single center studies have widely disparate definitions. This makes NEC metadata of very limited value. The world of neonatology needs a comprehensive, universal, consensus definition of NEC. It also needs a de-identified, international data warehouse.

Elevated fecal calprotectin levels during necrotizing enterocolitis are associated with activated neutrophils extruding neutrophil extracellular traps

OBJECTIVE

Neonates with necrotizing enterocolitis (NEC) have higher calprotectin levels in stool than do healthy neonates. However, it is not known whether high stool calprotectin at the onset of bowel symptoms identifies neonates who truly have NEC vs other bowel disorders.

STUDY DESIGN

Neonates were eligible for this study when an x-ray was ordered to 'rule-out NEC'. Stool calprotectin was quantified at that time and in a follow-up stool. Each episode was later categorized as NEC or not NEC. The location of calprotectin in the bowel was determined by immunohistochemistry.

RESULTS

Neonates with NEC had higher initial and follow-up stool calprotectin levels than did neonates without NEC. Calprotectin in bowel from neonates with NEC was within neutrophil extracellular traps (NETs).

CONCLUSION

At the onset of signs concerning for NEC, fecal calprotectin is likely to be higher in neonates with NEC. Calprotectin in their stools is exported from neutrophils via NETs.

Late Presentation of Fulminant Necrotizing Enterocolitis in a Child with Hyperinsulinism on Octreotide Therapy

Congenital hyperinsulinism (HI) is the most common cause of persistent hypoglycemia in infants and children. In cases of diazoxide-unresponsive HI, alternative medical and surgical approaches may be required to reduce the risk of hypoglycemia. Octreotide, a somatostatin analog, often has a role in the management of these children, but a dose-dependent reduction in splanchnic blood flow is a recognized complication. Necrotizing enterocolitis (NEC) has been reported within the first few weeks of initiating predominantly high doses of octreotide. We describe the case of an infant with Beckwith-Wiedemann syndrome and diazoxide-unresponsive HI, who had persistent hypoglycemia after two pancreatectomy surgeries. She developed NEC 2 months after beginning octreotide therapy at a relatively low dose of 8 µg/kg/day. This complication has occurred later, and at a lower dose, than has previously been described. We review the case and identify the known and suspected multifactorial risk factors for NEC that may contribute to the development of this complication in patients with HI.