Platelet transfusions in neonates: questions and answers

Meropenem-induced pancytopenia in a preterm neonate: a case report

BACKGROUND

A post-marketing surveillance study has reported an association between meropenem use and the incidence of hematologic abnormalities, including leukopenia, thrombocytopenia, hemolysis, and neutropenia, but the precise incidence in neonates is unknown. Here, we report meropenem-induced pancytopenia in a preterm neonate.

CASE PRESENTATION

A preterm newborn Pakistani received intravenous meropenem 40 mg/kg every 8 hours to treat Klebsiella pneumoniae in blood cultures and suspected meningitis. The baby developed severe thrombocytopenia, with a platelet count of 22 × 103 cells/mm3, low hemoglobin level of 9.7 g/dl, and low absolute neutrophil count (ANC) of 816 cells/mm3 on days 3, 14, and 17 of meropenem therapy, respectively. Based on the blood culture and institutional guidelines, meropenem treatment was continued with monitoring and supportive care for a total of 19 days. After discontinuation of meropenem, the baby was monitored continuously for hematological changes, and low counts persisted for 3 days. ANC improved to > 1500 cells/mm3 on the fourth day, and the platelet count reached > 150 × 103 cells/mm3 for the first time on the seventh day of meropenem discontinuation. All subsequent complete blood count (CBC) reports showed improving trends. The baby was discharged on the 48th day of life (DOL), with follow-up monitoring of CBC. The baby was kept on iron supplements, and hemoglobin level of 11.2 g/dl was observed on the 59th DOL.

CONCLUSION

Neonatal pancytopenia may lead to serious health complications; therefore, clinicians and pharmacists need to vigilantly monitor CBC in this vulnerable population, even when administering meropenem in septic doses for the recommended duration.

Neonatal thrombocytopenia: etiology, management and outcome

Thrombocytopenia is a very common hematological abnormality found in newborns, especially in preterm neonates. Two subgroups can be distinguished: early thrombocytopenia, occurring within the first 72 hours of life, and late thrombocytopenia, occurring after the first 72 hours of life. Early thrombocytopenia is associated with intrauterine growth restriction, whereas late thrombocytopenia is caused mainly by sepsis and necrotizing enterocolitis (NEC). Platelet transfusions are the hallmark of the treatment of neonatal thrombocytopenia. Most of these transfusions are prophylactic, which means they are given in the absence of bleeding. However, the efficacy of these transfusions in preventing bleeding has never been proven. In addition, risks of platelet transfusion seem to be more pronounced in preterm neonates. Because of lack of data, platelet transfusion guidelines differ widely between countries. This review summarizes the current understanding of etiology and management of neonatal thrombocytopenia.

Evidence-based advances in transfusion practice in neonatal intensive care units

BACKGROUND

Transfusions to neonates convey both benefits and risks, and evidence is needed to guide wise use. Such evidence is accumulating, but more information is needed to generate sound evidence-based practices.

OBJECTIVE

We sought to analyze published information on nine aspects of transfusion practice in neonatal intensive care units.

METHODS

We assigned 'categories of evidence' and 'recommendations' using the format of the United States Preventive Services Task Force of the Agency for Healthcare Research and Quality.

RESULTS

The nine practices studied were: (1) delayed clamping or milking of the umbilical cord at preterm delivery - recommended, high/substantial A; (2) drawing the initial blood tests from cord/placental blood from very low birth weight (VLBW, <1,500 g) infants at delivery - recommended, moderate/moderate B; (3) limiting phlebotomy losses of VLBW infants - recommended, moderate/substantial B; (4) selected use of erythropoiesis-stimulating agents to prevent transfusions - recommended, moderate/moderate-moderate/small B, C; (5) using platelet mass, rather than platelet count, in platelet transfusion decisions - recommended, moderate/small C; (6) permitting the platelet count to fall to <20,000/µl in 'stable' neonates before transfusing platelets - recommended, low/small I; (8) permitting the platelet count to fall to <50,000/µl in 'unstable' neonates before transfusing platelets - recommended, moderate/small C, and (9) not performing routine coagulation test screening on every VLBW infant - recommended, moderate/small C.

CONCLUSIONS

We view these recommendations as dynamic, to be revised as additional evidence becomes available. We predict this list will expand as new studies provide more information to guide best transfusion practices.

A consistent approach to platelet transfusion in the NICU

Platelet transfusions are the principal means of treating thrombocytopenia in neonatal intensive care units (NICUs), and are generally used as treatment of thrombocytopenic neonates who have active bleeding and as prophylactic administration in thrombocytopenic neonates who do not have hemorrhage but appear to be at high risk for bleeding. In this article, we summarize the rationale, benefits and risks of platelet transfusions in neonates. We review the importance of choosing the best product available for platelet transfusion, and we emphasize the importance of adopting and adhering to transfusion guidelines.

Thrombocytopenia, bleeding, and use of platelet transfusions in sick neonates

Survival rates for infants born prematurely have improved significantly, in part due to better supportive care such as RBC transfusion. The role of platelet transfusions in neonates is more controversial. Neonatal thrombocytopenia is common in premature infants. The primary causal factors are intrauterine growth restriction/maternal hypertension, in which the infant presents with thrombocytopenia soon after birth, and sepsis/necrotizing enterocolitis, which are the common morbidities associated with thrombocytopenia in neonates > 72 hours of age. There is no evidence of a relationship between platelet count and occurrence of major hemorrhage, and cardiorespiratory problems are considered the main etiological factors in the development of intraventricular and periventricular hemorrhage in the neonatal period. Platelet transfusions are used commonly as prophylaxis in premature neonates with thrombocytopenia. However, there is widespread variation in the pretransfusion thresholds for platelet count and evidence of marked disparities in platelet transfusion practice between hospitals and countries. Platelet transfusions are biological agents and as such are associated with risks. Unlike other patient groups, specifically patients with hematological malignancies, there have been no recent clinical trials undertaken comparing different thresholds for platelet transfusion in premature neonates. Therefore, there is no evidence base with which to inform safe and effective practice for prophylactic platelet transfusions. There is a need for randomized controlled trials to define the optimal use of platelet transfusions in premature neonates, who at present are transfused heavily with platelets.

Restrictive guideline reduces platelet count thresholds for transfusions in very low birth weight preterm infants

BACKGROUND AND OBJECTIVES

Platelet transfusions are performed almost entirely according to expert experience. This study assessed the effectiveness of a restrictive guideline to reduce platelet transfusions in preterm infants.

METHODS

A retrospective cohort of preterm infants with a birth weight of <1500 g had been born in 2 periods. In Period 1, a transfusion was indicated for a platelet count of <50,000/ml in clinically stable neonates or <100,000/ml in bleeding or clinically unstable infants. In Period 2, the indications were restricted to <25,000/ml in clinically stable neonates, or <50,000/ml in newborns who were either on mechanical ventilation, subject to imminent invasive procedures, within 72 h following a seizure, or extremely premature and <7 days old. A count of <100,000/ml was indicated for bleeding or major surgery.

RESULTS

Periods 1 and 2 comprised 121 and 134 neonates, respectively. The rates of ventricular haemorrhage and intrahospital death were similar in both periods. The percentage of transfused infants, the odds of receiving a platelet transfusion, the mean platelet count before transfusion and the percentage of transfusions with a platelet count >50,000/ml were greater in Period 1. Among thrombocytopenic neonates, the percentage of transfused neonates and the number of transfusions were similar in both groups.

CONCLUSION

The restrictive guideline for platelet transfusions reduced the platelet count thresholds for neonatal transfusions without increasing the rate of ventricular haemorrhage.

Maintenance of storage properties of pediatric aliquots of apheresis platelets in fluoroethylene propylene containers

BACKGROUND

Platelet (PLT) aliquots for pediatric use have been shown to retain in vitro properties when stored in gas-impermeable syringes for up to 6 hours. As an alternative, PLT aliquots can be stored for longer periods in containers used for storage of whole blood-derived PLTs. These containers are not available separate from whole blood collection sets and PLT volumes less than 35 mL either have not been evaluated or may be unsuitable for PLT storage. Gas-permeable fluoroethylene propylene (FEP) containers have been used in the storage of cell therapy preparations and are available in multiple sizes as single containers but have not been evaluated for PLT storage.

STUDY DESIGN AND METHODS

A single apheresis unit was divided on Day 3 into small aliquots with volume ranging from 20 to 60 mL, transferred using a sterile connection device, and stored for an additional 2 days either in CLX (control) or in FEP containers. PLT storage properties of PLTs stored in FEP containers were compared to those stored in CLX containers. Standard PLT in vitro assays were performed (n =6).

RESULTS

PLT storage properties were either similar to those of CLX containers or differed by less than 20% excepting carbon dioxide levels, which varied less than 60%.

CONCLUSION

Pediatric PLT aliquots of 20, 30, and 60mL transferred on Day 3 into FEP cell culture containers adequately maintain PLT properties for an additional 2days of storage.

Transfusion medicine problems and solutions for the pediatric hematologist/oncologist

Blood component transfusion is an integral part of the care of children with oncologic and hematologic conditions. The complexity of transfusion medicine may however lead to challenges for pediatric hematologists/oncologists. In this review, three commonly encountered areas of transfusion medicine are explored. The approach to the investigation and management of suspected platelet refractoriness is reviewed. The unique transfusion related challenges encountered by children undergoing stem cell transplantation are also discussed. Finally, issues arising out of the care of children with hemoglobinopathies are explored, with an emphasis on the incidence of allo- and autoimmunization.

How I manage neonatal thrombocytopenia

Although neonatal thrombocytopenia (platelet count < 150×10(9) /l) is a common finding in hospital practice, a careful clinical history and examination of the blood film is often sufficient to establish the diagnosis and guide management without the need for further investigations. In preterm neonates, early-onset thrombocytopenia (<72h) is usually secondary to antenatal causes, has a characteristic pattern and resolves without complications or the need for treatment. By contrast, late-onset thrombocytopenia in preterm neonates (>72h) is nearly always due to post-natally acquired bacterial infection and/or necrotizing enterocolitis, which rapidly leads to severe thrombocytopenia (platelet count<50×10(9) /l). Thrombocytopenia is much less common in term neonates and the most important cause is neonatal alloimmune thrombocytopenia (NAIT), which confers a high risk of perinatal intracranial haemorrhage and long-term neurological disability. Prompt diagnosis and transfusion of human platelet antigen-compatible platelets is key to the successful management of NAIT. Recent studies suggest that more than half of neonates with severe thrombocytopenia receive platelet transfusion(s) based on consensus national or local guidelines despite little evidence of benefit. The most pressing problem in management of neonatal thrombocytopenia is identification of safe, effective platelet transfusion therapy and controlled trials are urgently needed.